Nishina H, Ozaki T, Hanson M A, Poston L
Department of Obstetrics and Gynaecology, University College London.
Br J Pharmacol. 1999 Jun;127(4):809-12. doi: 10.1038/sj.bjp.0702641.
Isolated arteries from the femoral circulation of Wistar rats mounted on a small vessel myograph demonstrated age related tension development to noradrenaline (NA, 1 x 10(-8) - 5 x 10(-5) M) day 20 greater than day 10 (P<0.005); day 100 greater than day 20 (P<0.001) and depolarizing potassium (125 mM) buffer day 20 greater than day 10 (P<0.001). NA evoked dilatation in femoral arteries from neonatal rats (10 days) when added to unstimulated vessels or to those preconstricted with the thromboxane mimetic, U46619. Relaxation to NA was inhibited by L-NAME (0.1 mM) (P<0.001), endothelial removal (P<0.001) and the alpha2-adrenoceptor antagonist, yohimbine (0.1 microM) (P<0.001). Alpha1- or beta-adrenoceptor antagonism was without effect. Relaxation was evoked in femoral arteries of the 10-day-old rats by the alpha2-adrenoceptor agonist UK14304 (1 x 10(-8) - 5 x 10(-5) M). This relaxation was also abolished by L-NAME (0.1 mM) (P<0.001) or endothelial removal (P<0.001). Alpha2-adrenoceptor-mediated vasorelaxation was the predominant response to NA stimulation in femoral arteries of the neonatal rat. These responses were endothelium-dependent and were NO-mediated.
将来自Wistar大鼠股循环的离体动脉安装在小型血管肌动描记器上，结果显示，与去甲肾上腺素（NA，1×10⁻⁸ - 5×10⁻⁵ M）相关的张力发展在第20天比第10天更大（P<0.005）；第100天比第20天更大（P<0.001），并且在第20天对去极化钾（125 mM）缓冲液的反应比第10天更大（P<0.001）。当将NA添加到未受刺激的血管或用血栓素类似物U46619预收缩的血管中时，NA会引起新生大鼠（10天）股动脉的扩张。L-NAME（0.1 mM）（P<0.001）、去除内皮（P<0.001）和α₂-肾上腺素能受体拮抗剂育亨宾（0.1 μM）（P<0.001）可抑制对NA的舒张反应。α₁-或β-肾上腺素能受体拮抗作用无效。α₂-肾上腺素能受体激动剂UK14304（1×10⁻⁸ - 5×10⁻⁵ M）可引起10日龄大鼠股动脉舒张。L-NAME（0.1 mM）（P<0.001）或去除内皮（P<0.001）也可消除这种舒张。α₂-肾上腺素能受体介导的血管舒张是新生大鼠股动脉对NA刺激的主要反应。这些反应是内皮依赖性的，且由一氧化氮介导。
