This presentation impart a knowledge about Histamine,receptor,and antagonist.
Recent advances also mentioned like H3 & H4 receptors role in cognitive impairment etc.
Neurotransmitters/General aspect and steps involved in neurotransmission.pptxSIRAJUDDIN MOLLA
Neurotransmission (Latin: transmission "passage, crossing" from transmitter "send, let through"), is the process by which signalling molecules called neurotransmitters are released by the axon terminal of a neuron and bind to and react with the receptors on the dendrites of another neuron
The document discusses various screening methods for evaluating potential anxiolytic drugs, including in vitro receptor binding assays and in vivo behavioral tests in animals like the elevated plus maze test, light-dark box test, and social interaction test, which measure anxiety-like behaviors that can be reduced by anxiolytic drug administration. Classification of anxiolytics and theories of anxiety involving neurotransmitters like GABA, serotonin and norepinephrine are also covered.
Preclinical screening methods of cns stimulantsRashmi116
This document describes various preclinical screening methods used to evaluate central nervous system (CNS) stimulants. It discusses behavioral manifestations of CNS stimulation like increased alertness. Various screening methods are described including the actophotometer test to measure locomotor activity, strychnine-induced convulsion test, sand displacement test, runway test and others. Each test is briefly explained along with its purpose, procedure, and evaluation method. A variety of behavioral tests in animals are used to screen for CNS stimulant activity of novel compounds.
Genetic variations in G protein-coupled receptors (GPCRs) can alter receptor function and cause diseases. Single nucleotide polymorphisms and other mutations have been linked to impaired or enhanced receptor signaling. For example, a mutation in the vasopressin V2 receptor causes nephrogenic diabetes insipidus by decreasing ligand binding and receptor expression. Similarly, mutations in chemokine receptors CCR5 and CCR2 impact HIV infection by altering receptor function or interaction with other coreceptors. Overall, GPCR polymorphisms are associated with diseases by changing ligand binding, receptor activation, trafficking, and coupling to downstream signaling pathways.
This document summarizes several preclinical models used to screen anxiolytic agents. It describes anxiety disorders and the goal of developing animal models that resemble human pathology. Several models are explained in detail, including the elevated plus maze test, light-dark exploration test, and social interaction test in rats. These tests measure anxiety-like behaviors in rodents and can determine if candidate drugs decrease inhibited behaviors. The document also reviews in vitro and in vivo methods for evaluating putative anxiolytics before clinical trials.
The document describes several screening models used to evaluate the effects of drugs on behavioral and muscle coordination in animals. It discusses tests such as the open field test, hole board test, chimney test, grip strength, and rota rod method. These tests measure parameters like locomotor activity, exploration, muscle strength, and motor coordination. The results of these tests can provide information about a drug's effects and allow the calculation of values like ED50 doses for sedative, stimulant, and muscle relaxant drugs.
This document summarizes models used to study anti-emetic drugs. It describes various in vivo, in vitro, and human models. For in vivo models, it outlines drug-induced (cisplatin, apomorphine, copper sulfate), motion, and radiation models using species like dogs, cats, ferrets, and rats. It discusses parameters assessed like retching episodes. For in vitro models, it notes evaluating drugs' activity at 5-HT3 receptors. Finally, it mentions human models like using apomorphine or ipecac to induce vomiting and assessing drug effectiveness.
Classification of receptors family by vivek sharmaAnimatedWorld
Definition- Receptor are the biologic molecule to which drug bind and produces a measurable response.
So, enzyme and structural proteins can be considerd to be pharmacologic receptors.
Majorly receptor are of 4 types and the molecule or a drug interact to receptor to give response often called as ligand.
The type of receptor a ligand will bind is depend on the nature of ligand.
Hydrophilliic ligand binds to the receptor found on the cell surface.
Hydrophobic ligand can enter the cell membrane to intract the receptor present on inside the cells.
Classification of Receptors
A. Cell surface receptor
Ligand-gated Ion Channel
G Protein Coupled Receptor
Enzyme linked Receptor
B. Intracellular Receptor
Nuclear Receptor
Neurotransmitters/General aspect and steps involved in neurotransmission.pptxSIRAJUDDIN MOLLA
Neurotransmission (Latin: transmission "passage, crossing" from transmitter "send, let through"), is the process by which signalling molecules called neurotransmitters are released by the axon terminal of a neuron and bind to and react with the receptors on the dendrites of another neuron
The document discusses various screening methods for evaluating potential anxiolytic drugs, including in vitro receptor binding assays and in vivo behavioral tests in animals like the elevated plus maze test, light-dark box test, and social interaction test, which measure anxiety-like behaviors that can be reduced by anxiolytic drug administration. Classification of anxiolytics and theories of anxiety involving neurotransmitters like GABA, serotonin and norepinephrine are also covered.
Preclinical screening methods of cns stimulantsRashmi116
This document describes various preclinical screening methods used to evaluate central nervous system (CNS) stimulants. It discusses behavioral manifestations of CNS stimulation like increased alertness. Various screening methods are described including the actophotometer test to measure locomotor activity, strychnine-induced convulsion test, sand displacement test, runway test and others. Each test is briefly explained along with its purpose, procedure, and evaluation method. A variety of behavioral tests in animals are used to screen for CNS stimulant activity of novel compounds.
Genetic variations in G protein-coupled receptors (GPCRs) can alter receptor function and cause diseases. Single nucleotide polymorphisms and other mutations have been linked to impaired or enhanced receptor signaling. For example, a mutation in the vasopressin V2 receptor causes nephrogenic diabetes insipidus by decreasing ligand binding and receptor expression. Similarly, mutations in chemokine receptors CCR5 and CCR2 impact HIV infection by altering receptor function or interaction with other coreceptors. Overall, GPCR polymorphisms are associated with diseases by changing ligand binding, receptor activation, trafficking, and coupling to downstream signaling pathways.
This document summarizes several preclinical models used to screen anxiolytic agents. It describes anxiety disorders and the goal of developing animal models that resemble human pathology. Several models are explained in detail, including the elevated plus maze test, light-dark exploration test, and social interaction test in rats. These tests measure anxiety-like behaviors in rodents and can determine if candidate drugs decrease inhibited behaviors. The document also reviews in vitro and in vivo methods for evaluating putative anxiolytics before clinical trials.
The document describes several screening models used to evaluate the effects of drugs on behavioral and muscle coordination in animals. It discusses tests such as the open field test, hole board test, chimney test, grip strength, and rota rod method. These tests measure parameters like locomotor activity, exploration, muscle strength, and motor coordination. The results of these tests can provide information about a drug's effects and allow the calculation of values like ED50 doses for sedative, stimulant, and muscle relaxant drugs.
