Pertussis toxin distinguishes between muscarinic receptor-mediated inhibition of adenylate cyclase and stimulation of phosphoinositide hydrolysis in Flow 9000 cells.
Pretreatment of human embryonic pituitary tumour cells (Flow 9000) with pertussis toxin significantly reduced carbachol-mediated inhibition of isoprenaline and prostaglandin E2 stimulation of cyclic AMP formation. This is in accord with an action on the inhibitory Gi-protein by pertussis toxin. In contrast, pertussis toxin-pretreatment had no effect on either muscarinic agonist or GTP[S] (a non-hydrolysable GTP analogue) stimulation of [3H]inositol phosphate production in intact and permeabilized [3H]inositol-prelabelled Flow 9000 cells, respectively. These results suggest that muscarinic receptors are linked to the inhibition of adenylate cyclase and the stimulation of phosphoinositidase C via two different G-proteins in Flow 9000 cells.
D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006868:Hydrolysis; D007545:Isoproterenol / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000502:physiology; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000187:drug effects* / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; C029152:G-substrate; D009419:Nerve Tissue Proteins; D010716:Phosphatidylinositols; D011976:Receptors, Muscarinic; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D007545:Isoproterenol