Physiological Role of Vasoactive Intestinal Polypeptide on Penile Erection in Rats

Mun, Ki Hak; Suh, Jun Kyu

Abstract

Vasoactive intestinal polypeptide (VIP) has a vasodilatory effect as a non-adrenergic, non-cholinergic neurotransmitter. The role of VIP on penile erection has been controversial. This study was undertaken to elucidate the effect of VIP on penile erection in-vivo and to predict whether this drug can be clinically applied to the diagnosis and/or treatment of impotence. The results are as follows. Intracavernosal injection of VIP alone (0.000000001to 0.00001M, n=10) did not show any increase in basal ICP Pretreatment of VIP (0.000005M, 0.00001M, n=7) enhanced partial erection induced by electric intensity with suboptimal level(frequency; 1 Hz, intensity; 1.2-2.0 volt, pulse duration, 1 msec.) (p<0.05)Intracavernosal injection of VIP-antagonist (0.000000001 to 0.00001M,n=7) was found to suppress the full erection induced by the optimal electric stimulation(frequency; 1 Hz, intensity; 3-4 volt, pulse duration; 1 msec.) in dose dependent manner (p<0.05). These results suggest that VIP may induce penile erection in rat through its receptor on corpus cavernosum, although it requires the cooperative action of other neurotransmitter(s).