Measurement of the oxime HI-6 after peripheral administration in tandem with neurotransmitter levels in striatal dialysates: Effects of soman intoxication

In the present study, the technique of microdialysis combined with tandem high-performance liquid chromatography was used to determine the striatal levels of HI-6 and neurotransmitters following peripheral administration of HI-6 (50 mg/kg i.m.) in conscious, freely moving rats. The results were compared with those obtained in animals given soman (135 mu g/kg i.p.) 1 min before HI-6 (50 mg/kg i.m.). Principal component analysis was used to study the effects of the different treatments on neurotransmitters and signs of poisoning. In all animals given HI-6, maximum levels of HI-6 appeared in the second 20-min fraction after administration of HI-6, then gradually declined, reaching the lower limits of detection after 3 hr. There was a correlation between severity of poisoning and neurochemical changes observed; dopamine and GABA levels increased as the severity of signs of poisoning increased. These results clearly demonstrate that HI-6 can penetrate into the brain of control and soman-intoxicated animals. Tandem measurement of dopamine electrochemically and HI-6 by UV detection provides a simple method for obtaining data on HI-6 penetration into the brain in neurochemical studies of soman poisoning and its treatment.