[Functional homology between alcohol dependence and mood disorder].

Acute and chronic consumption of alcohol (ethanol) has been reported to modify a multitude of molecular events such as membrane fluidity, neurotransmitter turnover, function of neurotransmitter receptors and intracellular signal transduction systems coupling to neurotransmitter receptors, and biochemical processes in the central nervous system. Long-term consumption of alcohol produces alcohol dependence with comorbidity such as mood disorder, schizophrenic disorder and neurotic disorder. We examined functional changes in serotonin transporter (SERT) and serotonin receptors (5-HT(1A) and 5-HT(2A) receptors) related with depression using alcohol physical dependent mice and found correlated changes between depression and alcohol dependence. That is, SERT expression increased in the cingulate cortex, nucleus accumbens, hippocampal CA1-CA3 layers, and mediodorsal nucleus of the thalamus. Moreover, 5-HT(1A) receptors in the cingulate cortex and hippocampus and 5-HT(2A) receptors in hippocampus decreased. In addition, increase of glucocorticoid with activation of the hypothalamus-pituitary-adrenal (HPA) axis is reported in both depression and alcohol dependence. These data suggest that similar changes of serotonin system and glucocorticoid response in brain may occur in both depression and alcohol dependence.