Nose H, Sugimoto E, Okuno T, Morimoto T
Am J Physiol. 1987 Jul;253(1 Pt 2):R15-9. doi: 10.1152/ajpregu.1987.253.1.R15.
Changes in blood volume (BV) and Na+ concentration of plasma ([Na+]) were measured continuously during recovery from thermal dehydration in rats. At least 5 days prior to the experiments rats were cannulated into both the jugular vein and the descending aorta. After thermal dehydration (DBT: 36 degrees C, RH: 20%) amounting to approximately 6% of body wt, catheters were connected to a system for continuous monitoring of BV and [Na+]. Water was made available and water intake, BV, and [Na+] were recorded at 30-s intervals for 4 h. The rats took 2-3 ml of water/100 g of body wt in the first 10 min and then drank 1 ml at 30- to 60-min intervals to reach equilibrium in 2-3 h. The relations between water intake and delta BV and between delta[Na+] were analyzed for 2 h after the start of water supply. BV was unchanged until 18.9 +/- 3.6 min after access to water, whereas [Na+] started to decrease after 3.6 +/- 0.6 min. The retention ratio of ingested fluid in the vascular space was 20.8 +/- 2.8%, and the decrease of [Na+] was 1.5 +/- 0.2 meq X l-1 X ml ingested fluid-1 X 100 g body wt-1. These results indicate that drinking causes the change of [Na+] more rapidly than that of blood volume.
在大鼠从热脱水恢复过程中，连续测量其血容量（BV）和血浆钠浓度（[Na+]）的变化。实验前至少5天，将大鼠的颈静脉和降主动脉插管。热脱水（干球温度：36℃，相对湿度：20%）至体重约6%后，将导管连接到一个用于连续监测BV和[Na+]的系统。提供饮水，并每隔30秒记录一次饮水量、BV和[Na+]，持续4小时。大鼠在最初10分钟内每100克体重摄入2 - 3毫升水，然后每隔30至60分钟饮用1毫升，在2 - 3小时内达到平衡。在供水开始后2小时分析饮水量与ΔBV以及与Δ[Na+]之间的关系。在获得水后18.9±3.6分钟之前BV没有变化，而[Na+]在3.6±0.6分钟后开始下降。摄入液体在血管空间中的潴留率为20.8±2.8%，[Na+]的下降为1.5±0.2毫当量×升-1×每摄入1毫升液体×100克体重-1。这些结果表明，饮水导致[Na+]的变化比血容量的变化更快。
