Immune Activation During Pregnancy in Mice Leads to Dopaminergic Hyperfunction and Cognitive Impairment in the Offspring: A Neurodevelopmental Animal Model of Schizophrenia

Background Maternal viral infection is associated with increased risk for schizophrenia. It is hypothesized that the maternal immune response to viruses may influence fetal brain development and lead to schizophrenia. Methods To mimic a viral infection, the synthetic double strand RNA polyriboinosinic-polyribocytidilic acid (poly I:C) was administered into pregnant mice. Behavioral evaluations (thigmotaxis, methamphetamine [MAP]-induced hyperactivity, novel-object recognition test [NORT]), sensorimotor gating (prepulse inhibition [PPI]), and biochemical evaluation of the dopaminergic function of the offspring of phosphate-buffered saline (PBS)-treated dams (PBS-mice) and that of poly I:C-treated dams (poly I:C-mice) were examined. Results In juveniles, no difference was found between the poly I:C-mice and PBS-mice. However, in adults, the poly I:C-mice exhibited attenuated thigmotaxis, greater response in MAP-induced (2 mg/kg) hyperlocomotion, deficits in PPI, and cognitive impairment in NORT compared with the PBS-mice. Cognitive impairment in the adult poly I:C-mice could be improved by subchronic administration of clozapine (5.0 mg/kg) but not haloperidol (.1 mg/kg). Increased dopamine (DA) turnover and decreased receptor binding of D2-like receptors, but not D1-like receptors, in the striatum were found in adult poly I:C-mice. Conclusions Prenatal poly I:C administration causes maturation-dependent increased subcortical DA function and cognitive impairment in the offspring, indicating a neurodevelopmental animal model of schizophrenia.