Adrenergic Receptor Subtypes, Location, Function

Question 1

Major blood vessels and vasculature in dermal, GI, renal, bladder, nasal membranes (excluding skeletal/hepatic)

Answer 1

Vasoconstriction of major blood vessels –> ↑PR ↑DBP

Question 2

Eyes

Answer 2

A1= mydriasis (contraction of radial muscle --> mydriasis)
A2= ↓aqueous humor production
B1/B2= ↑ aqueous humor

Question 3

Bladder & GI Sphincters

Answer 3

A1= constriction of sphincter, decreasing outflow

Question 4

Pancreatic Islets

Answer 4

A2= inhibit insulin secretion –> ↑ [glucose]

Question 5

Presynaptic nerve terminals

Answer 5

A2= activating autoreceptors = ↓NT release = ↓BP

Question 6

CNS/ Brainstem

Answer 6

A2= ↓BP & inhibit baroreflex

Question 7

Spinal cord

Answer 7

A2= inhibit pain transmission

Question 8

Nasal Vasculature

Answer 8

A2= vasoconstriction of the nasal vasculature

Question 9

Heart

Answer 9

B1= ↑HR, ↑contractility, ↑force == ↑CO –> ↑SBP

Question 10

Kidney

Answer 10

B1 = ↑renin secretion, = vasoconstriction

Question 11

Hepatic/Skeletal muscle, vascular smooth muscle

Answer 11

B2= relaxes smooth muscle = ↑ blood flow to the liver and skeletal muscle

Question 12

pulmonary smooth muscle

Answer 12

B2 relaxes SM = bronchodilation to ↑airflow

Question 13

GI longitudinal smooth muscle

Answer 13

B2 relaxes SM = ↓motility (don’t need to be digesting food while running for your life)

Question 14

bladder detrusor muscle

Answer 14

B2 relaxes = ↓ outflow

Question 15

pregnant uterus (myometrium)

Answer 15

B2 relaxes

Question 16

skeletal muscle

Answer 16

B2 = ↑glycogenolysis to ↑K+ uptake

Question 17

mast cells

Answer 17

B2 inhibits mast cell degranulation –> inhibit histamine release

Question 18

liver

Answer 18

B2 = ↑ glycogenolysis = ↑[glucose]

Question 19

pancreas

Answer 19

B2 = ↑ glucagon release = ↑ [glucose]

Question 20

A1 receptor

Answer 20

G alpha Q

↑PLC –> ↑IP3, DAG, ↑Ca (increasing Ca is going to stimulate SM contraction)

Question 21

A2 receptor

Answer 21

G alpha I (inhibitory)
↓ adenylyl cyclase & ↑K+ channels –>
↓cAMP (low cAMP = SM contraction, ↓HR & contractility)
↑K+ channels is going to inhibit presynaptic NT release –> tremors

Question 22

B (1,2,3)

Answer 22

G alpha s
↑ adenylyl cyclase –> ↑cAMP & ↑Ca++ (heart)
↑cAMP is going to relax smooth muscles, but ↑HR & contractility