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" whole-cell recordings and Fura-2 microfluorimetry. Carbachol (50 microM) and cyclopiazonic acid (10 microM) 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) propoxyl]-4-methoxyphenethyl}-1H-imidazole; 10 microM) and Cd2+ (100 microM) inhibited both I(DOC) and the sustained increase in intracellular Ca2+; La3+ (400 microM) inhibited neither response. The results confirm that the non-selective cation current I(DOC) underlies capacitative Ca2+ influx supporting sustained contractions in this tonic smooth muscle.
Wayman
C P
CP
Division of Pharmacology and Therapeutics, School of Biomedical Sciences, King's College London, UK.
Wallace
P
P
Gibson
A
A
McFadzean
I
I
D000818:Animals; D002118:Calcium / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D016623:Ion Pumps / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D015290:Second Messenger Systems / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology
D002121:Calcium Channel Blockers; D007093:Imidazoles; D007211:Indoles; D016623:Ion Pumps; D014665:Vasodilator Agents; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole; D002118:Calcium; C000543:cyclopiazonic acid