Localization of leucomyosuppressin-like peptides in the central nervous system of the stable fly with immunocytochemistry.

An antiserum raised against leucomyosuppressin (LMS), the first insect neuropeptide shown to inhibit contraction of both visceral and skeletal muscles of insects, revealed the presence of LMS-like material in neurons of the adult stable fly, Stomoxys calcitrans (L.). Cells and their processes immunoreactive to the LMS antiserum were found in the brain, subesophageal, and thoracico-abdominal ganglia, with the majority of these neurons in the thoracico-abdominal ganglion. Positive immunostaining after preabsorption of the antibodies with the molluscan tetrapeptide FMRFamide, which absorbs the antibodies directed against the C-terminal FLRFamide of LMS, indicates that structural similarities between LMS and the stable fly neuropeptide(s) extend beyond a similar C-terminal tetrapeptide sequence.