血管紧张素II对兔近端小管液体转运作用的细胞内信使。

Intracellular messenger for action of angiotensin II on fluid transport in rabbit proximal tubule.

作者信息

Dominguez J H, Snowdowne K W, Freudenrich C C, Brown T, Borle A B

出版信息

Am J Physiol. 1987 Mar;252(3 Pt 2):F423-8. doi: 10.1152/ajprenal.1987.252.3.F423.

DOI:10.1152/ajprenal.1987.252.3.F423

Abstract

These studies were designed to examine the cellular messenger that mediates the action of angiotensin II on fluid transport (Jv) in the rabbit proximal tubule. We measured the effects of angiotensin II on Jv, activation of adenylate cyclase, and the concentration of cytosolic free calcium (Cai) in the rabbit proximal tubule. In nine rabbit proximal convoluted tubules (PCT), angiotensin II, 10(-8) M and 10(-6) M, decreased Jv by 18 and 25%, P less than 0.05. In eleven rabbit proximal straight tubules (PST), 10(-8) and 10(-6) M angiotensin II decreased Jv by 20 and 23%, P less than 0.02. Angiotensin II did not affect lumen-to-bath phosphate fluxes in PCT or PST, and it did not activate adenylate cyclase in PST. In a preparation of proximal tubules (PCT and PST) loaded with aequorin, angiotensin II, 10(-8) and 10(-6) M, transiently increased Cai by 13 and 32%, P less than 0.001. We propose that Cai surges, activated by angiotensin II, are part of a cellular message that inhibits Jv in the rabbit proximal tubule.

摘要

这些研究旨在检测介导血管紧张素II对兔近端小管液体转运（Jv）作用的细胞信使。我们测量了血管紧张素II对兔近端小管Jv、腺苷酸环化酶激活以及胞质游离钙（Cai）浓度的影响。在9个兔近端曲管（PCT）中，10^(-8) M和10^(-6) M的血管紧张素II使Jv分别降低了18%和25%，P<0.05。在11个兔近端直小管（PST）中，10^(-8) M和10^(-6) M的血管紧张素II使Jv分别降低了20%和23%，P<0.02。血管紧张素II不影响PCT或PST中管腔到浴液的磷酸盐通量，且不激活PST中的腺苷酸环化酶。在装载水母发光蛋白的近端小管（PCT和PST）制剂中，10^(-8) M和10^(-6) M的血管紧张素II使Cai瞬时增加了13%和32%，P<0.001。我们提出，由血管紧张素II激活的Cai激增是抑制兔近端小管Jv的细胞信息的一部分。