Norepinephrine and neuropeptide Y increase intracellular Ca2+ in cultured porcine aortic smooth muscle cells.
We used the fluorescent Ca2+ indicator Fura-2 in cultured porcine aortic smooth muscle cells (PASMC) to study effects of the sympathetic neurotransmitters norepinephrine (NE) and neuropeptide Y (NPY) on free intracellular Ca2+ (Cai). Both transmitters transiently increased intracellular Ca2+ in a concentration-dependent manner. Selective agonists and antagonists demonstrated that the NE-stimulated Cai increase is predominantly (if not exclusively) mediated by alpha 2-adrenoceptors, whereas the NPY response appears to be mediated by the peptide YY-insensitive Y3-like receptor subtype. Pretreatment of cells with pertussis toxin abolished NPY and alpha-adrenoceptor agonist-stimulated intracellular Ca2+ elevations (but not those stimulated by angiotensin II) suggesting involvement of a Gi-like G-protein. alpha 2-Adrenoceptor-stimulated Ca2+ increases resulted from mobilization from intracellular stores, whereas Y3-like NPY receptors mobilized Ca2+ from intracellular stores and also promoted Ca2+ influx.
Erdbrügger
W
W
Institute for Arteriosclerosis Research, University of Münster, Germany.
Vischer
P
P
Bauch
H J
HJ
Michel
M C
MC
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects; D001161:Arteriosclerosis / Q000473:pathology; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004195:Disease Models, Animal; D019204:GTP-Binding Proteins / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects*; D009478:Neuropeptide Y / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology*; D013552:Swine
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D009478:Neuropeptide Y; D019204:GTP-Binding Proteins; D002118:Calcium; D009638:Norepinephrine