CRUSTACEAN CARDIOACTIVE PEPTIDE-IMMUNOREACTIVE NEURONS IN THE HAWKMOTH MANDUCA-SEXTA AND CHANGES IN THEIR IMMUNOREACTIVITY DURING POSTEMBRYONIC DEVELOPMENT

An antiserum against crustacean cardioactive peptide was used, in indi rect immunocytochemistry on whole-mounts and Vibratome sections, to ma p immunoreactive neurons at various stages of postembryonic developmen t of the hawkmoth Manduca sexta. About 90 immunoreactive neurons were identified. Many of these cells are immunoreactive at hatching and per sist into the adult stage; others become immunoreactive late in postem bryonic development. During adult development, transient immunoreactiv ity is expressed in several cells in the subesophageal and thoracic ga nglia. Two sets of immunoreactive neurons are found in the protocerebr um of larvae, but only one of these sets persists into the adult stage . Paired lateral interneurons and neurosecretory neurons are segmental ly repeated in the abdominal ganglia and are present from the first la rval stage to the adult; the abdominal interneurons project contralate rally to arborizations in adjacent ganglia, and some ascend to tritoce rebral arborizations. The abdominal neurosecretory cells, which corres pond to a pair of cells reported to contain bursicon, project posterio rly to neurohemal release organs. Motor neurons of dorsal external obl ique abdominal muscles become immunoreactive in the fourth larval stag e. Paired median neurosecretory cells of abdominal ganglia become immu noreactive during the fifth larval stage. The immunoreactive median an d lateral abdominal neurosecretory cells are a subset of a group of ce lls known to contain cardioactive peptides. Paired lateral neurosecret ory cells of the subesophageal ganglion become immunoreactive during p upation and project to the corpora cardiaca and aorta of the adult. Ma ny of the neurons identified here are comparable to crustacean cardioa ctive peptide-immunoreactive cells described previously in locusts and the mealworm beetle. (C)1993 Wiley-Liss, Inc.