Effects of cariprazine, a novel antipsychotic, on cognitive deficit and negative symptoms in a rodent model of schizophrenia symptomatology.

Negative symptoms and cognitive impairment associated with schizophrenia are strongly associated with poor functional outcome and reduced quality of life and remain an unmet clinical need. Cariprazine is a dopamine D3/D2 receptor partial agonist with preferential binding to D3 receptors, recently approved by the FDA for the treatment of schizophrenia and manic or mixed episodes associated with bipolar I disorder. The aim of this study is to evaluate effects of cariprazine in an animal model of cognitive deficit and negative symptoms of schizophrenia. Following sub-chronic PCP administration (2mg/kg, IP for 7 days followed by 7 days drug-free), female Lister Hooded rats were administered cariprazine (0.05, 0.1, or 0.25mg/kg, PO) or risperidone (0.16 or 0.1mg/kg, IP) before testing in novel object recognition (NOR), reversal learning (RL), and social interaction (SI) paradigms. As we have consistently demonstrated, sub-chronic PCP significantly impaired behavior in these tests. Deficits were significantly improved by cariprazine, in a dose dependent manner in the operant RL test with efficacy at lower doses in the NOR and SI tests. Locomotor activity was reduced at the highest doses of 0.1mg/kg and 0.25mg/kg in NOR and SI. Risperidone also reversed the PCP-induced deficit in all tests. In conclusion, cariprazine was effective to overcome PCP-induced deficits in cognition and social behavior in a thoroughly validated rat model in tests representing specific symptom domains in schizophrenia patients. These findings support very recent results showing efficacy of cariprazine in the treatment of negative symptoms in schizophrenia patients.

The preclinical profile of asenapine: clinical relevance for the treatment of schizophrenia and bipolar mania.

INTRODUCTION: Asenapine is a novel antipsychotic drug approved for the treatment of acute schizophrenia, manic, or mixed episodes associated with bipolar I disorder, as a maintenance treatment of schizophrenia and as an adjunctive therapy with lithium or valproate for the acute treatment of manic or mixed episodes associated with bipolar I disorder in adults. AREAS COVERED: This review focuses on the preclinical profile of asenapine. It analyzes the pharmacological, neurochemical, behavioral, and molecular mechanisms of asenapine and their contribution to the beneficial therapeutic advantages of the drug as reported in published preclinical and clinical studies, product labels, and poster presentations. EXPERT OPINION: Asenapine exhibits a broad pharmacological profile that targets a wide range of neurotransmitter receptors with variable affinities. The drug preferentially increases dopamine, norepinephrine, and acetylcholine levels in cortical and limbic brain areas. It also potentiates cortical glutamatergic neurotransmission, and is active in behavioral animal models predictive of antipsychotic, antidepressant, and pro-cognitive activities. Chronic administration of asenapine alters the abundance of dopamine, serotonin, glutamate, adrenergic, and cholinergic receptor subtypes in different brain regions. These action mechanisms of asenapine might contribute to its unique psychopharmacological properties in the improved treatment of schizophrenia and other psychotic disorders.