Lecture 1 Dl.ppt
•Download as PPT, PDF•
1 like•587 views
This document provides an overview of ion channels and membrane transport proteins. It lists 14 learning objectives related to understanding ion transport mechanisms, membrane potentials, the Nernst equation, Ohm's law, different types of ion channels, and patch clamp techniques. Key concepts covered include the distribution of ions inside and outside cells, equilibrium potentials, selectivity and permeation of potassium channels, and the role of PIP2 in channel gating.
Report
Share
Report
Share
Recommended
Ion channels
Human ion channels are tiny pores in cell membranes that allow the regulated passage of ions and water, underpinning many physiological processes like nerve impulses, muscle contraction, and hormone secretion. They are composed of integral membrane proteins that form water-filled pores and undergo conformational changes to open and close in response to stimuli like voltage changes or ligand binding. Dysfunctions in ion channels can cause diseases like epilepsy, cardiac arrhythmias, and cognitive disorders.
Ion channels as drug target
This document discusses ion channels, which are pore-forming membrane proteins that control the flow of ions across cell membranes. There are two main classes of ion channels: voltage-gated channels, whose gating is controlled by membrane polarization, and ligand-gated channels, whose gating is controlled by the binding of intracellular ligands. The document provides examples of different types of ion channels including potassium channels, calcium channels, chloride channels, GABA and glycine receptors. It also discusses some drugs that work by blocking specific ion channels and their potential applications.
Lecture 3 Dl.ppt
This document discusses voltage-gated ion channels and the action potential. It describes Hodgkin and Huxley's experiments identifying sodium and potassium currents in the squid giant axon. It contrasts the topology of different voltage-gated channels and discusses how voltage sensitivity is recognized in single-channel recordings. Finally, it explains how sodium and potassium channel activation shape the action potential and discusses channelopathies that can lead to disease.
Unit 5 ion channel receptor
1. ION CHANNELS
2. ION CHANNEL RECEPTORS- PRINCIPLES
3. STRUCTURE OF ION CHANNEL RECEPTORS
4. VOLTAGE GATED ION CHANNELS
5. LIGAND GATED ION CHANNELS
6. THANKS
Ion channels, types and their importace in managment of diseases
This topic covers voltage gated type of ion channel, general structure and functioning of ion channels and involvement of different ion channel types in the pathogenesis as wella as a target for the development of various diseases.
Ion channels
This document discusses ion channels, which are protein molecules that span cell membranes and allow passage of ions. Ion channels are essential for neural signaling and functions like generation of action potentials. The document covers the history of ion channels, types of ion channels like voltage-gated sodium and potassium channels, calcium channels, ligand-gated channels, and their structure and functions. It also discusses ion channelopathies, diseases caused by mutations in ion channel genes, including epilepsy, muscle disorders, and inherited channelopathies affecting potassium channels.
Ion channelopathy
The document discusses ion channelopathies and provides details on the cardiac action potential and the ion channels involved in each phase. It describes the major ion channels that generate the cardiac action potential, including sodium channels, transient outward potassium current, ultra-rapidly activating delayed outward rectifying current, and rapidly activating delayed outward rectifying current. It also discusses channelopathies associated with these ion channels like Brugada syndrome and long QT syndrome.
Ion channels
Transmembrane ion channels are protein pores that regulate the passage of ions across cell membranes. There are two main types - voltage-gated ion channels, which open and close in response to changes in membrane potential, and ligand-gated ion channels, which open when certain chemical messengers bind to them. Key voltage-gated channels include sodium, calcium, and potassium channels. Major ligand-gated channels are nicotinic acetylcholine receptors, GABAA receptors, glutamate receptors, and ATP-sensitive potassium channels. The discovery and study of ion channels over time has provided crucial insights into nerve signaling and other cellular processes.
Recommended
Ion channels
Human ion channels are tiny pores in cell membranes that allow the regulated passage of ions and water, underpinning many physiological processes like nerve impulses, muscle contraction, and hormone secretion. They are composed of integral membrane proteins that form water-filled pores and undergo conformational changes to open and close in response to stimuli like voltage changes or ligand binding. Dysfunctions in ion channels can cause diseases like epilepsy, cardiac arrhythmias, and cognitive disorders.
Ion channels as drug target
This document discusses ion channels, which are pore-forming membrane proteins that control the flow of ions across cell membranes. There are two main classes of ion channels: voltage-gated channels, whose gating is controlled by membrane polarization, and ligand-gated channels, whose gating is controlled by the binding of intracellular ligands. The document provides examples of different types of ion channels including potassium channels, calcium channels, chloride channels, GABA and glycine receptors. It also discusses some drugs that work by blocking specific ion channels and their potential applications.
Lecture 3 Dl.ppt
This document discusses voltage-gated ion channels and the action potential. It describes Hodgkin and Huxley's experiments identifying sodium and potassium currents in the squid giant axon. It contrasts the topology of different voltage-gated channels and discusses how voltage sensitivity is recognized in single-channel recordings. Finally, it explains how sodium and potassium channel activation shape the action potential and discusses channelopathies that can lead to disease.
Unit 5 ion channel receptor
1. ION CHANNELS
2. ION CHANNEL RECEPTORS- PRINCIPLES
3. STRUCTURE OF ION CHANNEL RECEPTORS
4. VOLTAGE GATED ION CHANNELS
5. LIGAND GATED ION CHANNELS
6. THANKS
Ion channels, types and their importace in managment of diseases
This topic covers voltage gated type of ion channel, general structure and functioning of ion channels and involvement of different ion channel types in the pathogenesis as wella as a target for the development of various diseases.
