GSE159019
Oxytocin Signaling Regulates the Homeostatic Response to Cold Stress in Ectothermic Vertebrate
Homeothermic vertebrates exposed to low temperature challenge activate multiple central and physiological pathways in order to regain homeostatic balance within the new environmental constrains. Such homeostatic responses include shivering and non-shivering thermogenesis, altered carbohydrate and lipid metabolism and protein catabolism synchronized by neuroendocrine responses. Pending their evolutionary life history, some of these physiological responses were also identified in poikilothermic vertebrates, yet a conception of heat seeking behavior and lack of cold-related metabolic regulation prevails. Using various physiological parameters and hypothalamic transcriptome analysis in the tropical poikilotherm Nile tilapia, we now demonstrate that cold stress in a poikilotherm induce complex central and physiological homeostatic responses. We further show that oxytocin which is a known thermoregulator in homeotherms, actively regulates temperature related homeostasis in poikilotherms. Moreover, we show that pharmacological or genetic blockage of oxytocin signaling affects oxygen-dependent metabolic rate in two cold exposed poikilothermic models. Therefore, our study identifies oxytocin as an adaptive and evolutionarily conserved metabolic regulator and show that poikilotherms brain actively respond to cold temperature stress by regulating metabolic physiology. Overall design: RNAseq of midbrains from cold exposed (N=4) and normothermy-maintained Nile tilapia (N=4).