Cholinergic Agonists

Direct Acting

(4)

a) acetylcholine

b) bethanechol

c) carbachol

d) pilocarpine

Cholinergic Agonists

Indirect acting (reversible)

a) Edrophonium

b) Neostigmine

c) Physostigmine

e) Pyridostigmine

Cholinergic Agonists

Indirect Acting - irreversible

(2)

a) Echothiophate

b) Isoflurophate

Reactivation of acetylcholine esterase

(1)

Pralidoxime

Muscarinic Receptors

Binds, Subclasses, Antagonist (1)

a) Bind - acetylcholine and muscarine (in posionous mushrooms)

b) Subclasses - M1 & M3 (Gq/increase Ca); M2 (Gi/inhibits adenyl cyclase and increases K conductance)

c) Pirenzepine - trycyclic anticholinergic drug, selectively inhibits M1 muscarinic receptors like the gastric mucosa.  Treat gastric and duodenal ulcers.

Nicotinic Receptors

Bind, Blockers (2)

a) Binds - acetylcholine and nicotine (stimulates then blocks);

b) Hexamethonium - selectively blocks ganglionic receptors;

c) Tubocurarine - blocks neuromuscular junction receptors.

Acetylcholine

General

a) neurotransmitter of parasympathetic and cholinergic nerves; Has both muscarinic and nicotinic activity;

b) not used b/c: 1) multiplicity of actions; 2) rapid inactivation by acetylcholinesterase;

c) Decrease in HR and CO.

d) Decrease in BP/vasodilation

e) Atropine - blocks muscarinic receptors and prevents acetylcholine from producing vasodilation;

f) in GI increases salivary secretion and motility