Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, MO 65212, USA.
J Physiol. 2010 Sep 15;588(Pt 18):3593-603. doi: 10.1113/jphysiol.2010.191866. Epub 2010 Jul 19.
Recent animal studies indicate that insulin increases arterial baroreflex control of lumbar sympathetic nerve activity; however, the extent to which these findings can be extrapolated to humans is unknown. To begin to address this, muscle sympathetic nerve activity (MSNA) and arterial blood pressure were measured in 19 healthy subjects (27 ± 1 years) before, and for 120 min following, two common methodologies used to evoke sustained increases in plasma insulin: a mixed meal and a hyperinsulinaemic euglycaemic clamp. Weighted linear regression analysis between MSNA and diastolic blood pressure was used to determine the gain (i.e. sensitivity) of arterial baroreflex control of MSNA. Plasma insulin was significantly elevated within 30 min following meal intake (34 ± 6 uIU ml(1); P < 0.05) and remained above baseline for up to 120 min. Similarly, after meal intake, arterial baroreflex-MSNA gain for burst incidence and total MSNA was increased and remained elevated for the duration of the protocol (e.g. burst incidence gain: 3.29 ± 0.54 baseline vs. 5.64 ± 0.67 bursts (100 heart beats)(1) mmHg(1) at 120 min; P < 0.05). During the hyperinsulinaemic euglycaemic clamp, in which insulin was elevated to postprandial concentrations (42 ± 6 μIU ml(1); P < 0.05), while glucose was maintained constant, arterial baroreflex-MSNA gain was similarly enhanced (e.g. burst incidence gain: 2.44 ± 0.29 baseline vs. 4.74 ± 0.71 bursts (100 heart beats)(1) mmHg(1) at 120 min; P < 0.05). Importantly, during time control experiments, with sustained fasting insulin concentrations, the arterial baroreflex-MSNA gain remained unchanged. These findings demonstrate, for the first time in healthy humans, that increases in plasma insulin enhance the gain of arterial baroreflex control of MSNA.
最近的动物研究表明，胰岛素会增加动脉压力反射对腰椎交感神经活动的控制；然而，这些发现可以在多大程度上推广到人类身上尚不清楚。为了开始解决这个问题，在 19 名健康受试者（27±1 岁）中测量了肌肉交感神经活动（MSNA）和动脉血压，这些受试者在之前和之后 120 分钟内进行了两种常见的方法来诱发持续增加血浆胰岛素：混合餐和高胰岛素正常血糖钳夹。使用加权线性回归分析 MSNA 和舒张压之间的关系，以确定动脉压力反射对 MSNA 控制的增益（即敏感性）。进餐后 30 分钟内，血浆胰岛素显著升高（34±6 uIU ml(1)；P<0.05），并持续升高 120 分钟以上。同样，在进餐后，MSNA 爆发发生率和总 MSNA 的动脉压力反射-MSNA 增益增加，并在整个实验过程中保持升高（例如，爆发发生率增益：3.29±0.54 基线 vs. 5.64±0.67 个（100 次心跳）(1)mmHg(1)在 120 分钟时；P<0.05）。在高胰岛素正常血糖钳夹期间，胰岛素升高至餐后浓度（42±6 μIU ml(1)；P<0.05），而葡萄糖保持不变，动脉压力反射-MSNA 增益也得到了类似的增强（例如，爆发发生率增益：2.44±0.29 基线 vs. 4.74±0.71 个（100 次心跳）(1)mmHg(1)在 120 分钟时；P<0.05）。重要的是，在持续禁食胰岛素浓度的时间对照实验中，动脉压力反射-MSNA 增益保持不变。这些发现首次在健康人类中表明，血浆胰岛素的增加增强了动脉压力反射对 MSNA 的控制增益。
