title: Calcium-dependent nerve growth factor-stimulated hydrolysis of phosphoinositides in PC12 cells.
abstract: The effect of nerve growth factor (NGF) on the hydrolysis of phosphoinositides in PC12 cells was examined. Addition of NGF to PC12 cells prelabeled with [3H]-inositol resulted in an increase in the formation of labeled inositol trisphosphate ([3H]IP3), inositol bisphosphate ([3H]IP2), and inositol monophosphate ([3H]IP), an observation indicating that NGF stimulated hydrolysis of the polyphosphoinositides. The increase in these inositol phosphates was detected as early as 15 s after addition of NGF. In the presence of LiCl, the accumulation of [3H]IP was linear for at least 20 min. The NGF-stimulated accumulation of [3H]IP was dose-dependent with a Kact of 0.17 nM and was dependent on the presence of extracellular calcium. In a calcium-free buffer containing EGTA, the NGF-dependent increase in accumulation of [3H]IP was not seen, and the basal level of [3H]IP accumulation was lower than that observed in the presence of extracellular calcium. Lanthanum inhibited both the basal and NGF-stimulated accumulation of [3H]IP, whereas the calcium ionophore A23187, in the absence of NGF, stimulated an accumulation of [3H]IP. The maximal accumulation of [3H]IP in the presence of A23187 was the same as that observed in the presence of NGF. Incubation of the cells with both A23187 and NGF resulted in an accumulation of [3H]IP that was not significantly different from the effect of either agent alone. These results suggest that NGF rapidly stimulates the hydrolysis of phosphoinositides in PC12 cells and that this NGF-stimulated hydrolysis of phosphoinositides occurs by a calcium-dependent mechanism.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002460:Cell Line; D005110:Extracellular Space / Q000378:metabolism; D006868:Hydrolysis; D009414:Nerve Growth Factors / Q000494:pharmacology*; D010716:Phosphatidylinositols / Q000378:metabolism*; D013268:Stimulation, Chemical
chemical_list: D009414:Nerve Growth Factors; D010716:Phosphatidylinositols; D002118:Calcium