D1-like receptor activation improves PCP-induced cognitive deficits in animal models: Implications for mechanisms of improved cognitive function in schizophrenia

Abstract

Phencyclidine (PCP) produces cognitive deficits of relevance to schizophrenia in animal models. The aim was to investigate the efficacy of the D1-like receptor agonist, SKF-38393, to improve PCPinduced deficits in the novel object recognition (NOR) and operant reversal learning (RL) tasks. Rats received either sub-chronic PCP (2 mg/kg) or vehicle for 7 days, followed by a 7-day washout. Rats were either tested in NOR or the RL tasks. In NOR, vehicle rats successfully discriminated between novel and familiar objects, an effect abolished in PCP-treated rats. SKF-38393 (6 mg/kg) significantly ameliorated the PCP-induced deficit (Pb0.01) an effect significantly antagonised by SCH-23390 (0.05 mg/kg), a D1-like receptor antagonist (Pb0.01). In the RL task sub-chronic PCP significantly reduced performance in the reversal phase (Pb0.001); SKF-38393 (6.0 mg/kg) improved this PCPinduced deficit, an effect antagonised by SCH-23390 (Pb0.05). These results suggest a role for D1-like receptors in improvement of cognitive function in paradigms of relevance to schizophrenia.