CHARACTERIZATION OF AN ANTISERUM AGAINST AN ACHETAKININ-I ANALOG AND ITS USE FOR THE LOCALIZATION OF CULEKININ DEPOLARIZING PEPTIDE-II IN THE MOSQUITO, CULEX-SALINARIUS

ELISA experiments revealed that an antiserum raised against an achetak inin-analog could specifically detect the recently isolated Culekinin Depolarizing Peptide (CDP)-II from the mosquito, Culex salinarius. The characterization indicated that two different epitopes in the C-termi nal region of achetakinin I and CDP-II are recognized. One epitope is the -F-Y-region, the other is the -P-W-region. Among the peptides isol ated from C. salinarius, the antiserum reacts only with CDP-II. Pre-ab sorption tests of the antiserum with CDP-II in immunohistological stai nings abolished the reaction, while tests with pre-immune sera did not cause any immunopositive reactions. In the mosquito head ganglia, imm unoreactive neurons were detected in the pars lateralis, the optic lob e and the suboesophageal ganglion. Although some immunopositive axons extended into the nervi corporis cardiacii II, no immunoreactivity was observed in the retrocerebral complex. In the thoracic ganglia, immun oreactive neurons were found in the pro-, meso- and metathoracic neuro meres. No immunoreactivity was found elsewhere. With this study we dem onstrate that CDP-II, isolated from a whole body extract, is truly a n europeptide, and the data suggest that its function is neuromodulating or neurotransmitting rather than neurohormonal.