IMMUNOCYTOCHEMICAL LOCALIZATION OF DIPLOPTERA-PUNCTATA ALLATOSTATIN-LIKE PEPTIDE IN DROSOPHILA-MELANOGASTER

Allatostatins isolated from the cockroach Diploptera punctata are a fa mily of neuropeptides that inhibit juvenile hormone synthesis in cockr oaches and related insects but not in flies. In cockroaches, these wid ely distributed peptides have been shown to have other functions. This report provides evidence for the presence of allatostatin-like peptid es in Drosophila melanogaster by demonstration of allatostatic activit y of extracts of central nervous system from larvae and adults on corp ora allata of Diploptera and by immunocytochemical localization of pep tides in Drosophila with monoclonal antibody against Diploptera allato statin I. Extract of adult central nervous system showed four times mo re allatostatic activity than that of the larva or twice the activity per unit volume of central nervous system. This is reflected in an inc rease in number and arborization of immunoreactive neurons in the adul t. The immunoreactive neurons in the central nervous system appear to be interneurons, with the exception of motoneurons in the last abdomin al neuromere that project to muscles of the hindgut, a pair of periphe ral cells in each of two thoracic segments in the larva and on nerves to wings and halteres in the adult, and endocrine cells of the midgut epithelium. Nerves to the corpus allatum were not immunoreactive. The presence of Diploptera allatostatin-like peptides in interneurons and motoneurons, in the neurohemal networks, and in endocrine cells of the midgut and their absence in nerves to the corpus allatum in Drosophil a suggests that these peptides may function as neuromodulators, myomod ulators, and neurohormones and not as regulators of the corpus allatum . (C) 1995 Wiley-Liss, Inc.