Thornton R M, Proppe D W
Am J Physiol. 1986 Jan;250(1 Pt 2):R30-5. doi: 10.1152/ajpregu.1986.250.1.R30.
The influence of dehydration on hindlimb vasodilation during environmental heating (EH) was examined in eight unanesthetized chronically instrumented baboons. Mean iliac blood flow (MIBF), arterial blood pressure, and core temperature (Tc) were measured during EH of baboons in euhydrated and dehydrated states. EH consisted of acute exposure to high ambient temperatures (39-44 degrees C) until Tc reached 39.5 degrees C. Dehydration was produced by 68-72 h of fluid deprivation, which caused increases in plasma osmolality [291 +/- 1 (SE) to 338 +/- 6 mosmol/kg H2O] and sodium concentration (143 +/- 2 to 163 +/- 3 meq/l) and a 16% fall in plasma volume. The primary influence of dehydration was attenuation of the progressive rise in MIBF and iliac conductance (IC) during EH. Absolute MIBF and IC levels at Tc = 39.5 degrees C during EH were 44 and 52%, respectively, lower in the dehydrated state. Also, the MIBF-Tc and IC-Tc linear regression coefficients during EH were lower by 33 and 43%, respectively, in the dehydrated state. Since limb skeletal muscle blood flow does not increase during EH, we conclude that dehydration attenuates the heat stress-induced rise in skin blood flow in baboons, an influence that is similar to what occurs in humans.
在八只未麻醉的、长期植入仪器的狒狒身上，研究了脱水对环境加热（EH）期间后肢血管舒张的影响。在处于水合状态和脱水状态的狒狒进行EH期间，测量了平均髂血流量（MIBF）、动脉血压和核心温度（Tc）。EH包括急性暴露于高环境温度（39 - 44摄氏度），直至Tc达到39.5摄氏度。通过68 - 72小时的液体剥夺产生脱水，这导致血浆渗透压升高[从291±1（标准误）至338±6毫摩尔/千克H₂O]、钠浓度升高（从143±2至163±3毫当量/升）以及血浆量下降16%。脱水的主要影响是在EH期间MIBF和髂血管传导率（IC）的逐渐升高受到减弱。在EH期间，当Tc = 39.5摄氏度时，脱水状态下的绝对MIBF和IC水平分别降低了44%和52%。此外，在脱水状态下，EH期间MIBF - Tc和IC - Tc的线性回归系数分别降低了33%和43%。由于在EH期间肢体骨骼肌血流量没有增加，我们得出结论，脱水减弱了狒狒中热应激诱导的皮肤血流量增加，这种影响与人类中发生的情况相似。
