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Pharmacology FINAL > Lecture 8 > Flashcards

Lecture 8 Flashcards

1
Q

what kind of receptors are muscarinic receptors

A

G-protein coupled receptors

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2
Q

what kind of receptors are nicotinic receptors

A

cation-selective ion channels

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3
Q

muscarinic receptors contain ______ transmembrane domains.

the ____ cytoplasmic loop is coupled to _______ that function as _______

A

7 transmembrane domains

3rd cytoplasmic loop is coupled to G proteins that function as TRANSDUCERS

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4
Q

true or false

all muscarinic receptors are GPCR’s

A

true

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5
Q

location of M1

A

nerves

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6
Q

location of M2

A

heart
nerves
smooth muscle

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7
Q

location of M3

A

glands
smooth muscle
endothelium

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8
Q

location of M4

A

CNS

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9
Q

location of M5

A

CNS

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10
Q

what is another name for M2

A

cardiac M2

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11
Q

postreceptor mechanism of M1

A

IP3, DAG cascade
(Gq!)

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12
Q

postreceptor mechanism of M2

A

Gi

inhibits cAMP production, activates K+ channels
results in decreased heart rate - good for HTN pts

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13
Q

post receptor mechanism of M3

A

IP3, DAG cascade
(Gq!)

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14
Q

postreceptor mechanism of M4

A

inhibits cAMP production

Gi

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15
Q

postreceptor mechanism of M5

A

IP3, DAG cascade (Gq)

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16
Q

structural features of M1, M3, M5

A

seven transmembrane segments
Gq/11 protein-linked

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17
Q

structural features of M2, M4

A

seven transmembrane segments
Gi/o protein-linked

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18
Q

TRUE OR FALSE

NM and NN have the same postreceptor mechanism

A

TRUE

Na+, K+ depolarizing ion channel

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19
Q

location of Nm

A

skeletal muscle – neuromuscular junction

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20
Q

location of Nn

A

CNS -
postganglionic cell body, dendrites

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21
Q

structural features of Nn, Nm

A

pentamer

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22
Q

early studies on the effects of muscarine were termed……..
what does this mean?

A

parasympathomimetic

does not increase the amount of neurotransmitter, but mimics the neurotransmitter

muscarine has action on receptors on effector cells

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23
Q

alkaloid nicotine stimulates _________ but NOT _______

A

stimulates autonomic ganglia and NMJ at skeletal muscle, but NOT autonomic effector cells

relaxes our muscles and makes us feel good

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24
Q

name 2 types of drugs that can be considered cholinergic agonists, but 1 is direct and 1 is indirect

A

DIRECT = drugs that activate cholinoreceptors. true agonists

INDIRECT = cholinesterase inhibiting drugs. not a true agonist, but produces the same effect by preventing the degradation of ACh

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25
Q

what can be considered ACh “amplifiers”

A

cholinesterase inhibiting drugs

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26
Q

true or false

a drug cannot be selective to nicotinic or muscarinic receptors

A

FALSE - they can

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27
Q

explain how some drugs are selective for certain nicotinic receptors

A

some drugs stimulate the nicotonic receptors at NMJ and have less effect on the nicotinic receptors in the autonomic ganglia

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28
Q

how can organ selectivity of drugs for nicotonic/muscarinic receptors be achieved?

give an example

A

by using different routes of administration

muscarinic stimulants can be administered to the eye to modify ocular function while also minimizing systemic side effects

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29
Q

what is “pharmacokinetic selectivity”

A

achieving organ selectivity by using different routes of administration

30
Q

which cholinoreceptor is found in the nerves

A

M1 (also M2 but mainly M1)

31
Q

which Cholinoreceptor is found in the heart and smooth muscle?

A

M2

(M3 also smooth muscle)

32
Q

which cholinoreceptor is found in the glands and endotheloium?

A

M3

33
Q

name 2 types of drugs that are DIRECT ACTING cholinergic stimulants

A

choline and carbamic acid esters

cholinomimetic alkaloids

34
Q

name 2 types of drugs that are indirect acting cholinergic stimulants

A

carbamates
organophosphates

35
Q

true or false

cholinomimetic alkaloids are indirect acting cholinergic stimulants

A

FALSE - direct acting

36
Q

true or false

carbamates are indirect acting cholinergic stimulants

A

true

37
Q

name 4 cholinomimetic alkaloids

are they direct acting or indirect acting?

A

DIRECT ACTING

muscarine
pilocarpine
nicotine
lobeline

38
Q

name 4 carbamates that are cholinergic stimulants

are they direct or indirect acting?

A

INDIRECT ACTING

neostigmine
carbaryl
physostigmine
edrophonium

39
Q

name 4 organophosphates

are they direct or indirecting cholinergic stimulants?

A

INDRECT

parathion
malathion
sarin
echothiophate

pesticides - not used in humans

40
Q

name 4 choline and carbamic acid esters

are they direct or indirect acting cholinergic stimulants?

A

direct acting

acetylcholine and methacholine = choline esters

bethanachol
carbachol
both are carbamic acid esters

41
Q

none of the clinically useful cholinergic stimulants are….

