Greenwood Maria A, Hammock Elizabeth A D
Program in Neuroscience, Florida State University, Tallahassee, FL, United States.
Department of Psychology, Florida State University, Tallahassee, FL, United States.
Front Neurosci. 2019 May 24;13:474. doi: 10.3389/fnins.2019.00474. eCollection 2019.
The oxytocin receptor (OXTR) has been observed in the periphery of neonatal C57BL/6J mice (), including facial regions and the anogenital area. In those studies, ligand specificity was confirmed with a congenital OXTR knockout mouse as well as competitive binding techniques. The aim of this study was to determine if OXTR is present in the same peripheral sites in the neonatal prairie vole () for cross-species comparisons. Receptor autoradiography was performed on 20 μm sagittal sections of whole postnatal day 0 (P0) male and female prairie voles using the iodinated-ornithine vasotocin ([I]-OVTA) radioligand. A competition binding assay was used to assess the selectivity of [I]-OVTA for peripheral OXTR. Radioactive ligand (0.05 nM [I]-OVTA) was competed against concentrations of 0 and 1000 nM excess unlabeled oxytocin (OXT). Previously identified regions of significant OXTR ligand binding in the mouse were analyzed for comparison: rostral and lateral periodontium, olfactory epithelium, ciliary bodies of the eye, whisker pads, adrenal gland, and anogenital area. We also evaluated the liver and scapular brown adipose tissue, which displayed strong but non-specific signal on film in mice. While there were some areas that showed conserved OXTR ligand binding in the prairie vole (e.g., ciliary body of the eye and the anogenital area), areas showing OXTR ligand binding in the neonatal prairie vole were not identical to OXTR ligand binding in the periphery of the C57BL/6J neonatal mouse. Further, some of the regions measured in the prairie vole suggest sex differences in OXTR ligand binding. Collectively, as is well-established in the central nervous system, these data indicate that patterns of OXTR ligand binding in the infant periphery are species-specific.
在新生C57BL/6J小鼠的外周组织中观察到了催产素受体（OXTR），包括面部区域和肛门生殖器区域。在这些研究中，通过先天性OXTR基因敲除小鼠以及竞争性结合技术证实了配体特异性。本研究的目的是确定新生草原田鼠的相同外周组织中是否存在OXTR，以便进行跨物种比较。使用碘化鸟氨酸加压素（[I]-OVTA）放射性配体，对出生后第0天（P0）的雄性和雌性草原田鼠的整个矢状切片（20μm）进行受体放射自显影。采用竞争结合试验评估[I]-OVTA对外周OXTR的选择性。放射性配体（0.05 nM [I]-OVTA）与0和1000 nM过量未标记的催产素（OXT）浓度进行竞争。分析了先前在小鼠中确定的OXTR配体显著结合区域进行比较：鼻侧和外侧牙周膜、嗅觉上皮、眼睫状体、触须垫、肾上腺和肛门生殖器区域。我们还评估了肝脏和肩胛棕色脂肪组织，它们在小鼠的胶片上显示出强烈但非特异性的信号。虽然在草原田鼠中有一些区域显示出保守的OXTR配体结合（例如，眼睫状体和肛门生殖器区域），但新生草原田鼠中显示OXTR配体结合的区域与C57BL/6J新生小鼠外周的OXTR配体结合并不相同。此外，在草原田鼠中测量的一些区域表明OXTR配体结合存在性别差异。总的来说，正如在中枢神经系统中所确立的那样，这些数据表明婴儿外周组织中OXTR配体结合模式具有物种特异性。
