Autonomics I

Question 1

M1, M3, M5 muscarinic cholinoceptors: result of ligand binding

Answer 1

Formation of IP3 and DAG thru inc in PLC from Gq, inc intracellular Ca2+. Sm muscle contraction by M3, neuroregulation by M1.

Question 2

M2, M4 muscarinic cholinoceptors: result of ligand binding

Answer 2

Act thru Gi, opening of K+ channels leading to polarization, inhibition of AC thru lowering cAMP. Slows heartbeat, and inhibits nt release via M2 (-feedback). cAMP-mediated relaxation inhibited by M2 in sm muscle.

Question 3

Nicotinic Nn location and result of ACh binding

Answer 3

Postgang neurons (at ganglia), some presyn cholinergic terminals. Opening of Na,K channels for depolarization.

Question 4

Nicotinic Nm location and result of ACh binding

Answer 4

Skel muscle neuromuscular end plates. Opening of Na,K channels for depolarization.

Question 5

a1

Answer 5

Gq PLC IP3+DAG leading to inc sm muscle contraction

Question 6

a2

Answer 6

Gi AC- cAMP decrease. Gi K+chan hyperpolarization. Inhibition of nt release.

Question 7

b1

Answer 7

Gs AC+ cAMP+ leading to increase in force and rate of contraction of heart

Question 8

b2

Answer 8

Gs AC+ cAMP+ leading to increased sm muscle relaxation. Relaxes bronchiolar sm muscle.

Question 9

b3

Answer 9

Gs AC+ cAMP+ increasing lipolysis