The toxicity of fluoride has been extensively studied in domestic and laboratory animals, but its effects on the nervous system have received relatively little consideration. Lu et al. (1961) reported that rats treated with sodium fluoride became more sensitive to convulsant agents, pentobarbital and diphenylhydantoin. Cholinesterase inhibition was considered to be a possible mechanism of action; in an attempt to gain some information on this matter, the experiments to be described were done.
Two series of experiments were done on female rats of a Wistar strain. In the first series the rats were fed for 16 weeks on a diet of ground fox chow containing sodium fluoride in a quantity sufficient to provide 70 p.p.m. of elemental fluoride.
In the second series two groups of rats were given fluoride as sodium fluoride at 1.68 or 3.36 mg/100 g body weight. This was given by stomach tube daily for 30 days. At the end of the fluoride treatment periods, the determinations recorded below were made.
Paralytic effect of succinylcholine. The method described by ALLMARK & BACHINSKI (1949) was used to determine paralytic activity. The drug was given by intramuscular injection, after which the rats were placed on a screen at an angle of 60 degrees. Animals that slid off the screen within 20 minutes were taken as a “positive”, although most of the rats reacting to the drug fell within 7 minutes. The PD50 was calculated by the probit method (BLISS 1935 a,b).
Toxicity of parathion and demeton. The compounds were given in an aqueous suspension by intraperitoneal injection. Ten rats were used at …