Characteristics of the histamine-sensitive calcium store in vascular smooth muscle. Comparison with norepinephrine- or caffeine-sensitive stores.
Using the microfluorometry of an intracellularly trapped calcium indicator dye, quin2, characteristics of intracellular Ca2+ store sites sensitive to histamine, norepinephrine, or caffeine were investigated using rat vascular smooth muscle cells in primary culture at 25 degrees C. With similar time courses, both histamine- and the norepinephrine-sensitive Ca2+ store sites were readily depleted in Ca2(+)-free medium and almost completely replenished by loading the cells with 1.0 mM Ca2+ solution for 3 min, while the caffeine-sensitive Ca2+ store site was little affected. In the absence of extracellular Ca2+, transient elevations of cytosolic Ca2+ repeatedly appeared in response to repetitive applications of histamine, norepinephrine, or caffeine, with progressive reductions in peak levels. Histamine released Ca2+ from the norepinephrine-sensitive store site and norepinephrine released Ca2+ from the histamine-sensitive one. On the other hand, caffeine had little effect on the histamine- and/or the norepinephrine-sensitive Ca2+ store site in Ca2(+)-free medium, and vice versa. We propose that the location and mechanisms of release of Ca2+ of the histamine-sensitive Ca2+ store site are identical with events at the norepinephrine-sensitive site, and differ from the caffeine-sensitive one, in vascular smooth muscle cells in primary culture.
Matsumoto
T
T
Research Institute of Angiocardiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Kanaide
H
H
Shogakiuchi
Y
Y
Nakamura
M
M
D000634:Aminoquinolines; D000818:Animals; D001011:Aorta; D002110:Caffeine / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002478:Cells, Cultured; D005456:Fluorescent Dyes; D006632:Histamine / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D008856:Microscopy, Fluorescence; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D000634:Aminoquinolines; D005456:Fluorescent Dyes; D002110:Caffeine; D006632:Histamine; C035739:Quin2; D002118:Calcium; D009638:Norepinephrine