Correlation between store-operated cation current and capacitative Ca2+ influx in smooth muscle cells from mouse anococcygeus

In mouse anococcygeus cells, simultaneous measurements of membrane currents and changes in intracellular Ca2+ were obtained using "perforated-patch" w hole-cell recordings and Fura-2 microfluorimetry. Carbachol (50 mu M) and c yclopiazonic acid (10 mu M) produced a biphasic inward current; a transient Ca2+-dependent chloride current (I-ClCa), followed by a smaller, sustained current (I-DOC). This response was mirrored by a biphasic increase in the intracellular Ca2+ concentration. SKF96365 (1-{beta-[3-(4-methoxyphenyl) pr opoxyl]-4-methoxyphenethyl)-1H-imidazole; 10 mu M) and Cd2+ (100 mu M) inhi bited both I-DOC and the sustained increase in intracellular Ca2+; La3+ (40 0 mu M) inhibited neither response. The results confirm that the non-select ive cation current I-DOC underlies capacitative Ca2+ influx supporting sust ained contractions in this tonic smooth muscle. (C) 1999 Elsevier Science B .V. All rights reserved.