Pressor effects of orexins injected intracisternally and to rostral ventrolateral medulla of anesthetized rats
Pressor effects of orexins injected intracisternally and to rostral ventrolateral medulla of anesthetized rats
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DOI：
10.1152/ajpregu.2000.278.3.r692
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发表时间：
2000-03-01
影响因子：
2.8
通讯作者：
Dun, NJ
中科院分区：
文献类型：
--
作者：
Chen, CT;Hwang, LL;Dun, NJ
食欲素A和B是最近分离的两种下丘脑肽，已报道在大鼠脑室内注射后增加食物消耗。除了下丘脑，食欲素A免疫反应性纤维已被观察到与心血管功能相关的几个领域的髓质。本研究旨在探讨食欲素可能通过与延髓神经元相互作用而影响心血管反应的假说。脑池内注射食欲素A（0.0056 - 7.0 nmol）或B（0.028 - 0.28 nmol）可剂量依赖性地增加麻醉大鼠的平均动脉压（MAP）4 - 27 mmHg和心率（HR）26 - 80次/min，其中食欲素A在这方面更有效。静脉注射高浓度食欲素对MAP和HR无明显影响。组织学检查证实，向延髓头端腹外侧区微量注射食欲素A（14 pmol/50.6 nl）可增加MAP和HR。我们的研究结果表明，除了在正性摄食行为中的作用外，食欲素还可通过对延髓神经元的作用增强心血管反应。
Orexin A and B, two recently isolated hypothalamic peptides, have been reported to increase food consumption upon intracerebroventricular injections in rats. In addition to the hypothalamus, orexin A-immunoreactive fibers have been observed in several areas of the medulla that are associated with cardiovascular functions. The present study was undertaken to evaluate the hypothesis that orexins may influence cardiovascular response by interacting with neurons in the medulla. Intracisternal injections of orexins A (0.0056-7.0 nmol) or B (0.028-0.28 nmol) dose dependently increased mean arterial pressure (MAP) by 4-27 mmHg and heart rate (HR) by 26-80 beats/ min in urethan-anesthetized rats, with orexin A being more effective in this regard. MAP and HR were not changed by intravenous injection of orexins at higher concentrations. Microinjection of orexin A (14 pmol/50.6 nl) to the rostral ventrolateral medulla, which was confirmed by histological examination, increased MAP and HR. Our results indicate that, in addition to a role in positive feeding behavior, orexins may enhance cardiovascular response via an action on medullary neurons.