This document summarizes models used to study anti-emetic drugs. It describes various in vivo, in vitro, and human models. For in vivo models, it outlines drug-induced (cisplatin, apomorphine, copper sulfate), motion, and radiation models using species like dogs, cats, ferrets, and rats. It discusses parameters assessed like retching episodes. For in vitro models, it notes evaluating drugs' activity at 5-HT3 receptors. Finally, it mentions human models like using apomorphine or ipecac to induce vomiting and assessing drug effectiveness.
Classification of receptors family by vivek sharmaAnimatedWorld
Definition- Receptor are the biologic molecule to which drug bind and produces a measurable response.
So, enzyme and structural proteins can be considerd to be pharmacologic receptors.
Majorly receptor are of 4 types and the molecule or a drug interact to receptor to give response often called as ligand.
The type of receptor a ligand will bind is depend on the nature of ligand.
Hydrophilliic ligand binds to the receptor found on the cell surface.
Hydrophobic ligand can enter the cell membrane to intract the receptor present on inside the cells.
Classification of Receptors
A. Cell surface receptor
Ligand-gated Ion Channel
G Protein Coupled Receptor
Enzyme linked Receptor
B. Intracellular Receptor
Nuclear Receptor
Non adrenergic and Non cholinergic transmission E Poovarasan
1. Co-transmission in the autonomic nervous system involves the release of multiple neurotransmitters and neuromodulators from neurons in addition to the primary neurotransmitters acetylcholine and norepinephrine. Common co-transmitters include ATP, neuropeptide Y, vasoactive intestinal peptide, and substance P.
2. Non-adrenergic non-cholinergic (NANC) transmission describes responses mediated by neurotransmitters other than acetylcholine or norepinephrine, such as purines like ATP, nitric oxide, and peptides.
3. In blood vessels, endothelium-derived nitric oxide is an important NANC transmitter that causes vasodilation in response to various stimuli through activation of
Non adrenergic non cholinergic transmission(nanc)Merlin Binu
Neurotransmitters other than Acetyl choline and NorAdrenaline of parasympathetic and sympathetic nervous system play important role in synaptic junction transmission. That neurotransmitters are called NANC.
Introduction to Screening Models of Anti-Atherosclerosis
Atherosclerosis, Screening models, In vitro models, In vivo models
Presented by
SHAIK FIRDOUS BANU
Department of Pharmacology
The document discusses various methods for screening hepatoprotective drugs. It describes in vitro models using primary hepatocyte cultures, hepatic stellate cell cultures, and assays measuring proline hydroxylation inhibition. In vivo models inducing liver injury in rats are also outlined, including models using Long Evans Cinnamon rats, hepatic ischemia, allyl alcohol, carbon tetrachloride, and galactosamine. The goal of these screening methods is to evaluate potential drug candidates for protecting against liver toxicity and damage.
This document describes several screening methods used to assess the effects of drugs on motor coordination and muscle function in mice. The methods include the open field test, hole board test, inclined plane test, vertical screen test, rotarod test, and chimney test. Each method is briefly described, including the purpose, apparatus used, procedures, and outcomes measured. The tests evaluate behaviors like locomotion, exploration and curiosity that can be altered by sedative or stimulant drugs.
Screening Methods for behavioural and muscle Coordinationpradnya Jagtap
Screening Methods for behavioural and muscle Coordination
A. Motor activity and behaviour
1. Method of intermittent observation
2.Open field test
3.Hole board test
4.Combined open field test
B.Test for muscle coordination
1.Inclined plane method
2.Chimny test
3.Grip strength
4.Rotarod method
The seminar discussed screening models for central nervous system stimulant and antidepressant drugs. Various in vitro and in vivo models were described for testing CNS stimulants, including assays measuring sand displacement, spontaneous activity in runways, and motor activity detection. Methods for screening antidepressants included assays measuring the inhibition of radiolabeled dopamine, serotonin, or norepinephrine uptake in rat brain synaptosomes. The mechanisms of action and types of antidepressants like tricyclic antidepressants, selective serotonin reuptake inhibitors, and monoamine oxidase inhibitors were also summarized.
Genetic variation in G protein coupled receptorsSachinGulia12
This document discusses genetic variation in G protein-coupled receptors (GPCRs). It notes that GPCRs are membrane proteins involved in cell signaling and the targets of many drugs. Genetic variations can influence drug efficacy and safety through several mechanisms: by altering the structure and function of GPCRs, their coupling to G proteins and signaling pathways, their binding pockets, and their spontaneous signaling. Specific examples of genetic variations in GPCRs that are associated with human diseases are also provided.
Histamine is an amine autocoid that is synthesized and stored in mast cells and basophils. It is released during allergic reactions and inflammation and acts both locally and systemically via four G protein-coupled receptors, H1-H4. The H1 receptor mediates smooth muscle contraction and increased capillary permeability. The H2 receptor increases gastric acid secretion and relaxes smooth muscles. Histamine plays an important role in allergic reactions, inflammation, gastric acid secretion, and neuronal signaling. It is involved in various physiological and pathological processes.
Screening models for aphrodisiac agents and anti fertility agentsCh. Bhargava krishna
This document discusses guidelines for conducting studies on aphrodisiac and anti-fertility agents in animals. It outlines various in vivo and in vitro screening models used to test the effects of these drugs, including mating behavior tests, libido tests, assessment of sperm parameters, and estimation of sex hormone levels. The guidelines specify how to properly house and train male and female animals, and evaluate behaviors like mounting frequency, intromission latency, and ejaculation. Common aphrodisiac drugs discussed include sildenafil, arginine, and testosterone, while benefits and screening of anti-fertility agents are also summarized.
This document provides information about Alzheimer's disease including its definition, history, pathophysiology, mechanisms, signs and symptoms, treatments, and screening methods. It discusses how Alzheimer's was first identified by Dr. Alois Alzheimer in 1906 and the characteristic brain abnormalities he observed. The two main hypotheses for the disease mechanism are the amyloid beta hypothesis and tau hypothesis which involve the accumulation of amyloid plaques and neurofibrillary tangles respectively. Several in vitro and in vivo screening methods are described to test potential drugs for treating Alzheimer's including assays measuring acetylcholinesterase inhibition and animal behavior tests.
