Rioux F, Quirion R, St-Pierre S, Regoli D, Jolicoeur F B, Bélanger F, Barbeau A
Eur J Pharmacol. 1981 Jan 29;69(3):241-7. doi: 10.1016/0014-2999(81)90469-6.
We have evaluated the cardiovascular effects of intracerebroventricular (i.c.v.) injections of neurotensin (NT) in pentobarbital-anesthetized rats. In most animals, the i.c.v. injection of NT (5.4, 10.8 and 16.2 nmol/rat) induced a dose-dependent fall of the arterial blood pressure. This effect was usually rapid in onset (30-60 sec) and of short duration (approximately 1-4 min). It was not preceded nor accompanied by any significant alteration of the heart rate. In about 25% of the animals, the vasodepressor effect of i.c.v. injections of NT was long lasting (30-45 min). Conscious rats were much less sensitive than anesthetized animals. The hypotensive effects of intravenously (i.v.) administered NT was fully maintained in animals made tolerant to the hypotensive effect of centrally administered NT. Similarly, the animals made unresponsive to i.v. injections of NT either by repeated i.v. injections of NT (e.g. tachyphylaxis) or by a chronic treatment with compound 48/80, still responded normally to centrally administered NT. The results suggest the existence of at least two anatomically distinct sites of action through which NT can induce hypotension in rats. One appears to be located in the periphery and the other, in the central nervous system.
我们评估了在戊巴比妥麻醉的大鼠中脑室内注射神经降压素（NT）对心血管系统的影响。在大多数动物中，脑室内注射NT（5.4、10.8和16.2 nmol/只大鼠）可引起动脉血压的剂量依赖性下降。这种效应通常起效迅速（30 - 60秒）且持续时间短（约1 - 4分钟）。心率在血压下降之前及过程中均无明显改变。在约25%的动物中，脑室内注射NT的血管降压作用持续时间较长（30 - 45分钟）。清醒大鼠对NT的敏感性远低于麻醉动物。静脉注射NT的降压作用在对中枢注射NT产生耐受的动物中完全维持。同样，通过重复静脉注射NT（如快速耐受）或用48/80化合物进行慢性处理而对静脉注射NT无反应的动物，对中枢注射NT仍有正常反应。结果表明，至少存在两个解剖学上不同的作用部位，通过这些部位NT可在大鼠中诱导低血压。一个部位似乎位于外周，另一个位于中枢神经系统。
