An Experimental Study of the Effect of Histamine on the Rabbit Corpus Cavernosum Tissue

Kim, Yong Tae; Paick, Jae Seung; Kim, Si Whang

Abstract

Penile erection is controlled by adrenergic and nonadrenergic-noncholinergic (NANC) neurotransmission. There are many other substances involved in the corpus cavernosum smooth muscle contraction and relaxation. Among them. histamine is supposed to play an important role to the penile erection mechanisms in both human and animals, but the exact effect and mechanisms are not established. To investigate the effects of histamine on the corpus cavernosum tissue and the intracellular signal transduction mechanisms, we have studied on the rabbit corpus cavernosum using organ bath and the following results were obtained. 1. Corpus cavernosum tissue showed contraction in response to histamine in a dose-dependent manner( ED50 = 2.59 x 0.00001mol). 2. Pheniramine maleate ( 0.00001mol), a H1-receptor antagonist, abolished histamine-induced contraction, but cimetidine(0.00001mol), a H2-receptor antagonist, had no effect on histamine- induced contraction. 3. Histamine-induced contraction was abolished by W-7 (0.0001mol), a calmodulin antagonist, but not affected by staurosporine ( 0.0000001mol), a protein kinase C inhibitor. 4. In the precontracted tissue by phenylephrine histamine produced no relaxation, but pheniramine maleate produced significant relaxation in precontracted tissue It is concluded that in rabbit, histamine induced a dose-dependent contraction mediated by H1- receptors and calcium-calmodulin complex as an intracellular second messenger, but there were few H2-receptors in rabbit corpus cavernosum tissue. By the results of this study, it is supposed that histamine or pheniramine maleate could be used as a drug of intracavernosal injection therapy, but human tissue study, in vivo study and/or in vitro study under electrical stimulation must be preceded.