Intracellular Ca2+ oscillations in vascular smooth muscle cells.
We monitored caffeine- and histamine-induced [Ca2+]i oscillations by patch-clamp whole-cell recordings of K(Ca)-current in single smooth muscle cells of rabbit cerebral (basilar) artery. Superfusion of caffeine (1 mM) or histamine (1-3 microM) induced periodic oscillations of large whole-cell K-current with fairly uniform amplitudes and intervals. Repetitive activations of the large-conductance K(Ca)-channels were recorded in the cell-attached patch mode. Inclusion of heparin (3 mg/ml) in the pipette solution failed to inhibit the oscillations caused by caffeine treatment, but blocked histamine-evoked oscillations. Ryanodine (1-10 microM) abolished both caffeine- and histamine-induced oscillations. Removal of extracellular Ca2+, but not verapamil or Cd2+, abolished the caffeine-induced oscillations, and the changes in the oscillatory frequency closely reflected the altered Ca2+ influx rate. These results indicate that in smooth muscle cells of the rabbit cerebral artery, ryanodine-sensitive Ca(2+)-induced Ca2+ release (CICR) pools play key roles for the generation of the [Ca2+]i oscillations.
Kang
T M
TM
Samsung Biomedical Research Institute (SBRI).
Rhee
P L
PL
Rhee
J C
JC
So
I
I
Kim
K W
KW
D000818:Animals; D001488:Basilar Artery / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D004594:Electrophysiology; D006632:Histamine / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D012433:Ryanodine / Q000494:pharmacology
D000697:Central Nervous System Stimulants; D012433:Ryanodine; D002110:Caffeine; D006632:Histamine; D011188:Potassium; D002118:Calcium