Pharmacology ofCHOLINERGIC SYSTEM<br />Dr.U.P.Rathnakar<br />MD.DIH.PGDHM<br /> R<br />
ANS<br />Clinically Relevant<br />Hypertension<br />Angina<br />Benign Prostatic <br />Hypertrophy <br />Heart Failure<br ...
Peripheral Nervous system<br />
Flight, Fight and Fright<br />Sit & Digest<br />Sympathetic<br />P.Sympathetic<br />
Parasympathetic outflow:Cranio-sacral<br />
Cholinergic system<br />NN<br />NN<br />NN<br />NM<br />M12345<br />
Cholinergic Transmission<br />
Steps in neurotransmission: <br />Impulse conduction<br />Arrival of impulse<br />Synthesis, Storage & release<br />of tra...
Inhibitory[IPSP]</li></ul>Termination of <br />neurotransmitter action<br />		[Diffusion, destruction, <br />			reuptake]<...
Pharmacology of cholinergic system<br />Ach and Cholinomimitics<br />Anticholinesterases<br />OP poisoning			<br />Glaucom...
Acetylcholine (ACh):<br />		Ach is synthesized in the cholinergic nerve endings.<br />		   ATP <br />		+ Acetate <br />		+...
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Cholinergic system Class I


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  • Ach not clinically used but…..These drugs act on vagusimpulses
  • Not by iv why?
  • Late onset
  • Late onset
  • Cholinergic system Class I

    1. 1. Pharmacology ofCHOLINERGIC SYSTEM<br />Dr.U.P.Rathnakar<br />MD.DIH.PGDHM<br /> R<br />
    2. 2. ANS<br />Clinically Relevant<br />Hypertension<br />Angina<br />Benign Prostatic <br />Hypertrophy <br />Heart Failure<br />Alzheimer’s Disease<br />Anaphylactic Shock <br />Asthma <br />
    3. 3. Peripheral Nervous system<br />
    4. 4. Flight, Fight and Fright<br />Sit & Digest<br />Sympathetic<br />P.Sympathetic<br />
    5. 5. Parasympathetic outflow:Cranio-sacral<br />
    6. 6. Cholinergic system<br />NN<br />NN<br />NN<br />NM<br />M12345<br />
    7. 7. Cholinergic Transmission<br />
    8. 8. Steps in neurotransmission: <br />Impulse conduction<br />Arrival of impulse<br />Synthesis, Storage & release<br />of transmitter<br />Combination of transmitter<br /> with P.J. receptors <br />Postjunctional activity: <br /><ul><li>Excitatory[EPSP] or
    9. 9. Inhibitory[IPSP]</li></ul>Termination of <br />neurotransmitter action<br /> [Diffusion, destruction, <br /> reuptake]<br />
    10. 10.
