The behavioral effects of anticholinesterase insult following exposure to different environmental temperatures

This study evaluates soman toxicity via a number of behavioral tasks after an 8-h exposure to one of five thermal stress conditions (-1,7,15,23, or 31 degrees C at 80 +/- 5% RH). Animals were removed from the environmental chamber, injected with soman (0-160 micrograms X kg-1), and tested 30 min post-injection. The test battery included: motor activity, grip strength, core temperature, sensitivity to heat, effects on memory and learning, and a subjective rating of the animal's state of health. A significant thermal stress/soman interaction was observed for all measures. This interaction was seen as a shift of the soman dose-response functions to the right for the higher temperature groups, i.e., the lower the stress temperature, the greater the susceptibility to soman. For example, the ED50 for the activity measure was 38 micrograms X kg-1 for the -1 degree C exposure group and 94 micrograms X kg-1 for the 31 degrees C group. The thermal stress influence on soman toxicity may be a function of previous motor activity.