Contributions of baroreceptor reflex to the hypothermic effect of intraventricular angiotensin II in rats.
Contributions of baroreceptor reflex to the hypothermic effect of intraventricular angiotensin II in rats.
复制标题
压力感受器反射对大鼠心室内血管紧张素 II 的低温作用的贡献。
DOI：
10.2170/jjphysiol.35.301
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
T. Nagasaka
中科院分区：
文献类型：
--
作者：
O. Shido;A. Kifune;T. Nagasaka
在常温18℃的非麻醉大鼠侧脑室注射血管紧张素II(AII)，连续监测平均血压(BP)、心率(HR)、代谢率(M)、结肠温度(TCOL)、肩峰间棕色脂肪组织(TBAT)和尾部皮肤温度(TSK)，探讨其降温作用的机制。AII 5微克剂量组大鼠血压明显升高并伴有心动过缓，M和Tco1显著降低。TBAT和TCOL之间的差异显著减小，这表明蝙蝠的非颤抖产热受到了抑制。注射AII对TSK无明显影响。然而，在去窦弓神经后，注射AII后，尽管血压显著升高，但Tco和M的下降明显减少。此外，静脉注射精氨酸加压素拮抗剂可抑制AII注射后血压的升高和HR、Tco、M的下降。上述结果表明，大鼠侧脑室注射AII后体温下降主要是由于M的压力反射抑制，并在一定程度上直接作用于体温调节中枢。
The mechanisms of the hypothermic effect of angiotensin II (AII) injected into the lateral ventricle were investigated in unanesthetized rats at an ambient temperature of 18 degrees C. Mean blood pressure (BP), heart rate (HR), metabolic rate (M), colonic temperature (Tcol), and temperatures of the interscapular brown adipose tissue (TBAT), and the tail skin (Tsk) were continuously monitored. AII at a dose of 5 micrograms produced a sharp and marked elevation in BP accompanied by bradycardia, and a decrease of M and Tco1 in the sinoaortic baroreceptor intact rats. The difference between TBAT and Tcol decreased significantly, which suggests a suppression of nonshivering thermogenesis of the BAT. Tsk was not changed by the AII injection. After sinoaortic denervation, however, the decrease in Tcol and M with AII injection was significantly reduced despite a marked elevation in BP. In addition, intravenous arginine-vasopressin antagonist pretreatment suppressed the elevation in BP and the decrease in HR, Tcol, and M after AII injection. From these results, it is concluded that the hypothermia which occurred after AII injection into the lateral ventricle can be largely attributed to the baroreflexive suppression of M, and to some extent to the direct effect on the thermoregulatory center in rats.