Autonomics II: Cholinergic Receptor-Activating Drugs

Question 1

Nicotinic Nn (N2) locations and result of ligand binding

Answer 1

Postganglionic neurons, some presynaptic cholinergic terminals. opens Na, K channels, and depolarizes

Question 2

Nicotinic Nm (N1) locations and ligand binding

Answer 2

skeletal muscle and neuromuscular end plates. opens Na, K channels, depolarizes

Question 3

Muscarinic M1 locations and ligand binding

Answer 3

CNS neurons, sympathetic postgang neurons, some presynaptic sites. forms IP3 and DAG, increases intracellular calcium

Question 4

Muscarinic M2 locations and ligand binding

Answer 4

myocardium, smooth muscle, some presynaptic sites; CNS neurons. opens potassium channels, inhibits adenylyl cyclase

Question 5

Muscarinic M3 locations and ligand binding

Answer 5

exocraine glands, vessels (smooth muscle and endothelium), and CNS neurons. like M1 receptor ligand binding (forms IP3 and DAG, increases calcium in cell)

Question 6

Muscarinic M4 locations and ligand binding

Answer 6

CNS neurons, possibly vagal nerve endings. Like M2 receptor ligand binding (opens potassium channels, inhibits adenylyl cyclase)

Question 7

Muscarinic M5 locations and ligand binding

Answer 7

Vascular endothelium, especially cerebral vessels. CNS neurons. Like M1 receptor-ligand binding

Question 8

how did they determine roles of receptors?

Answer 8

knock out mice studies

Question 9

do muscarinic agonists show selectivity?

Answer 9

no, they show no selectivity between the 5 receptor types. some nicotinic agonists show selectivity towards Nn rather than Nm receptors.

Question 10

direct acting cholinomimetics

Answer 10

bind to and activate muscarinic or nicotinic receptors

Question 11

indirect acting cholinomimetics

Answer 11

inhibit action of acetylcholinesterase, which hydrolyzes Ach to choline and acetic acid. increase endogenous Ach in the clefts and junctions, evoking increased responses

Question 12

primary cardiovascular effects of mascarinic agonist infusion

Answer 12

reduction in peripheral resistance due to vasodilation and changes in heart rate. acute for acetylcholine, but longer lasting for choline ester analogues and non esters. vasodilation due to muscarinic receptor induced NO (EDRF) production in endothelial cells causing relaxation of vascular smooth muscle

Question 13

primary effects of muscarinic agonist infusion in eye

Answer 13

reduces intraocular pressure by causing contraction of the ciliary body

Question 14

most important use of indirect acting cholinesterase inhibitors

Answer 14

insecticides.

Question 15

what does pralidoxime do?

Answer 15

reactivates the enzyme removes the inhibitory phosphate group! can be used as a cure to people poisoned with cholinesterase inhibitors

Question 16

what happens when you overdose and how can you fix it?

Answer 16

miosis, nausea, vomiting, diarrhea, salivation, sweating, cutaneous vasodilation, bronchial constriction. (SLUDGE)
blocked by atropine