Ion channels
This document discusses ion channels, which are protein molecules that span cell membranes and allow passage of ions. Ion channels are essential for neural signaling and functions like generation of action potentials. The document covers the history of ion channels, types of ion channels like voltage-gated sodium and potassium channels, calcium channels, ligand-gated channels, and their structure and functions. It also discusses ion channelopathies, diseases caused by mutations in ion channel genes, including epilepsy, muscle disorders, and inherited channelopathies affecting potassium channels.
Ion channelopathy
The document discusses ion channelopathies and provides details on the cardiac action potential and the ion channels involved in each phase. It describes the major ion channels that generate the cardiac action potential, including sodium channels, transient outward potassium current, ultra-rapidly activating delayed outward rectifying current, and rapidly activating delayed outward rectifying current. It also discusses channelopathies associated with these ion channels like Brugada syndrome and long QT syndrome.
Ion channels
Transmembrane ion channels are protein pores that regulate the passage of ions across cell membranes. There are two main types - voltage-gated ion channels, which open and close in response to changes in membrane potential, and ligand-gated ion channels, which open when certain chemical messengers bind to them. Key voltage-gated channels include sodium, calcium, and potassium channels. Major ligand-gated channels are nicotinic acetylcholine receptors, GABAA receptors, glutamate receptors, and ATP-sensitive potassium channels. The discovery and study of ion channels over time has provided crucial insights into nerve signaling and other cellular processes.
Sodium Ion Channel
Voltage gated sodium ion channels are transmembrane proteins that open in response to changes in the electric field across the cell membrane. They are responsible for initiating action potentials in neurons and other excitable cells. The channel is composed of alpha and beta subunits. The alpha subunit forms the core of the channel and has four homologous domains, each with six transmembrane helical segments. The beta subunits modulate the kinetics of activation. The selectivity filter of the channel is highly selective for sodium ions over other ions. The channel can exist in resting, activated, or inactivated states that control the passage of sodium ions. Sodium channels are the target of drugs used to treat conditions like epilepsy and cardiac arrhythmias.
voltage gated ion channel
This document presents a summary of a student's assignment on voltage-gated ion channels. It begins with an introduction to membrane ion channels and an outline of the presentation. It then discusses the basic structure and mechanism of voltage-gated ion channels, describing how the voltage sensor detects changes in membrane potential. The four major types of voltage-gated channels are identified as sodium, calcium, potassium, and chloride channels. Key details are provided about the structure and function of sodium and potassium channels.
Sodium channel modulators
DRUGS AFFECTING THE SODIUM CHANNEL BOTH BLOCKER AND OPENERS, STRUCTURE OF SODIUM CHANNEL AND ITS LOCATION. SODIUM CHANNEL GATTING MECHANISM BY WITCH THEY ACTING. TYPES OF SODIUM CHANNEL AND ITS FUCTIONS. THEIR THERAPEUTIC APPLICATION WITH EXAMPLES OF DRUGS.
The Nervous System2
The document discusses the structure and function of neurons and the nervous system. It covers topics such as sensory input and motor output, signal transmission through neurons via action potentials, synaptic transmission between neurons through neurotransmitters, and the role of glial cells in supporting neuronal function. Key points include that neurons transmit signals through electrical and chemical processes, synaptic transmission involves the release and binding of neurotransmitters, and glial cells provide insulation and structural/metabolic support to neurons.
Voltage Gated Calcium Channels (VGCC) and Its Role in Neurological Diseases
Voltage-gated calcium channels (VGCCs) play an important role in regulating brain, heart, and muscle function. Dysfunction of VGCCs can lead to neurological conditions and diseases. VGCCs mediate calcium entry from outside the cell and open in response to membrane depolarization. There are several types of VGCCs including L-type, N-type, and T-type calcium channels. VGCCs are involved in various pathways and diseases such as primary afferent pain pathways, thalamocortical circuitry, degeneration of dopaminergic neurons in Parkinson's disease, and drug addiction. Calcium channel blockers have been used successfully to treat some conditions and may be a potential therapeutic approach
cardiac ion channels and channelopathies
The document discusses ion channels and their role in generating cardiac action potentials. It begins by defining ion channels as pore-forming proteins that gate the flow of ions across cell membranes. It then describes the key properties of ion channels including selectivity, gating, and their role in establishing membrane potentials. The remainder of the document details the specific ion channels involved in each phase of the cardiac action potential, including the fast sodium current underlying the upstroke in Phase 0, the potassium and chloride currents producing Phase 1 repolarization, the calcium and potassium currents maintaining the Phase 2 plateau, and the currents responsible for Phase 3 repolarization. Pacemaker cell action potentials are also discussed, noting their unique pacemaker potential in Phase 4 and lack of Phase
Physiol 04 nervous system 1
This document discusses the physiology of coordination in the nervous system. It describes the different types of neurons found in animals and the functional divisions of the nervous system. The resting membrane potential is explained, which is normally around -90 mV due to mechanisms like the sodium-potassium pump and Donnan equilibrium. Ion concentrations differ inside and outside cells, with higher potassium and lower sodium and chloride inside. Ion permeability is selective, with potassium able to pass more easily than hydrated sodium ions. Diseases can impact ion concentrations and membrane potentials.
Introduction to body fluid & cell membrane
(I) The document discusses different types of transport across cell membranes, including diffusion, facilitated diffusion, active transport, and vesicular transport.
(II) It also discusses concepts like the Donnan effect, which describes how a nondiffusible ion on one side of a membrane affects the distribution of diffusible ions.
(III) The Gibbs-Donnan equilibrium establishes that at equilibrium, the concentration ratios of diffusible ions will be equal across a membrane permeable to some ions but not others.
Lecture 3 Dl.doc
1) The document discusses voltage-gated ion channels and how they generate action potentials. It provides historical context from Hodgkin and Huxley's experiments identifying sodium and potassium currents.
