NADPH-d (nicotinamide-adenine dinucleotide phosphate-diaphorase) neurons are thought to migrate improperly during development in the brains of schizophrenic patients. This enzyme is a nitric oxide synthase (NOS). Nitric oxide (NO) is known to affect neurodevelopmental processes in the CNS. Therefore, we hypothesized that interference of NO generation during development may produce some aspects of schizophrenia symptomatology in a rat model. In these experiments, neonatal rats were challenged with a NOS inhibitor (L-nitroarginine 1-100 mg/kg s.c.) daily on post-natal days 3-5. L-Nitroarginine (L-NoArg) treated male rats developed a hypersensitivity to amphetamine in adulthood versus vehicle treated controls, whereas female rats did not. However, L-NoArg treated female rats developed a hypersensitivity to phencyclidine (PCP) at juvenile and adult ages versus vehicle treated controls, whereas male animals did not. L-NoArg treated male rats also had deficits in pre-pulse inhibition of startle whereas adult female rats did not. The results are discussed in terms of a new neurodevelopmental model of schizophrenia and male/female differences inherent in this disease.