Neuropeptide Y potentiates calcium-channel currents in single vascular smooth muscle cells.
The effect of neuropeptide Y (NPY) on Ca(2+)-channel currents in isolated vascular smooth muscle cells was studied with the perforated-patch recording technique. Using Ba2+ (10 mM) as the charge carrier, inward currents sensitive to Cd2+ and nifedipine were potentiated by NPY in a concentration-dependent manner. The threshold concentration for the potentiating effect of NPY was 50 nM and reached a maximum at 150 nM. NPY shifted the steady-state activation curve to less positive membrane potentials by about 6 mV so that the potentiating effect was most prominent near the activation threshold of the current. It had no effect on steady-state inactivation of the current. These results suggest that NPY may potentiate vasoconstriction by promoting calcium entry through L-type voltage-dependent Ca(2+)-channels.
Xiong
Z
Z
University of Ottawa, Heart Institute, Canada.
Bolzon
B J
BJ
Cheung
D W
DW
D000818:Animals; D001464:Barium / Q000494:pharmacology; D002104:Cadmium / Q000494:pharmacology; D002120:Calcium Channel Agonists / Q000494:pharmacology*; D004594:Electrophysiology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009478:Neuropeptide Y / Q000494:pharmacology*; D009543:Nifedipine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D002120:Calcium Channel Agonists; D009478:Neuropeptide Y; D002104:Cadmium; D001464:Barium; D009543:Nifedipine