2) Single channel recordings show channels fluctuating between open and closed states, with open probability increasing with depolarization.
3) Voltage-gated sodium and potassium channels underlie the upstroke and repolarization of action potentials, respectively, through their changing open probabilities with membrane potential.
Cellular electrophysiology
this presentation on cellular electrophysiology carry the information of electrical properties of biophysiology in cellular level. i hope it help you all.
Resting membrane potential
The document discusses resting membrane potential in neurons. It defines resting membrane potential as the difference in charge between the inside and outside of a neuron membrane when the neuron is not conducting an action potential. The inside of the membrane is negatively charged at -70mV due to differences in sodium, potassium, calcium, and protein ion concentrations across the membrane and the selective permeability of the membrane to different ions. Ion channels and the sodium-potassium ATPase pump help maintain the ion gradients and resting membrane potential. Factors like axon diameter and myelination affect how quickly impulses propagate along neurons.
Membrane potentials
The document discusses membrane potentials, including resting membrane potential and graded and action potentials. Resting membrane potential is maintained by ion concentration gradients established by the sodium-potassium pump and differential membrane permeability. It varies between cell types but is around -70 mV for neurons. Graded potentials are caused by neurotransmitters and can summate to reach threshold for an action potential. Action potentials are rapid, regenerative changes in membrane potential triggered by voltage-gated sodium and potassium channels. They propagate along neurons to transmit signals in the nervous system.
Action potential and resting potential
The document discusses resting membrane potential and action potential in cells. At resting potential, the intracellular fluid is negatively charged compared to extracellular fluid due to higher potassium ion and chloride ion concentrations inside cells. This creates a potential difference of -60mV to -100mV across the cell membrane. During an action potential, the membrane becomes permeable to sodium ions, depolarizing the intracellular space until it reaches +20mV. Then, the membrane repolarizes back to its resting potential.
Membrane Potentials.
This document provides an overview of membrane potentials and resting membrane potential by Dr. Rashid Mahmood. It defines key terms like excitation, stimulus, and excitable tissues. It explains that the Nernst potential is the diffusion potential level that opposes net ion diffusion through a membrane. Diffusion potentials are +61 mV for sodium and -94 mV for potassium. The Goldman equation is used to calculate diffusion potential when multiple ions are involved. The resting membrane potential of large myelinated nerve fibers is approximately -90 mV, contributed to by the potassium diffusion potential of -94 mV, sodium diffusion potential of +61 mV, and the sodium-potassium pump of -4 mV.
Membrane potentials
Membrane potentials are electrical gradients created by differences in ion concentrations across cell membranes. The lipid bilayer structure of cell membranes allows selective permeability of ions like sodium, potassium, and chloride. Active transport of ions against their gradients by proteins like the sodium-potassium pump helps maintain concentration differences and the resulting membrane potential. Membrane potentials allow cells like neurons to transmit electrochemical signals and are essential for processes like cellular respiration that generate energy in living organisms.
1. lectura potencial de membrana
The membrane potential of excitable cells is determined by a balance of ion concentrations and electrical forces across the cell membrane. At rest, the membrane potential of skeletal muscle cells is approximately -95 mV, close to the potassium equilibrium potential, due to higher potassium conductance. Chloride conductance also contributes, acting to stabilize the membrane potential. During an action potential, sodium conductance dominates as sodium channels open, causing the membrane potential to rise close to the sodium equilibrium potential of around +40 mV.
Ion channel RECEPTOR
The document summarizes ion channels and ion channel receptors. It discusses several key points:
1) Ion channels transport specific ions across cell membranes and generate electrical signals. Voltage-gated and ligand-gated ion channels open and close in response to changes in membrane potential or ligand binding.
2) Common types of ion channels include voltage-gated sodium, potassium, and calcium channels, as well as ligand-gated channels like GABA, glycine, and glutamate receptors.
3) Ion channels play important physiological roles in nerve impulse conduction, muscle contraction, and other processes. Dysfunctions can lead to channelopathies and medical conditions. Many drugs target ion channels.
Cell Bio101
This document provides an overview of ion channels and transporters. It discusses that ion channels are integral membrane proteins that form pores to allow passive transport of ions across cell membranes. Ion channels can be voltage-gated, opening and closing in response to changes in membrane voltage, or ligand-gated, opening when neurotransmitters or other ligands bind. The document also describes different types of ion channels, including sodium, potassium, calcium, and anion channels. Additionally, it discusses ion transporters like uniporters and antiporters that actively transport ions against gradients using ATP.
Excitable tissue Physiology
1. Excitable tissues include nervous, muscle and glandular epithelial tissues. They have the ability to generate action potentials in response to stimuli.
2. Galvani discovered "animal electricity" by stimulating muscles in a frog's leg with two different metals, founding the field of electrophysiology. Volta proved the electricity came from the metals, not from within the animal.
3. The membrane potential of cells is measured using microelectrodes. At rest, excitable cells maintain a negative interior potential of around -70mV due to ion pumps and selective ion permeability.
Patch clamp lecture
This document discusses patch clamp electrophysiology as a technique for investigating ion channels and the action potential. It explains that patch clamping allows researchers to voltage clamp the membrane potential and measure currents through individual ion channels or populations of channels. This provides information about the voltage dependence and characteristics of sodium and potassium channels, which generate action potentials through their combined activity in response to changes in membrane potential. Patch clamping thus allows investigation of the interaction between ion channel activity at the microscopic level and changes in membrane potential at the macroscopic level.
