Mechanical Response of the Rat Isolated Seminal Vesicle to High Potassium

Original article


A.A. El Zarouk, S.D. Gokhale

Department of Pharmacology, Faculty of Medicine, Al-Arab Medical University, Benghazi, G.S.P.L.A.J.

Garyounis Medical Journal Vol.13, No.1-2. January/July 1990:19-29


The contractile response of the rat seminal vesicle to stimulation with high K+ was biphasic and consisted of an initial rapid but transient contraction (Phase A) which was followed, after a brief relaxation, by a slow but more sustained contraction (Phase B). However, the precise shape of the con traction as well as the relative contribution of the two phases varied considerably in individual experiments and on the basis of these the mechanical response could be divided into two types. The contraction observed was purely due to excess K+ as neither sodium deprivation nor hypertonicity induced by sucrose was able to cause contraction. Both phases of the K +con traction were con centration dependent and yielded sigmoidal concentration-response (C-R) curves. However, the parameters of their C-R curves were different suggesting differences in origin. Neither drugs that block nerve function e.g. tetrodotoxin, guanethidine or reserpine nor receptor antagonists like prazosin or atropine had any effect on C-R curves to KCl. This would largely exclude involvement of endogenous bioactive substances in the response to high K+.

Keywords: Mechanical Response of the Rat Isolated Seminal Vesicle to High Potassium