Three second messengers involved in penile erections are
A) nitric oxide, inositol trisphosphate, and calcium ions.
B) adenylcyclase, phospholipase C, and calcium ions.
C) cyclic AMP, nitric oxide, and cyclic GMP.
D) adenylyl cyclase, calcium ions, and nitric oxide.
E) cyclic GMP, acetylcholine, and inositol trisphosphate.

Question

Quizplus · Accepted Answer

Nitric oxide, inositol trisphosphate, and calcium ions are all second messengers involved in penile erections. Nitric oxide is released from the endothelial cells of the corpus cavernosum in response to sexual stimulation. It activates guanylate cyclase, which converts guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP). cGMP relaxes the smooth muscle of the corpus cavernosum, allowing blood to flow into the penis and causing an erection. Inositol trisphosphate is released from the phospholipase C pathway in response to sexual stimulation. It activates calcium channels in the smooth muscle of the corpus cavernosum, causing calcium ions to enter the cells. Calcium ions promote the contraction of the smooth muscle, which helps to maintain the erection.

Three Second Messengers Involved in Penile Erections Are