Bernstein I L
Department of Psychology, University of Washington, Seattle 98195.
Dev Psychobiol. 1988 Nov;21(7):663-70. doi: 10.1002/dev.420210705.
Adult Fischer-344 (F-344) rats fail to prefer NaCl solutions of any concentration to water and, in fact, avoid NaCl at solution concentrations which other strains of rats reliably prefer. In contrast, immature rats of a number of strains have been reported to express an elevated salt preference relative to adults. The present studies examine the development of the F-344 rat's salt aversion by testing salt preference in the preweaning (Day 10) and weanling (Days 20-24) F-344 rat. At Day 10, F-344 rats ingested significantly more 1% and 2% NaCl solutions than water during "towel testing" and their preference was comparable to that displayed by other strains at this age. By the time of normal weaning (Days 20-24) significant avoidance of NaCl solutions in the isotonic range was displayed by F-344 rats, and their preference was strikingly different from other rat strains. This was evident in a 24-hr 2-bottle preference test as well as a 25 min "towel test." Since NaCl preference of F-344 rats is comparable to other rat strains at Day 10 but dramatically different by Day 20, a change must occur during this time which reverses the hedonic value of NaCl stimulation. Identification of factors responsible for this reversal may provide insight into the causes both of the F-344 rat's dislike of salt and the immature rats elevated salt preference.
成年费希尔344（F-344）大鼠对任何浓度的氯化钠溶液都没有表现出相对于水的偏好，实际上，在其他品系大鼠稳定偏好的溶液浓度下，它们会避开氯化钠。相比之下，有报道称，一些品系的幼鼠相对于成年鼠表现出更高的盐偏好。本研究通过测试断奶前（第10天）和断奶期（第20 - 24天）的F-344大鼠的盐偏好，来研究F-344大鼠盐厌恶的发展情况。在第10天，F-344大鼠在“毛巾测试”中摄入的1%和2%氯化钠溶液比水多得多，它们的偏好与这个年龄段的其他品系大鼠相当。到正常断奶时（第20 - 24天），F-344大鼠对等渗范围内的氯化钠溶液表现出明显的回避，它们的偏好与其他品系大鼠显著不同。这在24小时的双瓶偏好测试以及25分钟的“毛巾测试”中都很明显。由于F-344大鼠在第10天对氯化钠的偏好与其他品系大鼠相当，但在第20天时却有显著差异，因此在这段时间内一定发生了某种变化，从而逆转了氯化钠刺激的享乐价值。确定导致这种逆转的因素，可能有助于深入了解F-344大鼠不喜欢盐的原因以及幼鼠盐偏好升高的原因。
