Autonomic Drugs

Question 1

How are anti-cholinesterase agents classified?

Answer 1

based on duration of enzyme inhibition; related to the speed with which inhibitor dissociates from the esteric site of AChE

Question 2

What receptors does norepinephrine not interact with in the ANS?

Answer 2

Beta 2

Question 3

Cholinergic stimulation causes smooth muscle to _________

Answer 3

Contract

Question 4

Five clinical signs you expect to see when using anti-cholinesterase agents

Answer 4

1. Constriction of pupils
2. Increased secretion of sweat, saliva, tears
3. Slow heart rate
4. Mucus secretion in the resp tract
5. Constriction of bronchioles

Question 5

Stronger beta2 agonist:

isoproterenol, epinephrine, or norepinephrine?

Answer 5

Iso > Epi >>Norepi

Question 6

What happens if you activate Gi in a smooth muscle cell?

Answer 6

Contraction

Question 7

mAChR activation promotes/inhibits urination?

Answer 7

promotes

• contracts detrusor mm
• relaxes sphincter mm
• increases peristalsis in ureters

Question 8

What enzyme breaks down ACh in the synaptic cleft?

Answer 8

acetylcholinesterase

Question 9

mAChR activation has what two effects on the eye?

Answer 9

1. contraction of sphincter muscle > miosis (pupil constriction)
2. contraction of ciliary muscle > incr curvature of lens

Question 10

If you use a cholinergic agonist with high muscarinic receptor activity, what effect do you need to be concerned about on the heart?

Answer 10

Bradycardia

Question 11

Stronger alpha1 agonist:

isoproterenol, epinephrine, or norepinephrine?

Answer 11

Norepi > Epi >> Iso

Question 12

Descrbie muscarinic receptors

Answer 12

• stimulated by natural alkaloid - muscarine
• 5 subtypes
• tx drugs exhibit little/no subtype selectivity

Question 13

What is the MOI of organophosphates, such as sarin?

Answer 13

Anticholinesterase

Question 14

What type of GI tract disorder would anticholinergic drugs be used to treat?

Answer 14

GI spasms; these are called “spasmolytics” or “antispasmotics”

Question 15

Stronger alpha2 agonist:

isoproterenol, epinephrine, or norepinephrine?

Answer 15

Epi = Norepi >> Iso

Question 16

M1, M2 and M3 receptors couple with what G-protein?

Answer 16

Gq

Question 17

Why do anticholinergic drugs disrupt sweating?

Answer 17

Because sympathetic neurons use acetylcholine for sweat gland neurons

Question 18

What happens if you activate Gi in a cardiac muscle cell?

Answer 18

Decreased contraction

Question 19

5 Therapeutic Uses for Anti-Cholinergic Agents

Answer 19

1. Reduce smooth muscle spasms
2. Antisecretory effects
3. Ophthalmic exams
4. Prevent heart block
5. Antidotes

Question 20

What does SLUD/BLUD stand for?

Answer 20

Salivation/Bradycardia

Lacrimation

Urination

Defecation

Question 21

Nictonic receptors

Answer 21

• stimulated by natural plant alkaloid nicotine
• some subtypes undergo rapid desensitization with over-stimulation - tachyphylaxis
• tx drugs exhibit selectivity for nicotinic receptors in sk mm (muscle relaxants) vs. receptors in neural tissues

Question 22

Stronger beta1 agonist:

isoproterenol, epinephrine, or norepinephrine?

Answer 22

Iso > Epi = Norepi

Question 23

Explain the effects of mAChR activation on blood vessels

Answer 23

• agonists cause pronounced atypical relaxation of vascular smooth muscle and fall in blood pressure
• mAChR are located on endothelial cells
• mediated by nitric oxide

Question 24

What receptors does isoproterenol not interact with in the ANS?

Answer 24

alpha 1 and 2

Question 25

M2 and M4 receptors are coupled with what G-protein receptor?

Answer 25

Gi

Question 26

Does mAChR activation causes bronchial smooth muscle contraction or dilation?

Answer 26

Contraction \> bronchoconstriction

Question 27

mAChR activation _promotes/inhibits_ secretions from most secretory glands?

Answer 27

Promotes (SLUD)

Question 28

Key differences between glycopyrrolate and atropine

Answer 28

1. less CNS effects (sedation, amnesia, etc.) 2. longer half life & more potent 3. less tachycardia

Question 29

Major effects of ACh on the GI tract

Answer 29

* incr motility & peristalsis * incr smooth muscle tone * incr amplitude of contractions * incr secretions (acid)

Question 30

What type of GI disorder would cholinergic agonists be used to treat?

Answer 30

constipation/impactions; these are "prokinetic agents"

Question 31

What happens if you activate Gq in a smooth muscle cell?

Answer 31

Contraction

Question 32

Signs of acute organophosphate poisoning

Answer 32

* inhaled: ocular, respiratory * oral: GI, systemic signs * cutaneous: sweating, muscle fasciculations

Question 33

What is acetylcholine important for in the CNS?

Answer 33

cognition

Question 34

What are the parasympathetic effects on cardiac tissue mediated by?

Answer 34

the vagal release of ACh\> activates cardiac mAChR \> baroreceptor reflex \> **reduction in heart rate**

Question 35

Describe a typical parasympathetic pre- and post-ganglionic neuron

Answer 35

Two synapses; long pre-ganglionic axon, short post-ganglionic axon

Question 36

What is the function of the parasympathetic nervous system?

Answer 36

provides "vegetative" or resting control of visceral organs; excessive activity causes SLUD/BLUD syndrome

Question 37

What happens if you activate a nicotinic receptor on a neuron, smooth muscle, or cardiac muscle cell?

Answer 37

* You will increase cell activity, and thus increase probability of neurotransmitter release, as well as cause smooth muscle contraction and cardiac muscle contraction. * increased alertness (neurons), heart rate (cardiac muscles), and blood pressure (smooth muscle)