Calcium and cyclic adenosine monophosphate as second messengers for vasopressin in the rat inner medullary collecting duct.
Calcium and cyclic adenosine monophosphate as second messengers for vasopressin in the rat inner medullary collecting duct.
复制标题
DOI：
10.1172/jci113534
复制
发表时间：
1988-06
期刊：
影响因子：
--
通讯作者：
R. Star;H. Nonoguchi;R. Balaban;M. Knepper
中科院分区：
文献类型：
--
作者：
R. Star;H. Nonoguchi;R. Balaban;M. Knepper
未标记加压素可增加肾内髓集合管（终末IMCD）末端部分的尿素渗透性和渗透水渗透性。为了确定介导这些反应的第二信使，我们测量了尿素渗透性，渗透水渗透性，细胞内钙离子浓度，并在孤立的终端IMCD环AMP积累。加压素加入后，细胞内钙离子出现短暂升高，这与环磷酸腺苷积累和尿素渗透性的增加一致。0.01 nM加压素可使尿素渗透性和渗透水渗透性增加一半。可测量的环AMP积累增加的阈值浓度约为0.01 nM，而细胞内钙的可测量增加需要更高的加压素浓度（大于0.1 nM）。外源性cAMP（1 mM 8-Br-cAMP）模拟加压素对尿素渗透性的影响，但没有产生可测量的细胞内钙离子浓度的变化。结论：（a）cAMP是介导大鼠终末IMCD对加压素的尿素通透性反应的第二信使。(b)加压素增加大鼠终末IMCD细胞内钙浓度，但这种反应的生理作用尚不清楚。
UNLABELLED Vasopressin increases both the urea permeability and osmotic water permeability in the terminal part of the renal inner medullary collecting duct (terminal IMCD). To identify the second messengers that mediate these responses, we measured urea permeability, osmotic water permeability, intracellular calcium concentration, and cyclic AMP accumulation in isolated terminal IMCDs. After addition of vasopressin, a transient rise in intracellular calcium occurred that was coincident with increases in cyclic AMP accumulation and urea permeability. Half-maximal increases in urea permeability and osmotic water permeability occurred with 0.01 nM vasopressin. The threshold concentration for a measurable increase in cyclic AMP accumulation was approximately 0.01 nM, while measurable increases in intracellular calcium required much higher vasopressin concentrations (greater than 0.1 nM). Exogenous cyclic AMP (1 mM 8-Br-cAMP) mimicked the effect of vasopressin on urea permeability but did not produce a measurable change in intracellular calcium concentration. CONCLUSIONS (a) Cyclic AMP is the second messenger that mediates the urea permeability response to vasopressin in the rat terminal IMCD. (b) Vasopressin increases the intracellular calcium concentration in the rat terminal IMCD, but the physiological role of this response is not yet known.