29,31 Drugs targeting the glutamate system may also prove beneficial; LY293558, an aminoiso propyl propionic acid (AMPA) antagonist, is highly efficient in blocking hyperlocomotion in the neonatally lesioned rats at doses that do not affect, locomotor activity in controls,36 as is the glycine transporter inhibitor.66 Thus, this model may have predictive validity and heuristic

potential to identify drugs with new mechanisms of action. The model also appears to mimic a spectrum of neurobiological and behavioral features of schizophrenia, including functional pathology in presumably critical brain regions #find more keyword# interconnected with the hippocampal formation and targeted by antipsychotic drugs: the striatum/nucleus accumbens and the prefrontal cortex. It is noteworthy that in the nonhuman primate, early postnatal damage of the hippocampal region also alters development of the dorsal prefrontal cortex and the

mechanisms whereby the dorsal prefrontal cortex regulates Inhibitors,research,lifescience,medical subcortical dopamine function, phenomena similar to those described in patients with schizophrenia.13,14,67 Thus, neonatal damage to the hippocampus of the rat appears to reproduce a broad spectrum of schizophrenia-related phenomena (Table I), and establishes the neurobiological plausibility Inhibitors,research,lifescience,medical of early damage having a delayed impact on neural functions implicated in schizophrenia. Transient VH inactivation model Although developmental lesion models represent a. rather crude technique to study the role of particular brain regions, transmitter systems, or the connections between them, they have confirmed the plausibility of neurodevelopmental damage Inhibitors,research,lifescience,medical having selected

deleterious effects after a prolonged period of relative normalcy. In this respect, they appear to have face validity not just, in terms of behavioral, cellular, and pharmacological phenomena, but also in terms of the temporal course of the clinical disorder. Inhibitors,research,lifescience,medical As models of developmental pathology, they certainly lack construct validity, from as the schizophrenic brain does not manifest a “lesion” analogous to any of these models; but they may have heuristic value in discovering molecular consequences of early brain damage and new treatment strategies. In the next series of studies, we hypothesized that transient inactivation of the VH during a critical period of development, that produces subtle, if any, anatomical changes in the hippocampus, may be sufficient, to disrupt, normal maturation of the prefrontal cortex (and perhaps, other interconnected late maturing regions). We explored whether this developmental disruption would, in turn, trigger behavioral changes similar to those observed in animals with the permanent excitotoxic lesion.