Li E T, Anderson G H
Life Sci. 1984 Jun 18;34(25):2453-60. doi: 10.1016/0024-3205(84)90281-9.
After a meal of protein, in contrast to a meal of carbohydrate (CHO) at 1915 hr, rats allowed to choose from high carbohydrate and high protein diets during 2000-2100 hr prefer CHO (1). Thus the hypothesis that this regulation of macronutrient selection involves brain 5-hydroxytryptamine (5-HT) metabolism was tested. Compared to three baseline days during which rats (250- 300g ) consumed 1 g CHO, rats fed tryptophan (TRP, 5-HT precursor; 15 mg in 1 g CHO) selected meals higher in protein concentration (35.4% vs 46.6%, F (1,12) = 20.05, p less than 0.001) from 10% and 60% casein diets during 2000-2100 hr. Associated with the higher protein selection was an elevated brain 5-HT turnover in rats killed 30 minutes after consuming CHO + TRP. Pretreating rats with p-chlorophenylalanine, an inhibitor of TRP hydroxylase, blocked this effect of TRP (36.3% vs 37.0%). Fenfluramine (1 and 2 mg/kg i.p. at 1945 hr), which transiently enhances neuronal 5-HT release, increased the rat's relative preference for protein from 28.8% to 37.5% (2 mg/kg, t = 3.21, p less than 0.025) during 2000-2100 hr. These rats, also exhibited a selective preference for CHO between 3-12 hrs post injection which paralleled the known subsequent depletion of 5-HT by fenfluramine. We conclude that the relative proportion of protein and carbohydrate selected in a meal is controlled, at least in part, by prior food effects on brain 5-HT metabolism.
与1915时进食碳水化合物（CHO）餐不同，在2000 - 2100时允许从高碳水化合物和高蛋白饮食中进行选择的大鼠更喜欢CHO（1）。因此，对这种常量营养素选择调节涉及大脑5-羟色胺（5-HT）代谢的假说进行了测试。与大鼠（250 - 300克）在三个基线日消耗1克CHO相比，喂食色氨酸（TRP，5-HT前体；1克CHO中含15毫克）的大鼠在2000 - 2100时从10%和60%酪蛋白饮食中选择了蛋白质浓度更高的餐食（35.4%对46.6%，F(1,12)=20.05，p小于0.001）。与更高的蛋白质选择相关的是，在摄入CHO + TRP后30分钟处死的大鼠中，大脑5-HT周转率升高。用对氯苯丙氨酸（一种TRP羟化酶抑制剂）预处理大鼠可阻断TRP的这种作用（36.3%对37.0%）。氟苯丙胺（1945时腹腔注射1和2毫克/千克）可短暂增强神经元5-HT释放，在2000 - 2100时将大鼠对蛋白质的相对偏好从28.8%提高到37.5%（2毫克/千克，t = 3.21，p小于0.025）。这些大鼠在注射后3 - 12小时内也表现出对CHO的选择性偏好，这与已知的随后氟苯丙胺对5-HT的消耗情况相似。我们得出结论，一餐中选择的蛋白质和碳水化合物的相对比例至少部分受先前食物对大脑5-HT代谢的影响所控制。
