Two orcokinins and the novel octapeptide orcomyotropin in the hindgut of the crayfish Orconectes limosus identified myostimulatory neuropeptides originating together in neurones of the terminal abdominal ganglion.

The tridecapeptides Asn(13)-orcokinin and Val(13)-orcokinin, two known members of the orcokinin neuropeptide family native to crustaceans, and a novel octapeptide, orcomyotropin, FDAFTTGFamide, have been identified from extracts of hindguts of the crayfish Orconectes limosus using an isolated hindgut contractility bioassay, high-performance liquid chromatography, microsequencing and mass spectr…