Global map of oxytocin/vasopressin-like neuropeptide signalling in insects

Abstract

Oxytocin and vasopressin mediate a range of physiological functions that are important for osmoregulation, reproduction, social behaviour, memory and learning. The origin of this signalling system is thought to date back ~600 million years. Oxytocin/vasopressin-like peptides have been identified in several invertebrate species and they appear to be functionally related across the entire animal kingdom. There is little information available about the biology of this peptide G protein-coupled receptor signalling system in insects. Recently over 200 insect genome/transcriptome datasets were released allowing investigation of the molecular structure and phylogenetic distribution of the insect oxytocin/vasopressin orthologue – inotocin peptides and their receptors. The signalling system is present in early arthropods and representatives of some early-diverging lineages. However, Trichoptera, Lepidoptera, Siphonaptera, Mecoptera and Diptera, lack the presence of inotocin genes, which suggests the peptide-receptor system was probably lost in their common ancestor ~280 million-years-ago. In addition we detected several losses of the inotocin signalling system in Hemiptera (white flies, scale insects and aphids), and the complete absence in spiders (Chelicerata). This unique insight into evolutionarily patterns and sequence diversity of neuroendocrine hormones will provide opportunities to elucidate the physiology of the inotocin signalling system in one of the largest group of animals.

Oxytocin‐like signaling in ants influences metabolic gene expression and locomotor activity

“…1B). Because there was only 1 significant hit in the L. neglectus transcriptome for each (IR and IP), we suggested that the OT/VP-like signaling system in L. neglectus is composed of a single peptide and receptor, as is observed in other insect species (3). After cloning of the L. neglectus receptor into a suitable expression vector and synthesis of the inotocin peptide, we performed second messenger analysis and binding studies of this signaling system in vitro.…”

“…In earlier work, we discovered the genes and transcripts encoding the IP and IR in insects and particularly in ants (3, 22). We validated the expression of the receptor by molecular cloning and confirmed the functionality of the peptide/receptor pair by pharmacological characterization of the inotocin signaling system of the black garden ant ( L. niger ) (23).…”

“…Oxytocin (OT) and vasopressin (VP) neuropeptides and their GPCRs comprise one of the oldest and best-studied peptidergic signaling systems. It has been present across a range of distantly related species throughout the evolution of animals, dating back more than 600 million years (2, 3). In humans and other mammalian species, OT and VP mediate a range of peripheral and central physiologic functions by signaling via 1 OT and 3 VP receptors (4, 5).…”

“…Recently it has become evident that most insect orders contain components of this peptidergic signaling system (3, 7). We identified transcripts encoding the inotocin receptor (IR) and the inotocin precursor (IP) in 20 ant species (3, 22). Furthermore, inotocin was shown to activate its cognate receptor in vitro in the ant Lasius niger (23), and expression of the receptor was confirmed in the heads of queens (24).…”

The osmoresponsiveness of oxytocin and vasopressin neurones: Mechanisms, allostasis and evolution

“…Most modern vertebrates have at least two oxytocin-and vasopressin-like peptides, whereas most invertebrates, including mollusks, annelids and many insects,166,167 have only one. Most modern vertebrates have at least two oxytocin-and vasopressin-like peptides, whereas most invertebrates, including mollusks, annelids and many insects,166,167 have only one.…”