下丘脑内血管升压素在紧张应激引起大鼠血压升高反应中的作用

Effect of Hypothalamic Vasopressin in Blood Increase Reaction in Stressed Rats

目的观察下丘脑血管升压素（ｖａｓｏｐｒｅｓｓｉｎ，ＡＶＰ）在慢性紧张应激引起大鼠血压升高过程中的作用。方法实验在给予慢性应激刺激后，引起动物血压出现显著升高的雄性Ｓｐｒａｇｕｅ－Ｄａｗｌｅｙ大鼠中进行。在通过侧脑室（ｉｃｖ．）及外周静脉（ｉｖ．）给予大鼠注射血管升压素Ｖ１受体拮抗剂ｄ（ＣＨ２）５Ｔｙｒ（Ｍｅ）ＡＶＰ后，观察其对动物平均动脉压（ＭＢＰ）的影响。结果在正常大鼠中ｉｃｖ．或ｉｖ．注射ｄ（ＣＨ２）５Ｔｙｒ（Ｍｅ）ＡＶＰ后，动物ＭＢＰ无显著改变，但在慢性应激引起血压出现显著升高的大鼠中，ｉｃｖ．ｄ（ＣＨ２）５Ｔｙｒ（Ｍｅ）ＡＶＰ后，动物血压出现显著降低，降压反应持续约２ｈ，最大效应出现在给药后约４５ｍｉｎ，大鼠ＭＢＰ从给药前的１３４±１１．９ｍｍＨｇ的基础上，平均下降３５．６±１２．６ｍｍＨｇ，而通过ｉｖ．ｄ（ＣＨ２）５Ｔｙｒ（Ｍｅ）ＡＶＰ后，却未观察到ＭＢＰ有显著改变。结论由下丘脑合成并释放的ＡＶＰ参与慢性应激引起的大鼠血压升高反应。

Aim\ To investigate the role of hypothalamic vasopressin (AVP) in chronic stress induced increasing blood pressure in rats.\ Methods\ Experiments were carried out on male Sprague Dawley rats. Chronic stress of repeated foot electric shock combined with noise were given twice a day (2 h each time ) for 15 days.\ Results\ The arterial pressure of stressed rats was increased after 15 days stimulations. No significantly change in mean blood pressure (MBP) was observed in control rats after administration of AVP V 1 receptor antagonist d(CH 2) 5Tyr(Me)AVP 0.3 μg via either intracerebroventricular (icv.) or intravenous (iv.) injection. Injection d(CH 2) 5Tyr(Me)AVP(icv.) resulted in a decrease in MBP in the stressed rats with high blood pressure. The effect of icv. d(CH 2) 5Tyr(Me)AVP lasted about 2 h with the peak effect appeared about 45 min after icv. injection. The MBP decreased by 35.6±12.6 mmHg from 134±11.9 mmHg before injection( n =5). No significant change in the MBP was observed after iv. injection of the same dose of d(CH 2) 5Tyr(Me)AVP.\ Conclusion\ Theses data suggest that the hypothalamic vasopressin participates in the mechanisms of the chronic stress induced increase in blood pressure in rats. The effect of AVP is mediated mainly by central V 1 receptors.