Effects of atropine, trimedoxime and methylprednisolone on the developmentof organophosphate-induced delayed polyneuropathy in the hen

In this study we have examined the effects of atropine, trimedoxime (TMB-4) and methylprednisolone (MP) on the development of organophosphate-induced delayed polyneuropathy (OPIDP) in the hen. The birds were treated with stan dard neuropathic dose of diisopropylfluorophosphate (DFP) (1.1 mg/kg, sc), which produced OPIDP that could be graded as 5 on the 8-point scale, and th e development of OPIDP was observed for the next 22 days. The results obtai ned have shown that atropine (20 mg/kg, ip), TMB-4 (15 mg/kg, im) and MP (2 or 10 mg/kg, ip) either alone or in different combinations are able to imp rove the condition of the birds. The most potent effect was obtained with a tropine, TMB-4 (given 20 min before DFP) and MP (2 mg/kg, sc, given 20 min before and at 48 hour intrevals after poisoning) since the signs of OPIDP c ould hardly be seen (grade 1 at the 8-point scale). When TMB-4 acid MP were given 15 or 40 min after DFP the protective/therapeutic effects of these d rugs appeared to be diminished since walking disorders were more serious an d graded as 2 or 4, respectively. The possible mechanisms of the action of the drugs in respect to OPIDP are discussed. In conclusion, the results of this study have shown that it is possible to prevent the development of DFP -induced OPIDP in the hen by treatment with atropine, trimedoxime and methy lprednisolone when they were given before or soon after DFP.