MOLECULAR-CLONING AND CHARACTERIZATION OF AN INVERTEBRATE HOMOLOG OF A NEUROPEPTIDE-Y RECEPTOR

Neuropeptide Y is an abundant and physiologically important peptide in vertebrates having effects on food intake, sexual behaviour, blood pr essure and circadian rhythms. Neuropeptide Y homologues have been foun d in invertebrates, where they are very likely to play similar, import ant roles. Although five neuropeptide Y-receptor subtypes have been id entified in mammals, none has been reported from invertebrates. Here w e describe the cloning of a neuropeptide Y-receptor from the brain of the snail Lymnaea stagnalis. The identity of the receptor was deduced by expressing the neuropeptide Y-receptor-encoding cDNA in Chinese Ham ster Ovary cells, which were subsequently challenged with size-fractio nated Lymnaea brain extracts. An active peptide, selected on the basis of its ability to induce changes in cAMP levels, was purified to homo geneity, analysed by mass spectrometry and amino acid sequence determi nation, and turned out to be a Lymnaea homologue of neuropeptide Y.