Cui Jian, Wilson Thad E, Crandall Craig G
Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, Dallas 75231, Texas, USA.
Am J Physiol Regul Integr Comp Physiol. 2002 Jan;282(1):R252-8. doi: 10.1152/ajpregu.00337.2001.
To identify whether whole body heating alters arterial baroreflex control of muscle sympathetic nerve activity (MSNA), MSNA and beat-by-beat arterial blood pressure were recorded in seven healthy subjects during acute hypotensive and hypertensive stimuli in both normothermic and heat stress conditions. Whole body heating significantly increased sublingual temperature (P < 0.01), MSNA (P < 0.01), heart rate (P < 0.01), and skin blood flow (P < 0.001), whereas mean arterial blood pressure did not change significantly (P > 0.05). During both normothermic and heat stress conditions, MSNA increased and then decreased significantly when blood pressure was lowered and then raised via intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure during heat stress (-128.3 +/- 13.9 U x beats(-1) x mmHg(-1)) was similar (P = 0.31) with normothermia (-140.6 +/- 21.1 U x beats(-1) x mmHg(-1)). Moreover, no significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. These data suggest that arterial baroreflex modulation of MSNA and heart rate are not altered by whole body heating, with the exception of an upward shift of these baroreflex curves to accommodate changes in these variables that occur with whole body heating.
为了确定全身加热是否会改变动脉压力反射对肌肉交感神经活动（MSNA）的控制，在正常体温和热应激条件下，对7名健康受试者在急性低血压和高血压刺激期间记录了MSNA和逐搏动脉血压。全身加热显著提高了舌下温度（P < 0.01）、MSNA（P < 0.01）、心率（P < 0.01）和皮肤血流量（P < 0.001），而平均动脉血压没有显著变化（P > 0.05）。在正常体温和热应激条件下，当分别通过静脉推注硝普钠和盐酸去氧肾上腺素降低和升高血压时，MSNA均先升高然后显著降低。热应激期间MSNA与舒张压之间关系的斜率（-128.3±13.9 U·次⁻¹·mmHg⁻¹）与正常体温时（-140.6±21.1 U·次⁻¹·mmHg⁻¹）相似（P = 0.31）。此外，心率与收缩压之间关系的斜率未观察到显著变化。这些数据表明，除了这些压力反射曲线向上移位以适应全身加热时这些变量的变化外，全身加热不会改变动脉压力反射对MSNA和心率的调节。
