Effect of Glucocorticoid on Rabbit Corpus Cavernosum Smooth Muscle

Choi, Young Deuk; Mah, Sang Yol; Choi, Hyung Ki

Abstract

PURPOSE: Glucocorticoid contribute to the pathogenesis of hypertension through intracellular signals that stimulate vascular smooth muscle contraction. However, some in vitro and in vivo studies have shown that glucocorticoid has the potential role of vasorelaxation. Therefore, we tried to investigate the effect of short acting glucocorticoid (hydrocortisone; HCS) on the isolated rabbit cavernosal smooth muscle for evaluation of the possibility of using this material as a pharmacoerecting agent.
MATERIALS AND METHODS
Strips of rabbit corpus cavernosum were mounted in organ chambers. On the precontracted muscle strips with phenylephrine(PHE; 5x10-6M), HCS was treated with increasing concentration from 10microgram/mL. The relaxing activity of ACh(10-7M), phentolamine(10-8M), papaverine(10-8M), verapamil(10-6M), PGE1(10-2M), SNAP(5x10-5M) were observed with the preparation of HCS. Depolarization by KCl were observed with HCS to investigate the relationship of HCS effects to K+.
RESULTS
Pretreatment of muscle strips with low dose of HCS caused concentration-related increase of a PHE induced contraction. On muscle strips submaximally precontracted with PHE, HCS(10microgram/mL to 100microgram/mL) showed no relaxations. Pretreatment of muscle strips with 10microgram/mL dose of HCS caused a potentiation of a relaxation effects of ACh, papaverine, verapamil, SNAP, PGE1 and 50microgram/mL dose of HCS caused a potentiation of a relaxation effects of ACh, phentolamine. However, 100microgram/mL dose of HCS did not produce changes of these potentiating responses to relaxation. Also, HCS did not influenced the depolarization with any concentrations of KCl.
CONCLUSIONS
HCS has the potentiating effect of both the PHE-induced contraction, and the relaxation of the ACh, phentolamine, papaverine, verapamil, SNAP, PGE1 at 10-50microgram/mL concentration on the cavernosal smooth muscle.