Oxytocin mediated behavior in invertebrates: An evolutionary perspective

Abstract

The molecular and functional conservation of oxytocin-related neuropeptides in behavior is striking. In animals separated by at least 600 million years of evolution, from roundworms to humans, oxytocin homologs play critical roles in the modulation of reproductive behavior and other biological functions. Here, we review the roles of oxytocin in invertebrate behavior from an evolutionary perspective. We begin by tracing the evolution of oxytocin through the invertebrate animal lineages, and then describe common themes in invertebrate behaviors that are mediated by oxytocin-related peptides, including reproductive behavior, learning and memory, food arousal, and predator/prey relationships. Finally, we discuss interesting future directions that have recently become experimentally tractable. Studying oxytocin in invertebrates offers precise insights into the activity of neuropeptides on well-defined neural circuits; the principles that emerge may also be represented in the more complex vertebrate brain. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 128-142, 2017.

Ancient role of vasopressin/oxytocin-type neuropeptides as regulators of feeding revealed in an echinoderm

“…Investigation of the actions of VP/OT-type neuropeptides in chordates, and protostomian invertebrates has revealed conserved and evolutionarily ancient roles in the regulation of processes such as reproduction and water homeostasis [10][11][12]. To obtain new insights into the evolution of VP/OT-type neuropeptide function in the animal kingdom, here we functionally characterised VP/OT-type signalling in an echinoderm-the starfish A. rubens.…”

“…More recently, comparative analysis of genome/ transcriptome sequence data has enabled the discovery of genes encoding VP/OT-type neuropeptides and their putative cognate receptors in many bilaterian animal phyla. Furthermore, this has enabled comparative analysis of the physiological roles of VP/OT-type neuropeptides in species belonging to different phyla [10][11][12]. Interestingly, this has provided evidence that not only the structures but also the functions of VP/OT-type neuropeptides are evolutionarily conserved.…”

The long and the short of it – a perspective on peptidergic regulation of circuits and behaviour

“…Another emerging theme in peptidergic signalling is the evolutionary conservation of related neuropeptide-receptor pairs in the regulation of similar aspects of animal behaviour across species (Beets et al, 2012;Garrison et al, 2012;Lockard et al, 2017;Scott et al, 2017;Tian et al, 2016;Van Sinay et al, 2017). Thus, comparative investigations have the potential to lead to a more global understanding of fundamental and conserved aspects of peptidergic neural networks, and their roles in behavioural plasticity.…”

Oxytocin – The Sweet Hormone?

“…In invertebrates, oxytocin/vasopressin-like peptides emerged at about the same time as bilateral symmetry in body plans, and they are found in many modern nematodes, insects, annelids and molluscs [12]. In annelids and zebrafish, the neurons that produce the oxytocin homolog express common tissue-restricted microRNAs and a common cell-type-specific combination of transcription factors, indicating that they evolved from an ancient cell type with both sensory and neurosecretory properties [12]. These invertebrate peptides are consistently implicated in the regulation of reproductive behaviors, and, in many species, reproduction depends on food availability and is regulated by metabolic cues.…”