Role of the angiotensin II of the central nervous system

外周循环的肾素-血管紧张素的功能是调节体液动态平衡。它们通过影响许多方面来控制血流动力学，如血管张力的控制，肾脏刺激钠的重吸收，以及肾上腺皮质产生的醛固酮。除了这种心血管调节外，。现在已经证明，血管紧张素II在大脑中作为一种神经递质样物质发挥作用。血管紧张素II(AGII)样免疫反应见于中枢神经系统。受体配体结合实验还发现了脑内AgII受体的结合部位，神经系统中也检测到了AgII受体的信息。目前，血管紧张素Ⅱ受体分为四类：血管紧张素受体1(1a和1b)、2、3和4。在本项目中，我们试图利用AT1a基因敲除小鼠(Sugaya et al.)来阐明AgII受体1a(AT1a)在中枢神经系统中的位置以及AT1a在压力感受器反射中的作用。J.B.C.Vol270：18719-18722,1995年)1)我们成功地记录了麻醉和自由活动小鼠股动脉的牵拉率和血压，然后分析了压力感受器的作用。2)基因敲除小鼠的压力感受器反射的增益比Wilde小鼠的小。3)ATLA在中枢神经系统的定位比免疫组织化学方法或信使RNA探针原位杂交的结果要广泛得多。

The function of the peripherally circulating renin- angiotensin is the regulation of body-fluid homeostasis. They control hemodynamics by influencing many aspects such as the control of vascular tone, stimulation of sodium reabsorption by the kidney, and of aldosterone production from the adrenal cortex. In addition to such cardio-vascular regulation, . it has now been shown that angiotensin II is functioning as a neurotransmitter-like substance in in the brain. Angiotensin II (AgII)-like immunoreactivity is observed in the central nervous system. The receptor ligand binding experiment also revealed AgII binding sites in the brain, and messages of Ag II receptors were detected in the nervous system. Ag II receptors are now classified into four groups ; Angiotnsin receptor 1(la and 1b), 2, 3 and 4. In the present project, we tried to clarify the location of the Ag II receptor la (AT1a) in the central nervous system and function of AT1a in the baroreceptor reflex, using AT1a gene knock out mice (Sugaya et al. J.B.C.vol 270 : 18719-18722, 1995).1) We succeeded to record the haeart rate and the blood pressure directly from the femoral artery in ananesthesized and free moving mice, then analyze the barorecptor function.2) The gain of the baroreceptor reflex in knockout mice is smaller than that of wilde mice.3) Locarization of the ATl a in the central nervous system is much wider in comparing with results obtained by mmunohistochemical methods or in situ hybridization by messenger RNA probe.