Pharmacological screening of Anti-psychotic agentsAbin Joy
This document provides information on screening models used to evaluate potential antipsychotic drugs. It begins with an introduction to psychosis and classification of antipsychotic agents. It then describes several in vivo and in vitro models used for screening including tests measuring catalepsy in rodents, inhibition of amphetamine-induced stereotypy, and D2 receptor binding assays. The in vivo models assess behaviors relevant to antipsychotic effects while the in vitro assays measure binding to specific receptors like the D2 receptor that contribute to antipsychotic mechanisms of action.
Neurotransmission (Latin: transmission "passage, crossing" from transmitter "send, let through"), is the process by which signalling molecules called neurotransmitters are released by the axon terminal of a neuron and bind to and react with the receptors on the dendrites of another neuron
The document summarizes screening models for Alzheimer's disease. It describes two in vitro methods - inhibition of acetylcholine-esterase activity in rat striatum and inhibition of butyrylcholine-esterase activity in human serum. It also describes two in vivo methods - the step-down test and scopolamine-induced amnesia in mice. The step-down test measures learning and memory in rats using an elevated platform and electric shock. The scopolamine-induced amnesia test measures the ability of drugs to reverse memory deficits caused by the antimuscarinic scopolamine in mice. The document provides details on the procedures and evaluations of these screening methods.
1. The document discusses various models used to study Alzheimer's disease, including both in vitro and in vivo models. It describes assays such as inhibitory avoidance, step-down avoidance, and scopolamine-induced amnesia in mice that are used to test drugs for improving memory and cognition.
2. The pathological hallmarks of Alzheimer's disease involve extracellular amyloid plaques, neurofibrillary tangles, and loss of cortical cholinergic neurons. Several genetic models have also been developed to study the disease.
3. A variety of screening models are used to evaluate potential pharmacological treatments for Alzheimer's disease and assess their ability to inhibit acetylcholinesterase activity, affect nicotinic receptors, or antagonize
This document discusses various screening models for Parkinson's disease, including pharmacological models using tremoring-inducing drugs and reserpine, toxin models using MPTP, 6-OHDA, rotenone, and paraquat, and genetic models using genes associated with Parkinson's like alpha-synuclein, LRRK2, parkin, and DJ-1. Alternative models discussed include Drosophila, C. elegans, zebrafish, and mouse models that aim to replicate features of Parkinson's like neurodegeneration of dopaminergic neurons and motor deficits. In summary, the document compares strengths and limitations of different Parkinson's disease models.
This seminar is my attempt to discuss screening of anti-emetic drugs using different animal models. The materials used in the presentation is derived from different standard textbooks, internet and journals. Please feel free to suggest ways to improve it.
The document describes several in vitro and in vivo methods used to study anti-allergic and anti-inflammatory drugs. In vitro methods include inhibition of histamine release from mast cells and inhibition of T cell proliferation. In vivo methods include a rat anaphylaxis model, guinea pig Schultz-Dale reaction, and passive cutaneous anaphylaxis in rats. One method involves sensitizing rats with ovalbumin, then challenging them to induce shock, which can be counteracted by test drugs. Another involves sensitizing guinea pigs to egg albumin to study contractions in response to ovalbumin.
Opioids are psychoactive chemicals that bind to opioid receptors in the central nervous system, peripheral nervous system, and gastrointestinal tract. Opioid receptors are classified into μ, κ, and δ types. Opioids can function as agonists, partial agonists, or antagonists at these receptors. Opioids are classified based on their origin, such as natural, semisynthetic, or synthetic, and based on their strength and function, such as pure agonists, partial agonists, agonist-antagonists, or pure antagonists. The pharmacological actions of opioids include analgesia, respiratory depression, sedation, myosis, and decreased blood pressure through effects on the central nervous system, eyes,
Histamine is a chemical mediator that causes inflammatory responses. It is produced and stored in mast cells and basophils and released during allergic reactions. There are four types of histamine receptors: H1, H2, H3, and H4. H1 receptors mediate various inflammatory effects while H2 receptors stimulate gastric acid secretion. Antihistamines work by competitively binding histamine receptors to block their activation. First generation H1 antihistamines have anticholinergic effects while second generation ones are less sedating. H2 antihistamines like ranitidine are used prevent acid aspiration during surgery. Both H1 and H2 antihistamines have various adverse effects that must be considered when
Non adrenergic and Non cholinergic transmission E Poovarasan
1. Co-transmission in the autonomic nervous system involves the release of multiple neurotransmitters and neuromodulators from neurons in addition to the primary neurotransmitters acetylcholine and norepinephrine. Common co-transmitters include ATP, neuropeptide Y, vasoactive intestinal peptide, and substance P.
2. Non-adrenergic non-cholinergic (NANC) transmission describes responses mediated by neurotransmitters other than acetylcholine or norepinephrine, such as purines like ATP, nitric oxide, and peptides.
3. In blood vessels, endothelium-derived nitric oxide is an important NANC transmitter that causes vasodilation in response to various stimuli through activation of
Non adrenergic non cholinergic transmission(nanc)Merlin Binu
Neurotransmitters other than Acetyl choline and NorAdrenaline of parasympathetic and sympathetic nervous system play important role in synaptic junction transmission. That neurotransmitters are called NANC.
Introduction to Screening Models of Anti-Atherosclerosis
Atherosclerosis, Screening models, In vitro models, In vivo models
Presented by
SHAIK FIRDOUS BANU
Department of Pharmacology
The document discusses various methods for screening hepatoprotective drugs. It describes in vitro models using primary hepatocyte cultures, hepatic stellate cell cultures, and assays measuring proline hydroxylation inhibition. In vivo models inducing liver injury in rats are also outlined, including models using Long Evans Cinnamon rats, hepatic ischemia, allyl alcohol, carbon tetrachloride, and galactosamine. The goal of these screening methods is to evaluate potential drug candidates for protecting against liver toxicity and damage.
This document describes several screening methods used to assess the effects of drugs on motor coordination and muscle function in mice. The methods include the open field test, hole board test, inclined plane test, vertical screen test, rotarod test, and chimney test. Each method is briefly described, including the purpose, apparatus used, procedures, and outcomes measured. The tests evaluate behaviors like locomotion, exploration and curiosity that can be altered by sedative or stimulant drugs.
