IMMUNOCHEMICAL DEMONSTRATION OF EISENIA TETRADECAPEPTIDE, A BIOACTIVEPEPTIDE ISOLATED FROM THE GUT OF THE EARTHWORM EISENIA-FOETIDA, IN TISSUES OF THE EARTHWORM

The quantity and localization of Eisenia tetradecapeptide which was is olated from the gut of the earthworm Eisenia foetida were examined in tissues of the same species by enzyme-linked immunosorbent assay and i mmunohistochemistry. Analysis by enzyme-linked immunosorbent assay sho wed that Eisenia-tetradecapeptide-like immunoreactivity was present in both the central nervous system (cerebral ganglion, subesophageal gan glion, ventral ganglia, and ventral nerve cord) and the gut (esophagus , crop, gizzard, and intestine). The central nervous system contained a higher amount of Eisenia-tetradecapeptide-like immunoreactivity (1.3 pmol/mg wet weight) than the gut (0.2-0.6 pmol/mg wet weight). Eiseni a-tetradecapeptide-like immunoreactivity was scarcely detected in the body-wall muscle, nephridia, and sexual organs (testis, ovary, seminal vesicle, and ovisac). Immunohistochemical analysis demonstrated that intense Eisenia-tetradecapeptide-like immunoposi tive cells and nerve fibers were present in the central nervous system. Immunoreactivity wa s found in the epithelial cells lining the esophagus and in the submuc ous plexus in various parts of the gut. Thus, the present study sugges ts that Eisenia tetradecapeptide is a neuropeptide and/or peptide horm one present in both the central nervous system and the gut of the eart hworm and that its role involves the regulation of gut motility.