Studies on the pharmacology of fluoroacetate; effects on the central nervous systems of dogs and rabbits.

1. Spike and dome waves of high voltage occurring at a 3 per second rate have been produced in the EEG of curarized dogs by the administration of fluoroacetic acid. 2. Six of 8 dogs receiving intravenous injections of 0.05 to 1.0 mgm./kgm. of fluoroacetate (sodium salt or methyl ester) developed cerebral dysrhythmias strongly resembling clinical grand mal and petit mal seizures. 3. Fourteen of 16 dogs receiving intracranial injections of fluoroacetate (sodium salt or methyl ester) of 41 to 250 per cent of the LD 50 developed similar dysrhythmias. 4. No definite relation was found between the use or dosage of water or lipoid soluble fluoroacetates; the sex, age or size of the dog and the occurrence of the petit mal type dysrhythmias. The grand mal seizures were produced more frequently with larger doses. 5. Rabbits, a species which can not be convulsed by the intravenous administration of fluoroacetates in any dosage, convulse when very small doses (40 and 80 per cent of the intravenous LD 50 ) are injected intracranially.