Screening Methods for behavioural and muscle Coordinationpradnya Jagtap
Screening Methods for behavioural and muscle Coordination
A. Motor activity and behaviour
1. Method of intermittent observation
2.Open field test
3.Hole board test
4.Combined open field test
B.Test for muscle coordination
1.Inclined plane method
2.Chimny test
3.Grip strength
4.Rotarod method
The seminar discussed screening models for central nervous system stimulant and antidepressant drugs. Various in vitro and in vivo models were described for testing CNS stimulants, including assays measuring sand displacement, spontaneous activity in runways, and motor activity detection. Methods for screening antidepressants included assays measuring the inhibition of radiolabeled dopamine, serotonin, or norepinephrine uptake in rat brain synaptosomes. The mechanisms of action and types of antidepressants like tricyclic antidepressants, selective serotonin reuptake inhibitors, and monoamine oxidase inhibitors were also summarized.
Genetic variation in G protein coupled receptorsSachinGulia12
This document discusses genetic variation in G protein-coupled receptors (GPCRs). It notes that GPCRs are membrane proteins involved in cell signaling and the targets of many drugs. Genetic variations can influence drug efficacy and safety through several mechanisms: by altering the structure and function of GPCRs, their coupling to G proteins and signaling pathways, their binding pockets, and their spontaneous signaling. Specific examples of genetic variations in GPCRs that are associated with human diseases are also provided.
Histamine is an amine autocoid that is synthesized and stored in mast cells and basophils. It is released during allergic reactions and inflammation and acts both locally and systemically via four G protein-coupled receptors, H1-H4. The H1 receptor mediates smooth muscle contraction and increased capillary permeability. The H2 receptor increases gastric acid secretion and relaxes smooth muscles. Histamine plays an important role in allergic reactions, inflammation, gastric acid secretion, and neuronal signaling. It is involved in various physiological and pathological processes.
Screening models for aphrodisiac agents and anti fertility agentsCh. Bhargava krishna
This document discusses guidelines for conducting studies on aphrodisiac and anti-fertility agents in animals. It outlines various in vivo and in vitro screening models used to test the effects of these drugs, including mating behavior tests, libido tests, assessment of sperm parameters, and estimation of sex hormone levels. The guidelines specify how to properly house and train male and female animals, and evaluate behaviors like mounting frequency, intromission latency, and ejaculation. Common aphrodisiac drugs discussed include sildenafil, arginine, and testosterone, while benefits and screening of anti-fertility agents are also summarized.
This document provides information about Alzheimer's disease including its definition, history, pathophysiology, mechanisms, signs and symptoms, treatments, and screening methods. It discusses how Alzheimer's was first identified by Dr. Alois Alzheimer in 1906 and the characteristic brain abnormalities he observed. The two main hypotheses for the disease mechanism are the amyloid beta hypothesis and tau hypothesis which involve the accumulation of amyloid plaques and neurofibrillary tangles respectively. Several in vitro and in vivo screening methods are described to test potential drugs for treating Alzheimer's including assays measuring acetylcholinesterase inhibition and animal behavior tests.
Pharmacological screening of Anti-psychotic agentsAbin Joy
This document provides information on screening models used to evaluate potential antipsychotic drugs. It begins with an introduction to psychosis and classification of antipsychotic agents. It then describes several in vivo and in vitro models used for screening including tests measuring catalepsy in rodents, inhibition of amphetamine-induced stereotypy, and D2 receptor binding assays. The in vivo models assess behaviors relevant to antipsychotic effects while the in vitro assays measure binding to specific receptors like the D2 receptor that contribute to antipsychotic mechanisms of action.
Neurotransmission (Latin: transmission "passage, crossing" from transmitter "send, let through"), is the process by which signalling molecules called neurotransmitters are released by the axon terminal of a neuron and bind to and react with the receptors on the dendrites of another neuron
The document summarizes screening models for Alzheimer's disease. It describes two in vitro methods - inhibition of acetylcholine-esterase activity in rat striatum and inhibition of butyrylcholine-esterase activity in human serum. It also describes two in vivo methods - the step-down test and scopolamine-induced amnesia in mice. The step-down test measures learning and memory in rats using an elevated platform and electric shock. The scopolamine-induced amnesia test measures the ability of drugs to reverse memory deficits caused by the antimuscarinic scopolamine in mice. The document provides details on the procedures and evaluations of these screening methods.
1. The document discusses various models used to study Alzheimer's disease, including both in vitro and in vivo models. It describes assays such as inhibitory avoidance, step-down avoidance, and scopolamine-induced amnesia in mice that are used to test drugs for improving memory and cognition.
2. The pathological hallmarks of Alzheimer's disease involve extracellular amyloid plaques, neurofibrillary tangles, and loss of cortical cholinergic neurons. Several genetic models have also been developed to study the disease.
3. A variety of screening models are used to evaluate potential pharmacological treatments for Alzheimer's disease and assess their ability to inhibit acetylcholinesterase activity, affect nicotinic receptors, or antagonize
This document discusses various screening models for Parkinson's disease, including pharmacological models using tremoring-inducing drugs and reserpine, toxin models using MPTP, 6-OHDA, rotenone, and paraquat, and genetic models using genes associated with Parkinson's like alpha-synuclein, LRRK2, parkin, and DJ-1. Alternative models discussed include Drosophila, C. elegans, zebrafish, and mouse models that aim to replicate features of Parkinson's like neurodegeneration of dopaminergic neurons and motor deficits. In summary, the document compares strengths and limitations of different Parkinson's disease models.
This seminar is my attempt to discuss screening of anti-emetic drugs using different animal models. The materials used in the presentation is derived from different standard textbooks, internet and journals. Please feel free to suggest ways to improve it.
The document describes several in vitro and in vivo methods used to study anti-allergic and anti-inflammatory drugs. In vitro methods include inhibition of histamine release from mast cells and inhibition of T cell proliferation. In vivo methods include a rat anaphylaxis model, guinea pig Schultz-Dale reaction, and passive cutaneous anaphylaxis in rats. One method involves sensitizing rats with ovalbumin, then challenging them to induce shock, which can be counteracted by test drugs. Another involves sensitizing guinea pigs to egg albumin to study contractions in response to ovalbumin.