A

selective for receptor subtypes

just selective for either nicotinic or muscarinic as a group

42
Q

explain the structure of choline esters and name 2 choline esters

are they direct or indirect acting?

A

direct acting
acetylcholine
methacholine

have permanently charged quaternary ammonium group and are thus relatively insoluble in lipids

43
Q

many naturally occuring and synthetic cholinomimetic drugs are……..

A

alkaloids

44
Q

the ________ receptor is strongly stereoselective

explain

A

muscarinic

(S)-bethanechol is almost 1000x more potent than R bethanechol

45
Q

what is bethanechol

A

a carbamic acid ester.
direct acting cholinergic stimulant

46
Q

name a pharmacokinetic property of choline esters

A

they are poorly absorbed and poorly distributed into the CNS bc they are hydrophilic

all are hydrolyzed in the GI tract and are thus less active by oral route

47
Q

explain a pharmacokinetic consideration of acetylcholine

A

it is very rapidly hydrolyzed in the GI tract (it’s a choline ester!), so to achieve desired effects large amounts have to be infused IV

48
Q

differentiate between the resistance to hydrolysis between the choline and carbamic acid esters

A

negligible susceptibility to choline esterase: carbachol and bethanacol (the carbamic acid esters)

little susceptibility: methacholine

VERY SUSCEPTIBLE to cholinesterase: ACETYLCHOLINE

49
Q

The carbamic acid esters have extremely little susceptibility to hydrolysis by cholinesterase

methanachol has a little susceptibility, and acetycholine is EXTREMELY SUSCEPTIBLE

what does this mean for duration of action?

A

the carbamic acid esters have much longer durations of action (bethanchol, carbachol)

50
Q

the ______ group on bethanachol and methacholine reduces the potency of these drugs at _______ receptors

A

beta methyl group

nicotinic

51
Q

rank the carbamic acid esters and choline esters based on their muscarinic action

A

most: methacholine

acetylcholine

tied for last: carbachol and bethanchol

52
Q

rank the carbamic acid and choline esters according to their nicotinic action

A

acetylcholine and carbachol tied for 1st

methacholine and bethanachol have NO NICOTINIC ACTION (bc of beta methyl group!)

53
Q

the beta methyl group of ___ and ___ reduces the potency of these drugs at nicotinic receptors

A

bethanachol and methacholine

54
Q

explain the absorption of the natural tertiary cholinomimetic alkaloids (also name 3)

A

well absorbed from most sites of administration

pilocarpine nicotine lobeline

55
Q

can nicotine be absorbed across the skin?

A

yes
it is sufficiently lipid soluble

56
Q

is muscarine a tertiary amine?
what does this mean about it’s absorption?

A

not a tertiary amine - a quaternary amine

it is less absorbed from the GI tract than the tertiary amines

TOXIC when ingested from certain mushrooms - enters the brain

57
Q

the tertiary amine natural cholinomimetic alkaloids - pilocarpine, nicotine, and lobeline are excreted mainly be the kidneys

what accelerates their clearance?

A

acidification of the urine

58
Q

when acetylcholine binds to M2, what happens?

A

decreased heart rate

BY complex dissociates

adenylyl cyclase activity is decreased and cAMP production is decreased

PKA is also decreased - required to open calcium channel

59
Q

where is the nicotinic receptor present in extremely high concentration

A

in the membranes of electric organs of electric fish

60
Q

what happens when acetylcholine binds to nicotinic receptors?

A

in case of a NMJ - will cause depolariazation — OPENING OF LIGAND-GATED SODIUM CHANNEL and EPSP generation and contraction of the muscle

in case of neuron - will cause excitation

61
Q

what does nicotinic and muscaranic action do?

A

causes parasympathetic nervous system events - rest and digest

62
Q

PSNS: what happens to the eye?

A

the sphincter muscle of the iris contracts (miosis)

the ciliary muscle contracts for near vision

pupil gets smoler

63
Q

what happens to the sinoatrial node when PSNS is activated

A

decreased rate
(negative chronotrophy)

64
Q

what happens to the atria and ventricles of the heart when PSNS is activated

A

atria - decrease in contractile strength (called negative inotropy) and decrease in refractory period

ventricles - small decrease in contractile strength

65
Q

what happens to the VA node when PSNS is activated

A

decrease in conduction velocity (negative dromotropy)

increase in refractory period

66
Q

what happens to the blood vessels (arteries and veins) when PSNS is activated

A

dilation via EDRF (endothelial derived relaxation factor)

high dose direct effect - constriction

67
Q

what happens to bronchial muscle and bronchial glands when PSNS is activated

A

bronchoconstriction

bronchial glands are stimulated to release their secretions

68
Q

what happens to:

GI motility
GI sphincters
GI secretion

when PSNS is stimulated

A

increased GI motility

sphincters relax

secretion is stimulated

69
Q

true or false

all glands release secretions when PSNS is activated

A

FALSE - all exc sweat glands

sweat glands are under sympathetic control

70
Q

what happens to urinary bladder:

detrussor
trigone
sphincter

when PSNS is stimulated

A

detrusor contracts

trigone and sphincter relax

71
Q
A

Pharmacology FINAL (11 decks)

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