Prenatal exposure to ketamine in rats: Implications on animal models of schizophrenia

Schizophrenia is a complex neuropsychiatric disorder characterized by hallucinations, delusions, anhedonia, flat affect and cognitive impairments. The aim of this study was to propose a prenatal treatment with ketamine, a psychedelic drug that acts as a non-competitive inhibitor of glutamate NMDA receptors, as a neurodevelopmental animal model of schizophrenia. The drug was applied (i.m. 60 mg.kg^-1  h^-1 ) in pregnant Sprague-Dawley rats on gestational Day 14. Offspring behavior was studied on pubertal (4 weeks old) and adult (10 weeks old) stages. Also, hippocampal CA1-CA3 morphology was assessed in adult animals through a Nissl stain. Results showed a disinhibition and hyperactive behavior in pubertal animals exposed to ketamine, followed in adulthood with cognitive impairments, social withdrawal, anxiety, depression, and aggressive-like behaviors. In the hippocampus, a reduction of the CA3 layer thickness was observed, without changes in cell density. These results strongly suggest a robust link between prenatal pharmacologic manipulation of NMDA receptors and schizophrenia.