A guanine nucleotide-dependent regulatory protein couples substance P receptors to phospholipase C in rat parotid gland.
Electrically permeabilized cells of rat parotid gland, prelabelled with [3H]-inositol, synthesized [3H]-inositol phosphates (IP3 and IP2) when stimulated with alpha 1-adrenergic, muscarinic-cholinergic, and substance P receptor-agonists. Non-hydrolyzable analogues of GTP (GTP gamma S and GppNHp) also stimulated [3H]-IP3 formation by permeabilized cells and they potentiated the stimulation by receptor-agonists. These effects of guanine nucleotides occurred only with GTP analogues and only in permeabilized cells indicating an intracellular site of action. NaF stimulated [3H]-IP3 accumulation, an effect that was not entirely attributable to the ability of F- to inhibit (1,4,5)IP3 degradation. These results suggest that a guanine nucleotide-dependent regulatory protein couples Ca2+-mobilizing receptors to phospholipase C in parotid gland.
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006157:Guanosine Monophosphate / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D008297:Male; D010306:Parotid Gland / Q000201:enzymology*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D012969:Sodium Fluoride / Q000494:pharmacology; D013873:Thionucleotides / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism*
D007295:Inositol Phosphates; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter; D013873:Thionucleotides; D006165:Guanylyl Imidodiphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006157:Guanosine Monophosphate; D006160:Guanosine Triphosphate; D002217:Carbachol; D012969:Sodium Fluoride; D011433:Propranolol; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D004837:Epinephrine