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Changes in potassium currents of vascular smooth muscle cells isolated from hindquarter arteries of rats after 4 weeks simulated weightlessness

Fu Zhaojun, Cheng Hongwei, Zhang Lifan, Ma Jin

Department of Aerospace Physiology,Fourth Military Medical University.Xi^an 710032,Shaanxi

Abstract

The changes in potassium currents of vascular smooth muscle cells (VSMCs) isolated from saphenous arteries and the 2nd-6th order branches of the mesenteric arteries of 4-week tail-suspended rats (SUS) were examined using whole cell patch clamp technique. The resting potential (RP) of the VSMCs from SUS group was more negative compared with that of the control group (CON). The whole cell potassium current densities of VSMCs isolated from the saphenous arteries and small mesenteric arteries in SUS gruop were significantly larger thanthose of the CON group. The BK_(Ca) and K_(V) current densities of VSMCs from saphenous arteries and small mesenteric arteries from SUS group were also significantly larger than those from the CON group. It is speculated that the hyperpolarization of VSMCs and decreased calcium influx through voltage-dependent calcium channels might be one of the electrophysiological mechanisms involved in the depressed vasoreactivity of hindquarter arteries induced by simulated weightlessness.

Key words: Weightlessness simulation;Patch-clamp techniques;Potassium channels;Vascular smooth muscle

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Citing This Article：

Fu Zhaojun, Cheng Hongwei, Zhang Lifan, Ma Jin. Changes in potassium currents of vascular smooth muscle cells isolated from hindquarter arteries of rats after 4 weeks simulated weightlessness. Acta Physiol Sin 2002; 54 (6): (in Chinese with English abstract).