Muscarinic cholinergic receptor-induced enhancement of PGE1-stimulated cAMP accumulation in neuroblastoma X glioma cells: prevention by pertussis toxin

Abstract

Chronic treatment of neuroblastoma X glioma hybrid cells (NG 108-15) with the muscarinic cholinergic agonist carbachol, which acutely inhibits adenylate cyclase, resulted in a 104 +/- 10% increase in PGE1-stimulated cAMP accumulation. Pretreatment of intact cells with pertussis toxin can structurally modify the inhibitory regulatory protein, Gi, by ADP-ribosylation and thus abolish the acute inhibition by carbachol. Pretreatment of the cells with pertussis toxin also resulted in a 27 +/- 8% increase in PGE1-stimulated cAMP accumulation. In the pertussis toxin-treated cells, chronic treatment with carbachol did not further enhance the PGE1 stimulation. These results suggest that functional Gi is required for the development of muscarinic cholinergic-induced enhancement of PGE1-stimulated cAMP accumulation.