Electrophysiology
Electrophysiology involves measuring electrical properties of cells and tissues using electrodes inserted into biological preparations. Common techniques include voltage clamp, current clamp, and patch clamp. Voltage clamp holds membrane potential constant and measures current, while current clamp injects current and measures potential. Patch clamp can record from single ion channels by forming a high resistance seal between a micropipette and cell membrane. Extracellular recordings like field potentials and single/multi-unit recordings measure activity of cells from outside the membrane. These techniques provide insights into neuronal signaling and brain function.
Patch Clamp Technique By Aqif Siddique
The document provides an overview of the patch clamp technique, which allows the study of single or multiple ion channels in cells. It describes the historical development of the technique from early experiments in electrophysiology to its refinement by Sakmann and Neher in the 1970s-1980s. The basic principle is explained, where a glass pipette applies suction to isolate a patch of cell membrane and measure current flow through ion channels. Different configurations are also summarized, including cell-attached, inside-out, and whole-cell recordings. Applications in areas like cardiac myocytes and drug development are highlighted. Recent research incorporates the technique into automated microfluidic chips.
More Related Content
What's hot
Sodium Ion Channel
Voltage gated sodium ion channels are transmembrane proteins that open in response to changes in the electric field across the cell membrane. They are responsible for initiating action potentials in neurons and other excitable cells. The channel is composed of alpha and beta subunits. The alpha subunit forms the core of the channel and has four homologous domains, each with six transmembrane helical segments. The beta subunits modulate the kinetics of activation. The selectivity filter of the channel is highly selective for sodium ions over other ions. The channel can exist in resting, activated, or inactivated states that control the passage of sodium ions. Sodium channels are the target of drugs used to treat conditions like epilepsy and cardiac arrhythmias.
voltage gated ion channel
This document presents a summary of a student's assignment on voltage-gated ion channels. It begins with an introduction to membrane ion channels and an outline of the presentation. It then discusses the basic structure and mechanism of voltage-gated ion channels, describing how the voltage sensor detects changes in membrane potential. The four major types of voltage-gated channels are identified as sodium, calcium, potassium, and chloride channels. Key details are provided about the structure and function of sodium and potassium channels.
Sodium channel modulators
DRUGS AFFECTING THE SODIUM CHANNEL BOTH BLOCKER AND OPENERS, STRUCTURE OF SODIUM CHANNEL AND ITS LOCATION. SODIUM CHANNEL GATTING MECHANISM BY WITCH THEY ACTING. TYPES OF SODIUM CHANNEL AND ITS FUCTIONS. THEIR THERAPEUTIC APPLICATION WITH EXAMPLES OF DRUGS.
The Nervous System2
The document discusses the structure and function of neurons and the nervous system. It covers topics such as sensory input and motor output, signal transmission through neurons via action potentials, synaptic transmission between neurons through neurotransmitters, and the role of glial cells in supporting neuronal function. Key points include that neurons transmit signals through electrical and chemical processes, synaptic transmission involves the release and binding of neurotransmitters, and glial cells provide insulation and structural/metabolic support to neurons.
Voltage Gated Calcium Channels (VGCC) and Its Role in Neurological Diseases
Voltage-gated calcium channels (VGCCs) play an important role in regulating brain, heart, and muscle function. Dysfunction of VGCCs can lead to neurological conditions and diseases. VGCCs mediate calcium entry from outside the cell and open in response to membrane depolarization. There are several types of VGCCs including L-type, N-type, and T-type calcium channels. VGCCs are involved in various pathways and diseases such as primary afferent pain pathways, thalamocortical circuitry, degeneration of dopaminergic neurons in Parkinson's disease, and drug addiction. Calcium channel blockers have been used successfully to treat some conditions and may be a potential therapeutic approach
cardiac ion channels and channelopathies
The document discusses ion channels and their role in generating cardiac action potentials. It begins by defining ion channels as pore-forming proteins that gate the flow of ions across cell membranes. It then describes the key properties of ion channels including selectivity, gating, and their role in establishing membrane potentials. The remainder of the document details the specific ion channels involved in each phase of the cardiac action potential, including the fast sodium current underlying the upstroke in Phase 0, the potassium and chloride currents producing Phase 1 repolarization, the calcium and potassium currents maintaining the Phase 2 plateau, and the currents responsible for Phase 3 repolarization. Pacemaker cell action potentials are also discussed, noting their unique pacemaker potential in Phase 4 and lack of Phase
Physiol 04 nervous system 1
This document discusses the physiology of coordination in the nervous system. It describes the different types of neurons found in animals and the functional divisions of the nervous system. The resting membrane potential is explained, which is normally around -90 mV due to mechanisms like the sodium-potassium pump and Donnan equilibrium. Ion concentrations differ inside and outside cells, with higher potassium and lower sodium and chloride inside. Ion permeability is selective, with potassium able to pass more easily than hydrated sodium ions. Diseases can impact ion concentrations and membrane potentials.
Introduction to body fluid & cell membrane
(I) The document discusses different types of transport across cell membranes, including diffusion, facilitated diffusion, active transport, and vesicular transport.
(II) It also discusses concepts like the Donnan effect, which describes how a nondiffusible ion on one side of a membrane affects the distribution of diffusible ions.
(III) The Gibbs-Donnan equilibrium establishes that at equilibrium, the concentration ratios of diffusible ions will be equal across a membrane permeable to some ions but not others.
Lecture 3 Dl.doc
1) The document discusses voltage-gated ion channels and how they generate action potentials. It provides historical context from Hodgkin and Huxley's experiments identifying sodium and potassium currents.
2) Single channel recordings show channels fluctuating between open and closed states, with open probability increasing with depolarization.
3) Voltage-gated sodium and potassium channels underlie the upstroke and repolarization of action potentials, respectively, through their changing open probabilities with membrane potential.
Cellular electrophysiology
this presentation on cellular electrophysiology carry the information of electrical properties of biophysiology in cellular level. i hope it help you all.
