PRETREATMENT WITH PHYSOSTIGMINE, MECAMYLAMINE AND ATROPINE REDUCES THE IMPACT OF SOMAN ON THE CORTICAL VISUAL EVOKED-POTENTIAL OF THE CAT

A pretreatment regimen of physostigmine, mecamylamine and atropine was evaluated for its ability to alleviate the impact of soman on visual system function as measured by changes in the cortical visual evoked potential (VEP) of the cat. Data from unprotected animals showed a threshold (30% depression in the VEP) of 6.4-mu-g/kg, while in pretreated animals, the threshold dose was 32.7-mu-g/kg, yielding a protection ratio of 5:1. Extending the time between pretreatment and exposure reduced the degree of protection. Pretreatment also reduced the degree of VEP depression at suprathreshold doses, indicating a therapeutic effect even in cases of severe exposure.