Effects of ultraviolet light on the tension of isolated human cavernosal smooth muscle from non-diabetic and diabetic impotent men

Abstract

The effects of ultraviolet (UV) light (310 nm) on human cavernosal smooth muscles were investigated. Cavernosal strips were obtained from men during penile prosthetic surgery. When the cavernosal strips were irradiated with UV light in an organ bath, after precontraction by norepinephrine (100 nM) for 10, 20, 40 and 90 s at intervals of 3 min, the contracted cavernosal smooth muscles from the impotent men without vascular risk factors (controls) showed relaxation depending on the duration of irradiation. However, the relaxation was not found when the strips were pretreated with methylene blue (10 μM) or their epithelia were denuded. The relaxation response of the cavernosal strips from the patients with diabetogenic impotence was significantly reduced compared with that of the controls. Photorelaxation of human cavernosal strips therefore seems to be dependent on endothelium.