Opioids are psychoactive chemicals that bind to opioid receptors in the central nervous system, peripheral nervous system, and gastrointestinal tract. Opioid receptors are classified into μ, κ, and δ types. Opioids can function as agonists, partial agonists, or antagonists at these receptors. Opioids are classified based on their origin, such as natural, semisynthetic, or synthetic, and based on their strength and function, such as pure agonists, partial agonists, agonist-antagonists, or pure antagonists. The pharmacological actions of opioids include analgesia, respiratory depression, sedation, myosis, and decreased blood pressure through effects on the central nervous system, eyes,
Histamine is a chemical mediator that causes inflammatory responses. It is produced and stored in mast cells and basophils and released during allergic reactions. There are four types of histamine receptors: H1, H2, H3, and H4. H1 receptors mediate various inflammatory effects while H2 receptors stimulate gastric acid secretion. Antihistamines work by competitively binding histamine receptors to block their activation. First generation H1 antihistamines have anticholinergic effects while second generation ones are less sedating. H2 antihistamines like ranitidine are used prevent acid aspiration during surgery. Both H1 and H2 antihistamines have various adverse effects that must be considered when
The document discusses drug toxicity and adverse drug reactions. It defines toxicity as unwanted or harmful effects caused by a drug, which can sometimes be deadly. Toxicity results from excessive pharmacological action of a drug due to overdosing or prolonged use, and can damage organs like the brain, heart, kidneys, liver, lungs and blood. Mechanisms of toxicity include on-target effects from binding to the intended receptor inappropriately, off-target binding to unintended receptors, production of toxic metabolites, idiosyncratic immune responses, and toxicity from drug metabolites. Common toxic outcomes are cytotoxicity, carcinogenicity, mutagenicity and teratogenicity. Ways to manage toxicity involve banning dangerous drugs, controlling drug
This document provides information about histamine including its formation, locations in the body, pharmacological effects, and roles. It discusses the four types of histamine receptors (H1-H4), their locations, functions, therapeutic uses, and adverse effects. Histamine is formed from the amino acid l-histidine and is involved in various physiological processes like gastric acid secretion, sleep-wake regulation, and vascular dilation. It also mediates immune responses and acts as a neurotransmitter.
This document provides an overview of histamines and antihistamines. It discusses the synthesis, storage, and distribution of histamine in the body. Histamine acts through four receptors (H1, H2, H3, H4) and has various effects including vasodilation, increased permeability, and gastric acid secretion. Antihistamines like H1 blockers (diphenhydramine, cetirizine) and H2 blockers (cimetidine, ranitidine) are used to treat allergic reactions and acid reflux by blocking histamine receptors. First generation antihistamines are more sedating while second generation have less side effects.
This document discusses autacoids and related drugs, focusing on histamine. It describes how histamine is formed, stored, and released from mast cells and basophils. It discusses the pharmacokinetics and pharmacodynamics of histamine, including its effects on various organ systems mediated through H1, H2, H3, and H4 receptors. The document also describes H1 receptor antagonists, including their pharmacokinetics and mechanisms of action in blocking the effects of histamine and treating conditions like allergies and insomnia.
Antihistamines are used to treat conditions caused by the release of histamine such as allergic reactions and inflammation. There are first-generation and second-generation antihistamines that work by blocking the H1 and H2 receptors where histamine binds. First-generation antihistamines are more likely to cause sedation and anticholinergic side effects while second-generation antihistamines have fewer side effects. Antihistamines are used to treat acute and chronic urticaria, physical urticarias, pruritus, and symptoms of mastocytosis. Drug interactions and the risk of side effects must be considered when selecting an antihistamine, especially for special patient populations such as children, elderly
This document discusses autacoids, specifically histamine and antihistamines. It defines autacoids as hormone-like substances that are produced locally and act on nearby tissues. Histamine is an important autacoid that binds to four receptor types (H1-H4) and is involved in allergic responses. Antihistamines work by blocking histamine receptors, especially H1 receptors. The document compares first, second, and third generation antihistamines and their mechanisms of action, uses, and side effects. It also discusses five common antihistamine drugs produced in Bangladesh.
This document discusses histamine and histamine antagonists (antihistamines). It begins by outlining the objectives which are to describe the histamine receptor subtypes, distinguish between first and second generation antihistamines, and discuss the actions and side effects of histamine and antihistamines. It then provides details on the distribution, synthesis, and physiological and pathophysiological actions of histamine. The mechanisms of action, indications, and side effect profiles of first and second generation antihistamines are compared. In summary, the document is a review of histamine pharmacology and the clinical applications of antihistamines.
Chemistry of histamine and antihistamine drugs (H-1 and H-2 antagonist)Akhil Nagar
This document discusses the chemistry and pharmacology of histamine and antihistamine drugs. It provides details on:
- The discovery and properties of histamine.
- Histamine synthesis from histidine, release from mast cells and other tissues, and metabolism by histamine-N-methyltransferase and diamine oxidase.
- The four types of histamine receptors (H1-H4), their distribution, and role in various physiological effects.
- The pharmacological effects of histamine release including allergic reactions and anaphylaxis.
- Classes of antihistamine drugs including H1 and H2 receptor antagonists, as well as mast cell stabilizers that inhibit histamine release
This document discusses histamine and antihistamines. It covers the topics of histamine synthesis, storage, release and receptors. Histamine causes vasodilation, increased permeability and smooth muscle contraction through H1 receptors. Antihistamines such as fexofenadine and loratadine are second generation drugs that selectively block H1 receptors without crossing the blood brain barrier, thereby reducing sedation. H2 receptor antagonists such as cimetidine and ranitidine are used to suppress gastric acid secretion by blocking histamine and other stimuli at the parietal cell.
This document discusses histamine and antihistamines. It provides details on histamine including its synthesis, storage, receptors, and role in allergic reactions and inflammation. It then describes first and second generation antihistamines that act as H1 receptor antagonists to relieve symptoms of allergic rhinitis, urticaria, and other conditions by blocking the effects of histamine. The patient described has seasonal allergic rhinitis, so a second generation antihistamine with fewer side effects would be most suitable. First generation antihistamines that cause drowsiness should be avoided.
Medicinal Chemistry of Antihypertensive agents pptxSameena Ramzan
This document provides an overview of antihypertensive agents. It begins with an introduction to hypertension and classifications of hypertension. It then discusses the pharmacological classifications of antihypertensive drugs and provides details on the synthesis, mechanisms of action, adverse effects and dosage of various classes of antihypertensive agents including diuretics, ACE inhibitors, calcium channel blockers, beta-blockers, central sympatholytics, and arterial dilators. It also discusses structure-activity relationships of ACE inhibitors and ARBs. The document aims to inform healthcare professionals about the different types of antihypertensive drugs.
Histamine is a local hormone that is involved in physiological and pathological processes. It is stored in mast cells and released during allergic reactions. Histamine acts through four histamine receptors (H1-H4) and causes effects such as vasodilation, increased capillary permeability, bronchconstriction, and gastric acid secretion. Antihistamines are drugs that competitively block the H1 receptor and are used to treat allergic conditions. First generation antihistamines are sedating while second generation antihistamines are non-sedating but have fewer adverse effects. Histamine and antihistamines play important roles in allergic inflammation and disease.
