Direct inhibitory effects of taurine on norepinephrine-induced contraction in mesenteric artery of stroke-prone spontaneously hypertensive rats

The effect of taurine on vascular reactivity was investigated in the mesenteric artery of Wistar Kyoto (WKY), and stroke-prone spontaneously hypertensive rats (SHRSP). Administration of taurine significantly decreased blood pressure of SHRSP but not WKY. The mesenteric artery of taurine-treated SHRSP was excised to observe the contractile responses to transmural electrical stimulation and to several vasoactive substances. Vasocontraction induced by norepinephrine (NE) was significantly decreased by taurine. However, contraction elicited by the other substances tested was not affected. Consistently, when the vessels of SHRSP were pretreated with taurine in vitro, only the NE-induced vasocontraction was specifically attenuated. No effect was observed in WKY vessels. These results indicate that the hypotensive effect of taurine is accounted for at least in part its direct action on blood vessels.