TACHYKININ-RELATED AND LEUCOKININ-RELATED PEPTIDES IN THE NERVOUS-SYSTEM OF THE BLOWFLY - IMMUNOCYTOCHEMICAL AND CHROMATOGRAPHIC DIVERSITY

We are interested in the presence and function in insects of neuropept ides related to the vertebrate tachykinins. Hence, we have used antise ra raised against the tachykinins substance P and kassinin, and agains t the insect neuropeptide leucokinin I, for localization studies and i mmunochemical analysis of related peptides in the nervous system of th e blowfly Phormia terraenovae. In radioimmunoassays (with antisera aga inst kassinin and leucokinin I) used in combination with reverse-phase HPLC, it was shown that the antisera recognize immunoreactive materia l with distinctly different hydrophobic properties and each antiserum appear to detect several forms of immunochemically related peptides. W ith immunocytochemistry it was shown that the kassinin and leucokinin antisera each reacted with material in a distinct set of neurons. The leucokinin-immunoreactive material is present both in interneurons and in neurosecretory cells, suggesting roles of native leucokinin-like p eptides as neuromodulators in the nervous system and as neurohormones acting on peripheral targets. The kassinin immunoreactivity was seen i n interneurons, but could not be conclusively localized in neurosecret ory cells, possibly indicating a role only within the nervous system.