Effect of capsazepine on [Ca2+]i in MDCK renal tubular cells

• Published in: Drug development research Vol. 72; no. 4; pp. 323 - 329
• Main Authors: Tsai, Jeng-Yu, Kuo, Chun-Chi, Chou, Chiang-Ting, Chao, David, Cheng, He-Hsiung, Wang, Jue-Long, Cheng, Jin-Shiung, Lin, Ko-Long, Huang, Jong-Khing, Chang, Hong-Tai, Jan, Chung-Ren
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.06.2011
• Subjects: Ca super(2+)-transporting ATPase; Ca2; Calcium; Calcium (extracellular); Calcium (reticular); Calcium channels; Calcium channels (L-type); Calcium influx; Calcium signalling; capsazepine; Drug development; Drugs; Endoplasmic reticulum; Fluorescence; Fura-2; Kidney; MDCK cells; phorbol 12-myristate 13-acetate; Phorbol esters; Phospholipase C; thapsigargin
• ISSN: 0272-4391; 1098-2299; 1098-2299
• DOI: 10.1002/ddr.20433

The current study explored whether capsazepine changed basal cytosolic free Ca2+ concentrations ([Ca2+]i) levels in suspended Madin Darby canine kidney (MDCK) cells cells by using fura‐2 as a Ca2+‐selective fluorescent dye. At concentrations of 10–200 µM, capsazepine increased [Ca2+]i in a concentration‐dependent manner. The Ca2+ signal was partially reduced by 40% by removing extracellular Ca2+. Capsazepine induced Mn2+ quench of fura‐2 fluorescence, indirectly implicating Ca2+ entry. Capsazepine‐induced Ca2+ influx was unchanged by L‐type Ca2+ entry inhibitors and protein kinase C modulators [phorbol 12‐myristate 13‐acetate (PMA) and GF109203X]. In Ca2+‐free medium, 100 µM capsazepine‐induced Ca2+ release was substantially suppressed by pretreatment with thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor). Pretreatment with capsazepine nearly abolished thapsigargin‐induced Ca2+ release. Inhibition of phospholipase C with U73122 did not change capsazepine‐induced [Ca2+]i rises. Collectively, in MDCK cells, capsazepine induced [Ca2+]i rises by causing phospholipase C‐independent Ca2+ release from the endoplasmic reticulum and Ca2+ influx via non‐L‐type Ca2+ channels. Drug Dev Res 72: 323–329, 2011. © 2010 Wiley‐Liss, Inc.