Cholinergic Receptors (Direct & Indirect Agonists)

Question 1

What are the main actions of M1, M2, and M3?

Answer 1

M1: Enteric and CNS
M2: Heart depression
M3: Vasodilation, Gland secretion, GI smooth muscle contraction, Miosis

Question 2

What are the direct agonists of aceytlcholine?

Answer 2

Metacholine and Bethanechol. Both are more resistant to hydrolysis than ACh

Question 3

What are the 3 groups of indirect acting cholinomimetics?

Answer 3

1. Simple alcohols (short DOA)
2. Carbamic acid esters (Intermediate DOA)
3. Organic derivatives of phosphoric acid (Long lasting DOA)

Question 4

Discuss Edrophonium

Answer 4

(Simple Alcohol)Reversibly binds to cholinesterases, preventing ACh from binding them. Used to test myasthenia gravis

Question 5

Name the carbamates

Answer 5

Neostigmine, pyridostigmine

Question 6

Name the organophosphates

Answer 6

Parathion, malathion, soman and sarin

Question 7

Discuss the toxicity of cholinomimetics

Answer 7

SLUDGE; salivation, lacrimation, urination, defecation, GI motility, Eye miosis

Question 8

What 2 pathological circumstances can AChE inhibitors be useful?

Answer 8

1. Myasthenia gravis: AChE inhibitors enhance action of ACh at NMJs
2. Alzheimer Disease: AChE inhibitors slow progression of symptoms.