The protective actions of some anticholinergic drugs in sarin poisoning.

1. The central and peripheral anticholinergic activities of a series of drugs comprising atropine, hyoscine, caramiphen and one of its analogues, and three glycollic acid esters, have been measured.2. The ability of the same drugs used alone, and in conjunction with N-methyl pyridinium-2-aldoxime methanesulphonate (P2S), to protect mice, rats and guinea-pigs from the lethal effects of sarin has been assessed.3. No correlation was found to exist between central or peripheral anticholinergic activity and ability to protect from sarin.4. On the indirectly stimulated isolated rat phrenic nerve-diaphragm preparation all drugs with the exception of hyoscine caused potentiation of responses to low frequency stimulation but partial block of responses to high frequency stimulation. The drugs did not reverse the effects of sarin on the phrenic nerve-diaphragm preparation.6. It is concluded that a pharmacological action other than an anticholinergic one is involved, in part, in the protective actions against sarin of some of the drugs studied. Whether their effects on skeletal muscle are of any relevance in this respect is unresolved.