Keung Wendy, Vanhoutte Paul M, Man Ricky Y K
Department of Pharmacology, Faculty of Medicine, The University of Hong Kong, Level 2, Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Hong Kong SAR, People's Republic of China.
Br J Pharmacol. 2005 Dec;146(8):1148-55. doi: 10.1038/sj.bjp.0706422.
The aim of the present study was to investigate the gender differences in the acute effects of 17beta-estradiol on the rat superior mesenteric artery. Isometric tension was measured in rings of mesenteric arteries from both male and female Sprague-Dawley rats. Relaxation to acetylcholine was not significantly different between arteries (with endothelium) from male and female rats in the absence or presence of 17beta-estradiol. After blockade of endothelium-dependent hyperpolarizations with apamin (0.3 microM) plus charybdotoxin (0.1 microM), acute exposure to 17beta-estradiol (1 nM) for 30 min resulted in enhancement of relaxation to acetylcholine in arteries from male but not female rats. After acute exposure to 17beta-estradiol, mesenteric arteries from male rats were more sensitive to sodium nitroprusside than arteries from female rats. Contractions of mesenteric arteries to phenylephrine and 9,11-dideoxy-11alpha,9alpha-epoxymethanoprostaglandin F(2alpha) (U46619) were greater in arteries from male rats than female rats. This difference was not detected after acute exposure to 17beta-estradiol. In preparations without endothelium, the enhancement of relaxation and reduction in contraction in arteries from male rats were preserved. These results suggest that there exists a gender difference in the response to the acute nongenomic modulatory effect of 17beta-estradiol in rat mesenteric arteries. Arteries from male rats seem to be more sensitive to the modulatory effects of 17beta-estradiol than arteries from female rats. The effect appears to be mainly at the level of the vascular smooth muscles.
本研究的目的是调查17β-雌二醇对大鼠肠系膜上动脉急性作用的性别差异。在雄性和雌性Sprague-Dawley大鼠的肠系膜动脉环中测量等长张力。在不存在或存在17β-雌二醇的情况下，雄性和雌性大鼠有内皮的动脉对乙酰胆碱的舒张反应无显著差异。在用蜂毒明肽（0.3微摩尔）加蝎毒素（0.1微摩尔）阻断内皮依赖性超极化后，急性暴露于17β-雌二醇（1纳摩尔）30分钟导致雄性大鼠动脉对乙酰胆碱的舒张增强，而雌性大鼠动脉则无此现象。急性暴露于17β-雌二醇后，雄性大鼠的肠系膜动脉对硝普钠比雌性大鼠的动脉更敏感。雄性大鼠肠系膜动脉对去氧肾上腺素和9,11-二脱氧-11α,9α-环氧甲前列腺素F2α（U46619）的收缩作用比雌性大鼠更强。急性暴露于17β-雌二醇后未检测到这种差异。在无内皮的制备物中，雄性大鼠动脉的舒张增强和收缩减弱得以保留。这些结果表明，大鼠肠系膜动脉对17β-雌二醇急性非基因组调节作用的反应存在性别差异。雄性大鼠的动脉似乎比雌性大鼠的动脉对17β-雌二醇的调节作用更敏感。这种作用似乎主要在血管平滑肌水平。
