The Effect of Nitric Oxide on Cat Corpus Cavernosum Relaxation Under Hypoxia (In vivo Study)

Kim, Yong Woo; Kim, Je Jong

Abstract

One of the pathophysiologic change of priapism is known as hypoxic condition of corpus cavernosum. In vitro study of corpus cavernosum under hypoxia showed suppressed endothelium- dependent relaxation caused by cholinergic and nonadrenergic noncholinergic neuroeffector system, but in vivo study it is not fully evaluated yet. So this study aimed to identify the changes of corpus cavernosum related to cholinergic neuroeffector system and endothelium derived relaxation factor (EDRF) under hypoxia in animal study and to understand the Physiologic change of priapism. Under the general anesthesia with tracheostomy, adult male cats were conditioned at normoxia and hypoxia with ventilation. Acetylcholine, Nc-monomethyl-L- arginine (L-NMMA) and L-arginine was infused via internal pudendal artery. The change of intracavernosal pressure in response to drugs were monitored with physiograph (Gilson, IC-MP) in both normoxic and hypoxic state. The relaxation effect of acetylcholine under hypoxia was weaker than under normoxia (n=5, p suppressed by L-NMMA under normoxia but not under hypoxia. L-arginine showed the relaxation effect under normoxia but, no relaxation under hypoxia. These result suggest that acetylcholine induced relaxation was influenced in a some by hypoxic condition but not suppressed completely. EDRF pathway via nitric oxide synthesis does not play a role in relaxation of cat corpus cavernosum under hypoxia.