Ramirez I
Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104-3308.
Am J Physiol. 1994 Mar;266(3 Pt 2):R682-7. doi: 10.1152/ajpregu.1994.266.3.R682.
Rats were trained in an apparatus that infused water or nutritive fluids into their stomachs every time that they drank flavored fluids. Rats given saccharin to drink by mouth drank more fluid than rats given cherry-flavored water to drink. Furthermore, rats given saccharin to drink ingested much more fluid if they were given intragastric infusions of 6% carbohydrate than intragastric infusions of plain water. This stimulatory effect of carbohydrate infusion occurred within 1 or 2 days of training and was very large, amounting to > or = 70% increase in fluid intake compared with rats drinking saccharin and infused with water. On the other hand, infusions of 6% carbohydrate had no effect on the intake of rats given cherry-flavored water to drink. In an attempt to determine whether rats could be trained to respond to cherry flavor at all, rats were infused with a liquid diet whenever they drank cherry or saccharin-flavored water. When dry food was withheld, the rats learned to increase fluid intake so as to feed themselves. The rats given saccharin to drink acquired this task more readily than rats given cherry flavor to drink, but both groups took in normal amounts of food by the end of the 10-day training period. It is concluded that it is much easier to condition an increase in fluid intake with intragastric infusions of carbohydrate than with an arbitrary nonsweet flavor.
将大鼠置于一种装置中进行训练，每当它们饮用有味道的液体时，该装置就会向其胃内注入水或营养液。经口给予糖精饮用的大鼠比给予樱桃味水饮用的大鼠喝的液体更多。此外，经口给予糖精饮用的大鼠，如果胃内注入6%的碳水化合物，比注入纯水时摄入的液体要多得多。碳水化合物注入的这种刺激作用在训练的1至2天内就会出现，而且非常显著，与饮用糖精并注入水的大鼠相比，液体摄入量增加了≥70%。另一方面，注入6%的碳水化合物对给予樱桃味水饮用的大鼠的摄入量没有影响。为了确定大鼠是否根本无法被训练对樱桃味做出反应，每当大鼠饮用樱桃味或糖精味的水时，就给它们注入流食。当不给干粮时，大鼠学会增加液体摄入量以便自行进食。给予糖精饮用的大鼠比给予樱桃味饮用的大鼠更容易完成这项任务，但在10天的训练期结束时，两组大鼠摄入的食物量都正常。得出的结论是，与任意一种非甜味相比，通过胃内注入碳水化合物来调节液体摄入量的增加要容易得多。
