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Neuropeptide F (NPF)-like immunoreactivity was previously found to be abundant in the eastern subterranean termite, Reticulitermes flavipes. Purification of the NPF from a whole body extract of worker termites was accomplished in the current study by HPLC and heterologous radioimmunoassay for an NPF-related peptide, Helicoverpa zea Midgut Peptide-I. A partial amino acid sequence allowed determination of the corresponding cDNA that encoded an open reading frame deduced for authentic R. flavipes NPF (Ref NPF): KPSDPEQLADTLKYLEELDRFYSQVARPRFa. Effects of synthetic NPFs on muscle contractions were investigated for isolated foreguts and hindguts of workers, with Drm NPF inhibiting spontaneous contractions of hindguts. Phylogenetic analysis of invertebrate NPF sequences reveals two separate groupings, with Ref NPF occurring within a clade composed exclusively of arthropods., ((c) 2009 Elsevier Inc. All rights reserved.)

FMRFamide-like immunoreactivity (FLI) was detected in the nervous system of the crayfish Procambarus clarkii using an antiserum that recognizes extended RFamide peptides. Immunocytochemistry revealed FLI in neuronal somata, axons and varicose processes within the central nervous system. In the periphery, plexuses of immunoreactive varicosities were present in the pericardial organs (POs), in thoracic roots and on the hindgut. The hindgut plexus arose from 3-5 axons leaving the sixth abdominal ganglion (A6) via the intestinal nerve. The presence of FLI in these locations was confirmed by radioimmunoassay. In contrast, no FLI was detected in motor axons innervating exoskeletal muscles of the abdomen. The POs contained by far the largest amount of FLI of all tissues examined. The immunoreactive material was partially characterized by extraction and separation on two consecutive reversed-phase high performance liquid chromatography (RP-HPLC) columns. The largest amount of immunoreactivity on the second column co-eluted with a synthetic peptide, SDRNFLRFamide (F2), previously identified as one of two or more FMRFamide-related peptides contained in lobster POs. The immunoreactive fractions and peptide F2 elicited similar effects on isolated crayfish hearts; all increased the rate and amplitude of spontaneous cardiac contractions. As with the immunoreactivity, the highest level of bioactivity was contained in the fraction that co-eluted with F2. The results suggest that FMRFamide-related peptides act as neurohormones in crayfish and are likely to play roles in controlling circulation and defecation.