Acetylcholinesterase resynthesis after DFP poisoning; histochemical and biochemical study.

DFP (0.4 to 2.0 mg/kg) was injected into the rat spinal ganglion leads to N. ischiadicus model system and examinations were made of the AChE inhibitory affect and the influence on the transport and resynthesis of the enzyme. It was concluded that the intraganglionically administered DFP inhibits the enzyme activity of the pseudo-unipolar large ganglion cells, but the specific ChE remains in some of the small neurones. Autoradiographically, 3H-DFP could be demonstrated at the same morphological sites as the AChE histochemically. The labelled material migrates from the perikaryon towards the axon terminal by slow transport (10 mm/24 h). The intraganglionically administered DFP inhibits (96%) the AChE activity of the spinal ganglion. However, the enzyme activity of the ganglion cells begins to return 3 h later, and in 12 h it has attained 27% of the original activity. The enzyme undergoing transport from the perikaryon displays a proximo-distal gradient in the axon, and hence the results do not support the hypothesis of local axonal synthesis of AChE.