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

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

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

The Chinese Journal of Physiology

47卷3期（2004 / 09 / 30）

129 - 135

英文

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.

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