Wright J W, Harding J W
Department of Psychology, Washington State University, Pullman 99164-4820, USA.
Brain Res Brain Res Rev. 1997 Sep 30;25(1):96-124. doi: 10.1016/s0165-0173(97)00019-2.
Considerable evidence now suggests that the precursors and enzymes necessary for the formation and degradation of biologically active forms of angiotensins are present in brain tissues, accompanied by at least three specific binding sites. It also appears that several forms of angiotensin may serve as signaling agents at these sites. There is accumulating support for the notion that AngII must be converted to AngIII in order to bind at the AT1 and AT2 receptor subtypes, and AngIII must be converted to AngIV in order to activate the AT4 receptor subtype. Further, AngII(1-7) may activate a separate binding site concerned with antidiuresis, however, characterization of this site has not been completed. The AT1 site appears to mediate the classic angiotensin functions concerned with body water balance, maintenance of blood pressure, and cyclicity of reproductive hormones and sexual behaviors. This receptor site also exerts some control over the secretion of pituitary hormones. Less is known about the functional importance of the AT2 site, however, it has been implicated in vascular growth, control of blood flow, and perhaps modulation of NMDA receptors. The AT4 site is heavily distributed in neocortex, hippocampus, cerebellum, and basal ganglia structures, as well as several peripheral tissues. This site appears to mediate memory acquisition and retrieval, the regulation of blood flow, neurite outgrowth, angiogenesis, and kidney function. In addition to the well-studied functions of the brain renin-angiotensin system, additional less well investigated responses are reviewed. These include electrophysiological activation, tachyphylaxis, long term potentiation, learning and memory, and cognitive affect.
现在有大量证据表明，血管紧张素生物活性形式的形成和降解所必需的前体和酶存在于脑组织中，同时至少伴有三个特异性结合位点。似乎几种形式的血管紧张素可能在这些位点充当信号传导剂。越来越多的证据支持这样一种观点，即AngII必须转化为AngIII才能与AT1和AT2受体亚型结合，而AngIII必须转化为AngIV才能激活AT4受体亚型。此外，AngII(1 - 7)可能激活一个与抗利尿有关的单独结合位点，然而，该位点的特性尚未完全明确。AT1位点似乎介导了与身体水平衡、血压维持以及生殖激素和性行为周期性相关的经典血管紧张素功能。该受体位点还对垂体激素的分泌有一定控制作用。关于AT2位点的功能重要性了解较少，不过，它与血管生长、血流控制以及可能对NMDA受体的调节有关。AT4位点大量分布于新皮层、海马体、小脑和基底神经节结构以及一些外周组织中。该位点似乎介导记忆获取和检索、血流调节、神经突生长、血管生成和肾功能。除了对脑肾素 - 血管紧张素系统的深入研究功能外，还综述了其他较少研究的反应。这些包括电生理激活、快速耐受性、长时程增强、学习和记忆以及认知影响。
