EFFECT OF DI-ISOPROPYL FLUORPHOSPHATE (DFP) ON ACTION POTENTIAL AND CHOLINESTERASE OF NERVE, II

Abstract

In expts. on the lobster cord exposed to di-isopropyl fluorphosphate (DFP), a striking parallelism was found between the rate of cholinesterase destruction and that of the abolition of conduction. The material presented in this paper extends the previous observations on the correlation between action potential and cholinesterase. The effect of DFP on these 2 processes was tested on the giant fibers of the stellar and fin nerves of Squid (Loligo pealii). Essentially, the same results were obtained as with the lobster cord. The technique has been modified to permit continuous recordings of the action potential of the nerves during exposure to, and recovery from, the compound. The effect of various concns. of DFP was also studied and compared in a few instances, with the effect of eserine. The correlation established between the presence of cholinesterase and the electrical activity of nerves of the Squid and lobster has also been extended to the sciatic of the bullfrog and frog. Two hrs. after injn. of massive doses of DFP, cholinesterase was still present in nerves. The manometric method was found to be inadequate in this particular case due to a combination of adverse factors.