The Release of a Neuroactive Agent by the American Cockroach after Exposure to DDT or Electrical Stimulation1

Abstract

A neuroactive substance is released into the blood of American cockroaches (Periplaneta americana (L.)), during the course of DDT poisoning. The active principle is soluble in water, methanol, and ethanol, but insoluble in nonpolar solvents. Biological activity of the toxicant is destroyed by acetone and alkaline conditions. Although the chemical structure of the toxicant is unknown, it is chemically, chroinatographically, and biologically distinct from acetylcholine, epinephrine, norepinephrine, histamine, γ-aminobutyric acid and 5-hydroxytryptamine. A substance with the same biological, chromatographic, and chemical properties as the DDT-induced agent can be produced in cockroaches by repeated mild electrical shocks. Electrical stimulation of isolated thoracic and abdominal nerve cords also results in the release of the substance into the perfusing saline, as does topical application of DDT to the intactcerci of an isolated central nerve cord. The source of the toxicant is apparently the central nervous system itself during periods of great nervous activity, whether initiated by electrical stimulation or by constant bombardment of sensory-central synapses due to excessive afferent impulses generated in the sensory nerves by direct action of DDT.