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Interleukirr 2 induced endothelium dependent relaxation of rat thoracic aorta

CAO Chuir Mei, YE Song, YU Hu, XU Qing Sheng, YE Zhi- Guo, SHEN Yue-Liang, LU Yuan, XIA Qiang

Department of Physiology，Zhejiang University School of Medicine，Hangzhou 310031

Abstract

Interleukixr 2(IL 2) therapy often results in potentially life-threatening side effects including hypotension .However，the mechanism has not been completely elucidated.In order to determine whether IL -2 modifies vascular tone，we investigated the effect of IL -2 on rat thoracic aorta rings and the underlying mechanisms.Effects of IL -2 on the contraction of high KCl and phenylephrine(PE) preconstricted rat thoracic aorta with or without endothelium were determined by organ bath technique .To explore the mechanism，nitric oxide synthase inhibitor L一N( G)一nitroarginine methyl ester(L- NAME)，
guanylyl cyclase inhibitor methylene blue，and cyclooxygenase inhibitor indomethacin were used .IL 2(10一1000 U/ ml) caused concentration dependent relaxation of aorta rings preconstricted with PE(10p mol/ L) in endothelium-intact rings，but had no effect on KCl(120 m mol/ L) preconstricted rings.Re-
moval of the endothelium，or pretreatment with L- NAME(0. 1 m mol/ L) or methylene blue(10 umol/L) or indomethacin(10 pmol/L)，inhibited the relaxation of IL -2.The results indicate that the relaxation by IL -2 in rat aorta ring is endothelium7dependent and is possibly mediated by the NO-guanylyl cy-
clase pathway and cyclooxygenase-dependent pathway.

Key words: interleukin-2;NO;;

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Citing This Article：

CAO Chuir Mei, YE Song, YU Hu, XU Qing Sheng, YE Zhi- Guo, SHEN Yue-Liang, LU Yuan, XIA Qiang . Interleukirr 2 induced endothelium dependent relaxation of rat thoracic aorta. Acta Physiol Sin 2003; 55 (1): (in Chinese with English abstract).