A pharmacologically active choline ester and other substances in the garden tiger moth, Arctia caja (L.)

Abstract

A pharmacologically active choline ester closely resembling β, β-dimethylacrylylcholine is present in very high concentrations in the cervical (prothoracic) defensive glands of the garden tiger moth, Arctia caja (L.). It is suggested that the active substance is acrylylcholine itself, β, β-dimethylacrylylcholine, or a closely related derivative. Another substance, non-dialyzable and heat-labile, is present in the abdominal tissues of A. caja. This substance markedly increases capillary permeability on intradermal injection and causes death on intravenous injection into guinea-pigs. Its lethal action appears to be due to constriction of bronchial smooth muscle. The tissues of A. caja contain neither histamine nor 5-hydroxytryptamine. Very high concentrations of histamine are present, however, in the abdominal tissues of some other moths.