Update on corpus cavernosum smooth muscle contractile pathways in erectile function: a role for testosterone?

Area of Science:

• Urology
• Endocrinology
• Molecular Biology

Background:

• Normal erectile function (EF) depends on penile artery and corpus cavernosum smooth muscle (CCSM) relaxation.
• CCSM contraction is mediated by norepinephrine and endothelins, involving smooth muscle myosin (SMM) phosphorylation and RhoA/Rho-kinase (ROK) signaling.
• The influence of androgens on EF is significant but remains controversial.

Purpose of the Study:

• To review CCSM contractile pathways and their role in EF.
• To elucidate the influence of androgens on these pathways.

Main Methods:

• Literature review of peer-reviewed publications.
• Inclusion of previously unpublished data on CCSM contraction signaling.
• Analysis of androgen modulation of these pathways.

Main Results:

• Decreased testosterone (T) upregulates CCSM contractility, increasing responsiveness to agonists and SMM phosphorylation.
• Reduced T activates RhoA/ROK signaling and alters sphingosine-1-phosphate regulation of CCSM tone.
• Decreased T downregulates pro-erectile mechanisms and CCSM relaxation pathways.

Conclusions:

• Decreased testosterone levels enhance CCSM contractile signaling and impair relaxation, leading to erectile dysfunction (ED).
• Understanding androgenic influence on these molecular mechanisms provides evidence for their role in EF.
• This knowledge can guide the development of novel therapeutic targets for ED.