大鼠穹窿下器血管紧张素Ⅱ的升压效应和中枢机制

Central neural mechanism underiying pressor response of subfomid to agniotensin Ⅱ in rats

目的本实验在于分析穹窿下器-室旁核-延髓头端腹外侧区(SFO-NPV-RVL)血管紧张素Ⅱ(AⅡ)升压系统,通过外侧下丘脑/穹窿周围区(LH/PF)AⅡ能神经纤维,与中央杏仁核(AC)情绪升压环路中之间的关系。方法脑内微量注射不同的药物,记录血压和心率的变化。结果 (1)L-谷氨酸钠(Glu)微量注射到AC或LH/PF可引起升压反应。(2)[Sar^1,Thr^8]-AⅡ(ST-AⅡ,AⅡ的拮抗剂)分别预注入SFO、双侧NPV、双侧RVL,AC或LH/PF的升压反应均被所衰减。(3)NPV升压反应还可被双侧蓝斑(LC)内预注射ST-AⅡ衰减,但SFO的升压反应不受影响。结论以上的结果表明SFO-NPV-RVL AⅡ升压系统,通过LH/PF投射到SFO的AⅡ能神经纤维,参与AC的情绪升压反应,而LC不参与SFO的升压反应。

Objective the present study was to examine whether the suhfornical organ - nucleus paraventricularis - rostral ventrolateral medulla (SFO- NPV- RVL) angiotensin Ⅱ (A Ⅱ ) pressor system is involved in the central amygdaloid nucleus (AC) - emotional pressor circuit via A Ⅱ ergic neurons in the lateral hypothalamus (LH/PF) .Method Intrabrain microinjection of drugs combined with observation of changes in arterial pressure and heart rate were used. Results (1) the pressor responses can be Induced by L- glutamate (Glu) microinjection into the AC or LH/PF; (2) Both the AC - and LH/PF-pressor responses could be decreased by preinijection of [Sar1, Thr8] - angiotensin Ⅱ (ST-A Ⅱ, an antagonist of A Ⅱ) into either SFO, NPV, orRVL. (3) ST-A Ⅱ preinjection into bilateral LC could only attenuate NPV pressor responses but affecting SFO pressor responses. Conclusion The above results prove that the ( SFO - NPV - RVL) A Ⅱ pressor system involves the AC - emotional pressor response via A Ⅱ ergic projections from the LH/PF to the SFO. Whereas LC was not involved in the SFO pressor responses.