The effect of the calcium channel agonist, Bay K-8644 on human vascular smooth muscle.
Bay K-8644, a calcium channel activator, caused a dose-dependent (ED50 = 12.8 nM) elevation of tone in the human umbilical artery. The response to Bay K-8644 was dependent upon extracellular calcium (Ca2+), competitively antagonized by the channel antagonist, nifedipine, and, in addition, the sensitivity to Bay K-8644 was increased by, but not dependent upon, elevating extracellular potassium. Bay K-8644 competitively displaced, IC50 = 1.8 nM, specific [3H]nitrendipine binding to a microsome fraction derived from the umbilical artery, suggesting that the Ca2+ channel activator and the structurally related dihydropyridine antagonists bind to a single site to affect Ca2+ channel function in human vascular smooth muscle.
V
V
Gopalakrishnan
L E
LE
Park
C R
CR
Triggle
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D002462:Cell Membrane / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007473:Ion Channels / Q000378:metabolism*; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D009568:Nitrendipine; D011188:Potassium / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D014469:Umbilical Arteries / Q000187:drug effects
D007473:Ion Channels; D012701:Serotonin; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D009568:Nitrendipine; D009543:Nifedipine; D011188:Potassium