Second-generation antipsychotic drugs, olanzapine, quetiapine, and clozapine enhance neurite outgrowth in PC12 cells via PI3K/AKT, ERK, and pertussis toxin-sensitive pathways

Second-generation antipsychotic drugs, olanzapine, quetiapine, and clozapine, were found to enhance neurite outgrowth induced by nerve growth factor (NGF) in PC12 cells. These drugs increased the number of cells bearing neurites, the length of primary neurites, and the size of the cell body of NGF-differentiated PC12 cells. In addition, the drugs induced sprouting of neurite-like processes in PC12 cells in the absence of NGF. Olanzapine, quetiapine, and clozapine enhanced the phosphorylation. of Akt and ERK in combination with NGF, and specific inhibitors of these pathways attenuated these effects. Pretreatment of cells overnight with pertussis toxin had no effect on NGF-induced differentiation but significantly decreased the effects of the antipsychotic drugs on neurite outgrowth, suggesting that G(i)/G(o)-coupled receptors are involved in the response to drug. Abetter understanding of the mechanisms underlying the effects of the second-generation drugs might suggest new therapeutic targets for enhancement of neurite outgrowth.