[Significance of the pharmacotherapy of schizophrenia in the emotional context processing of cognition]

Abstract

Emotional disorders and cognitive dysfunctions are important treatment targets in psychiatric clinical settings. The biological mechanisms of emotional disorders have been studied with methods that include fear conditioning, schizophrenia models are studied with methamphetamine-induced reverse tolerance in rats, and dynamic changes in brain neurotransmitters are studied with microdialysis and high-performance liquid chromatography. We combined these methods in order to evaluate dopamine dynamics in the amygdala and the biological bases and relationships of emotional disorder and cognitive dysfunction. Fear-conditioned rats showed freezing behavior and dopamine release in the amygdala in response to conditioned stimuli. Methamphetamine-induced reverse tolerance rats showed increased dopamine release in the amygdala in response to conditioned stimuli. The increased release of dopamine continued after the freezing behavior had ended. This increased and long-lasting dopamine release may reflect abnormal emotional context processing in cognition in schizophrenia. Antipsychotic drugs, such as haloperidol, aripiprazole, and clozapine, suppress this increased release of dopamine in the amygdala in response to conditioned stimuli. These findings suggest that antipsychotic drugs may stabilize abnormal emotional context processing in cognition in this model. We conclude that the significance of pharmacotherapy in schizophrenia is that antipsychotic drugs stabilize the emotional context processing in cognition and adjust the relationship of emotion and cognition.