Pressor response to microinjection of orexin/hypocretin into rostral ventrolateral medulla of awake rats
Pressor response to microinjection of orexin/hypocretin into rostral ventrolateral medulla of awake rats
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DOI：
10.1016/s0167-0115(01)00351-2
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发表时间：
2002-03-15
影响因子：
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通讯作者：
Dun, NJ
中科院分区：
文献类型：
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作者：
Machado, BH;Bonagamba, LGH;Dun, NJ
大鼠下丘脑外侧部的食欲素A（或下丘脑泌素1）免疫反应神经元投射到与心血管调节密切相关的延髓的几个区域。本研究旨在进一步证实食欲素A通过激活大鼠延髓头端腹外侧区（RVLM）的交感神经元来加速心血管反应的假说。首先，免疫组织化学研究揭示了食欲素A免疫反应纤维的RVLM的存在。双标记的部分与食欲素A-和酪氨酸羟化酶（TH）-抗血清进一步表明，食欲素A-免疫反应纤维与TH-免疫反应神经元，其中一些可能是压力敏感的，球脊髓神经元的RVLM在密切接近。第二，将食欲素A（6.35、12.7和38.1 μ M）微量注射到RVLM中，这在稍后通过组织学检查证实，引起清醒大鼠的平均动脉压（MAP）显著增加和心率（HR）适度增加。L-谷氨酸（33.3 mM）注射到相同的网站，造成了更大的MAP增加，但在HR下降，而盐水注射没有显着的效果。这项研究的结果表明，食欲素A，这可能是释放的神经纤维起源于下丘脑外侧的神经元，作用于RVLM神经元在髓质，增加交感神经流出的心脏和血管在清醒的动物。(C)2002 Elsevier Science B. V.保留所有权利。
Orexin A (or hypocretin 1)-immunoreactive neurons in the rat lateral hypothalamus project to several areas of the medulla oblongata that are closely associated with cardiovascular regulation. The present study was undertaken to further strengthen the hypothesis that orexin A accelerates cardiovascular response by activating sympathoexcitatory neurons in the rat rostral ventrolateral medulla (RVLM). First, immunohistochemical studies revealed the presence of orexin A-immunoreactive fibers in the RVLM. Double labeling the sections with orexin A- and tyrosine hydroxylase (TH)-antisera further showed that orexin A-immunoreactive fibers are in close proximity with TH-immunoreactive neurons, some of which may be barosensitive, bulbospinal neurons in the RVLM. Second, microinjection of orexin A (6.35, 12.7 and 38.1 muM) into the RVLM, which was verified later by histological examination, caused a significant increase of mean arterial pressure (MAP) and a moderate increase of heart rate (HR) in awake rats. L-glutamate (33.3 mM) injected into the same sites, caused a larger increase in MAP, but a decrease in HR; whereas, saline injection was without significant effect. Results from this study suggest that orexin A, which may be released from the nerve fibers originating from the neurons in the lateral hypothalamus, acting on RVLM neurons in the medulla, increases sympathetic outflow targeted to the heart and blood vessels in awake animals. (C) 2002 Elsevier Science B.V. All rights reserved.