Allen A M, Zhuo J, Mendelsohn F A
Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Parkville, Victoria, Australia.
J Am Soc Nephrol. 1999 Jan;10 Suppl 11:S23-9.
The distributions of angiotensin AT1 and AT2 receptors have been mapped by in vitro autoradiography throughout most tissues of many mammals, including humans. In addition to confirming that AT1 receptors occur in sites known to be targets for the physiologic actions of angiotensin, such as the adrenal cortex and medulla, renal glomeruli and proximal tubules, vascular and cardiac muscle, and brain circumventricular organs, many new sites of action have been demonstrated. In the kidney, AT1 receptors occur in high density in renal medullary interstitial cells. The function of these cells, which span the interstitial space between the tubules and the vasa rectae, remains to be determined. Renal medullary interstitial cells possess receptors for a number of vasoactive hormones in addition to AT1 receptors and this, in concert with their anatomical location, suggest that they may be important for the regulation of fluid reabsorption or renal medullary blood flow. In the heart, the highest densities of AT1 receptors occur in association with the conduction system and vagal ganglia. In the central nervous system, high AT1 receptor densities occur in many regions behind the blood-brain barrier, supporting a role for neurally derived angiotensin as a neuromodulator. The physiologic role of angiotensin in many of these brain sites remains to be determined. The AT2 receptor also has a characteristic distribution in several tissues including the adrenal gland, heart, and brain. The role of this receptor in physiology is being elucidated, but it appears to participate in development. Thus, receptor binding studies, localizing the distribution of AT1 and AT2 receptors, outline a number of regions where the actions of angiotensin are known but also provide many insights into novel physiologic roles of this peptide.
通过体外放射自显影技术，已绘制出血管紧张素AT1和AT2受体在包括人类在内的许多哺乳动物的大多数组织中的分布图谱。除了证实AT1受体存在于已知为血管紧张素生理作用靶点的部位，如肾上腺皮质和髓质、肾小球和近端肾小管、血管和心肌以及脑室内器官外，还发现了许多新的作用位点。在肾脏中，AT1受体在肾髓质间质细胞中高密度表达。这些细胞横跨肾小管和直小血管之间的间质空间，其功能尚待确定。肾髓质间质细胞除了AT1受体外，还拥有多种血管活性激素的受体，这与其解剖位置相结合，表明它们可能对液体重吸收或肾髓质血流的调节很重要。在心脏中，AT1受体的最高密度与传导系统和迷走神经节相关。在中枢神经系统中，血脑屏障后的许多区域AT1受体密度较高，这支持了神经源性血管紧张素作为神经调节剂的作用。血管紧张素在许多这些脑区的生理作用尚待确定。AT2受体在包括肾上腺、心脏和大脑在内的几种组织中也有特征性分布。该受体在生理学中的作用正在阐明，但它似乎参与了发育过程。因此，定位AT1和AT2受体分布的受体结合研究，不仅勾勒出了血管紧张素作用已知的一些区域，还为该肽的新生理作用提供了许多见解。