Resting membrane potential
The document discusses resting membrane potential in neurons. It defines resting membrane potential as the difference in charge between the inside and outside of a neuron membrane when the neuron is not conducting an action potential. The inside of the membrane is negatively charged at -70mV due to differences in sodium, potassium, calcium, and protein ion concentrations across the membrane and the selective permeability of the membrane to different ions. Ion channels and the sodium-potassium ATPase pump help maintain the ion gradients and resting membrane potential. Factors like axon diameter and myelination affect how quickly impulses propagate along neurons.
Membrane potentials
The document discusses membrane potentials, including resting membrane potential and graded and action potentials. Resting membrane potential is maintained by ion concentration gradients established by the sodium-potassium pump and differential membrane permeability. It varies between cell types but is around -70 mV for neurons. Graded potentials are caused by neurotransmitters and can summate to reach threshold for an action potential. Action potentials are rapid, regenerative changes in membrane potential triggered by voltage-gated sodium and potassium channels. They propagate along neurons to transmit signals in the nervous system.
Action potential and resting potential
The document discusses resting membrane potential and action potential in cells. At resting potential, the intracellular fluid is negatively charged compared to extracellular fluid due to higher potassium ion and chloride ion concentrations inside cells. This creates a potential difference of -60mV to -100mV across the cell membrane. During an action potential, the membrane becomes permeable to sodium ions, depolarizing the intracellular space until it reaches +20mV. Then, the membrane repolarizes back to its resting potential.
Membrane Potentials.
This document provides an overview of membrane potentials and resting membrane potential by Dr. Rashid Mahmood. It defines key terms like excitation, stimulus, and excitable tissues. It explains that the Nernst potential is the diffusion potential level that opposes net ion diffusion through a membrane. Diffusion potentials are +61 mV for sodium and -94 mV for potassium. The Goldman equation is used to calculate diffusion potential when multiple ions are involved. The resting membrane potential of large myelinated nerve fibers is approximately -90 mV, contributed to by the potassium diffusion potential of -94 mV, sodium diffusion potential of +61 mV, and the sodium-potassium pump of -4 mV.
Membrane potentials
Membrane potentials are electrical gradients created by differences in ion concentrations across cell membranes. The lipid bilayer structure of cell membranes allows selective permeability of ions like sodium, potassium, and chloride. Active transport of ions against their gradients by proteins like the sodium-potassium pump helps maintain concentration differences and the resulting membrane potential. Membrane potentials allow cells like neurons to transmit electrochemical signals and are essential for processes like cellular respiration that generate energy in living organisms.
1. lectura potencial de membrana
The membrane potential of excitable cells is determined by a balance of ion concentrations and electrical forces across the cell membrane. At rest, the membrane potential of skeletal muscle cells is approximately -95 mV, close to the potassium equilibrium potential, due to higher potassium conductance. Chloride conductance also contributes, acting to stabilize the membrane potential. During an action potential, sodium conductance dominates as sodium channels open, causing the membrane potential to rise close to the sodium equilibrium potential of around +40 mV.
Ion channel RECEPTOR
The document summarizes ion channels and ion channel receptors. It discusses several key points:
1) Ion channels transport specific ions across cell membranes and generate electrical signals. Voltage-gated and ligand-gated ion channels open and close in response to changes in membrane potential or ligand binding.
2) Common types of ion channels include voltage-gated sodium, potassium, and calcium channels, as well as ligand-gated channels like GABA, glycine, and glutamate receptors.
3) Ion channels play important physiological roles in nerve impulse conduction, muscle contraction, and other processes. Dysfunctions can lead to channelopathies and medical conditions. Many drugs target ion channels.
Cell Bio101
This document provides an overview of ion channels and transporters. It discusses that ion channels are integral membrane proteins that form pores to allow passive transport of ions across cell membranes. Ion channels can be voltage-gated, opening and closing in response to changes in membrane voltage, or ligand-gated, opening when neurotransmitters or other ligands bind. The document also describes different types of ion channels, including sodium, potassium, calcium, and anion channels. Additionally, it discusses ion transporters like uniporters and antiporters that actively transport ions against gradients using ATP.
Excitable tissue Physiology
1. Excitable tissues include nervous, muscle and glandular epithelial tissues. They have the ability to generate action potentials in response to stimuli.
2. Galvani discovered "animal electricity" by stimulating muscles in a frog's leg with two different metals, founding the field of electrophysiology. Volta proved the electricity came from the metals, not from within the animal.
3. The membrane potential of cells is measured using microelectrodes. At rest, excitable cells maintain a negative interior potential of around -70mV due to ion pumps and selective ion permeability.
What's hot (19)
Voltage Gated Calcium Channels (VGCC) and Its Role in Neurological Diseases
Voltage Gated Calcium Channels (VGCC) and Its Role in Neurological Diseases
Viewers also liked
Patch clamp lecture
This document discusses patch clamp electrophysiology as a technique for investigating ion channels and the action potential. It explains that patch clamping allows researchers to voltage clamp the membrane potential and measure currents through individual ion channels or populations of channels. This provides information about the voltage dependence and characteristics of sodium and potassium channels, which generate action potentials through their combined activity in response to changes in membrane potential. Patch clamping thus allows investigation of the interaction between ion channel activity at the microscopic level and changes in membrane potential at the macroscopic level.
Electrophysiology
Electrophysiology involves measuring electrical properties of cells and tissues using electrodes inserted into biological preparations. Common techniques include voltage clamp, current clamp, and patch clamp. Voltage clamp holds membrane potential constant and measures current, while current clamp injects current and measures potential. Patch clamp can record from single ion channels by forming a high resistance seal between a micropipette and cell membrane. Extracellular recordings like field potentials and single/multi-unit recordings measure activity of cells from outside the membrane. These techniques provide insights into neuronal signaling and brain function.
