Effects of papaverine and prostaglandin E1 on corpus cavernosum smooth muscle of arteriogenically and diabetically impotent men.

Relaxant effect of prostaglandin E1 (PGE1) and papaverine (PAP) were measured in strips of corpus cavernosum smooth muscle taken from a healthy control group of men (A; n = 5), from arteriogenically impotent men (B; n = 6) and from additionally diabetic impotent men (C; n = 5) with venous leakage. Maximal relaxant effect was achieved with PAP at a mean of 10(-4) mol/l and PGE1 at a mean of 5.8 x 10(-6) mol/l. PAP induced complete relaxation in all strips. There was no difference in relaxant effects between groups. Relaxant effect was less pronounced and depended significantly on etiology: phenylephrine-induced tension was reduced by 76 +/- 8% (A), 54 +/- 14% (B) and 23 +/- 18% (C), respectively. In conclusion, our data suggest degradation of PGE1 receptors depending on the cause of erectile dysfunction. Furthermore, relaxant capacity of cavernous smooth muscle per se seems not to be impaired in impotence. Therefore, pathophysiology of venous leakage cannot sufficiently be explained by a lack of relaxation.