Departamento de Biociencias Veterinarias, Unidad de Bioquímica, Facultad de Veterinaria, Universidad de la República, Lasplaces 1550, Montevideo, CP 11600, Uruguay.
Departamento de Biociencias Veterinarias, Unidad de Bioquímica, Facultad de Veterinaria, Universidad de la República, CENUR Litoral Norte, Salto, Universidad de la República, Rivera 1350, Salto, CP 50000, Uruguay.
Physiol Behav. 2021 Mar 1;230:113282. doi: 10.1016/j.physbeh.2020.113282. Epub 2020 Dec 8.
Oxytocin (OT) is a neuropeptide hormone that modulates several social behaviors and can affect the anxiety and stress response. The aim of this study was to determine if administration of intranasal OT affects the stress response to social isolation in sheep. Twenty adult Merino ewes were assigned to two groups; 1) Control group (CG, n = 10), which received an intranasal administration of isotonic saline and 2) Oxytocin-treated group (OTG, n = 10), which received an intranasal administration of OT (24 IU) 40 min before the animals were placed in the social isolation test. During the social isolation test (10 min), the behavior of the sheep was recorded, and blood samples were obtained before and after the test for the determination of cortisol, glucose and serum proteins, and heart rate and surface temperature were recorded. The OTG ewes had a higher cortisol concentration (P = 0.04) after social isolation, tended to vocalize more (P = 0.06) during isolation, and tended to have lower globulin concentrations (P = 0.10) than the CG ewes. Contrary to what we expected, the administration of intranasal OT increased the stress response to social isolation in ewes, which was evidenced by endocrine (greater increase in cortisol concentration), physiological (a tendency to present lower concentration of globulins in blood) and behavioral (a tendency to vocalize more) indicators. This study suggests that the administration of intranasal OT increased the stress response to isolation possibly by strengthening the social bond among ewes.
催产素（OT）是一种神经肽激素，可调节多种社交行为，并影响焦虑和应激反应。本研究旨在确定鼻内给予 OT 是否会影响绵羊对社会隔离的应激反应。将 20 只成年美利奴母羊分为两组；1）对照组（CG，n=10），接受鼻内给予等渗盐水；2）催产素处理组（OTG，n=10），在将动物置于社会隔离测试前 40 分钟接受鼻内给予 OT（24IU）。在社会隔离测试（10 分钟）期间，记录绵羊的行为，并在测试前后采集血液样本以测定皮质醇、葡萄糖和血清蛋白，记录心率和体表温度。OTG 母羊在社会隔离后皮质醇浓度更高（P=0.04），在隔离期间更倾向于发声（P=0.06），球蛋白浓度更低（P=0.10）。与我们的预期相反，鼻内给予 OT 增加了绵羊对社会隔离的应激反应，这表现在内分泌（皮质醇浓度增加更大）、生理（血液中球蛋白浓度较低的趋势）和行为（发声更多的趋势）指标上。本研究表明，鼻内给予 OT 可能通过增强绵羊之间的社交联系，增加对隔离的应激反应。
