Posterior pituitary

Question 1

What type of GPCR is the oxytocin receptor?

Answer 1

A Gq receptor.

Question 2

What does activation of the oxytocin receptor lead to in target cells?

Answer 2

Increased intracellular Ca2+ (Gq leading to PLC and IP3, ect). This leads to the Ca-Calmodulin complex activating MLCK, leading to smooth muscle contraction.

Question 3

What type of GPCR is the V1 vasopressin receptor?

Answer 3

Gq. This leads to increased intracellular Ca2+ in vascular SM leading to vasoconstriction.

Question 4

What type of GPCR is the V2 vasopressin receptor?

Answer 4

Gs. Leads to increased cAMP leading to the insertion of AQP2 on the apical side of renal collecting tubule principle cells.