Detection of incipient effects of anticholinesterase insecticides in rats and humans by electromyography and cholinesterase assay

Abstract Rats, fed low levels of diazinon (0.5 and 5.0 mg/kg) and parathion (0.1, 0.5 and 1.0 mg/kg) daily for 26 weeks, and agricultural workers chronically exposed to anticholinesterase insecticides, were monitored by electromyographic (EMG) and blood cholinesterase determinations. The two diazinon‐fed and the highest parathion‐fed groups of rats gained less weight, whereas the lowest parathion‐fed group gained more weight than the control; rats fed 0.5 mg/kg parathion daily did not show any difference in weight gain when compared to the control. In addition, the two diazinon‐fed groups of rats gained significantly less weight than the three parathion‐fed groups. Both erythrocyte acetylcholinesterase (AChE) and plasma cholinesterase (ChE) activities were severely inhibited in the treated groups. However, parathion inhibited ChE much less than diazinon, and slight recovery of both enzymes was evident in the parathion‐treated groups. No changes in amplitudes of EMGs were observed in the treated rats. Agri...