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目的探讨延髓腹外侧头端区（ＲＶＬＭ）内血管紧张素Ⅱ（ＡｎｇⅡ）在ＳＨＲ大鼠血压调节及高血压形成中的作用。方法实验在１６周龄ＳＨＲ大鼠及ＷＫＹ大鼠上进行，氨基甲酸乙酯麻醉，自主呼吸，暴露ＲＶＬＭ。ＲＶＬＭ经Ｌ－谷氨酸及组织学定位，微量注射人工脑脊液，ＡｎｇⅡ和［Ｓａｒ１，Ｔｈｒ８］ＡｎｇⅡ至ＲＶＬＭ，观察给药前后血压、心率的变化。结果在ＳＨＲ大鼠及ＷＫＹ大鼠，ＲＶＬＭ微量注射人工脑脊液，不引起明显的心血管效应。注射递增剂量的ＡｎｇⅡ（ｐｍｏｌ：０．１，１．０，１０，１００），引起血压升高，心率增加。两组实验动物血压、心率的变化无统计学差别。ＡｎｇⅡ的效应可被预先注射［Ｓａｒ１，Ｔｈｒ８］ＡｎｇⅡ阻断。相反，ＲＶＬＭ微量注射不同剂量的［Ｓａｒ１，Ｔｈｒ８］ＡｎｇⅡ，引起血压、心率下降。在ＳＨＲ大鼠，血压下降的幅度明显大于ＷＫＹ大鼠（ｍｍＨｇ：－１８±４，－２３±５，－２７±６，－３３±６ｖｓ－１１±３，－１３±４，－１７±５，－１９±５），而心率的变化在两组动物中无显著差别。结论（１）大鼠ＲＶＬＭ内ＡｎｇⅡ具有升高血压的作用。ＡｎｇⅡ的升压作用是通过ＡｎｇⅡ受体介导的。（２）ＳＨＲ大鼠ＲＶＬＭ内神经元对内源性Ａ?
Objective To investigate the role of angiotensin Ⅱ (AngⅡ) in the rostral ventrolateral medulla (RVLM) in the regulation of blood pressure and hypertension in SHR rats. Methods The experiment was performed on 16-week-old SHR rats and WKY rats. Urethane anesthesia, spontaneous respiration, and RVLM exposure were performed. The localization of RVLM by L-glutamic acid and histology, microinjection of artificial cerebrospinal fluid, AngⅡand [Sar1, Thr8] AngⅡto RVLM, observed changes of blood pressure and heart rate before and after administration. Results In SHR rats and WKY rats, microinjection of RVLM into artificial cerebrospinal fluid did not cause obvious cardiovascular effects. Increasing doses of Ang II (pmol: 0.1, 1.0, 10, 100) resulted in an increase in blood pressure and an increase in heart rate. There was no significant difference in blood pressure and heart rate between two groups of experimental animals. The effect of Ang II can be blocked by pre-injection of [Sar1, Thr8] Ang II. In contrast, RVLM microinjected with different doses of [Sar1, Thr8] AngII, causing blood pressure and heart rate to drop. In SHR rats, the amplitude of blood pressure drop was significantly greater than that of WKY rats (mmHg: -18 ± 4, -23 ± 5, -27 ± 6, -33 ± 6 vs -11 ± 3, -13 ± 4, -17 ± 5 , -19 ± 5), while changes in heart rate did not differ significantly between the two groups. Conclusions (1) Ang Ⅱ in rat RVLM can increase blood pressure. Ang II is up-regulated by Ang II receptors. (2) SHR rats RVLM neurons to endogenous A?