Patch Clamp Technique By Aqif Siddique
The document provides an overview of the patch clamp technique, which allows the study of single or multiple ion channels in cells. It describes the historical development of the technique from early experiments in electrophysiology to its refinement by Sakmann and Neher in the 1970s-1980s. The basic principle is explained, where a glass pipette applies suction to isolate a patch of cell membrane and measure current flow through ion channels. Different configurations are also summarized, including cell-attached, inside-out, and whole-cell recordings. Applications in areas like cardiac myocytes and drug development are highlighted. Recent research incorporates the technique into automated microfluidic chips.
Patch clamp technique
The patch clamp technique allows researchers to study single or multiple ion channels in cells. It involves forming a high resistance seal between a glass micropipette and a cell membrane to record electric currents. There are several variations of the technique, including cell-attached, inside-out, whole-cell, and outside-out patches, that provide different ways to manipulate and study ion channels. The patch clamp technique was developed in the 1970s-1980s and was a major breakthrough that enabled recording electric currents from single ion channels for the first time.
Patch clamp technique
The patch-clamp technique allows the study of single ion channels in cells. It was developed in the late 1970s and early 1980s by Erwin Neher and Bert Sakmann, who received the Nobel Prize for this work. There are different variations of the patch-clamp technique that provide access to the inside or outside of the cell membrane to study channel properties under various conditions. The technique uses a glass pipette pressed against a cell to form a high resistance seal and then precisely measures electric currents flowing through individual or multiple ion channels.
Patch clamp technique
The patch clamp technique allows for the study of single or multiple ion channels in cells. Developed in the 1970s-1980s by Sakmann and Neher, it involves pressing a glass pipette against a cell to form a high resistance seal, and then recording small currents through ion channels. There are different configurations (whole-cell, outside-out, etc) depending on the scientific question. Applications include evaluating drug interactions with ion channels and measuring electrophysiological properties of cells. Recent developments incorporate microfluidics for improved measurements.
Viewers also liked (6)
Similar to Lecture 1 Dl.ppt
Lecture 1 Dl.doc
This document outlines the goals and objectives of a lecture on ion transport through membrane transport proteins. Specifically, it will discuss:
1. The three main classes of membrane transport proteins - transporters, ion channels, and ATP-powered pumps - and how they differ in transport rates and energy utilization.
2. Uniporter-catalyzed transport through GLUT1 glucose transporters as a representative example, including the Michaelis-Menten kinetics of transport and the current model of GLUT1's transport mechanism.
3. How ion movement through ion channels serves electrical signaling roles by changing membrane potential and intracellular ion concentrations, allowing rapid cell-environment communication.
Membranes new
Biological membranes allow for the transmission of electrical signals in living cells and tissues. The resting membrane potential is maintained by selective ion channels and transport proteins that regulate ion concentrations. An action potential occurs when the membrane rapidly depolarizes due to sodium ion influx and repolarizes due to potassium ion efflux. Action potentials propagate along membranes and between neurons at synapses, allowing communication in the nervous system.
Ps1.Dl.doc
This document contains 4 practice problems about membrane potentials and ion concentrations:
1. It asks the reader to calculate equilibrium potentials for Na+, K+, and Ca2+ ions in a muscle cell based on given concentrations, and asks which ion the membrane is most permeable to at the peak of an action potential.
2. It asks the reader to calculate the membrane potential across mitochondria given concentrations of a lipid-soluble ion on both sides of the membrane.
3. It asks whether a neurotransmitter that opens proton channels would be excitatory or inhibitory given internal and external pH levels and the resting potential.
4. It asks about the Nernst equilibrium potential for Cl- in skeletal muscle
Ion channels
Ion channels are pore-forming membrane proteins that regulate the flow of ions across cell membranes. There are several types of ion channels classified by their gating mechanism and selectivity for specific ions like potassium, sodium, calcium, and chloride. Voltage-gated ion channels open or close in response to changes in membrane potential, while ligand-gated channels are activated by binding of neurotransmitters or other ligands. Ion channels play crucial roles in generating electrical signals in excitable cells and regulating various cellular processes. Diseases caused by mutations in ion channel genes are known as channelopathies.
Mechanism of transport of small molecules across membrane.pptx
This document discusses mechanisms of transporting small molecules across cell membranes. It begins by explaining that while some molecules like oxygen and carbon dioxide can diffuse through lipid bilayers, charged and polar molecules require transport mechanisms. It then describes three main types of transport - passive transport down concentration gradients or electrochemical gradients, active transport using transporter proteins and ion pumps, and transport through ion channels. Specific examples are given of aquaporin water channels, glucose and sodium symporters, calcium and sodium pumps, and different gated ion channels. The role of the sodium-potassium pump and potassium leak channels in generating the resting membrane potential is also explained.
Membrane Channels And Pump
》MEMBRANE CHANNELS AND PUMPS
1) INTRODUCTION:
2) MEMBRANE (COMPOSITION,STRUCTURE,SIGNIFICANCE )
3) TRANSPORT ACROSS MEMBRANE (SIMPLE DIFFUSION,
PASSIVE,ACTIVE)
4) MEMBRANE CHANNELS AND TYPES
5) MEMBRANE PUMP AND TYPES
6) COTRANSPORT: ●UNIPORT
●SYMPORT
●ANTIPORT
7) BULK TRANSPORT:●EXOCYTOSIS
●ENDOSMOSIS
●PINOCYTOSIS
SUMMERY
PLasma_membrane_transport_lecture__.pptx
The document discusses the movement of substances across cell membranes, including selective permeability, passive diffusion, active transport, and the mechanisms that drive these processes like concentration gradients and ATP hydrolysis. Specific examples covered include facilitated diffusion of glucose, active transport by the sodium-potassium pump, and ion channels that facilitate diffusion of ions like potassium. The role of these transport mechanisms in generating membrane potentials and propagating nerve impulses is also summarized.