Introduction to Autocids And Histamine and Antihistamine.pdfrishi2789
This document discusses autacoids and antihistamines. It defines autacoids as locally acting substances produced by cells that have intense biological activity, such as histamine. Classical autacoids include amines, lipids, and peptides. Antihistamines work by competitively blocking the actions of histamine at H1 receptors. First-generation antihistamines can cause sedation as a side effect, while second-generation antihistamines are less sedating. Antihistamines are used to treat allergic disorders, motion sickness, nausea, vertigo, and conditions involving excess histamine release.
This document discusses histamine, an amine that acts as a chemical messenger in many cellular responses. It is released from mast cells and basophils during allergic reactions and causes symptoms like congestion and itching. Antihistamines block the H1 receptor to reduce these symptoms. H2 blockers inhibit gastric acid secretion by blocking the H2 receptor. Research continues on the roles and potential drug targets of other histamine receptors like H3, H4, and ligands that may treat conditions like sleep disorders, pruritus, and autoimmune disease.
Similar to Histamine as a cns neurotransmitter (20)
Muktapishti is a traditional Ayurvedic preparation made from Shoditha Mukta (Purified Pearl), is believed to help regulate thyroid function and reduce symptoms of hyperthyroidism due to its cooling and balancing properties. Clinical evidence on its efficacy remains limited, necessitating further research to validate its therapeutic benefits.
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
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Here is the updated list of Top Best Ayurvedic medicine for Gas and Indigestion and those are Gas-O-Go Syp for Dyspepsia | Lavizyme Syrup for Acidity | Yumzyme Hepatoprotective Capsules etc
These lecture slides, by Dr Sidra Arshad, offer a quick overview of the physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
6. Describe the flow of current around the heart during the cardiac cycle
7. Discuss the placement and polarity of the leads of electrocardiograph
8. Describe the normal electrocardiograms recorded from the limb leads and explain the physiological basis of the different records that are obtained
9. Define mean electrical vector (axis) of the heart and give the normal range
10. Define the mean QRS vector
11. Describe the axes of leads (hexagonal reference system)
12. Comprehend the vectorial analysis of the normal ECG
13. Determine the mean electrical axis of the ventricular QRS and appreciate the mean axis deviation
14. Explain the concepts of current of injury, J point, and their significance
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
2. 1. Histamine 1
2. Biosynthesis of Histamine 2
3. Release of Histamine 3-6
4. Histamine Receptors 7
5. Pharmacological Action 8
6. Drugs acts on H1 Receptor 17
a. First Generation 18
b. Second Generation 19-20
c. Third Generation 21
7. Drugs acts on H2 Receptor 24-33
3. 8. Drugs acts on H3 Receptor & role in Neuro-
- Disease 34-50
a. Schizophrenia
b. Alzheimer Disease
c. Addiction
d. ADHD
9. H4 Receptor 51
10. References 52-53
3
4. Histamine is found in most tissues and
released by mast cells.
Released during inflammatory or
allergic reaction.
Synthesized from Histidine.
Act as autacoids means secreted locally
to decrease & increase the activity of
nearby cells.
1
6. The release of histamine from tissues is caused
by the destruction of cells as a result of cold,
bacterial toxins, bee sting venoms, or trauma.
Allergies, anaphylaxis can also trigger release
of histamine.
3
7. In mast cells, histamine is stored in granules as
an inactive complex.
Inactive complex composed of histamine and
the polysulfated anion, heparin,along with
anionic protein.
Histamine is also known as a neuromodulator,
since it regulates the release of
other neurotransmitter,
like acetylcholine, norepinephrine , and
serotonin.
4
8. Histamine also has presynaptic receptor(H3)
inhibit the release of histamine.
Inverse agonist or antagonist of this receptors
may increase histamine leading to wakefulness
and decrease appetite(induces anorexia).
Pitolisant (tiprolisant) drug approved for
Narcolepsy.
Ciproxifan drugs antagonist, showing an
exclusively high species-specific affinity at
rodent compared to human H3 receptor.
5
9. It is well studied as reference compound for H3
receptor in rodent models for neurological
diseases connected with neurotransmitter
dysregulation, e.g. attention deficit
hyperactivity disorder or Alzheimer’s disease.
6
11. Nervous System
Histamine is a powerful stimulant of sensory nerve
endings may results in pain and pruritis(itching).
This above results produced by H1 receptor, is
important component of urticarial response to insect
bites and stings.
Histamine is powerful contractor of visceral smooth
muscles through H1 receptors and results in
bronchoconstriction and abdominal cramps.
8
12. Glands
Histamine increases gastric secretion by stimulation
of H2 receptor.
This action is exerted directly on parietal cells and
mediated by increased cAMP generation and results
in turn activates the membrane proton pump
(H+ , K + ATPase)
9
13. Autonomic ganglia and adrenal medulla
These are stimulated and release of Adrenaline occurs,
which can cause a secondary rise in BP.
CNS
The histaminergic neurons originate from the
tuberomammillary nucleus ( TMN ) of the posterior
hypothalamus & send projections to most parts of the
brain
Histamine does not penetrate blood brain barrier- no
central effects are produced on i.v. injection.
Intracerebroventricular administration produces rise in
BP, cardiac stimulation, behavioral arousal,
hypothermia, vomiting and ADH release
10
14. The TMN of the
hypothalamus is
the sole source of
histaminergic innervations
of the CNS.
The most densely
innervated target
of the histaminergic
neurons in the
Hypothalamus.
14
15. Histaminergic TMN neurons are active during
wakefulness and exert multiple functions.(thus
can be used to treat sleep-wake disorders, like
narcolepsy , via modulation of H3 receptor
function.)
12
16. Blood vessel
Histamine causes dilation of small blood vessels and
can results in flushing and hypotension.
Fall in blood pressure is mediated by both H1 (early;
by release of NO) as well as H2 (delayed and
persistent; direct actions on smooth muscles of
blood vessels) receptors.
Increases the capillary permeability and results in
exudation of plasma(edema) due to separation
of endothelial cells.
13
17. Triple response
Intradermal injection of histamine may results in
1. Red reaction/Flush(due to vasodilation)
2. Wheal/formation of oedematous patch(exudation of fluid
due to increased permeability)
3. Flare/Red irregular surrounding the wheal(spreading
redness due to axon reflex)
It is primarily an H1 response.
