Minson J B, Llewellyn-Smith I J, Chalmers J P, Pilowsky P M, Arnolda L F
Department of Medicine, Flinders Medical Centre, Adelaide, Australia.
Neuroreport. 1997 Sep 29;8(14):3015-21. doi: 10.1097/00001756-199709290-00005.
Hypertension in the conscious rat, elicited by i.v. infusion of phenylephrine, evoked expression of the immediate early gene c-fos in discrete groups of brain stem neurons. Fos-immunoreactive neurons were located in the caudal ventrolateral medulla (CVLM); others were located in the nucleus of the tractus solitarius (NTS). Because of their sensitivity to alterations in arterial pressure, these neurons are likely to subserve the arterial baroreceptor reflex. The aim of this study was to identify the brain stem projections and the neurotransmitter content of the barosensitive CVLM neurons using neuronal tracing and immunohistochemistry. Some of the barosensitive CVLM neurons projected directly to the rostral ventrolateral medulla (RVLM), and many contained the GABA synthesizing enzyme, glutamic acid decarboxylase (GAD). Other CVLM neurons, containing markers of glutamate or catecholamine synthesis, were insensitive to baroreceptor stimulation. This study delineates neuronal pathways acting in the arterial baroreceptor reflex and identifies precisely GABA-synthesizing CVLM neurons as the source of inhibitory input to the RVLM.
通过静脉注射去氧肾上腺素诱发清醒大鼠高血压，可引起脑干离散神经元群中即刻早期基因c-fos的表达。Fos免疫反应性神经元位于延髓尾端腹外侧（CVLM）；其他的位于孤束核（NTS）。由于这些神经元对动脉血压变化敏感，它们可能参与动脉压力感受器反射。本研究的目的是利用神经元追踪和免疫组织化学鉴定对压力敏感的CVLM神经元的脑干投射和神经递质含量。一些对压力敏感的CVLM神经元直接投射到延髓头端腹外侧（RVLM），并且许多含有γ-氨基丁酸合成酶，即谷氨酸脱羧酶（GAD）。其他含有谷氨酸或儿茶酚胺合成标志物的CVLM神经元对压力感受器刺激不敏感。本研究描绘了在动脉压力感受器反射中起作用的神经元通路，并精确鉴定出合成GABA的CVLM神经元是RVLM抑制性输入的来源。
