The Effect of Immobilization Stress and Corticosterone on Haloperidol-induced c-fos Expression in Rat Brain / 대한정신약물학회지

ABSTRACT

OBJECTIVE: Immediate early gene (IEG), c-fos is known to encode a 62 kDa nuclear protein (Fos) which has a critical role in the stimulus response process of many cells. c-fos can be activated in the central nervous system by a variety of physiological and pharmacological treatment. Recently evidences has been reported suggesting that glucocorticoid hormones, which are released from adrenal cortex in response to stress, may regulate IEG expression. We observed whether immobilization stress or corticosterone altered the induction of c-fos by haloperidol in the nucleus accumbens, lateral striatum, and prefrontal cortex. METHODS: Twenty-four healthy Wistar rats of male sex, weighing 300-450 g, were divided into 6 groups according to injection agents [vehicle (1 mg/kg), haloperidol (1 mg/kg), corticosterone (1 mg/kg), immobilization stress, haloperidol (1 mg/kg) and corticosterone (1 mg/kg), haloperidol (1 mg/kg) and immobilization stress] respectively. Fos-immunoreactivity was measured by counting of Fos-positive neurons in the nucleus accumbens, lateral striatum, and prefrontal cortex. RESULTS: (1) The number of Fos-positive neurons in the nucleus accumbens was significantly decreased in the haloperidol plus immobilization stress group and haloperidol plus corticosterone group compared with that in the haloperidol group (p<0.05). (2) The number of Fos-positive nurons in the lateral striatum was significantly decreased in the haloperidol plus corticosterone group compared with that in the haloperidol group, but the number of Fos-positive neurons in the lateral striatum was not significantly different between the haloperidol plus immobilization stress group and the haloperidol group (p<0.05). (3) The number of Fos-positive neurons in the prefrontal cortex was significantly increased in the haloperidol plus immobilization stress group and haloperidol plus corticosterone group compared with that in the haloperidol group (p<0.05). CONCLUSION: These results suggest that regulatory process exerted by corticosterone may alter the antipsychotic effect of haloperidol.