Xiong Y, Okada J, Tomizawa S, Takayama K, Miura M
Department of Physiology 1st Division, Gunma University School of Medicine, Maebashi-shi, Japan.
J Auton Nerv Syst. 1998 Jun 10;70(3):200-8. doi: 10.1016/s0165-1838(98)00052-6.
We hypothesized that there may be a significant difference in the neuronal composition of the baroreceptor reflex pathway between normotensive Wistar Kyoto (WKY) and spontaneously hypertensive SHR rats. Using the double-immunoreactive (IR) method, the topology and numbers of barosensitive neurons that contain glutamate (Glu), glutamic acid decarboxylase (GAD), tyrosine hydroxylase (TH), phenylethanolamine N-methyltransferase (PNMT) and choline acetyltransferase (ChAT) were compared between the two strains. The control rats were sham-operated only for cannulation of the trachea and femoral artery/vein. The test rats were injected with the pressor agent phenylephrine to raise blood pressure and stimulate arterial baroreceptors. In both the control and test experiments, the c-Fos/Glu-, GAD-, TH- and PNMT-IR neurons were found in the nucleus tractus solitarii (NTS) and ventrolateral medulla (VLM), while the FosB/ChAT-IR neurons were found in the NTS, dorsal motor nucleus of the vagus (DMX) and nucleus ambiguus (AMB). In the control experiment, no significant difference in numbers was recognized in any of the double-IR neurons between the two strains. In the test experiment, the numbers of FosB/ChAT-IR neurons in the NTS, DMX and AMB were significantly smaller in SHR than in WKY. The numbers of c-Fos/TH-IR neurons in the caudal VLM were significantly larger in SHR than in WKY. These results suggest that a smaller number of barosensitive cholinergic neurons in the DMX and AMB in SHR causes the weaker baroreceptor-cardiac vagal reflex in SHR, and that a larger number of barosensitive catecholaminergic neurons in the caudal VLM in SHR are involved in the stronger baroreceptor-vasopressin reflex in SHR.
我们推测，正常血压的Wistar Kyoto（WKY）大鼠和自发性高血压的SHR大鼠之间，压力感受器反射通路的神经元组成可能存在显著差异。采用双重免疫反应（IR）方法，比较了两种品系中含有谷氨酸（Glu）、谷氨酸脱羧酶（GAD）、酪氨酸羟化酶（TH）、苯乙醇胺N-甲基转移酶（PNMT）和胆碱乙酰转移酶（ChAT）的压力感受神经元的拓扑结构和数量。对照大鼠仅为气管和股动脉/静脉插管进行假手术。给试验大鼠注射升压药去氧肾上腺素以升高血压并刺激动脉压力感受器。在对照和试验实验中，在孤束核（NTS）和延髓腹外侧（VLM）中发现了c-Fos/Glu-、GAD-、TH-和PNMT-IR神经元，而在NTS、迷走神经背运动核（DMX）和疑核（AMB）中发现了FosB/ChAT-IR神经元。在对照实验中，两种品系之间的任何双重IR神经元数量均未发现显著差异。在试验实验中，SHR中NTS、DMX和AMB中FosB/ChAT-IR神经元的数量明显少于WKY。SHR中尾侧VLM中c-Fos/TH-IR神经元的数量明显多于WKY。这些结果表明，SHR中DMX和AMB中压力感受胆碱能神经元数量较少导致SHR中压力感受器-心脏迷走神经反射较弱，并且SHR中尾侧VLM中压力感受儿茶酚胺能神经元数量较多参与了SHR中较强的压力感受器-血管加压素反射。
