Developmental trajectories and influences of environmental complexity on oxytocin receptor and vasopressin 1A receptor expression in male and female prairie voles

Abstract

Nonapeptide receptors, like oxytocin receptor (OTR) and vasopressin 1a receptor (V1aR), modulate a variety of functions across taxa, and mediate phenotypic variation within and between species. Despite the popularity of studying nonapeptides in adults, developmental perspectives on properties of OTR and V1aR expression are lacking. Study of prairie voles (Microtus ochrogaster) has facilitated an understanding of mechanisms of social behavior and provides great potential to inform how early life experiences alter phenotype. We provide the first comprehensive profiling of OTR and V1aR in male and female prairie voles across postnatal development and into adulthood. Differences in receptor densities across the forebrain were region- and sex-specific. Postnatal changes in receptor expression fell into four themes: (a) constant over time, (b) increasing with age, (c) decreasing with age, or (d) peaking during late pre-weaning (postnatal day 15-21). We also examined the influence of post-weaning social and spatial enrichment (i.e., environmental complexity) on OTR and V1aR. Environmental complexity appeared to promote expression of OTR in males and females, and reduced expression of V1aR across several brain regions in males. Our results show that nonapeptide receptor profiles are plastic over development and suggest that different patterns of expression might represent functional differences in sensitivity to nonapeptide activation over a period when social environments are dynamic. Our results on environmental complexity suggest that nonapeptide sensitivity responds flexibly to different environmental contexts during development. Understanding the developmental trajectories of nonapeptide receptors provides a better understanding of the dynamic nature of social behavior and the underlying mechanisms.

Role of oxytocin in the control of stress and food intake

“…116 On the other hand, deprivation of early maternal care in rhesus macaques has been reported to suppress expression of the oxytocin receptor in the hippocampus via epigenetic regulation and induce higher separation anxiety, which was rescued by a certain oxytocin receptor gene single nucleotide polymorphism (SNP). 116 On the other hand, deprivation of early maternal care in rhesus macaques has been reported to suppress expression of the oxytocin receptor in the hippocampus via epigenetic regulation and induce higher separation anxiety, which was rescued by a certain oxytocin receptor gene single nucleotide polymorphism (SNP).…”

Central distribution of oxytocin and vasopressin 1a receptors in juvenile Richardson’s ground squirrels

“…While significant sex differences were found for Oxtr in 26% of regions, and for Avpr1a in 10% of regions, age‐related differences were detected in 71 and 59% of studied regions for Oxtr and Avpr1a, respectively (Smith et al, ). In prairie voles, Oxtr and Avpr1a expression changes over development, with Oxtr density typically increasing with age, and Avpr1a density showing varied changes dependent on region and sex (Prounis et al, ). For Richardson’s ground squirrels, it tentatively appears that juveniles and adults also differ, with adults having relatively denser Oxtr binding in the central amygdala, and denser Avpr1a binding in the dentate gyrus, medial amygdala, lateral septum and superior colliculus (da Costa Araujo, ).…”

“…For Oxtr, juveniles had binding in the ventral pallidum and medial preoptic area while adults had no reported binding (da Costa Araujo, ). Prairie vole juveniles were not reported as differing from adults with respect to Oxtr in the medial preoptic area, though juvenile rats had less binding than adults (Prounis et al, ; Smith et al, ). The ventral pallidum was not noted as having age‐specific differences in binding in either rats or prairie voles (Prounis et al, ; Smith et al, ).…”

“…Prairie vole juveniles were not reported as differing from adults with respect to Oxtr in the medial preoptic area, though juvenile rats had less binding than adults (Prounis et al, ; Smith et al, ). The ventral pallidum was not noted as having age‐specific differences in binding in either rats or prairie voles (Prounis et al, ; Smith et al, ). While a direct statistical comparison cannot be made due to differences in processing and quantification, relative density patterns within juveniles and within adults appear to differ, and future research should directly compare adult and juvenile Richardson’s ground squirrels among seasons and between sexes.…”

“…Collapsing data over both sexes and considering existing data from adults suggests that receptor densities may change with development from early life to adulthood, which has been demonstrated in other species of rodent (Hammock & Levitt, 2013;Miller & Caldwell, 2015;Prounis, Thomas, & Ophir, 2018;Tamborski, Mintz, & Caldwell, 2016;Wang et al, 1997). A recent study on Oxtr and Avpr1a in rat juveniles and adults showed that there are many age-dependent receptor density differences, compared to sex-dependent differences.…”