    11. 11. Pharmacology of cholinergic system<br />Ach and Cholinomimitics<br />Anticholinesterases<br />OP poisoning <br />Glaucoma/Ganglion blockers<br />Antimuscarinics<br />Skeletal muscle relaxants<br />
    12. 12. Acetylcholine (ACh):<br /> Ach is synthesized in the cholinergic nerve endings.<br /> ATP <br /> + Acetate <br /> + CoEn-A <br />Acetylcholine + CoEn-A<br />= Acetyl CoEn-A<br /> + Choline acetyl transferase<br />Choline<br />
    13. 13. Synthesis and Release of Acetylcholine<br />[Cholinergic transmission] <br />
    14. 14. Modification of synthesis & release of ACh<br />Hemicholinium blocks choline uptake<br />Vesamicol blocks vesicular uptake of ACh.<br />Botulinum toxin prevents the release of ACh<br />Black widow spider toxin induces massive release and depletion of ACh.<br />Anticholinesterases<br />
    15. 15. Black widow spider<br />
    16. 16. The male of the species deliberately seeks out a 'fat' female who is full-up before mating<br />
    17. 17. Cholinoceptors<br />Muscarinic(M) – M1,M2,M3,M4&M5<br /> Nicotinic ( N ) – NM & NN.<br /> M – G-protein coupled receptor.<br /> N - Ion channel receptor.<br />
    18. 18. Subtypes and Characteristics of Cholinoceptors<br />Location<br />Rec types<br /> G<br /> P<br /> C<br /> R<br />Gastric glands, Autonomic ganglia & CNS<br />M1<br />SA node, AV node, Atrium, Ventricle, Auto rec., <br />M2<br />Visceral smooth muscle, Iris, Ciliary muscle, Exocrine glands, Vascular endothelium.<br />M3<br />CNS<br />M4<br />M5<br />Ion<br />Channel<br />NM junction<br />NM<br />Autonomic ganglia, Adrenal gland.<br />NN<br />
    19. 19. Location of cholinergic receptors:<br />M1: Gastric glands, Autonomic ganglia & CNS.<br />M2: SA node, AV node, Atrium, Ventricle, <br /> Cholinergic nerve endings.<br />M3 : Visceral smooth muscle, Iris, Ciliary<br /> muscle, Exocrine glands, Vascular endothelium.<br />M4 & M5 : Brain<br />NM : Neuromuscular junction.<br />NN : Autonomic ganglia, Adrenal gland.<br />
    20. 20. Metabolism of ACh:<br />ACh is metabolized by <br />acetylcholinesterase.<br />1.Acetylcholinesterase (True) :<br />Cholinergic sites, RBC, <br />Gray matter.<br />2.Pseudocholinesterase:<br />Plasma, Liver, Intestine, <br />White matter.<br />+<br />Acetylcholinesterase<br />
    21. 21. Metabolism of ACh:<br />By Acetylcholinesterase[AChE]<br />Acetyation<br />[Ach]<br />[AChE]<br />Choline<br /><1msec<br />
    22. 22. Cholinesterases<br />True<br />Pseudo<br />Butyrylcholinesterase<br />Liver, plasma<br />Slow<br />Sensitive<br />-OrganoPhospahtes<br />Hydrolysis of ingested esters<br />Pseudocholinesterase deficiency and succinylcholine<br />Acetylcholinesterase <br />Cholinergic sites, RBC<br />Fast<br />Sensitive –Physostigmine<br />Termination of Ach action<br />
    23. 23. Pharmacological actions of AcH<br />[Effects of Parasympathetic system]<br />SIT<br />REST<br />DIGEST<br />
    24. 24.
    25. 25. Ach on CNS<br />Does not cross BBB<br />Ach on Eye<br />Ach on Heart<br />
    26. 26. Ach on BV<br />Ach on GIT<br />Ach on RS<br />
    27. 27. Ach on UB<br />Ach on Exocrine glands<br />
    28. 28.
