一肾一包型高血压大鼠动脉压力反射敏感性的变化

本文用苯肾上腺素和硝普钠改变血压,同步记录心动周期,用平均动脉血压-心动周期关系为指标,研究了 Grollman一肾一包型肾性高血压大鼠动脉压力感受性反射敏感性(Ar-terial baroreflex sensitivity,ABS)的变化。实验分为三组:Grollman 高血压组,假手术组和正常组,手术后三周进行实验,结果如下:Grollman 高血压组的 ABS 明显低于假手术组(P<0.01);侧脑室注射150μg Captopril 后,Grollman 高血压组和假手术组的 MAP都下降,但 Grollman 组更明显(注射35 min 时,P<0.01 Fig.1),注射后35到60 min时,假手术组的 MAP 已趋稳定水平,而 Grollman 组仍有下降趋势。注射后60 min 时高血压组的 ABS 比注射前60 min 值明显增加,而假手术组的增加不明显(Fig.2)。此外向正常动物 i.v.c.注射8μg 血管紧张素Ⅱ,MAP 显著增加但 ABS 则显著下降。上述结果提示在Grollman 肾性高血压形成期,ABS 下降,这可能与中枢血管紧张素Ⅱ含量的增加有关。

CHANGES OF THE ARTERIAL BAROREFLEX SENSITIVITY IN ONE-KIDNEY GROLLMAN HYPERTENSIVE RATS

The objective of this study was to investigate the changes of arterial baroreflex sensitivity (ABS) in one-kidney Grollman hypertensive rats. The blood pressure was altered with phenylephrine or sodium nitroprusside. Mean arterial pressure (MAP) and pulse interval were recorded simultaneously and the MAP-pulse interval regression line was constructed. All rats were divided into three groups: Grollman-operation group, sham-operated group and normal group. ABS was determined at the 3rd week after operation. The results were as follows: The ABS of the Grollman hypertensive group was significantly lower than that of the sham-operated group (P less than 0.01). After i.v.c. injection of 150 micrograms captopril the MAP of both groups are lowered, but more significantly in Grollman than in the sham-operated group (P less than 0.05, at 35 min after injection). From 35 to 60 min after injection, the MAP of the sham-operated group has practically reached a steady level while that of the Grollman group still shows significant tendency of decline. At 60th min, the ABS of the hypertensive was significantly increased than that measured 60 min before injection (P less than 0.05), while similar measurements for the sham-operated group showed only a slight or much less significant increase. MAP was increased and ABS was decreased by i.v.c. injection of 8 micrograms angiotension II in the normal group. The results of the present investigation indicate that ABS decreases during the development of one-kidney Grollman hypertensive rats, and that this change appears to be related to the increased concentration of angiotension II in the brain.