Effect of superoxide anion on contractility of aortic smooth muscle cells

Aim: To investigate the changes of [Ca²⁺]_i and contractility of aortic smooth muscle cells induced by superoxide anion. Methods: The aortic smooth muscle cells were primarily cultured. The effect of superoxide anion on [Ca²⁺]_i was measured by a digital fluorescence microscopy system. Muscle contractility was analyzed by collagen gel contraction system. Results High-K⁺ and A-23187 -induced [Ca ²⁺]_i elevated both in control and X/XO-treated cells. The net increment of [Ca²⁺]_i was not significantly different between control and X/XO-treated cells (P > 0.05). Collagen gel contraction area in X/XO-treated cells induced by High-K⁺ and A-23187 was impaired from 18.32% ± 2.11% to 5.13% ± 0.45% (P < 0.01) and 17.16% ± 1.10% to 4.31% ± 0.04% (P < 0.01). Conclusion: The results demonstrate that superoxide anion attenuates smooth muscle contraction, whereas [Ca²⁺]_i increased by these agents were not affected.