Change in Expression of Rho-kinase and Nitric Oxide Synthase in Penile Tissue of Rats Under Stress

Kim, Kyu Hyun; Yoon, Hana

Abstract

PURPOSE: The autonomic nervous system (ANS) and stress hormones are important mediators in the stress response. The ANS controls the tone of corpus cavernosal smooth muscle. Clinically, it is not uncommon to develop erectile dysfunction as the sequelae of acute or chronic stress, with or without loss of libido. In this study, we investigated the effect of stress on the expression of mediators of penile corpus cavernosal smooth muscle relaxation and contraction.
MATERIALS AND METHODS
Forty-eight male Sprague-Dawley rats were used, with 8 rats in each group. They were divided into six groups; stress+10, stress+20, and stress+30, which were named after their duration (days) of exposure, and a control group for each stress group. The stress group was maintained under a scheduled stress condition, while the control group was provided a comfortable general environment. Penile tissues were sampled and expressions of Rho-kinase, inducible nitric oxide synthase (iNOS), endothelial NOS (eNOS) and neuronal NOS (nNOS) were measured and analyzed by Western blotting.
RESULTS
Penile Rho-kinase expression was significantly increased in the stress groups compared with the control group (p<0.05), with a greater increase during longer stress. Expression of iNOS was increased in stress+30 group (p<0.05). Expression of eNOS, nNOS, and Rho-kinase were increased in stress+20, stress+30 group (p<0.05).
CONCLUSIONS
These results suggest that stress may alter penile corpus cavernosal smooth muscle relaxation by affecting mediators.