14
18. Heart/Cardiovascular system
H1 receptor stimulation has negative dromotropic
(decreased AV conduction) on isolated heart.
H2 receptor stimulation increases the force of
contraction on isolated heart.
Effect on intact heart is not prominent means direct
effects of histamine on in situ heart are not
prominent.
15
19. These drugs act as competitive antagonist.
Classified into first generation & second
generation compounds on the basis of CNS
penetration and anticholinergic properties.
First Gen drugs are highly lipid soluble, cross
the BBB and hence cause sedation &
psychomotor impairment.
C/I in persons requiring constant attention ,
children and elderly(>65 years).
17
21. Based On H1 blocking action
Allergic condition like itching, urticaria, hay fever
etc.
Insect bite, ivy poisoning and to prevent adverse
effects due to histamine releasers.
Based On Anticholinergic properties
Common cold(to control rhinorrhoea)
Motion sickness(as prophylactic agent)
Parkinsonism(Promethazine may be used)
Acute muscular dystonia
19
22. Other Uses
Antihistaminics are drug of choice for idiopathic
pruritis.
Cinnarizine is used in vertigo
20
23. These drugs are less lipid soluble, don’t cross
BBB and hence are nonsedating.
Preferred in persons requiring constant
attention. E.g. Truck drivers etc.
More potent and more efficacious than first
generation.
Long acting as compared to first generation.
All second generation antihistaminics are
metabolized to active products except cetrizine
and mezolastine.
21
25. Some authorities describe the term 3rd
generation antihistaminics which are
derivatives of the second generation.
Examples-
• Levocetrizine
•Desloratadine
•Fexofenadine
23
26. These drugs competitively inhibit H2 receptors
in parietal cells, thus inhibiting the acid
secretion.
ACh and gastrin act partly by causing the
release of histamine, therefore acid secreting
capacity of these agents also is decreased by H2
blockers.
Histamine is primarily responsible for
nocturnal acid secretion, which is inhibited by
H2 blockers.
24
27. 1. Cimetidine
2. Ranitidine
3. Famotidine
4. Roxatidine
5. Nizatidine
6. Loxatidine
These drugs are used for peptic ulcer, Zollinger -
Ellison syndrome and gastro esophageal reflux
disease(GERD).
25
28. Cimetidine is not used routinely because:
It can cross blood brain barrier and result in
mental state changes.
It inhibits binding of dihydrotestosterone to
androgen receptors that can manifest as
impotence in males.
It inhibits metabolism of estradiol and
increases serum prolactin levels on long term
use, thus can cause gynaecomastia (in males)
and galactorrhoea (in females).
26
29. It is a potent inhibitor of CYP enzymes and can
increase plasma concentration of warfarin,
theophylline and many other drugs.
It is the least potent H2 blocker.
Ranitidine recently banned in India due to
contamination by cancer causing substance
NDMA( N-nitrosodimethylamine).
27
30. 28
The metabolic degradation of
NDMA produces
formaldehyde and methanol,
and the alkylating intermediate
reacts with nucleic acids and
proteins to form methylated
macromolecules called as O6 -
methylguanine as the likely
proximal carcinogenic
agent.
Pathogenesis Of NDMA Induced Hepatic Carcinoma
31. Methanol and Formeldihyde are highly toxic to liver
and initiates severe inflammation and
confluent hemorrhagic necrosis.
These processes results in extreme oxidative
stress and production of reactive oxygen
species (ROS) that further contributes to
hepatocyte damage and necrosis.
Furthermore, NDMA decreases catalase and
glutathione peroxidase, the major antioxidant
enzymes present in the liver.
29
32. NDMA decreases serum and liver
concentrations of ascorbic acid, another major
antioxidant.
The persistent treatment of NDMA further
increases oxidative stress and lipid
peroxidation that enhances hemorrhagic
necrosis and collapse of liver parenchyma.
The extensive panlobular and multilobular
necrosis lead to massive hepatic necrosis,
which in turn initiates mitosis and hepatic
regeneration.
30
33. On the other hand, the resting HSCs(Hepatic
Stellets Cells) transform into myofibroblast like
cells and start extensive synthesis of connective
tissue proteins.
This causes deposition of mature collagen
fibrils in the extracellular matrix of the liver
and results in hepatic fibrosis.
All these processes lead to condensation of
hepatic reticulin framework, production of
granulation tissue, and ultimately scar
formation.
31
34. The ischemic consequences of the hepatic tissue
and confluent necrosis amplify the process of
nodular regeneration and drive towards to liver
cirrhosis.
The repeated tissue repair and regeneration
process can lead to aberrations and mutations in
genes and end up in development of HCC(
Hepatocellular carcinoma).
Alternatively, the methyl carbonium ions
produced during metabolic degradation of NDMA
methylate the hepatocyte DNA that results in gene
mutation and trigger HCC.
32
35. 33
The metabolic activation and
detoxification of NDMA cause
hepatocyte injury, inflammation,
neutrophilic infiltration, and
massive hepatic necrosis, which
results in oxidative stress and
production of reactive oxygen
species. These processes induce
activation of hepatic stellate cells
and increased synthesis of
connective tissue components,
especially collagens that end up
in hepatic fibrosis. The chronic
liver injury and perpetual
fibrosis lead to liver cirrhosis,
which could develop into
hepatocellular carcinoma
36. Histamine H3 receptor (H3R) antagonists/inverse
agonists have revealed potential to treat diverse
disease states of the central nervous system (CNS)
including Alzheimer’s disease (AD), attention-
deficit hyperactivity syndrome (ADHD),
schizophrenia, obesity, pain, epilepsy, narcolepsy,
substance abuse, etc
34
37. AD is a chronic and progressive neurodegenerative
brain disease.
In AD the histamine production is diminished but in
early stage histamine production is paralleled by
build up of neurofibrillary tangles (NFT) in the
Tuberomammillary Neuron.
A significant loss of large-sized histamine
containing neurons in the rostral TMN was
observed where numerous NFT were found,
indicative of a central histaminergic
dysfunction.
35
38. Central histaminergic fibres originating from the
TMN in the posterior hypothalamus widely projects
into different brain areas including the cerebral
cortex, thalamus, basal ganglia, amygdala, and
hippocampus, where histamine is crucially
associated with a large number of basic
physiological functions including sensory and motor
functions, cognition, attention, learning, and
memory.
36
39. Blockade of human H3 autoreceptor by
Thioperamide evokes the increase of the
neuronal histamine release.
