Role of 5-HT(1A) receptors in the modulation of stress-induced lactate metabolism in the medial prefrontal cortex and basolateral amygdala.

RATIONALE

Lactate has been shown to play a significant role in energy metabolism and reflect neural activity in the brain.

OBJECTIVES

Using in vivo microdialysis technique, we measured extracellular lactate concentrations in the medial prefrontal cortex (mPFC) and the basolateral amygdaloid (BLA) nucleus of rats under electric foot shock stress. Moreover, to examine the role of serotonin (5-HT)(1A) receptors in brain energy metabolism in response to stressors, we attempted to determine whether the stress-induced changes of extracellular lactate levels in the mPFC and BLA are attenuated by tandospirone, a partial agonist at 5-HT(1A) receptors, or perospirone, a novel atypical antipsychotic with a 5-HT(1A) receptor partial agonist and 5-HT(2A)/dopamine-D(2) antagonist property.

RESULTS

Foot shock stress led to an increase in extracellular lactate concentrations both in the mPFC and BLA. Tandospirone (2 mg/kg) attenuated the foot shock stress-induced increase of extracellular lactate concentrations in both of the brain regions, which was blocked by pretreatment with WAY-100635, a selective 5-HT(1A) antagonist. On the other hand, perospirone (0.3 mg/kg) attenuated the increment of extracellular lactate concentrations in the mPFC and BLA, which was unaltered by pretreatment with WAY-100635.

CONCLUSIONS

These results indicate that the foot shock stress-induced increase in lactate metabolism is partly regulated by 5-HT(1A) receptors both in cortical and limbic regions.