Oxytocin and metabolic tissue

The neuropeptide oxytocin (OXT) is most commonly associated with parturition, lactation, and social behavior but also modulates eating behaviors and homeostatic metabolic processes. Existing research relating metabolic disorders to OXT suggest a role for OXT in regulating the physiology of metabolic tissues. The implications of this role are relevant to Prader-Willi Syndrome (PWS), a genetic disorder which includes a deficit of OXT-producing neurons in the paraventricular nucleus of the hypothalamus, obesity, hypotonia, and hyperphagia. The purpose of this study is to assess the presence of oxytocin receptors (OXTR) in the skeletal muscles of neonatal OXTR wildtype and knockout mice and consider genotype-dependent differences in surrounding adipose tissue. Image analysis for OXTR in muscle was performed on archived autoradiographic samples and associated anatomical cresyl violet stains from 20 μm sagittal slices of postnatal day 0 (P0) whole body OXTR wild-type (WT) and OXTR knock-out (KO) mice. Quantification of radioligand binding in regions of interest (forelimb, hindlimb, and masseter muscles) revealed higher OXTR binding in OXTR-KO males than wildtype males across regions while OXTR-WT females demonstrate higher binding across regions than wildtype males. BODIPY lipid staining of neonatal OXTR-WT and OXTR-KO mice suggest density of lipid droplets in adipose tissue above forelimb does not differ between knock-outs and wildtypes. Failed immunofluorescence staining of EGFP-OXTR transgene positive and negative P0 mice fixed with liquid and vapor paraformaldehyde (PFA) prompted investigation of vapor fixation protocol to optimize endogenous fluorescence. Endogenous fluorescence in trigeminal ganglion of OXTR-EGFP transgene positive and negative mice fixed for varying incubation periods was inconclusive and requires further investigation.