Chloride Channel Activity of Vascular Smooth Muscle in the Spontaneous Hypertensive Rats

Zhen Wang ； Qiang Chai ； Zhixiang Liu ； Dexiang Liu ； Lianbi Chen

《The Chinese Journal of Physiology》 47卷3期 (2004/09) Pp. 129-135

並列摘要

To characterize the activity of the Ca(superscript 2+)-activated Clˉ channels in vascular smooth muscle (VSM) of the spontaneous hypertensive rats (SHR), the isolated mesenteric vascular beds and tail artery strips were preparated from SHR and Wistar rats aged 7-8 weeks. The changes in contractile response to norepinphrine (NE) were taken as an index of vascular mortion. Results showed that the contractile responses of mesenteric arteries and tail arteries to NE in SHE were significantly greater than that in Wistar rats. The inhibition magnitude of the contractile response by Ca(superscript 2+)-activated Clˉ channel blocker, niflumic acid in SHR was significantly less than that in Wistar rats. Decreasing the extracellular Clˉ concentration increased the contractile response to NE significantly, but the amplitude of enhanced contractile response in SHR was greater than that in Wistar rats. It can be concluded that NE-induced contraction was enhanced in SHR, which is partly due to an increase in Clˉ efflux through the Ca(superscript 2+)-activated Clˉ channels. The chloride channel activity may be increased in association with the elevation of blood pressure.

並列關鍵字

calcium-activated chloride channels ； norepinephrine ； niflumic acid ； spontaneous hypertensive rats

參考文獻

Asano, M.,Matsuda, T.,Hayakawa, M.,Ito, K.M.,Ito, K.(1993).Increased resting calcium maintains the myogenic tone and activates K(superscript +) channels in arteries from young spontaneously hypertensive rats.Ear. J. Pharmacol..247,295-304.

Chipperfiled, A. R.,Davis, J.P.,Harper, A.A.(1993).An acetazolamide-sensitive inward chloride pump in vascular smooth muscle.Biochem. Biophys. Res. Commum..194,407-412.

Cox, R.H.,Lozinskaya, I.M.(1995).Augmented calcium currents in mesenteric artery branches of the spontaneously hypertensive rat.Hypertension.26,1060-1064.

Criddle, D.N.,de Moura, R. S.,Greenwood, I.A.,Large, W.A.(1996).Effect of niflumic acid on noradrenaline-induced contractions of the rat arota.Br. J. Pharmacol..118,1065-1071.

Criddle, D.N.,de Moura, R. S.,Greenwood, I. A.,Large, W.A.(1997).Inhibitory action of niflumic acid on noradrenaline-and 5-hydroxytryptamine-indnced pressor responses in the isolated mesenteric vascular bed of the rat.Br. J. Pharmacol..120,813-818.