The neurotransmitter modulates cognition
processes via both human H1 and H2 receptors
or via cholinergic and GABAergic interneurons
either directly via excitation of neocortical
pyramidal neurons and thalamic relay neurons
or indirectly via excitation of ascending
cholinergic neurons.
40. Amyloid plaque, consisting of extracellular deposits
of β-amyloid protein in selective areas of brain such
as cortex, hippocampus, amygdala and subcortical
nuclei etc.
Neurotoxicity in AD results from excessive
formation of Aβ protein.
Familial AD(rare) results from mutations in the
genes for amyloid precursor protein(APP) which
causes an increase in Aβ formation.
38
41. NFT arising from hyperphosphorylation of tau,
a microtubule-associated protein.
Activation of cellular path- ways that inhibit
tau kinase signaling and subsequent tau hyper-
phosphorylation is considered to be the most
feasible strategy to prevent tau aggregation
and associated pathological effects.
Suppression of tau protein can also block Aβ-
induced apoptosis there by reducing cognitive
deficits.
39
42. ADHD is a disorder most prevalent in children
characterized by persistent carelessness,
hyperactivity, and impulsivity.
In preclinical models, pharmacological
alterations that antagonize the cholinergic
system or enhance the various neurotrans-
mitter systems like DA, orexin, cannabinoids
systems including histamine cause
hyperactivity [an increase in locomotor activity
(LA)] that accompanies various neurological
disorders including ADHD ).
40
43. Recently, H3R antagonist (carnicine, a stable
analog of the naturally occurring dipeptide
carnosine) attenuated hyperlocomotion in an
ADHD-specific model with neonatal habenula
lesion without having an effect on attention-
deficit.
41
44. Schizophrenia, a chronic debilitating neurological
syndrome characterized by positive (e.g., hallucination
and delusion), negative (e.g., paucity of emotion and
motivation), and impaired cognitive symptoms.
Dysregulation in DA and other neurotransmitter
systems are involved in the development of the
disease.
Current pharmacotherapy for schizophrenia consists of
first generation (FGA) and second generation (SGA)
antipsychotics, which mainly act by DA antagonism in
CNS mediated mainly by DA D2- receptors
42
45. But also by D3R and/or D4R, serotonin receptor (5-
HTR) subtypes (5-HT2AR/5-HT2CR) and/or via
modulation of the glutamatergic system which may
evoke extrapyramidal (mainly FGAs) and/or serious
metabolic disorders.
H3R antagonist could be a pervasive therapeutic
strategy owing to its pro-cognitive property.
Histaminergic innervations into the brain areas
closely associated with the development of
schizophrenia raises the possibility of H3R
antagonists influencing its pathophysiology.
43
46. H3R antagonists, enjoy the advantage of
enhancing DA release from PFC(Prefrontal
cortex).
Thus may have a sparing effect on prefrontal
function over strong DA antagonizing
antipsychotics.
H3R antagonist ciproxifan also reduced LA in
methamphetamine induced chronic
sensitization model.
44
47. Addiction is a complex condition, a brain
disease that is manifested by compulsive
substance use despite harmful consequence.
One common mechanism for addiction caused
by various drugs of abuse is thought to be the
activation of brain’s reward circuitry.
Circuitry pathway is connected to the ventral
tagmental area (VTA) of the midbrain and their
targets in limbic forebrain especially nucleus
accumbens(NAc) where neurons release
Dopamine to make you feel pleasure.
45
48. However, other neurotransmitter systems
including histamine are known to modulate the
psychotropic effects of rewarding drugs.
The fact that histamine also modulates
mesolimbic DA transmission suggests that
histaminergic drugs may be tried
therapeutically in drug addiction.
Nucleus accumbens (NAc) the main region
involved in addiction, receive only weak his-
taminergic innervations, very high densities of
H3Rs which are present here.
46
49. Striatum contains one of the highest densities
of H3Rs in the brain.
Mainly, striatal H3Rs are located
postsynaptically in the GABAergic efferent
neurons where they are co-localized with D1
and D2 receptors.
They are also located presynaptically on
dopaminergic terminals in the striatum where
they have an inhibitory role on DA release.
47
50. Histamine can also activate mesolimbic
dopaminergic system possibly via presynaptic
H3Rs located on DA terminals or
postsynaptically on GABAergic neurons in
striatum or through H1 Rs located on striatal
cholinergic interneurons.
Addictive drugs modulate the histamine levels
in the brain.
For instance, alcohol affects histamine levels in
the brain by modulating histamine synthesis,
release and turnover.
48
51. Acute injection of cocaine increases histamine
levels and histamine-N-methyl transferase
activity in the striatum and NAc and opioids
(e.g., morphine) increases turnover of neuronal
histamine via opioid receptors.
On the other hand, histaminergic system can
modulate behavioral effects of various drugs of
abuse including cocaine, amphetamines,
opioids, and alcohol.
All addictive drugs stimulate LA (psychomotor
stimulant effects).
49
52. Locomotion activation by
amphetamine/methamphetamine and other
dopaminergic agonists was attenuated by H3R
block- ade by Thioperamide and Ciproxifan.
50
53. H4 receptor have been shown to play a role
inflammatory conditions by virtue of their
presence on the membrane of eosinophils and
mast cells.
Although no selective H4 ligand is available.
51
54. 1. Goodman & Gilman’s The pharmacological
Basis of Therapeutics 12th edition, editor
Laurence L.Brunton by Randal A, Skidgel,
Allen P. The McGraw-Hill Companies, Page
No 912-915.
2. Lippincott’s Illustrated Reviews :
Pharmacology 5th edition, Series Editor
Richard A. Harvey. By Michelle A. Clark.
Wolters Kluwer|Lippincott Williams &
Wilkins, Page No 550-551.
52
55. 3. Joseph George, Mutsumi Tsuchishima
& Mikihiro Tsutsumi(08 Jan 2019). Molecular
mechanisms in the pathogenesis of N-
nitrosodimethylamine induced hepatic
fibrosis. Nature Research (subsidiary
of Springer Nature)
4.https://www.ncbi.nlm.nih.gov/pmc/articles/P
MC5895478/
5. https://www.nature.com/articles/srep40541
6.https://www.sciencedirect.com/topics/psycho
logy/histamine
53
57. 9. Essentials Of Medical Pharmacology by KD
Tripathi 8th edition, Jaypee Brothers Medical
Publishers(P).Ltd.
10. 9.Sharma & Sharma’s Principles Of
Pharmacology 3rd edition, Paras Medical
Publisher.
57