Vasopressin increases cytosolic free calcium concentration in glomerular mesangial cells.
Cytosolic free calcium concentration ([Ca2+]f) was determined in cultured rat glomerular mesangial cells under basal conditions and after exposure to arginine vasopressin (AVP) or angiotensin II (ANG II). [Ca2+]f was determined using quin 2 or fura-2, two intracellular fluorescent probes. [Ca2+]f was measured to be 102 +/- 3 nM (n = 154) using quin 2 and 82 +/- 4 (n = 34) using fura-2. AVP and ANG II increased [Ca2+]f. Maximal levels of [Ca2+]f were achieved in less than 10 s after addition of the hormone. This peak value was followed by a rapid fall toward the base line. With fura-2 as the intracellular Ca2+ indicator, [Ca2+]f increased from 74 +/- 7 to a peak of 578 +/- 39 nM (n = 17) with 100 nM AVP. At 115 s after addition of AVP, [Ca2+]f was 125 +/- 9 nM. Similar peak levels of [Ca2+]f were observed using quin 2. The increase in [Ca2+]f was due in large part to release of Ca2+ from intracellular stores, since reduction in extracellular free [Ca2+] with EGTA did not prevent the hormone-induced increase in [Ca2+]f, although it did result in a decreased peak level and a more rapid return to base line. The AVP-induced increase in [Ca2+]f was blocked by the V1 receptor antagonist (CH2)5Tyr(Me)VDAVP. Neither isoproterenol, which increased adenylate cyclase activity, nor dibutyryl cAMP had any affect on [Ca2+]f directly or on the AVP-induced increase in [Ca2+]f. In this report we present the first direct measurements of [Ca2+]f and hormone-induced changes in [Ca2+]f in glomerular mesangial cells.(ABSTRACT TRUNCATED AT 250 WORDS)
D000262:Adenylyl Cyclases / Q000378:metabolism; D000634:Aminoquinolines / Q000378:metabolism; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D001572:Benzofurans / Q000378:metabolism; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D016257:Fura-2; D005920:Glomerular Mesangium / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D008433:Mathematics; D051381:Rats; D014667:Vasopressins / Q000494:pharmacology*; D014700:Verapamil / Q000494:pharmacology
D000634:Aminoquinolines; D001572:Benzofurans; D014667:Vasopressins; D000804:Angiotensin II; D001127:Arginine Vasopressin; D004533:Egtazic Acid; D003994:Bucladesine; D014700:Verapamil; D000262:Adenylyl Cyclases; D007545:Isoproterenol; C035739:Quin2; D002118:Calcium; D016257:Fura-2