Sodium nitroprusside inhibits the intracellular calcium storage and release in rabbit aorta

ABSTRACT

This study aimed to investigate the possible involvement of the K+ channels by performing concentration response curves of SNP on K+Cl- precontracted aorta. The effect of SNP on the process of Ca2+ release from ic stores by studying its effect on phenylephrine induced contractions in Ca2+ free solution was also studied. The effect of SNP on the process of filling of the ic stores after their emptying by repeated application of phenylephrine in Ca2+ free solution and before the filling period in which the aorta was incubated in normal salt solution containing Ca2+ was evaluated. The possible involvement of endothelium in the SNP induced vasorelaxation was also investigated. The results showed that the relaxant effect of SNP is not endothelium dependent. SNP completely abolished contractions induced by low K+ and partially abolished contractions induced by high K+. SNP produced a significant dose dependent inhibition of the process of filling of the ic stores of Ca2+ and the process of Ca2+ release from these stores