Cholinergic Agents

Question 1

Acetylcholine (Ach)

Answer 1

Neurotransmitter that plays a critical role in muscle contraction and restriction

Question 2

Nicotinic receptors

Answer 2

Bound by nicotine
When Ach binds, channels are opened, and the nerve is depolarized, leading to muscular contraction or continuation of the nerve impulse

Question 3

N1 receptors

Answer 3

Located at neuromuscular junction

Question 4

N2 receptors

Answer 4

Located in autonomic nerves

Question 5

Muscarinic receptors

Answer 5

Bound by muscarine or Ach
Regulate organs innervated by the autonomic nervous system to maintain homeostasis
7-domain G-protein coupled receptors

Question 6

M1 receptors

Answer 6

Wide variety of functions, including REM sleep, emotional regulation, and gastric secretion

Question 7

M2 receptors

Answer 7

Also called cardiac muscarinic receptors

Function in respiration

Question 8

M3 receptors

Answer 8

Stimulate glandular secretions and contract smooth muscle

Question 9

M4 receptors

Answer 9

Act on G proteins to inhibit cAMP (secondary messenger)

Question 10

Cholinergic receptors can be selective based on…

Answer 10

Stereochemistry

Question 11

5-atom rule

Answer 11

Muscarinic activity is maximized by a chain of 5 carbon atoms following a quaternary ammonium group

Question 12

Cholinergic agents SAR

Answer 12

Alpha and beta substitutions (relative to N) decrease cholinergic activity
Alpha: greater muscarinic change
Beta: greater nicotinic change

Question 13

Acetylcholinesterase

Answer 13

Catalyzes the hydrolysis of Ach to choline and acetic acid

Question 14

Butyrylcholinesterase

Answer 14

Biological function isn’t clear (has catalytic properties similar to acetylcholinesterase)

Question 15

Carbamates

Answer 15

Semi-reversible inhibitors of acetylcholinesterase

Question 16

Organophosphates

Answer 16

Irreversible inhbitors of acetylcholinesterase

Question 17

Cholinergic blocking agents

Answer 17

Inhibit the effect of Ach on cholinergic receptors

SAR: structurally similar to Ach but with additional substituents (hydroxyl group, cyclic substitution)

Question 18

Parasympathetic postganglionic blocking agents

Answer 18

3 therapeutic effects: dilation of pupils, slowing down of digestion, decrease in secretions

Question 19

Synthetic cholinergic blocking agents

Answer 19

Aminoalcohol esters (bind tightly to M1 and M3 receptors)
Aminoalcohol ethers
Aminoalcohols
Aminoamides

Question 20

Ganglionic blocking agents

Answer 20

Nondepolarizing competitive or nondepolarizing noncompetitive (treat hypertension by blocking sympathetic pathways)

Question 21

Neuromuscular blocking agents

Answer 21

Block transmission of Ach at the motor end plate

Relax skeletal muscle during surgical anesthesia

Question 22

Nondepolarizing blocking agents

Answer 22

Compete with Ach at the end plate receptors

Question 23

Depolarizing blocking agents

Answer 23

Desensitize end plate through repeated bombardment of Ach