Modulatory effect of sodium nitroprusside and 8Br-cGMP on mastoparan-7 induced contraction

Abstract

I n t r o d u c t i o n . Mastoparan-7 activates G-protein and stimulates apoptosis, but in smooth muscle cells leads to increase in perfusion pressure.

Main a i m of this study was to evaluate the modulatory effect of 8Br-cGMP and sodium nitroprusside on vascular smooth muscle contraction induced by direct stimulation of G-protein with mastoparan-7.

Ma t e r i a l  a n d  m e t h o d s . Experiments were performed on isolated and perfused tail artery of Wistar rats. Contraction force in our model was measured by increased level of perfusion pressure with a constant flow.

R e s u l t s . Concentration-response curves obtained for mastoparan-7 presented an sigmoidal relation. In presence of SNP and 8Br-cGMP the significant and dose dependent leftward shift with significant reduction in maximal responses was present. Moreover, analyzing function of calcium stores the significant inhibition of influx from both, intra- and extracellular calcium stores was present.

C o n c l u s i o n . Results of our experiments suggest that contraction induced by direct activation of G-protein with mastoparan-7 may by effectively inhibited in the presence of donors of nitric oxide such as sodium nitroprusside and in the presence of 8Br-cGMP.