Galanin immunoreactivity and 125I-galanin binding sites in the blowfly brain

We have used immunocytochemical, immunochemical (RIA) and chromatographic methods (HPLC, gel filtration) to provide evidence for presence of GAL-like peptide(s) in the blowfly Phormia terraenovae. HPLC indicates the presence of several forms of GAL-like peptides. Immunocytochemistry showed that there are about 160 GAL-IR neurons in the brain and subesophageal ganglia supplying the central body, superior protocerebrum, the optic lobe and tritocerebral neuropil. Autoradiography of binding with 125I-labelled porcine GAL on brain sections revealed GAL binding sites in the central body complex and deutocerebrum. The presence of galanin-like peptide(s) and putative receptor sites in the fly brain suggest a role in neuromodulation in specific circuits.