Adrenergic Pharmacology of the ANS

Question 1

What transmitter is mostly released from postganglionic sympathetic neurons?

Answer 1

NE.

Question 2

Which system relies mostly on DA?

Answer 2

Renal system

Question 3

Transmitter of eccrine sweat glands?

Answer 3

ACh. Eccrine = thermoregulatory

Question 4

A1 Receptors

Answer 4

Activate Gq, PLC, hydrolyze PIP2 to IP3 and DAG, PKC activation and release of intracellular Ca. Mediate contraction of smooth muscle. Are not in bronchioles and heart.

Question 5

Where are A1 receptors absent from?

Answer 5

Bronchioles and Heart

Question 6

What do all B receptors couple to?

Answer 6

Gs, causing relaxation of smooth muscle and increased contraction of cardiac muscle.

Question 7

Which receptor type predominates in heart?

Answer 7

B1. B1 in atria and ventricles. B2 just in atria.

Question 8

Which receptor type predominates in bronchioles and skeletal muscle vasculature?

Answer 8

B2, which dilates them.

Question 9

Epinephrine

Answer 9

Non-selective adrenergic agonist. Activates A1 B1 and B2. Constricts most arterioles, but dilates skeletal vessels. BP may decrease. Direct effects on heart: increased heart rate and contractile force. Dilates bronchioles.

Question 10

NE

Answer 10

Non-selective adrenergic agonist, but weak at B2. Large increase in BP, heart rate DECREASES. Large increase in BP because of activation of alpha receptors. Although B1 activated which should increase HR, baroreceptor response overwhelms it.

Question 11

Isoproterenol

Answer 11

Non-selective B agonist, activates both B1 and B2. Dilates skeletal muscle arterioles, decreases systolic BP. Increased heart rate and contractile force, large increase in pulse pressure. Baroreceptor reflex in same direction as direct effects on heart (increased). Bronchioles dilated.

Question 12

Phenylephrine

Answer 12

Alpha receptor agonist. Constricts vasculature, increases diastolic BP, decreases heart rate from baroreceptor reflex. No effect on airway.

Question 13

Phentolamine

Answer 13

Alpha receptor antagonist. Dilates vasculature, decreases diastolic BP, increases heart rate from baroreceptor reflex. Often causes fainting. Given to people with pheochromocytoma (tumor of adrenal gland, who produce too much epi)

Question 14

Propranolol

Answer 14

Nonselective B antagonist. Constricts vasculature, increase BP acutely (which decreases later due to other mechanisms, HR drops (direct and baroreflex), constricts airway.

Question 15

Metoprolol

Answer 15

B1 Antagonist. Construct vasculature, increases BP, HR drops, no effect on airway (which are B2).

Question 16

Albuterol

Answer 16

B2 agonist, dilates bronchioles, increase HR because of the baroreceptor reflex.