Muscarinic receptor-mediated hydrolysis of phosphatidylinositols in human neuroblastoma (SH-SY5Y) cells is sensitive to pertussis toxin

Effects of pertussis toxin or cholera toxin on carbachol-stimulated inositol-1-phosphate ([3H]IP1) accumulation were studied using the human neuroblastoma cell line (SH-SY5Y). The maximal carbachol-stimulated [3H]IP1 accumulation in the SH-SY5Y cells was decreased from 51.4 fmol/10(6) cells to 42.4 fmol/10(6) cells (P less than 0.05) and 22.1 fmol/10(6) cells (P less than 0.01) in the absence and presence of 1 microgram/ml and 10 micrograms/ml pertussis toxin, respectively while the EC50 values did not change. Cholera toxin (1 mg/ml) did not alter carbachol-stimulated [3H]IP1 accumulation in these cells. These results suggest that a pertussis toxin sensitive G-protein may be involved in muscarinic receptor-phosphatidylinositol hydrolysis coupling in SH-SY5Y cells.