Swithers Susan E, McCurley Melissa
Department of Psychological Sciences, Purdue University, West Lafayette, IN 47907-1364 USA.
Dev Psychobiol. 2002 Sep;41(2):103-11. doi: 10.1002/dev.10056.
Altering oxidation of fatty acids by administration of mercaptoacetate (MA) or methyl palmoxirate has been demonstrated to stimulate independent ingestion in rat pups by 12 to 15 days of age. However, in other work, neither agent has been demonstrated to affect intake in the context of suckling. In the present experiments, we tested the effects of MA on both suckling and independent ingestive behavior by examining changes in latency to initiate suckling or independent ingestion and by measuring intake in short-term (30 min) and longer term (4 hr) suckling and independent ingestion tests in pups aged 12 to 15 days of age. The results demonstrated that (a) MA does not affect suckling intake in short- or longer term tests; (b) MA does not affect latency to attach to a nipple, most likely due to floor effects on latency to attach in control pups; (c) MA stimulates independent ingestion in short-term, but not longer terms tests; and (d) MA reduces the latency to initiate independent ingestion. These results suggest that administration of MA preferentially stimulates the initiation of independent ingestion over suckling, and that this response develops at an age just prior to the time at which independent ingestion is typically first expressed by rat pups.
通过给予巯基乙酸盐（MA）或甲基棕榈酰肉碱来改变脂肪酸氧化，已被证明可刺激12至15日龄大鼠幼崽的自主摄食。然而，在其他研究中，尚未证明这两种物质在哺乳情况下会影响摄入量。在本实验中，我们通过检查开始哺乳或自主摄食的潜伏期变化，并在12至15日龄幼崽的短期（30分钟）和长期（4小时）哺乳及自主摄食测试中测量摄入量，来测试MA对哺乳和自主摄食行为的影响。结果表明：（a）在短期或长期测试中，MA不影响哺乳摄入量；（b）MA不影响附着乳头的潜伏期，很可能是由于对照幼崽中附着潜伏期存在下限效应；（c）MA在短期测试中刺激自主摄食，但在长期测试中无此作用；（d）MA缩短了开始自主摄食的潜伏期。这些结果表明，给予MA优先刺激自主摄食的开始而非哺乳，并且这种反应在大鼠幼崽通常首次表现出自主摄食之前的年龄就已出现。
