Cholinergics

Question 1

Fx of SNS

Answer 1

“Fight or Flight”

Is continually active to some degree (maintains tone of vascular beds)

• incr HR (tachy) & BP
• mobilizes E
• blood vessel constriction @ skin, mucus mem, & splanchnic area)
• blood vessel dilation @ skeletal & heart
• bronchodilation
• pupil dilation (mydriasis)
• CB relaxation (dist vision)
• decr urination
• stimulates ejaculation

Question 2

Fx of PNS

Answer 2

“Rest or Digest”

Maintains essential bodily fxs. Required for life.

• decr HR (Brady) & BP
• stores E
• blood vessel dilation @ skin, mucus mem, & splanchnic area)
• blood vessel constriction @ skeletal & heart
• bronchoconstriction
• pupil contriction (miosis)
• CB contraction (near vision)
• incr urination
• stimulates erection

Question 3

Actions of Muscarinic agonist

Answer 3

Parasympathetic-like

Question 4

Actions of Muscarinic Antagonist

Answer 4

Sympathetic-like

Question 5

Organs only receiving sympathetic inn.:

Answer 5

Blood vessels
Adrenal medulla
Pilomotor muscles
Sweat glands

Question 6

Important NTs in ANS

Answer 6

Acetylcholine (ACh)
Norepinephrine (NE)
Epinephrine (Epi)

Question 7

Neurons which release ACh

Answer 7

Cholinergic

Question 8

Mediates transmission of nerve impulses across ganglia in both SNS & PNS

Answer 8

ACh

Question 9

NT at adrenal medulla

Answer 9

ACh

Question 10

Transmits signal from autonomic postgang nerves to effector organ in PSN

Answer 10

ACh

Question 11

Transmitter at neuromuscular junction in somatic nervous system

Answer 11

ACh

Question 12

Neurons releasing NE or Epi are termed

Answer 12

Adrenergic

Question 13

Mediate the transmission of nerve impulses from autonomic postgang to effector organs

Answer 13

NE

Question 14

Released from adrenal medulla into blood, binds to and activates adrenergic receptors

Answer 14

Epi

Question 15

Rate limiting step in ACh synthesis is

Answer 15

Choline

Question 16

3 fates of ACh

Answer 16

• diffuse across synaptic cleft and bind with postsynaptic receptor (N or M)
• metabolized (choline part is recycled by ACh esterase)
• bind back w/ presynaptic receptor (usually M2)

Question 17

ACh estates rapidly or slowly metabolizes ACh?

Answer 17

Rapid —> reason ACh has such a short t(1/2)

Question 18

Drugs the effect ACh

Answer 18

• Muscarinic agonist
• ACh esterase inhibitors (incr t(1/2))
• Botox (inhibits ACh release, thus muscle can’t contract, stops sweating)
• spider venom (massive ACh release, constant muscle contraction)

Question 19

M3 found primarily where?

Answer 19

GI, urinary tract, blood vessels (physiologically unable to be activated, but can be activated by drugs)

Question 20

M2 are found primarily where?

Answer 20

Heart

Question 21

Muscarinic Agonist Drugs to know

Answer 21

BethaneCHOL, carbaCHOL, metaCHOLine,
Pilocarpine,
Cevimeline

Question 22

BethaneCHOL

Answer 22

• Muscarinic agonist
• stim GI & bladder
• gastric atony

Question 23

CarbaCHOL

Answer 23

• Muscarinic agonist
• decr IOP in glaucoma
• rarely used b/c of nicotinic effects on autonomic ganglia

Question 24

MethaCHOLine (inhaler)

Answer 24

• stim bronchoconstriction
• used to dx bronchial airway hyperreactivity in non-apparent asthma pts (methacholine challenge test)
• asthma pts will be more sensitive to this test

Question 25

Pilocarpine, Cevimeline

Answer 25

• used to treat glaucoma by incr drainage of aqueous humor; low priority (ophthalmic solution)
• used to treat xerostomia (decr in secretions = dryness; can be caused by head & neck radiation or with Sjögren’s syndrome); stim salivary secretions (oral administration);

Question 26

What is used to treat serious toxic rxns?

Answer 26

• Atropine (Muscarinic antagonist)

- Epi can also overcome serious cardiovascular or bronchoconstrictor responses