Hara S, Matsumura M, Ueda M
Shionogi Research Laboratories, Shionogi & Co., Ltd., Osaka, Japan.
Jpn Heart J. 1993 Jul;34(4):439-49. doi: 10.1536/ihj.34.439.
The effects of the endogenous pressor agents noradrenaline (NA), and angiotensin II (Ang II), and of the hypotensive agents acetylcholine (ACh) and adenosine (ADS), on blood pressure and heart rate in conscious and unrestrained stroke-prone spontaneously hypertensive rats (SHR-SP) and normotensive Wistar Kyoto rats (WKY) of different ages (4-9 weeks old) were investigated. Pressor responses to NA were enhanced in 7- and 9- week-old SHR-SP compared with those in WKY, but pressor responses to Ang II in SHR-SP were not different from those in WKY at all ages. The bradycardias following pressor responses to NA and Ang II were markedly attenuated in SHR-SP, especially older ones. Hypotensive responses to ACH were enhanced in SHR-SP, particularly at 9 weeks of age. However, hypotensive responses to ADS were attenuated in SHR-SP, especially at 7 weeks of age. Transient fall of heart rate due to ADS was also attenuated in 7- and 9- week-old SHR-SP. These alterations of hemodynamic or cardiovascular responses in SHR-SP became more evident in the established stages of hypertension. These results suggest intimate relationships of the enhanced pressor responses to NA, attenuated bradycardias following pressor effects with NA or Ang II, and the attenuated hypotensive responses to ADS with the development or the maintenance of hypertension in SHR-SP.
研究了内源性升压剂去甲肾上腺素（NA）和血管紧张素II（Ang II）以及降压剂乙酰胆碱（ACh）和腺苷（ADS）对不同年龄（4 - 9周龄）的清醒、自由活动的易中风自发性高血压大鼠（SHR - SP）和正常血压的Wistar Kyoto大鼠（WKY）血压和心率的影响。与WKY相比，7周龄和9周龄的SHR - SP对NA的升压反应增强，但SHR - SP对Ang II的升压反应在所有年龄段与WKY并无差异。SHR - SP中，尤其是年龄较大的大鼠，对NA和Ang II升压反应后的心动过缓明显减弱。SHR - SP对ACH的降压反应增强，尤其是在9周龄时。然而，SHR - SP对ADS的降压反应减弱，尤其是在7周龄时。7周龄和9周龄的SHR - SP中，ADS引起的心率短暂下降也减弱。SHR - SP中这些血液动力学或心血管反应的改变在高血压的发病阶段更为明显。这些结果表明，SHR - SP中对NA增强的升压反应、NA或Ang II升压作用后减弱的心动过缓以及对ADS减弱的降压反应与高血压的发生或维持密切相关。
