do Carmo Jussara M, da Silva Alexandre A, Romero Damian G, Hall John E
Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA;
Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA.
FASEB J. 2017 Jun;31(6):2418-2428. doi: 10.1096/fj.201601224R. Epub 2017 Feb 22.
Interactions of hypothalamic signaling pathways that control body temperature (BT), blood pressure (BP), and energy balance are poorly understood. We investigated whether the chronic BP and metabolic actions of leptin are differentially modulated by changes in ambient temperature ( ). Mean arterial pressure (MAP), heart rate (HR), BT, motor activity (MA), and oxygen consumption (o) were measured 24 h/d at normal laboratory (23°C), at thermoneutral zone (TNZ, 30°C) for mice or during cold exposure (15°C) in male wild-type mice. After control measurements, leptin (4 μg/kg/min) or saline vehicle was infused for 7 d. At TNZ, leptin reduced food intake (-11.0 ± 0.5 g cumulative deficit) and body weight by 6% but caused no changes in MAP or HR. At 15°C, leptin infusion did not alter food intake but increased MAP and HR (8 ± 1 mmHg and 33 ± 7 bpm), while o increased by ∼10%. Leptin reduced plasma glucose and insulin levels at 15°C but not at 30°C. These results demonstrate that the chronic anorexic effects of leptin are enhanced at TNZ, while its effects on insulin and glucose levels are attenuated and its effects on BP and HR are abolished. Conversely, cold caused resistance to leptin's anorexic effects but amplified its effects to raise BP and reduce insulin and glucose levels. Thus, the brain circuits by which leptin regulates food intake and cardiovascular function are differentially influenced by changes in -Do Carmo, J. M., da Silva, A. A., Romero, D. G., Hall, J. E. Changes in ambient temperature elicit divergent control of metabolic and cardiovascular actions by leptin.
控制体温（BT）、血压（BP）和能量平衡的下丘脑信号通路之间的相互作用目前还知之甚少。我们研究了环境温度变化是否对瘦素的慢性血压和代谢作用产生不同的调节。在正常实验室温度（23°C）、小鼠的热中性区（TNZ，30°C）或雄性野生型小鼠冷暴露期间（15°C），每天24小时测量平均动脉压（MAP）、心率（HR）、体温（BT）、运动活动（MA）和耗氧量（o）。在进行对照测量后，持续7天输注瘦素（4μg/kg/分钟）或生理盐水。在热中性区，瘦素减少了食物摄入量（累积减少-11.0±0.5克）和体重6%，但对MAP或HR没有影响。在15°C时，输注瘦素没有改变食物摄入量，但增加了MAP和HR（分别为8±1mmHg和33±7次/分钟），而耗氧量增加了约10%。瘦素在15°C时降低了血浆葡萄糖和胰岛素水平，但在30°C时没有。这些结果表明，瘦素的慢性厌食作用在热中性区增强，而其对胰岛素和葡萄糖水平的作用减弱，对血压和心率的作用消失。相反，寒冷导致对瘦素厌食作用的抵抗，但增强了其升高血压以及降低胰岛素和葡萄糖水平的作用。因此，瘦素调节食物摄入和心血管功能的脑回路受到环境温度变化的不同影响。——多卡尔莫，J.M.，达席尔瓦，A.A.，罗梅罗，D.G.，霍尔，J.E.环境温度变化引发瘦素对代谢和心血管作用的不同控制。
