Neuropeptide Y receptor in cultured vascular smooth muscle cells: ligand binding and increase in cytosolic free Ca2+.
We have previously shown that neuropeptide Y (NPY) increases cytosolic free Ca2+ concentration [( Ca2+]i) in porcine aortic smooth muscle cells. In this study, specific NPY receptor binding sites were identified in the cells by use of [125I]Bolton-Hunter NPY [( 125I]BH-NPY). Binding was to a single population of the sites with a Kd of 1.1 +/- 0.2 nM and a Bmax of 0.68 +/- 0.10 pmol/mg protein. [125I]BH-NPY binding was displaced by NPY-related peptides including members of the pancreatic polypeptide (PP) family. The potency of these peptides other than human PP for displacing [125I]BH-NPY binding was substantially consistent with their potency for increasing [Ca2+]i. Human PP had no effect on [Ca2+]i even at 10(-5) M, but it inhibited the NPY-induced increase in [Ca2+]i with a potency comparable to that for displacing [125I]BH-NPY binding. NPY(13-36) was about 500 and 300 times less effective than porcine NPY in increasing [Ca2+]i and in displacing [125I]BH-NPY binding, respectively, showing that the NPY receptor in cultured vascular smooth muscle cells is of the Y1-type.
Mihara
S
S
Shionogi Research Laboratories, Shionogi and Co., Ltd., Osaka, Japan.
Shigeri
Y
Y
Fujimoto
M
M
D000818:Animals; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D003600:Cytosol / Q000378:metabolism*; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D009478:Neuropeptide Y / Q000378:metabolism* / Q000494:pharmacology; D010191:Pancreatic Polypeptide / Q000378:metabolism / Q000494:pharmacology; D010446:Peptide Fragments / Q000378:metabolism / Q000494:pharmacology; D013388:Succinimides; D013552:Swine
D009478:Neuropeptide Y; D010446:Peptide Fragments; D013388:Succinimides; D010191:Pancreatic Polypeptide; C022581:Bolton-Hunter reagent; D002118:Calcium