The identification, localization, and pharmacology of FMRFamide-related peptides and SCPB in the penis and crop of the terrestrial slug, Limax maximus

Abstract 1. The molluscan neuropeptides FMRFamide, pQDPFLRFamide, and SCP B were tested on the isolated crop and penis of the terrestrial slug, Limax maximus . FMRFamide and pQDPFLRFamide stimulated the penis and inhibited contractions of the crop. In contrast, SCP B either stimulated or relaxed the penis and increased the tone of the crop. 2. Fibers and varicosities containing immunoreactive (ir-) FMRFamide and ir-SCP B were located in the penis and crop. 3. Extracts of penes, crops, ganglia, and whole animals all contained FMRFamide, FLRFamide, SDPFLRFamide, NDPFLRFamide, and pQDPFLRFamide. 4. These results suggest that the FMRFamide-related peptides and SCP B are involved in the regulation of the reproductive and digestive activities of Limax .