What factors are involved in contraction and relaxation of the penis in erectile dysfunction (ED)?

Updated: Aug 08, 2018
  • Author: Edward David Kim, MD, FACS; Chief Editor: Edward David Kim, MD, FACS  more...
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Answer

The degree of contraction of cavernosal smooth muscle determines the functional state of the penis. [11] The balance between contraction and relaxation is controlled by central and peripheral factors that involve many transmitters and transmitter systems.

The nerves and endothelium of sinusoids and vessels in the penis produce and release transmitters and modulators that control the contractile state of corporal smooth muscles. Although the membrane receptors play an important role, downstream signaling pathways are also important. The RhoA–Rho kinase pathway is involved in the regulation of cavernosal smooth muscle contraction. [12]

Factors that mediate contraction in the penis include noradrenaline, endothelin-1, neuropeptide Y, prostanoids, angiotensin II, and others not yet identified. Factors that mediate relaxation include acetylcholine, nitric oxide (NO), vasoactive intestinal polypeptide, pituitary adenylyl cyclase–activating peptide, calcitonin gene–related peptide, adrenomedullin, adenosine triphosphate, and adenosine prostanoids.


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