    29. 29. Actions of ACh: <br />ORGAN RESPONSE<br />EYE<br />Iris Miosis<br />Ciliary muscle Contraction for near vision <br />HEART<br />SA Node -ve chronotropy<br />Atria -ve inotropy<br />AV Node -ve dromotropy[conduction] <br />Ventricle Small decrease in contractile strength<br />BLOOD VESSELS<br />Arteries Dilation[EDRF], constriction-direct, high dose <br />Veins --------”””””””---------- <br />LUNG<br />Bronchial muscle Constriction <br />Bronchial glands Secretion <br />GIT<br />Motility Increase <br />Spincters Relax <br />Secretion Stimulation <br />SIT<br />REST<br />DIGEST<br />URINARY BLADDER<br />Detrusor Contraction <br />Trigone & Spincter Relaxation <br />GLANDS<br />Sweat, salivary,lacrimal, nasopharyngeal Secretion <br />
    30. 30. Actions of ACh: (Muscarinic)<br />Heart[Cardiac glycosides, antiarrhythmic agents,] <br /> Decrease in heart rate.<br />Decrease in contractile strength.<br />Decrease in conduction velocity.<br />Increase in refractory period.<br />Blood Vessels<br />Vasodilatation due to release of EDRF (Endothelium dependent relaxing factor) which is ‘NO’.<br />Also coronary<br />Symp/P.Symp interaction-not simple<br />
    31. 31. Actions of ACh: (Muscarinic)……..<br />Smooth muscle <br /> Contraction<br />Glands<br /> Secretions are increased.<br />Eye<br />Miosis.<br /> Spasm of accommodation.<br /> Decrease in intraocular tension. <br />
    32. 32. Cholinergic Drugs<br />[Cholinomimitics]<br />[Cholinergic <br />Agonists]<br />[Anticholinesterases]<br />
    33. 33. Cholinergic Agonists[Agonists]<br />Cholineesters<br />Acetylcholine<br />Methacholine<br />Carbachol<br />Bethanechol<br />Alkaloids<br />Pilocarpine<br />Muscarine<br />Arecoline<br />
    34. 34. Properties of Choline Esters<br />Uses<br />Ach-too short acting & non selective<br />Methacholine-PSVT-Obsolete<br />
    35. 35. Bethanochol<br />Therapeutic Uses:<br />To reverse Non obstructive urinary retention as in post-operative atony of bladder and neurogenic bladder.<br />To treat GIT atony without obstruction as in paralytic ileus.<br />Cevimeline-(EVOXAC) is a newer muscarinic agonist available orally for use in treatment of xerostomia<br />
    36. 36. Pilocarpine:[Pilocarpine is too toxic for systemic use]<br />Actions: Mainly muscarinic<br />[Initial]---- Fall of BP [Peripheral]<br />[Persistent]--- Rise in BP[Ganglionic]<br />Therapeutic uses:<br />Opthalmicuse: ( Eye drops) <br />Open angle glaucoma.<br />To counteract mydriasis.<br />In iridocyclitis to break adhesions <br /> between iris and lens.<br />This action exception to pilocarpine<br />
    37. 37. Muscarine:Muscarine occurs in poisonous mushrooms:<br />Symptoms of muscarine actions<br />Reversed by Atropine<br />Early mushroom poisoning<br />Inocybe<br />
    38. 38. Late mushroom poisoning<br />Symptoms of mucosal damage[GIT, Liver, Kidney-inhibition of RNA synthesis]<br />Supportive tt[No sp tt]<br />Amanita phalloides<br />Majority of fatal mushroom poisonings worldwide<br />
    39. 39. Hallucinogenic type<br />Blockmuscarinic receptors in brain-Hallucination<br />Atropine is contra indicated!<br />Pilocybe Mexicana<br />
    40. 40. Folk traditions concerning the defining features of poisonous mushrooms<br />Fly agaric<br />Non-poisonous<br />Destroying angel<br />Poisonous!<br />Poisonous mushrooms are brightly colored<br />
    41. 41. Folk traditions concerning the defining features of poisonous mushrooms<br />Poisonous!<br />Insects/animals will <br />avoid toxic mushroom<br />Poisonous mushrooms taste bad<br />
    42. 42. Anticholinesterases[Indirectly acting cholinergics]<br />Reversible anticholinesterases<br />CarbamatesAcridine<br />Tacrine.<br />Physostigmine<br />Neostigmine<br />Pyridostigmine<br />Edrophonium<br />Ambenonium<br />Demecarium<br />Rivastigmine, <br />Donepezil, <br />Galantamine.<br />Irreversible anticholinesterases<br />
    43. 43. Irreversible anticholinesterases<br />Organophosphates: Carbamates:<br />Carbaryl*<br />Propoxur*<br />Echothiophate<br />Parathion*<br />Malathion*<br />Diazinon*<br />Tabun#<br />Sarin#<br />Soman#<br />*Insecticides<br /># Nerve gases-chemical warfare<br />a<br />