Histamine activates whole cell K+ currents in swine carotid arterial smooth muscle cell.
1. The effects of histamine on whole cell K+ currents were evaluated in cultured smooth muscle cells that were derived from explants of swine carotid artery. These cells exhibited cytoplasmic protein and agonist-induced calcium responses typical of noncultured smooth muscle cells. 2. Upon obtaining whole cell configuration, depolarization from a holding potential of -80 mV elicited a slowly inactivating voltage-dependent outward current that was sensitive to tetraethylammonium and 4-aminopyridine. 3. These K+ currents were at least partially Ca2+ dependent since they were inhibited by extracellular bath application of verapamil or by substitution of external Ca2+ with Co2+. 4. The addition of extracellular histamine increased the outward current both in the presence and absence of extracellular Ca2+ and this response was blocked by (+/-)chlorpheniramine. 5. We conclude that swine carotid arterial smooth muscle cells exhibit voltage and calcium dependent potassium current and that these currents are modified by histamine stimulation.
Department of Internal Medicine, University of Virginia Health Sciences Center, Charlottesville 22908.
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Hashemzadeh-Gargari
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Rembold
D000818:Animals; D002118:Calcium / Q000502:physiology; D002339:Carotid Arteries / Q000502:physiology; D002478:Cells, Cultured; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D006632:Histamine / Q000502:physiology*; D007211:Indoles; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000502:physiology*; D015221:Potassium Channels / Q000502:physiology*; D013552:Swine / Q000502:physiology*
D005456:Fluorescent Dyes; D007211:Indoles; D015221:Potassium Channels; D006632:Histamine; C048960:indo-1; D002118:Calcium