Functional organization of brain pathways subserving the baroreceptor reflex: Studies in conscious animals using immediate early gene expression
Functional organization of brain pathways subserving the baroreceptor reflex: Studies in conscious animals using immediate early gene expression
复制标题
DOI：
10.1023/a:1025080314925
复制
发表时间：
2003-10-01
影响因子：
4
通讯作者：
Horiuchi, J
中科院分区：
文献类型：
--
作者：
Dampney, RAL;Polson, JW;Horiuchi, J
1. 本文回顾了我们在实验室进行的研究，在这些研究中，我们使用c-fos功能映射方法，结合其他方法，来确定中枢压力受体通路在意识兔子中运作时的功能组织。首先，我们发现，诱导高血压或低血压的每一个时期都会导致脑干和前脑神经元的特定和可重复的激活模式。特别是，低血压（但不是高血压）导致髓质和脑桥中儿茶酚胺神经元和下丘脑中抗利尿激素合成神经元的激活。在清醒的兔子中，髓质细胞群对诱导高血压或低血压的反应几乎完全依赖于动脉压力感受器的输入，而下丘脑抗利尿激素合成神经元对低血压的反应在很大程度上依赖于压力感受器，尽管循环血管紧张素的增加似乎也有贡献。压力感受器卸荷激活的脊髓突起神经元主要分布在延髓吻侧腹外侧（RVLM）和脑桥A5区。相反，下丘脑室旁核的脊髓突起神经元似乎基本上不受压力感受器信号的影响。RVLM神经元对动脉压升高或降低的直接传入输入主要来自其他髓核，特别是位于腹外侧髓核（CVLM和IVLM）尾端和中间水平的神经元，以及孤束核（NTS）。NTS中的压力感觉神经元也直接投射到CVLM/IVLM区域，这是由压力感受器输入激活的。总的来说，我们对有意识的动物的研究结果表明，压力感受器信号到达大脑的各个层面。关于交感神经活动的压力感受器反射控制，我们的研究与之前在麻醉动物中的研究是一致的，但同时也揭示了其他以前未被认识的途径也有助于这种反射调节。
1. This paper reviews studies carried out in our laboratory in which we have used the c-fos functional mapping method, in combination with other methods, to determine the functional organization of central baroreceptor pathways as they operate in the conscious rabbit.2. First, we showed that periods of induced hypertension or hypotension each result in a specific and reproducible pattern of activation of neurons in the brainstem and forebrain. In particular, hypotension ( but not hypertension) results in the activation of catecholamine neurons in the medulla and pons and vasopressin-synthesizing neurons in the hypothalamus.3. The activation of medullary cell groups in response to induced hypertension or hypotension in the conscious rabbit is almost entirely dependent on inputs from arterial baroreceptors, while the activation of hypothalamic vasopressin-synthesising neurons in response to hypotension is largely dependent on baroreceptors, although an increase in circulating angiotensin also appears to contribute.4. Discrete groups of neurons in the rostral ventrolateral medulla (RVLM) and A5 area in the pons are the major groups of spinally projecting neurons activated by baroreceptor unloading. In contrast, spinally projecting neurons in the paraventricular nucleus in the hypothalamus appear to be largely unaffected by baroreceptor signals.5. Direct afferent inputs to RVLM neurons in response to increases or decreases in arterial pressure originate primarily from other medullary nuclei, particularly neurons located in the caudal and intermediate levels of the ventrolateral medulla (CVLM and IVLM), as well as in the nucleus tractus solitarius (NTS).6. There is also a direct projection from barosensory neurons in the NTS to the CVLM/IVLM region, which is activated by baroreceptor inputs.7. Collectively, the results of our studies in conscious animals indicate that baroreceptor signals reach all levels of the brain. With regard to the baroreceptor reflex control of sympathetic activity, our studies are consistent with previous studies in anesthetized animals, but in addition reveal other previously unrecognized pathways that also contribute to this reflex regulation.