Reversal of cognitive deficits by an ampakine (CX516) and sertindole in two animal models of schizophrenia—sub-chronic and early postnatal PCP treatment in attentional set-shifting
Therapies treating cognitive impairments in schizophrenia especially deficits in executive functioning are not available at present. The current study evaluated the effect of ampakine CX516 in reversing deficits in executive functioning as represented in two animal models of schizophrenia and assessed by a rodent analog of the intradimensional–extradimensional (ID–ED) attentional set-shifting task. The second generation antipsychotic, sertindole, provided further validation of the schizophrenia-like disease models. Animals were subjected to (a) sub-chronic or (b) early postnatal phencyclidine (PCP) treatment regimes: (a) Administration of either saline or PCP (5 mg/kg, intraperitonally b.i.d. for 7 days) followed by a 7-day washout period and testing on day 8. (b) On postnatal days (PNDs) 7, 9, and 11, rats were subjected to administration of either saline or PCP (20 mg/kg, subcutaneously (s.c.)) and tested on PNDs 56–95, after reaching adulthood. The single test session required rats to dig for food rewards in a series of discriminations following acute administration of either vehicle, or CX516 (5–40 mg/kg, s.c.), or sertindole (1.25 mg/kg, perorally). The specific extradimensional deficits produced by sub-chronic or early postnatal PCP treatment were significantly attenuated by sertindole and dose-dependently by CX516. Findings here further establish PCP treatment as model of executive functioning deficits related to schizophrenia and provide evidence that direct glutamatergic interventions could improve these, when assessed in the ID–ED attentional set-shifting task.