Takamata A, Mack G W, Gillen C M, Nadel E R
John B. Pierce Laboratory, Yale University School of Medicine, New Haven, Connecticut 06519.
Am J Physiol. 1994 May;266(5 Pt 2):R1493-502. doi: 10.1152/ajpregu.1994.266.5.R1493.
After a 7-h H2O and Na+ depletion period (DP), produced by intermittent light exercise (8 bouts) at 35 degrees C, we examined thirst and taste palatability responses to 10 different NaCl solutions during 23 h of rehydration (RH) at 25 degrees C. During DP, net H2O and Na+ loss were 27.2 +/- 2.9 ml/kg and 3.29 +/- 0.45 meq/kg, respectively. Plasma osmolality (POsm) and plasma Na+ concentration ([Na+]p) increased significantly during DP by 3.4 +/- 1.2 mosmol/kgH2O and 3.0 +/- 1.0 meq/kgH2O, respectively. Plasma volume (PV) decreased by 6.5 +/- 1.9%. Thirst rating, renal fractional reabsorption of H2O, and plasma arginine vasopressin concentration (PAVP) increased as POsm increased. This increased thirst was accompanied by increased palatability ratings to H2O. During RH, subjects drank deionized H2O ad libitum and ate a Na(+)-free diet for 23 h. POsm and [Na+]p returned to control levels within 1 h RH and remained at or below the control thereafter. PV remained reduced by approximately 5% throughout RH. The increased thirst and PAVP returned to their respective control levels within 1 h of RH as POsm decreased, but thirst rating increased against between 17 and 23 h of RH without increase in POsm or PAVP. Palatability ratings to a 1 M NaCl solution at and after 3 h RH and palatability ratings to 0.3 M at 17 and 23 h RH were significantly higher than control. Plasma aldosterone concentration (PAldo) increased after DP, decreased with drinking, and increased again between 6 and 23 h of RH, accompanied by a marked decrease in fractional Na+ excretion to < 0.07%. Thus both Na+ preference and thirst in humans are influenced by body fluid and electrolyte status. The increased Na+ palatability (Na+ appetite) was preceded by osmotically induced thirst, and accompanied by nonosmotically driven thirst [extracellular fluid (ECF) thirst] and increased PAldo. The "Na+ appetite" and "ECF thirst" along with increased renal Na+ retention could contribute to ECF volume regulation after thermally induced H2O and Na+ depletion.
在35摄氏度下通过间歇性轻度运动（8组）造成7小时的水和钠离子缺失期（DP）后，我们研究了在25摄氏度下23小时补液期（RH）内对10种不同氯化钠溶液的口渴和味觉适口性反应。在DP期间，净失水量和净失钠量分别为27.2±2.9毫升/千克和3.29±0.45毫当量/千克。血浆渗透压（POsm）和血浆钠离子浓度（[Na⁺]p）在DP期间分别显著升高3.4±1.2毫摩尔/千克H₂O和3.0±1.0毫当量/千克H₂O。血浆容量（PV）下降了6.5±1.9%。随着POsm升高，口渴评分、肾脏对水的分数重吸收以及血浆精氨酸加压素浓度（PAVP）增加。这种口渴增加伴随着对水的适口性评分增加。在RH期间，受试者随意饮用去离子水并在23小时内食用无钠饮食。POsm和[Na⁺]p在RH开始后1小时内恢复到对照水平，此后一直保持在对照水平或低于对照水平。在整个RH期间，PV仍降低约5%。随着POsm下降，增加的口渴和PAVP在RH开始后1小时内恢复到各自的对照水平，但在RH的17至23小时之间口渴评分增加，而POsm或PAVP没有增加。在RH 3小时及之后对1M氯化钠溶液的适口性评分以及在RH 17和23小时对0.3M氯化钠溶液的适口性评分显著高于对照。血浆醛固酮浓度（PAldo）在DP后升高，随着饮水而降低，并在RH的6至23小时之间再次升高，同时伴随着钠分数排泄显著降低至<0.07%。因此，人体的钠偏好和口渴都受到体液和电解质状态的影响。钠适口性增加（钠食欲）之前是渗透压诱导的口渴，并伴随着非渗透压驱动的口渴[细胞外液（ECF）口渴]和PAldo增加。“钠食欲”和“ECF口渴”以及肾脏钠潴留增加可能有助于热诱导的水和钠缺失后ECF容量的调节。
