Yawata T, Okuno T, Nose H, Morimoto T
Department of Physiology, Kyoto Prefectural University of Medicine, Japan.
Physiol Behav. 1987;40(3):363-8. doi: 10.1016/0031-9384(87)90060-6.
Thermally dehydrated rats were given a choice of tap water and saline (0.9% or 1.8% NaCl), and the change in the salinity of their choice during rehydration was measured up to 15 hr. The rats consumed more water than saline for about 2 hr after the start of fluid replacement (about 55 mEq/l), while they consumed more saline than tap water (about 120 mEq/l) thereafter. Urine output and urinary Na output were only about 20% of their intake during the initial 4 hr of rehydration, while after 4 hr the output became almost equal with the intake. The change in salt intake occurred when about 90% of Na loss and 60% of fluid loss was regained. The results indicate that rats choose dilute salt solution to lower plasma osmolality during the initial period of the rehydration and then regain body fluid isotonically. Urine volume and urinary Na output increased only after volume repletion. Thus, osmoregulation with salt appetite has priority over fluid volume regulation in restitution from thermal dehydration.
给热脱水的大鼠提供自来水和盐水（0.9%或1.8%氯化钠）的选择，并在补液过程中测量它们在长达15小时内选择的盐度变化。在开始补液后的约2小时内（约55毫当量/升），大鼠摄入的水比盐水多，而此后它们摄入的盐水比自来水多（约120毫当量/升）。在补液的最初4小时内，尿量和尿钠排出量仅约为摄入量的20%，而4小时后排出量几乎与摄入量相等。当约90%的钠丢失和60%的液体丢失得到恢复时，盐摄入量发生了变化。结果表明，大鼠在补液初期选择稀释盐溶液以降低血浆渗透压，然后等渗地恢复体液。仅在容量补充后尿量和尿钠排出量才增加。因此，在从热脱水中恢复的过程中，通过盐食欲进行的渗透调节优先于液体容量调节。
