Isolation of periviscerokinin-2 from the abdominal perisympathetic organs of the American cockroach, Periplaneta americana.

Using the isolated hyperneural muscle as bioassay, a novel myotropin was isolated from the abdominal perisympathetic organs of Periplaneta americana. This is the second neuropeptide identified from insect perisympathetic organs. Peptide sequence analysis and mass spectrometry yielded the following structure: Gly-Ser-Ser-Ser-Gly-Leu-Ile-Ser-Met-Pro-Arg-Val-NH2. This peptide, named periviscerokinin-2, was confirmed to be amidated by chemical synthesis, bioassay, and comparison of retention times between native and synthetic peptides. A highly specific antiserum was used to determine sites of synthesis in the abdominal ganglia. Besides periviscerokinin-1, periviscerokinin-2 is the only putative myotropic neurohormone from the abdominal perisympathetic organs that is effective in the nanomolar range. This confirms the hypothesis that the neurohormonal system of the ventral nerve cord is remarkably different from that of the brain.