Cholinergic Pharmacology

Question 1

Muscarinic Agonists

Answer 1

Pilocarpine, Ach, Carbachol, Oxotremorine, Bethanechol
Cardiac inhibition
Vasodilation
Contraction of smooth muscle
Pupil constriction
Gland secretion
Selectives: M3(Cevimeline)

Question 2

Muscarinic Antagonists

Answer 2

Atropine (replaced by charged glycopyyronium), Tiotropium, Oxybutynin, Ipratropium, Dicycloverine
Opposite effects to Agonists
Competitively bind muscarinic receptors and dampen parasympathetic input
Blind as a bat, mad as a hat, hot as a flirt, dry as dirt , red as a yurt
Selectives: M1(Pirenzepine), M2(Gallamine)

Question 3

Muscular Nicotinic

Answer 3

At NMJ
Increase ion permeability
Agonists: Ach, Carbachol, Succinylcholine (depolarising mucle block)
Antagonists: Tubocurarine, Vecuronium, alpha Bungarotoxin, Atracurium, Pancuronium, alpha Conotoxin

Question 4

Ganglionic Nicotinic

Answer 4

Autonomic Ganglia, post-synaptic
Increase ion permeability
Agonists: Ach, Nicotine, Carbachol, Epibatidine
Antagonists: Mecamylamine, Trimetaphan, Hexamethonium, alpha Conotoxin

Question 5

Neuromuscular Blocking Agents

Answer 5

Non-Depolarising: Tubercararine- Competitive antagonists at NMJ which prevent receptor activation
Depolarising: succinylcholine, suxamethonium creates a depolarising block by repeatedly depolarising the NMJ until it is unexcitable

Question 6

Anticholinesterases

Answer 6

Reversible: Edrophonium, Distigmine, Physostigmine, Neostigmine bind transiently to enzyme instead of Ach
Irreversible: Organophosphates bind to enzyme premanently

Oxime Reactivators (Pralidoxime) reverse poison

Question 7

Pre-Synaptic Drugs

Answer 7

Hemocholinium- Blocks choline entering nerve terminal
Vesamicol- Blocks Ach from entering vesicles
Streptomycin and Neomycin- Inhibit Ca entry into nerve
Botulinum Toxin- Inhibits Ach release into synapse

Question 8

CNS Nicotinic

Answer 8

The brain pre and post-synaptic
Increase ion permeability, regulate release of glutamate and dopamine post-synaptically
Agonists: Nicotine, Ach, Cytosine, Varenicline, Epibatidine
Antagonists: Mecamylamine, Methylaconitine, alpha bungarotoxin, alpha conotoxin