RESUMEN
Changes in the plasma concentration of 8-amino butyric acid [GABA], the main inhibitory inhibitory neurotransmitter were studied in different types of narcotic drug addiction. Forty four adult male addicts were investigated. Simultaneously, urine analysis for detection of opiates, barbiturates and cannabmoids excreted during withdrawal and after withdrawal periods was done. Plasma concentration of GABA, showed a highly significant rise [P > 0.001] in addicts, when compared to normal healthy controls. The increase of mean values of GABA showed direct relation to the duration of addiction, although statistically nonsignificant. The rise of GABA was more pronounced in barbiturates than in opiates addiction during the withdrawal period, after which a decline of concentration was observed in barbiturate addicts, but still above the normal level, while opiate addicts showed a maintained significant rise. Combined narcotic addiction showed higher level of GABA, except in case of barbiturates with cannabinoids, indicating different mechanisms of drug interaction