Background Receptors Functioning in the Parasympathetic and Sympathetic Nervous System

Question 1

Nicotinic Receptor

Answer 1

Expressed in ganglia and NMJ

Ion channel for Na and Ca and causes depolarisation

Fast compared to GPCRs

Question 2

Muscarinic M1 or M3

Answer 2

Ach binds…receptor activates Gq protein…phospholipase C activates IP3 and DAG….IP3 leads to calcium release which leads to contraction of smooth muscle and glandular secretion

Question 3

muscarinic M2 receptor

Answer 3

Ach binds…receptor activates Gi which causes K to move out of the cell leading to hyperpolarization and slowing heart rate …also decreases cAMP formation

Question 4

Beta 1 adrenergic

Answer 4

Epi binds…activatates G protein and cyclase that make cAMP…cAMP phophorylates Ca channels, SR, and contractile proteins

Increase in Calcium results in inotropism and chronotrophism in the heart

Question 5

beta 2 adrenergic

Answer 5

in smooth muslce

Agonist binds…increases cAMP levels…increase in cAMP inactivates Ca channels, SR, and contractiles…leadss to relaxation

Question 6

Alpha 1 adrenergic

Answer 6

Agonist binds….increases IP3 and DAG….leads to increase in Ca from channels and SR…leads to contraction of fibers

Question 7

Vascular smooth muscle cells and B

Answer 7

Alpha 1 contracts and increases BP

beta 2 relaxes and decreases BP