In situ inhibition of cholinesterase in anopheles pharoenisis and culex pipiens by malathion and fenitrothion

ABSTRACT

Inhibition of cholinesterase after poisoning of Anopheles pharoensis and Culex pipiens with 1c50[s] of malathion and fenitrothion was studied histochemically. The pattern of inhibition of both insecticides was similar. Inhibition was to a greater or less extent confined to the peripheral region of the thoracic ganglia, while the brain and abdominal ganglia showed partial inhibition of the neuropiles. The data provided evidence that if death is caused by inhibition of cholinesterase of the nervous system it is due to local inhibition and not to generalized inhibition