Fig. 5.

Effectiveness of pretreatment with galantamine, donepezil, (±) huperzine A, or rivastigmine in preventing acute toxicity of 1.0 × LD₅₀ soman in guinea pigs in the absence of atropine. A, dose-response relationship illustrating the ability of galantamine to afford 24-h survival of guinea pigs challenged with 1.0 × LD₅₀ soman (28 μg/kg s.c.). Soman was injected 30 min after galantamine. Each point represents data from 8 to 12 animals. B, survival (24 h) of guinea pigs pretreated with donepezil (3 mg/kg i.m.), (±)huperzine A (0.3 mg/kg i.m.), or rivastigmine (6 mg/kg i.m.), and challenged 30 min later with 1.0 × LD₅₀ soman. Each experimental group consisted of eight guinea pigs. Ordinates in A and B represent the percentage of animals that were kept alive at 24 h after the treatment because they presented no life-threatening symptoms.