1 Sem Chap-3 Neuromuscular phys..pptx
The nervous system allows animals to detect and communicate information about the external and internal environment. It has two main parts: the central nervous system (CNS) and peripheral nervous system (PNS).
Neurons are the basic functional units and carry electrical signals through their cell body, dendrites, and axon. The axon is covered by a myelin sheath that insulates and speeds up signal transmission. At nodes of Ranvier, gaps in the myelin allow signals to travel faster.
The resting membrane potential of neurons is around -70mV, created by ion concentration gradients and selective permeability to ions like potassium and sodium. When stimulated, neurons generate action potentials through changes in sodium and potassium permeability that
Excitable Cells: Revision Notes
The document provides an overview of several lectures on excitable cells and neuronal biophysics. It discusses key topics including:
- The structure and properties of water and its role as a solvent.
- The structure of biological membranes and how they use lipid bilayers.
- How cells use protein pumps and ion channels to regulate ion concentrations and transport ions across membranes.
- Techniques for measuring ion fluxes including radiotracers, fluorescent dyes, and electrophysiology.
- Concepts from Newtonian mechanics like Newton's laws of motion that are relevant to understanding neuronal biophysics.
Biomembranes new
This document summarizes different types of membrane transport proteins and how they transport molecules across cellular membranes. It discusses:
- Passive transport mechanisms like diffusion and facilitated diffusion.
- Active transport mechanisms like ATP-powered pumps that use ATP to transport molecules against their gradients. Examples given include the Na+/K+ ATPase pump and V-ATPase pump.
- Different classes of membrane transport proteins including channels, carriers, uniporters, symporters, antiporters and ABC transporters. Their structures and functions are described.
Resting membrane potential
To understand how neurons communicate, one must first understand the basis of the baseline or “resting” membrane charge.
Membrane potential and its ionic basis.
The membrane potential is the voltage difference between the interior and exterior of a cell membrane. It arises from differences in ion concentrations across the membrane. Key ions that contribute to the membrane potential include sodium (Na+), potassium (K+), calcium (Ca2+), and chloride (Cl-). The resting membrane potential of most cells is approximately -70mV, due primarily to higher intracellular potassium concentration compared to extracellular. Movement of potassium and sodium ions through membrane channels works to maintain this voltage difference at equilibrium.
RESTING MEMBRANE POTENTIAL BY DR QAZI IMTIAZ RASOOL
The document discusses electrical properties of cell membranes, including diffusion potentials and equilibrium potentials. It defines diffusion potential as the potential generated across a membrane when an ion diffuses down its concentration gradient. Equilibrium potential is the diffusion potential that exactly balances the tendency for diffusion. The Nernst equation is introduced for calculating the theoretical equilibrium potential for a given ion. The Goldman equation accounts for membranes that are permeable to multiple ions by taking a weighted average of the individual ion equilibrium potentials.
Cell d pharma 1st year Human anatomy and physiology
1. The document describes the structure and functions of a typical animal cell. It discusses the discovery of cells and outlines the components of cells, including the cell membrane, nucleus, and cytoplasm.
2. The cell membrane is made of lipids and proteins and acts as a selective barrier for the cell. Transport across the membrane can occur through passive diffusion, facilitated diffusion, or active transport powered by the cell.
3. The key components of cells are the cell membrane, nucleus, and cytoplasm. Cells are the basic structural and functional units that make up living organisms.
Channels
This document provides an overview of ion channels. It discusses how ion channels and transport proteins maintain homeostasis by regulating ion concentrations across membranes. It describes the key differences between channel and carrier proteins, noting that channels act like tunnels and carriers act like gates. The document outlines different types of ion channels including voltage-gated sodium channels, voltage-gated potassium channels, and voltage-gated calcium channels. It provides details on the structure and function of these channel proteins.
Plant physiolgy
1) Electrogenic pumps like the Na+/K+ ATPase transport ions across membranes using energy from ATP hydrolysis. This leads to a net movement of charge across the membrane.
2) Early models assumed passive ion diffusion established ion gradients, but problems arose. Equations were developed but inconsistencies emerged when applying them to plant cells.
3) The mechanism of the Na+/K+ ATPase involves ions binding deep within the protein and moving through access channels to binding sites. Transient currents from external ions like K+ and Na+ moving through these channels have been measured.
Chloride Channel / Ion Channels / Integral Membrane Proteins .pdf
This pdf is about the Chloride Channel / Ion Channels / Integral Membrane Proteins.
For more details visit on YouTube; @SELF-EXPLANATORY; https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Membrane Physiology
The document summarizes key concepts about cell membrane physiology:
The plasma membrane is a fluid lipid bilayer embedded with proteins. It uses different transport mechanisms like diffusion, facilitated diffusion, and active transport to control what moves in and out. Active transport uses ATP and transports substances against their concentration gradient, like the sodium-potassium pump maintaining sodium and potassium gradients. The membrane potential and action potentials allow cells to communicate via opening and closing of ion channels.
Ion Channels, Ion transport and Electrical Signalling
This document provides an overview of ion channels, transporters, and electrical signaling in neurons. It discusses how ion gradients across the neuronal cell membrane are established and maintained by ion pumps and transporters, and how these gradients give rise to the resting membrane potential. It describes how voltage-gated ion channels regulate the permeability of ions like sodium and potassium, allowing for the generation and propagation of action potentials, which transmit electrical signals along axons. Finally, it discusses how calcium channels mediate neurotransmitter release at synapses to enable communication between neurons.
