Chromatophorotropins in the Central Nervous System of Uca pugilator, with Special Reference to Their Origins and Actions

Abstract

The central nervous system of U. pugilator contains 2 chromatophorotropically active substances, a black-pigment-dispersing principle and a white-pigment-concentrating principle. Extracts of the optic ganglia, sinus glands, supraesophageal ganglia, circumesophageal connectives and the thoracic cord when assayed on eyestalkless Uca produced a dispersion of the black pigment in the chromato-phores of the legs. Extracts of the connectives produced simultaneously a concn. of the white pigment. Relationships which were obtained when the total activities of various concns. of each organ extract were plotted against the log concns. indicated that the responses obtained were brought about by 2 separate substances. In addition to the connectives, the optic ganglia and the supraesophageal ganglia contained the white-pigment-concentrating principle although its activity was masked by the presence of a high concn. of black-pigment-dispersing substance. Results of expts. using extracts of all possible combinations in pairs of the supraesophageal ganglia, connectives and thoracic cord led to the suggestion that these 2 chromatophorotropins were mutually antagonistic in action. The duration of potency of both raw and boiled extracts of the connectives was detd. by assaying the extracts at various intervals of time following extraction. The maintenance in raw extracts and even potentiation of black activity in both raw and boiled extracts and the potentiation of white activity in boiled extracts led to the suggestion that both of these substances were being formed from inactive precursors.