Lecture 7 (Drugs Targeting Nicotinic & Muscarinic Receptors) Flashcards

1
Q

For the sympathetic system the preganglionic neurotransmitter is ___

A

Ach

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2
Q

For the sympathetic system the preganglionic receptors are ?

A

nicotinic ganglionic (NG)

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3
Q

For the sympathetic system the post ganglionic is ___

A

NA or NE (same chemical)

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4
Q

For the sympathetic system the post ganglionic receptors are ?

A

Adrenergic

alpha 1, beta 1, beta 2

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5
Q

For the parasympathetic system the preganglionic neurotransmitter is ___

A

Ach

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6
Q

For the parasympathetic system the preganglionic receptors are ?

A

nicotinic ganglionic (NG)

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7
Q

For the parasympathetic system the postganglionic neurotransmitter is ___

A

Ach

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8
Q

For the parasympathetic system the postganglionic receptors are ?

A

Muscarinic (M)

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9
Q

The somatic nervous system is ____ controlled.

A

consciously

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10
Q

Neurotransmitter for somatic nervous system is ?

A

ACh

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11
Q

Receptors for somatic nervous system are ?

A

nicotinic cholinergic (NM)

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12
Q

Explain the synapse for ACh

A
  • action potential
  • this opens calcium channels which acts as a stimulus for Ach to leave presynaptic cell and go into the synaptic cleft
  • Ach then attaches to Ach receptors on post synaptic cell
  • while in presynaptic cleft, Ach can be broken down by AChE into acetate + choline
  • choline can be reuptaked into the presynaptic cell and added to AcCoA to make Ach

*see slide 6 for diagram

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13
Q

ACh has what two groups on it?

A

ester

amine

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14
Q

AChE ____ Ach

A

hydrolyzes

(it chops the ester bond

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15
Q

When AChE hydrolyzes Ach, what are the two products?

A

acetic acid and choline

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16
Q

All cholinergic receptors bind ___ for activity

A

ACh

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17
Q

two types of cholinergic receptors?

A

nicotinic

muscarinic

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18
Q

What two types of nicotinic receptors are there?

A

NG - nicotinic ganglionic

NM - nicotinic cholinergic

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19
Q

How many types of muscarinic receptors are there?

A

5

M1-M5

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20
Q

All muscarinic receptors are _____

A

GPCRs

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21
Q

Nicotinic acetylcholine receptors us a ___ ion channel

A

sodium (Na+)

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22
Q

How does the nicotinic acetylcholine receptor work?

A

Ach binds to ion channel which opens the ion channel and allows Na+ to pass through

23
Q

2 examples of NM agonists

A

succinylcholine

decamethonium

24
Q

2 examples of NM antagonists

A

pancuronium

d-tubocurarine

25
Q

Although succinylcholine and pancuronium work via different mechanisms, they are used clinically for the same thing: which is?

A

muscle relaxation during surgery

26
Q

Succinylcholine is rapidly hydrolyzed by _____

A

esterases

27
Q

Pancuronium has a ____ duration of action than succinylcholine

A

longer

28
Q

2 examples of NG selective antagonists

A

trimetaphan

hexamethonium

29
Q

M1 receptor affects G alpha __

A

q

30
Q

M2 receptor affects G alpha __

A

i

31
Q

M3 receptor affects G alpha __

A

q

32
Q

M1 = _____

A

excitation

+PLC
increase IP3 and DAG
increase [Ca2+] intracellular
decrease K+ outflow

33
Q

M2 = _____

A

inhibition

-AC
decrease cAMP
decrease [Ca2+] intracellular
increase K+ outflow

34
Q

M3 = ______

A

excitation

+PLC
increase IP3 and DAG
increase [Ca2+] intracellular
decrease K+ outflow

35
Q

M1 reaches which tissue locations?

A

CNA (cortex hippocampus)
ganglia
parietal cells

36
Q

M2 reaches which tissue locations?

A

cardiac - atria and conducting tissue

neural - presynaptic terminals

37
Q

M3 reaches which tissue locations?

A

smooth muscle
vascular
endothelium

38
Q

M1 function

A

CNS excitation (memory)
gastric acid secretion
GI motility

39
Q

M2 function

A
cardiac inhibition
decrease HR
decrease force of contractility
presynaptic inhibition
neural inhibition
40
Q

M3 function

A

smooth muscle contraction (bladder)

41
Q

What does removing methyl groups on Ach do?

A

reduces potency

42
Q

On ACh what is required for activity

A

N+

43
Q

is the ACh molecule flexible?

A

yes

44
Q

Receptors for ACh have 2 sites - what are they?

A
anionic site (can accommodate two methyl groups and has a - change binding site)
esteratic site (ester O acts as H bond acceptor)
45
Q

For muscarinic agonists, as the length of the alkyl chain increases beyond _ atoms, intrinsic activity and affinity decrease

A

5

46
Q

> _ atoms usually have no activity or affinity (muscarinic agonists)

A

7

47
Q

Carbonyl on ACh is a strong __________

A

electrophile

48
Q

ACh is very susceptible to _______

A

hydrolysis

49
Q

What does adding a methyl group to ACh do? (it is now methacholine)

A

methyl group = steric shield

-reduces access to carbonyl carbon by nucleophiles also sterically inhibits binding to AChE

50
Q

_______ has delocalized electrons on the acetyl group which decreases the electrophilic nature of the carbonyl carbon - makes it resistant to hydrolysis by AChE

A

carbachol

51
Q

_____ and _____ are not orally active and not useful clinically

A

ACh

Carbachol

52
Q

What is ethacholine used for?

A
  • used as a test for asthma

- called the methacholine challenge test

53
Q

What is Bethanechol used for?

A
  • increase urinary output
  • used often after surgery
  • or used in prostatic hypertrophy that does not respond to convention treatments like Tamsulosin
54
Q

What is Pilocarpine used for?

A

treats glaucoma