Involvement of the cholinergic mechanism in DDT and dieldrin action in the insect central nervous system.

The effects of DDT and dieldrin on cholinergic neurotransmission were studied using the sixth abdominal ganglion of the cockroach. Spontaneous electrical discharges in the ganglion recorded with an extracellular electrode were augmented by 0.1 mM DDT and 1 microM dieldrin. This stimulating action was partly blocked by 0.5 mM d-tubocurarine and 0.1 mM hemicholinium-3 and disappeared in a high Mg2+-low Ca2+ medium. DDT and dieldrin increased both ACh release and ACh content in the ganglion. These results suggested that DDT and dieldrin stimulate both ACh release and synthesis.