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研究大鼠延髓腹面降压区对心率和肾血管紧张性的影响及其机制。方法采用延髓腹外侧部微量注射法，以整体灌流肾为模型，观察延髓腹面加压区预先注入不同受体阻断剂对延髓腹面降压区心血管效应的影响。结果（１）Ｌ－谷氨酸（Ｌ－ｇｌｕ）刺激大鼠延髓腹面降压区（ＶＳＭｄ），可见平均动脉压下降，心率（ＨＲ）减慢，肾灌流压（ＰＰｋ）下降。（２）延髓腹面升压区（ＶＳＭｐ）预先注射普萘洛尔或酚妥拉明，均能明显衰减Ｌ－ｇｌｕ兴奋ＶＳＭｄ的降压、降ＰＰｋ效应，但ＶＳＭｄ的降心率作用基本不受影响。（３）切断双侧迷走神经后预先在ＶＳＭｐ同时注射普萘洛尔和酚妥拉明，ＶＳＭｄ的降压效应可被完全取消。（４）将荷包牡丹碱注入ＶＳＭｐ可使基础血压升高，并使ＶＳＭｄ的降压降心率、降ＰＰｋ效应翻转。结论ＶＳＭｄ对外周血管紧张性的影响是通过ＶＳＭｐ内的加压神经元实现的。ＶＳＭｄ通过α和β受体作用于γ－氨基丁酸能中间神经元对ＶＳＭｐ的交感神经元产生抑制作用，使外周血管阻抗下降。
To investigate the effect of medullary ventricular hypotensive area on heart rate and renal vascular tone in rats and its mechanism. Methods The medulla oblongata microinjection was used to evaluate the effects of pre-injection of different blockers on the cardiovascular effects of medullary vasospasm in the medulla oblongata. Results (1) L-Glu stimulated the VSMC of the medulla oblongata in rats. Mean arterial pressure (MAP), heart rate (HR) and PPK decreased. (2) Propranolol or phentolamine pre-injected VSMC significantly attenuated the antihypertensive and PPK effects of L-glu stimulated VSMd, but the effect of VSMd on heart rate lowering was not affected . (3) After bilateral vagus nerve is cut off, propranolol and phentolamine are injected into VSMp at the same time. The antihypertensive effect of VSMd can be completely eliminated. (4) The injection of bicuculline into VSMp can raise the basic blood pressure, and make the antihypertensive heart rate and PPK effect of VSMd turn over. Conclusion The effect of VSMd on peripheral vascular tone is achieved by pressurized neurons in VSMp. VSMd through α and β receptors on γ-aminobutyric acid can interneurons on VSMp sympathetic neurons produce inhibition of peripheral vascular resistance decreased.