NPY and carbachol raise Ca2+ in SK-N-MC cells by three different mechanisms. Evidence for inositol phosphate-independent Ca2+ mobilization by NPY.
We have compared the mechanism of NPY- and carbachol-stimulated Ca2+ increases in SK-N-MC cells. NPY stimulated Ca2+ mobilization via a pertussis toxin-sensitive mechanism. Carbachol stimulated Ca2+ mobilization and influx via pertussis toxin-insensitive and -sensitive mechanisms, respectively. Carbachol but not NPY stimulated inositol phosphate accumulation by a pertussis toxin-insensitive mechanism. We conclude that carbachol promotes Ca2+ influx via a pertussis toxin-sensitive G protein and Ca2+ mobilization via a pertussis toxin-insensitive G-protein coupling to inositol phosphate generation; NPY stimulates Ca2+ mobilization via a pertussis toxin-sensitive G protein without apparent involvement of inositol phosphates.
Michel
M C
MC
Department of Medicine, University of Essen, Federal Republic of Germany.
Feth
F
F
Stieneker
M
M
Rascher
W
W
D002118:Calcium / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology*; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D007295:Inositol Phosphates / Q000502:physiology*; D009478:Neuropeptide Y / Q000494:pharmacology*; D037342:Pertussis Toxin; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D007295:Inositol Phosphates; D009478:Neuropeptide Y; D010566:Virulence Factors, Bordetella; D002217:Carbachol; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D002118:Calcium