Lecture 6
Diffusion is the random movement of molecules from areas of higher concentration to lower concentration. Osmosis is a type of diffusion where water moves through cell membranes from higher to lower concentrations, flowing into areas of higher solute concentration. The osmolarity, or total solute concentration, of extracellular fluid is normally higher than intracellular fluid, so water flows into cells by osmosis.
Similar to Lecture 1 Dl.ppt (20)
Mechanism of transport of small molecules across membrane.pptx
Mechanism of transport of small molecules across membrane.pptx
RESTING MEMBRANE POTENTIAL BY DR QAZI IMTIAZ RASOOL
RESTING MEMBRANE POTENTIAL BY DR QAZI IMTIAZ RASOOL
Cell d pharma 1st year Human anatomy and physiology
Cell d pharma 1st year Human anatomy and physiology
Chloride Channel / Ion Channels / Integral Membrane Proteins .pdf
Chloride Channel / Ion Channels / Integral Membrane Proteins .pdf
Ion Channels, Ion transport and Electrical Signalling
Ion Channels, Ion transport and Electrical Signalling
Lecture 1 Dl.ppt
- 1. • Ion Channels Lecture 1 –Nernst Equation, Ohm’s Law, Patch Clamp Permeation and Gating
- 2. Learning Objectives 1. Know the classes of all membrane transport proteins and distinguish them according to rates of transport. 2. Know the transporter reconstitution into liposomes method of studying the transport process. 3. Describe Glucose transport through GLUT1 transporters as an example of a uniport- catalyzed transport system. Know the mechanism thought to account for transport through uniporters. 4. Understand how distribution of unbalanced charges at the membrane boundary accounts for membrane potentials. 5. Know the distribution (low vs. high) of the four major ions in most mammalian cells. 6. Know the thermodynamic derivation of the Nernst Equation and be comfortable explaining it qualitatively. 7. Given a membrane potential be able to determine the flow of ions (for a particular distribution in and out of the cell) considering the relative magnitude and direction of the chemical and electrical forces. 8. Be able to use Ohm’s law to determine the currents flowing through the cell membrane. 9. Given a membrane potential be able to determine the flow of ions (for a particular distribution in and out of the cell) considering Ohm’s Law. 10. Know the different types of Ion Channels and the major features they possess. 11. Understand how the balance of currents determines the membrane potential. 12. Know the voltage clamp and all modes of the patch clamp techniques. 13. Predict how ion flux through a particular ion channel will influence the membrane potential. 14. Understand how K ion selectivity, permeation and gating occurs.
- 6. From: Structure and function of facilitative sugar transporters. Barrett et al, Current Opinion in Cell Biology 11, 496-502 (1999).
- 10. Distribution of Ions and the Resting Potential Na+ = 145 mM Ca++ = 2 mM K+ = 5 mM Cl- = 125 mM Na+ = 15 mM Ca++ = .0001 mM K+ = 145 mM Cl- = 10 mM
- 11. Equlibrium potentials for major permeable ionic species In myocytes: ENa = 61.5 log (145/15) = + 60 mV ECa = 61.5 log (2/.0001) = + 131 mV ECl = -61.5 log (125/ 10) = - 67 mV EK = 61.5 log (5/ 145) = - 89 mV
- 21. Atomic Resolution Structures Selectivity and Permeation
- 40. Inwardly rectifying K channels
- 41. Permeation pathways of Kir3.4 in a “closed” state and Kv1.2 in an “open” state
- 42. From Nishida et al., 2007 EMBO J 26:4005-4015
- 43. PIP2 and the cytoplasmic gates
Editor's Notes
- In the normal myocyte, depolarization results from inward sodium current. The plateau phase results from a balance of inward calcium current and outward potassium current, and finally, repolarization results from unopposed outward potassium current.
- The Figure shows the transmembrane permeation pathways a) of a model of the Kir3.41,2,3 channel that is gated open by the subunits of G proteins (G)4 but in their absence is thought to reside in the closed state (left), and b) the equivalent region of the Kv1.2 channel that is gated open by membrane depolarization and in the crystallographic snapshot shown5,6 it is thought to be partially open (right). The transmembrane pores of these two very different channels reveal a strikingly similar design with interesting variations. Substitutions of a prokaryotic pore into eukaryotic Kir or Kv channels have produced chimeric channels that have retained the respective functional hallmarks of the eukaryotic channels, indicating that the ion conduction pore is indeed conserved among K+ channels7 and that our approach of closely comparing the gating apparatus of Kir3.4 with that of Kv1.2 is likely to yield a detailed understanding of their similarities that serve both channels and their differences that serve specifically one or the other type of channel. Two Gates and control of the SF gate: Water and ions filling the permeation pathway (shown in blue) give a visual appreciation of the location of two putative gates: the Selectivity Filter (SF or extracellular gate) and the Inner Helix (TM2) Bundle Crossing (HBC or intracellular gate)8. The SF not only selects K+ over other ions but also serves as a gate. It possesses the triplet GYG, which is the most highly conserved motif among K+ channels. The HBC gate seems to be localized at exact corresponding positions in the two channels (Kir3.4 F1879 and Kv1.2 V40910). Systematic mutagenesis of each Kv1 residue shown in the structure has identified two clusters of mutants that affect gating: one where each inner helix contacts the Pore Helix (P-HLX) and the other where the inner helices cross each other at the HBC11. The SF gate of Kir3.4 seems to also be controlled by residues in its vicinity localized at the P-HLX or the P-loop (e.g. Kir3.4 S143 and Kir3.4 E147)12, 13, 14. LABEL THE HBC, Slide HLX/S4-S5 LNK, P-HLX, TM1, TM2