Mitochondrial respiratory chain activity in an animal model of mania induced by ouabain

Abstract

Objectives:Bipolar disorder (BD) is a mental illness associated with higher rates of suicide. The present study aims to investigate the brain mitochondrial respiratory chain activity in an animal model of mania induced by ouabain.Methods:Adult male Wistar rats received a single intracerebroventricular administration of ouabain (10−3and 10−2M) or vehicle. Locomotor activity was measured using the open field test. Mitochondrial respiratory chain activity was measured in the brain of rats 1 h and 7 days after ouabain administration.Results:Our results showed that spontaneous locomotion was increased 1 h and 7 days after ouabain administration. Complexes I, III and IV activities were increased in the prefrontal cortex, hippocampus and striatum immediately after the administration of ouabain, at the concentration of 10−3and 10−2M. Moreover, complex II activity was increased only in the prefrontal cortex at the concentration of 10−2M. On the other hand, no significant alterations were observed in complex I activity 7 days after ouabain administration. However, an increase in complexes II, III and IV activities was observed only in the prefrontal cortex at the concentration of 10−2M.Conclusion:Our findings suggest an increase in the activities of mitochondrial respiratory chain in this model of mania. A possible explanation is that these findings occur as a rebound effect trying to compensate for a decrease of ATP deprivation in BD. The present findings suggest that this model may present good face validity and a limitation in construct validity.