AN INVESTIGATION OF FACTOR S, A NEUROMUSCULAR EXCITATORY SUBSTANCE FROM INSECTS AND CRUSTACEA

¹ Metabolism and Radiation Research Laboratory, Entomology Research Division Agricultural Research Service, United States Department of Agriculture Fargo, North Dakota, 58102

1. A neuroactive substance has been found in extracts of the crayfish, Cambraus clarkii (Girard) and the following insect species: the cockroaches, P. americana (L.), Leucophaea maderae (F.), and Blaberus giganteus (L.), the grass-hopper, Schistocerca vaga, and the house fly, M. domestica (L.). This substance in low concentrations excites motor neuron activity in the American cockroach. It also potentiates the mechanical response of the indirectly stimulated extensor muscles of the trochanter in the same insect. There is also a high specific activity of the excitatory agent in the central nervous system of the cockroach.

2. Data from extraction, chromatogaphy, and chemical analyses suggest a biogenic amine. This amine appears distinct from all commonly known neuropharmacologically active agents.

3. The chemical and biological similarities between this substance and van der Kloot's Factor S and Ostlund's catechol-4 are discussed.