Increases in cellular sodium concentration by arginine vasopressin and endothelin in cultured rat glomerular mesangial cells.

摘要: The present study was undertaken to determine whether arginine vasopressin (AVP), angiotensin-II, and endothelin (ET) increase the cellular sodium concentration ([Na+]i) in cultured rat glomerular mesangial cells. [Na+]i measured using fluorescence indicator dye sodium-binding benzofuran isophthalate. These three vasoconstrictor hormones increased free calcium ([Ca2+]i) a dose-dependent manner ([Na+]i: basal, 11.5; 10(-7) M AVP, 20.5; 13.8; ET, 21.2 mM). mobilization of [Ca2+]i faster than that [Na+]i. AVP-induced completely blunted by potent V1 antagonist d(CH2)5Tyr(Me)AVP. Vasoconstrictor produced biphasic pH (pHi) change, characterized transient acidification, followed sustained alkalinization. Ca(2+)-free condition markedly reduced AVP- ET-induced increases changes pHi. In Na(+)-free state, hormonally mobilized significantly enhanced. Basal decreased below 3 mM, there little after addition hormones, suggesting source is extracellular space. Only early acidification obtained absence closely related change results indicate angiotensin-II cells, depends on Na+/Ca2+ exchange, phase Na+/H+ exchange. essential for activation an suggested play important role