Brot M D, Watson C H, Bernstein I L
Department of Orthodontics, University of Washington, Seattle, Washington 98195, USA.
Am J Physiol Regul Integr Comp Physiol. 2000 Oct;279(4):R1403-11. doi: 10.1152/ajpregu.2000.279.4.R1403.
Rats prefer hypotonic and isotonic NaCl solutions to water in long-access drinking paradigms. To focus on the role of taste signals in NaCl preference, licking patterns of rats with 30-s exposure to NaCl solutions (0-0.5 M) were examined when they were either water deprived, sodium depleted, or not deprived (NaCl mixed in dilute sucrose). In all three conditions, rats displayed a preference for NaCl. The addition of 100 microM amiloride, a sodium channel blocker, to NaCl did not change rats' licking when they were sodium replete but dramatically reduced licking when they were deplete. Transection of the chorda tympani (CT) nerve, an afferent pathway for amiloride-sensitive Na(+) signals, had no effect on NaCl preference in nondeprived rats and only a modest effect on those that were Na(+) deplete. Amiloride was found to exert significant suppression of NaCl intake in Na(+)-depleted rats with transection of the CT, supporting the existence of other afferent pathways for transmission of amiloride-sensitive Na(+) signalling. Together, these studies argue for the involvement of different neural signalling mechanisms in NaCl preference in the presence and absence of explicit Na(+) need.
在长期饮水模式中，大鼠更喜欢低渗和等渗的氯化钠溶液而非水。为了聚焦味觉信号在氯化钠偏好中的作用，研究了大鼠在水剥夺、钠缺乏或未剥夺（氯化钠混入稀蔗糖中）状态下，接触30秒氯化钠溶液（0 - 0.5M）时的舔舐模式。在所有这三种情况下，大鼠都表现出对氯化钠的偏好。当大鼠钠充足时，向氯化钠中添加100微摩尔的氨氯吡脒（一种钠通道阻滞剂）并不会改变大鼠的舔舐行为，但当大鼠钠缺乏时，会显著减少舔舐。切断鼓索（CT）神经（氨氯吡脒敏感的Na(+)信号的传入通路），对未剥夺大鼠的氯化钠偏好没有影响，对钠缺乏的大鼠只有适度影响。研究发现，在切断CT的钠缺乏大鼠中，氨氯吡脒对氯化钠摄入有显著抑制作用，这支持了存在其他氨氯吡脒敏感的Na(+)信号传递传入通路。总之，这些研究表明，在有和没有明确的钠需求时，不同的神经信号机制参与了大鼠对氯化钠的偏好。
