Horowitz M, Meiri U
Comp Biochem Physiol A Comp Physiol. 1985;82(3):577-82. doi: 10.1016/0300-9629(85)90436-0.
Hypothalamic temperature thresholds to heat-induced (40 degrees C ambient temperature) tail vasodilation (Vth) and salivation (Sth) as well as salivary flow rate and volume were studied in conscious rats, hypohydrated (24 hr water deprivation), hypovolemic (20% dextran sc), hypertonic (1M NaCL po), hypertonic and hypovolemic and heat-acclimated (5 days at 34 degrees C) before and after hypohydration. Sth was elevated in hypohydrated, hypovolemic, hypertonic and heat-acclimated hypohydrated rats concomitantly with a remarkable decrease in saliva volume, flow rate and heat tolerance. Heat acclimation alone resulted in a reduction in Vth, Sth, salivary flow and volume. Vth was not affected by hypohydration, but was elevated following hypovolemia and combined hypovolemia and hypertonicity. It is concluded that alterations in both plasma volume and osmolarity, which may occur during hypohydration, play a major role in the alteration in thermoregulatory responses during hypohydration. Heat acclimation does not improve tolerance during hypohydration. Thus, during hypohydration, the control of body fluids overrides thermoregulation.
在清醒大鼠中研究了下丘脑对热诱导（环境温度40摄氏度）引起的尾部血管舒张（Vth）和唾液分泌（Sth）的温度阈值，以及唾液流速和分泌量。这些大鼠在脱水（24小时禁水）、血容量减少（皮下注射20%葡聚糖）、高渗（口服1M氯化钠）、高渗合并血容量减少以及热适应（在34摄氏度环境下5天）状态下，脱水前后均进行了相关研究。在脱水、血容量减少、高渗以及热适应的脱水大鼠中，Sth升高，同时唾液分泌量、流速和耐热性显著降低。单纯热适应导致Vth、Sth、唾液流速和分泌量降低。Vth不受脱水影响，但在血容量减少以及血容量减少合并高渗状态下升高。研究得出结论，脱水过程中可能发生的血浆容量和渗透压变化，在脱水期间体温调节反应改变中起主要作用。热适应并不能改善脱水期间的耐受性。因此，在脱水期间，体液调节优先于体温调节。
