receptors

Question 1

A1 receptor signal pathway and location

Answer 1

increase in intracellular Ca2+

ventricular muscle, vascular smooth muscle of veins, arteries

Question 2

A2 receptor signal pathway and location

Answer 2

inhibition of adenylyl cyclase and reducing intracellular cAMP

vascular smooth muscle of arteries and veins

Question 3

B1 receptor signal pathway and location

Answer 3

activation of adenylyl cyclase and increase of cAMP intracellular and cAMP kinase activity

SAN, AVN, Purkinje system
Atrial and ventricular muscle

Question 4

B2 receptor signal pathway and location

Answer 4

Activation of adenylyl cyclase and
an increase in intracellular cAMP
and cAMP kinase activity

SAN, AVN, Purkinje system
Atrial and ventricular muscle

Only difference between B1 and B2 Vascular smooth muscle of arteries and veins

Question 5

B3 receptor signal pathway and location

Answer 5

Activation of nitric oxide synthase,
production of nitric oxide and
stimulation of the cGMP pathway

Ventricular muscle

Question 6

M2 receptor signal pathway and location

Answer 6

Activation of K+ channels and
increased K+ efflux

SAN, AVN, atrial
Ventricular muscle

Question 7

M3 receptor signal pathway and location

Answer 7

Increased intracellular Ca 2+ and
subsequent activation of nitric oxide
synthase and the production of
nitric oxide

Vascular endothelial cells

Question 8

A1 function

Answer 8

Vasoconstriction, increased contractility

Question 9

A2 function

Answer 9

vasoconstriction

Question 10

B1 and B2 function

Answer 10

 increase inward Na + conductance
 increases slope of pacemaker potential
 speeds up pacemaker (increases HR)
*increased contractility via AMP/PKA and Ca 2+
 increased rate of relaxation due to accelerated SR reuptake of Ca 2+ and accelerated sarcolemmal
extrusion of Ca 2+
 decrease in the duration of systole
Purkinje System
 increased conduction velocity

Question 11

B3 function

Answer 11

decreased cardiac contractility via NO and cGMP

Question 12

M2 function

Answer 12

 slows pacemaker (decreases HR)
 hyperpolarizes maximum diastolic potential
AVN
 slows action potential conduction velocity
 decreases upstroke velocity
Atrial muscle
 reduces contractility

Question 13

M3 function

Answer 13

relaxation of VSM and vasodilation ‐ mediated by NO release and production of cGMP