Acetylcholinesterase regeneration in mouse CNS studied by a microphotometric method

Acetylcholinesterase (AChE) regeneration after single and repeated doses of diisopropylfluorophosphate (DFP) was investigated in neostriatum of central nervous system of Balb mice, by means of a microphotometric method. In the present study, three experimental groups received the following DFP treatments: group I was administered a single dose of 3 mg/kg; group II received weekly doses of 3 mg/kg for 9 weeks, and group III was exposed to 28 weekly treatments of 1 mg/kg, plus a last treatment of 3 mg/kg, for a total of 29 doses. The results of microphotometric analysis for all the experimental groups have shown a distinct reversibility pattern of DFP inhibition, consistent with the process of AChE regeneration. Nevertheless, one week following the last DFP treatment, a persisting difference (approximately 22%) in the AChE concentration between control and the experimental groups was observed. Based on our results and on the correlation reported in the literature between AChE reduction and muscarinic receptor density, the hazardous implications of organophosphate environmental contamination on human and animal health are pointed out.