Short neuropeptide F in integrated insect physiology

The short neuropeptide F(sNPF)family of peptides is a multifunctional group of neurohormones involved in the regulation of various physiological processes in insects.They have been found in a broad spectrum of species,but the number of isoforms in the precursor molecule varies from one to four.The receptor for sNPF(sNPFR),which belongs to the G protein-coupled receptor family,has been characterized in various insect orders and was shown to be an ortholog of the mammalian prolactin-releasing peptide receptor(PrPR).The sNPF signaling pathway interacts with other neurohormones such as insulin-like peptides,SIFamide,and pigment-dispersing factors(PDFs)to regulate various processes.The main physiological function of sNPF seems to be involved in the regulation of feeding,but the observed effects are species-specific.sNPF is also connected with the regulation of foraging behavior and the olfactory system.The influence of sNPF on feeding and thus energy metabolism may also indirectly affect other vital processes,such as reproduction and development.In addition,these neurohormones are involved in the regulation of locomotor activity and circadian rhythm in insects.This review summarizes the current state of knowledge about the sNPF system in insects.

Myotropic activity and immunolocalization of selected neuropeptides of the burying beetle Nicrophorus vespilloides (Coleoptera: Silphidae)

Burying beetles (Nicrophorus sp.) are necrophagous insects with developed parental care. Genome of Nicrophorus vespilloides has been recently sequenced, which makes them interesting model organism in behavioral ecology. However, we know very little about their physiology, including the functioning of their neuroendocrine system. In this study, one of the physiological activities of proctolin, myosuppressin (Nieve? MS), myoinhibitory peptide (Trica-MIP-5) and the short neuropeptide F (Nicve-sNPF) in N. vespilloides have been investigated. The tested neuropeptides were myoactive on N. vespilloides hindgut. After application of the proctolin increased hindgut contraction frequency was observed (EC50 value was 5.47 x 10-8 mol/L). The other tested neuropeptides led to inhibition of N. vespilloides hindgut contractions (Nicve-MS: IC50 = 5.20 x 10~5 mol/L;Trica-MIP-5: IC50 = 5.95 x 10-6 mol/L;Nicvc-sNPF: IC50 = 4.08 x 10-5 mol/L). Moreover, the tested neuropeptides were immunolocalized in the nervous system of N. vespilloides. Neurons containing sNPF and MIP in brain and ventral nerve cord (VNC) were identified. Proctolin-immunolabeled neurons only in VNC were observed. Moreover, MIP-immunolabeled varicosities and fibers in retrocerebral complex were observed. In addition, our results have been supplemented with alignments of amino acid sequences of these neuropeptides in beetle species. This alignment analysis clearly showed amino acid sequence similarities between neuropeptides. Moreover, this allowed to deduce amino acid sequence of N. vespilloides proctolin (RYLPTa), Nicve-MS (QDVDHVFLRFa) and six isoforms ofNicve-MIP (Nicve-MIP-1一 DWNRNLHSWa;Nicve-MIP-2—AWQNLQGGWa;Nicve-MIP-3—AWQNLQGGWa;Nicve-MlP-4—AWKNLNNAGWa;Nicve-MIP-5—SEWGNFRGSWa;Nicve-MIP-6— DPAWTNLKGIWa;and Nicve-sNPF—SGRSPSLRLRFa).