Horowitz M, Samueloff S
Department of Physiology, Hadassah School of Dental Medicine, Hebrew University, Jerusalem, Israel.
Am J Physiol. 1988 Jan;254(1 Pt 2):R109-16. doi: 10.1152/ajpregu.1988.254.1.R109.
The effect of thermal dehydration (37 degrees C) on the integrated response of the circulation was studied in conscious laboratory rats and in the desert species Psammomys obesus, the latter being studied prior to and following acclimation to heat. Cardiac output (CO) and its distribution were measured using labeled microspheres with the reference organ technique. At low dehydration (7-9% body wt loss) rats showed peripheral vasodilation coincidentally with splanchnic vasoconstriction, whereas the desert species exhibited an increased CO and peripheral vasodilation with no change in splanchnic blood perfusion. At severe dehydration (10-18% body wt loss), closure of skin arteriovenous anastomoses together with splanchnic vasodilation was observed in both species. These changes were discussed in relation to plasma volume conservation mechanism and its deterioration. Acclimation to heat resulted in no change in CO, whereas blood flow to splanchnic and skin capillaries increased remarkably. Dehydration in heat-acclimated P. obesus (5-10% body wt loss) brought about a significant fall in CO. However, most organs maintained relatively stable blood flow. This might contribute to better survival during heat stress.
在清醒的实验大鼠和沙漠物种欧黄鼠中研究了热脱水（37摄氏度）对循环系统综合反应的影响，后者在适应热环境之前和之后进行了研究。使用标记微球和参考器官技术测量心输出量（CO）及其分布。在轻度脱水（体重减轻7 - 9%）时，大鼠出现外周血管舒张，同时内脏血管收缩，而沙漠物种则表现为心输出量增加和外周血管舒张，内脏血流灌注无变化。在严重脱水（体重减轻10 - 18%）时，两个物种均观察到皮肤动静脉吻合支关闭以及内脏血管舒张。这些变化结合血浆容量保存机制及其恶化情况进行了讨论。热适应导致心输出量无变化，而内脏和皮肤毛细血管的血流量显著增加。热适应的欧黄鼠脱水（体重减轻5 - 10%）导致心输出量显著下降。然而，大多数器官维持相对稳定的血流。这可能有助于在热应激期间更好地存活。
