During alcohol withdrawal, dramatic changes in the concentration of many neurotransmitters may be responsible for many of the adverse effects. In the present study, the technique of microdialysis was used to investigate the changes in excitatory and inhibitory amino acids following withdrawal from chronic alcohol intoxication.
Rats were physically deprived of alcohol by vapour inhalation for 4 weeks. Baseline concentrations of both arginine and GABA were significantly decreased in the alcohol-dependent rats, although there were no significant changes in any of the other baseline amino acid concentrations examined (i.e. glutamate and taurine).
During the first 12 hours after the last alcohol ingestion, only glutamate increased significantly by 6 hours (p < 0.05). To investigate whether taurine and alcohol interact with amino acids during alcohol withdrawal, two additional alcohol-dependent groups were given a single intraperitoneal injection of taurine or alcohol 5 hours after the onset of alcohol withdrawal. The IP injection of alcohol (2 g/kg) significantly increased taurine microdialysate content, and although this alcohol dose was not able to completely block the increase in glutamate release after alcohol withdrawal, a delayed decrease in glutamate content was observed by the end of the study period (i.e. 11-12 h).
However, IP injection of taurine (45 mg/kg) significantly blocked the increase in glutamate release during alcohol withdrawal. This latter finding suggests that taurine may interact with glutamate, possibly by inducing a blockade of glutamate release during alcohol withdrawal.