摘要:
目的 研究不同动脉对同一血管收缩剂的反应性是否存在差异,及其与L-型钙通道的关系.方法 采用离体血管张力测定实验方法,测定在累积浓度血管收缩剂处理下的大鼠胸主动脉、肾内动脉或冠状动脉的张力变化以及L-型钙通道阻断剂硝苯地平(nifedipine)的影响.结果 苯肾上腺素(phenylephrine,Phe)对冠状动脉无明显影响,但可诱导胸主动脉和肾内动脉产生明显的浓度依赖性收缩,胸主动脉的pEC50明显大于肾内动脉(P<0.05);给予硝苯地平孵育后,再给予累积浓度的Phe,胸主动脉收缩的下降幅度大于肾内动脉(P<0.05).5-羟色胺(5-hydroxy tryptamine,5-HT)对胸主动脉的收缩作用不明显,但可浓度依赖性诱导肾内动脉和冠状动脉收缩;给予硝苯地平孵育后,再给予累积浓度的5-HT,冠状动脉收缩的下降幅度明显大于肾内动脉(P<0.05).胸主动脉、肾内动脉和冠状动脉均对血栓素A2类似 物 (9, 11-dideoxy-11α, 9α- epoxymethanoprostaglandin, U46619)产生浓度依赖性收缩,肾内动脉收缩量效曲线的Emax最小(P<0.05),胸主动脉收缩量效曲线pEC50最大(P<0.05).给予硝苯地平孵育后,再给予累积浓度的U46619,冠状动脉收缩的下降幅度最大,胸主动脉收缩的下降幅度最小.结论 大鼠胸主动脉、肾内动脉及冠状动脉对同一血管收缩剂的反应存在异质性,其中L-型钙通道介导的收缩作用也不同.%Aim To study whether there was arterial heterogeneity and association with L-type calcium channel (LCC) in different parts of arteries in re-sponse to certain vasoconstrictor. Methods The aor-ta, renal arteries and coronary arteries were dissected from rats. Arterial ring contractions induced by pheny-lephrine (Phe), 5-hydroxyl tryptamine (5-HT) or U46619 in concentration-dependent manner were meas-ured using the Multi Myograph system and the response to nifedipne was observed. Results (1) Phe had no obvious effect on the tension of coronary artery,but in-duced concentration-dependent vasoconstriction in aor-ta and renal artery,and pEC50of aorta was significantly higher than that of renal artery (P<0.05). The inhi-bition rate of nifedipine on the aortic contractile re-sponses was significantly higher than that of renal arter-y (P<0.05). (2) The contraction induced by 5-HT on aorta was not obvious, but was significant on renal artery and coronary artery. The inhibitory rate of nife-dipine on coronary artery vasoconstriction was signifi-cantly higher than that of renal artery (P <0.05). (3) U46619 could induce aorta,renal artery and coro-nary artery concentration- dependent contraction, but the Emaxof them were both higher than that of renal ar-tery (P<0.05). And the pEC50of aorta was the lar-gest (P<0.05). Nifedipine significantly inhibited the contraction of aorta, renal artery and coronary artery induced by U46619 with the greatest inhibitory rate on the coronary artery vasoconstriction and minimal inhibi-tion on aortic vasoconstriction. Conclusions The re-sponse to certain vasoconstrictor is different among aor-ta, renal artery and coronary artery in rats, and the contraction mediated by L-type calcium channel is also different.