Blockade of platelet-activating factor receptor attenuates abnormal behaviors induced by phencyclidine in mice through down-regulation of NF-κB.

Repeated treatment of mice with phencyclidine (PCP), a drug that induces schizophrenia-like symptoms, increased expression of the platelet-activating factor receptor (PAF-R) in the prefrontal cortex and hippocampus, with a greater increase in the prefrontal cortex. This was accompanied by increased activity of the proinflammatory molecule nuclear factor kappa B (NF-κB). Blocking PAF-R with the antagonist ginkgolide B, using PAF-R knockout mice, or inhibiting NF-κB with pyrrolidine dithiocarbamate each reduced PCP-induced abnormal behaviors including reduced sociability, depression, cognitive impairment, and behavioral sensitization. The findings suggest PAF-R drives PCP-induced neuropsychotoxicity through an NF-κB-dependent mechanism and may be linked to schizophrenia-like behavior.

Study at a glance

Abstract

Accumulating evidence suggests that neuroinflammation is one of the important etiologic factors of abusive and neuropsychiatric disorders. Platelet-activating factor (PAF) is potent proinflammatory lipid mediat1or and plays a pivotal role in neuroinflammatory disorders through the specific PAF receptor (PAF-R). Phencyclidine (PCP) induces a psychotomimetic state that closely resembles schizophrenia. Here, we investigated the role of PAF-R in the abnormal behaviors induced by PCP in mice. Repeated treatment with PCP resulted in a significant increase in PAF-R gene expression in the prefrontal cortex (PFC) and in the hippocampus. This increase was more pronounced in the PFC than hippocampus. Treatment with PCP resulted in a significant increase in nuclear translocation of the nuclear factor kappa beta (NF-κB) p65 and DNA binding activity, indicating that the proinflammatory molecule NF-κB was increased through up-regulation of PAF-R. Consistently, NF-κB activation was significantly protected by the PAF-R antagonist, ginkgolide B (Gink B), in PAF-R knockout mice and by the NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC). In addition, PCP-induced abnormal behaviors (i.e., reduced sociability, depression, cognitive impairment, and behavioral sensitization) were significantly attenuated by Gink B, in PAF-R knockout mice, and by PDTC. Importantly, PDTC did not significantly alter the attenuations observed in Gink B-treated mice or PAF-R knockout mice, indicating that NF-κB is a critical target for neuropsychotoxic modulation of PAF-R. Therefore, the results suggest that PAF-R mediates PCP-induced neuropsychotoxicity via a NF-κB-dependent mechanism, and that up-regulation of PAF-R may be associated with schizophrenia-like behavior in animal models.