Bipolar disorder is a
psychiatric disease characterized by recurrent episodes of
mania and depression. Blueberries contain bioactive compounds with important pharmacological effects such as neuroprotective and
antioxidant actions. The aim of this study was to investigate the effects of
blueberry extract and/or
lithium on oxidative stress, and
acetylcholinesterase (AChE) and Na+, K+-
ATPase activity in an experimental
ketamine-induced model of
mania. Male Wistar rats were pretreated with vehicle,
blueberry extract (200 mg/kg), and/or
lithium (45 mg/kg or 22.5 mg/kg twice daily) for 14 days. Between the 8th and 14th days, the animals also received an injection of
ketamine (25 mg/kg) or vehicle. On the 15th day the animals received a single injection of
ketamine; after 30 min, the locomotor activity was evaluated in an open field test.
Ketamine administration induced an increase in locomotor activity. In the cerebral cortex, hippocampus and striatum,
ketamine also induced an increase in
reactive oxygen species, lipid peroxidation and
nitrite levels, as well a decrease in
antioxidant enzyme activity. Pretreatment with
blueberry extract or
lithium was able to prevent this change.
Ketamine increased the AChE and Na+, K+-
ATPase activity in brain structures, while the
blueberry extract partially prevented these alterations. In addition, our results showed that the
neuroprotective effect was not potentiated when
lithium and
blueberry extract treatment were given together. In conclusion, our findings suggest that
blueberry extract has a
neuroprotective effect against an experimental model of
mania. However, more studies should be performed to evaluate its effects as an adjuvant
therapy.