延髓腹面升压区提升大鼠肾灌流压作用依赖血管内皮

实验在３４只乌拉坦麻醉的雄性Ｗｉｓｔａｒ大鼠上进行，以肾灌流压（ＰＰｋ）指标，观察皂角苷和酚妥拉明灌流肾动脉对延髓腹面升压区（ＶＳＭｐ）兴奋诱发的肾血流阻抗增加效应的影响。结果表明：（１）皂角苷灌流肾动脉几乎完全取消了电刺激ＶＳＭｐ诱发的ＰＰｋ增加效应；（２）在电刺激ＶＳＭｐ诱发的ＰＰｋ升高期间，肾静脉收集液回灌同体肾动脉可提升ＰＰｋ；（３）酚妥拉明灌流肾动脉后，可明显抑制电刺激ＶＳＭｐ及肾上腺素灌流肾动脉诱发的ＰＰｋ升高作用；但对电刺激ＶＳＭｐ诱发ＰＰｋ升高期间肾静脉收集液回灌肾动脉产生的提升ＰＰｋ作用没有影响。提示ＶＳＭｐ提升肾血流阻抗作用依赖于血管内皮的存在。ＶＳＭｐ兴奋时可产生一种由α受体介导的内度依赖性，非α受体激动剂类的收缩因子。

Endothelium-dependence of Enhancement or Perfusion Pressure of Kidney Induced by Electrical Stimulation of Pressor Area on Ventral Surface of Medulla Oblongata in Rats

Experiments were performed on 34 Wistar rats,to assess the effects of perfusion with saponin or phentolamine into renal artery on enhancement of perfusion pressure of kidney(PPk)induced by electrical stimtilation of pressor area on ventral surface of medulla(VSMp).The results were as follows:(1)perfusion with saponin cancelled PPk enhancement induced by VSMp-excitation;(2)re-perfusion with the collected fluid into the same renal artery,which was obtained from renal vein in the period of enhancement of PPk induced by VSMp-excitation,can promote PPk;(3)pre-perfusion with phentolamine obviously attenuated PPk that was promoted by VSMp-excitation or adrenalin perfusion,but still retained PPk enhancement from perfusion with the collected fluid.The results indicated that the enhancement of PPk from VSMp-excitation was endothelium-dependent.An endotheliumdependent contraction factor mediated by alpha-adrenoreceptor was obtained during the VSMp-excitation.It may be a noradrenergic agonist substance.