Neurochemical correlates of ethanol withdrawal: alterations in serotoninergic function.

Cessation of chronic ethanol administration, and elimination of ethanol from the body, results in a withdrawal syndrome in mice characterized by behavioural symptoms and hypothermia. During withdrawal, the accumulation rate of [14C] 5-hydroxytryptamine (5-HT) from [14C]tryptophan, was significantly lower in the brainstem of the ethanol-withdrawn animals than in controls. A similar pattern was seen in forebrain. When the rate of 5-HT accumulation was determined using pargyline, no differences occurred between control and ethanol-treated animals. The endogenous concentrations of tryptophan in plasma, and tryptophan, 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) in brain were the same in ethanol-treated and control animals. It is suggested that the changes in accumulation of 14C-5-HT and 14C-5-HIAA in ethanol-withdrawn animals reflected alterations in electrical activity of serotoninergic neurons during withdrawal.