Edelbroek M, Sun W M, Horowitz M, Dent J, Smout A, Akkermans L
Dept. of Surgery and Gastroenterology, University Hospital, Utrecht, The Netherlands.
Scand J Gastroenterol. 1994 Dec;29(12):1088-95. doi: 10.3109/00365529409094893.
L-Tryptophan delays gastric emptying in animals to a greater extent than D-tryptophan, but none of the possible motor mechanisms responsible for this stereospecific effect have been evaluated.
In 11 healthy volunteers antropyloroduodenal pressures were recorded in the fasted state with a sleeve/sidehole manometric assembly during 20-min intraduodenal infusions (2 ml.min-1) of isotonic L- and D-tryptophan (50 mM, pH 5.7) and normal saline (pH 5.5), given in randomized order.
Intraduodenal L-tryptophan increased basal pyloric pressure (p < 0.05), whereas D-tryptophan had no effect. In contrast, L- and D-tryptophan both stimulated (p < 0.05) localized phasic pyloric pressure waves, and there was no significant difference in the responses. The number of duodenal pressure waves was greater during infusion of L-tryptophan than during D-tryptophan (p < 0.05).
We conclude that intraduodenal tryptophan has stereospecific effects on pyloric and duodenal motility. Although the precise contribution of these differential effects to gastric emptying remains to be clarified, they may be partially responsible for the differences in gastric emptying of D-tryptophan and L-tryptophan.
L-色氨酸比D-色氨酸在更大程度上延迟动物的胃排空，但尚未评估导致这种立体特异性效应的任何可能的运动机制。
对11名健康志愿者，在禁食状态下，使用套管/侧孔测压装置记录胃幽门十二指肠压力，在十二指肠内以2ml·min-1的速度输注等渗L-色氨酸、D-色氨酸（50mM，pH5.7）和生理盐水（pH5.5），输注时间为20分钟，输注顺序随机。
十二指肠内输注L-色氨酸可增加基础幽门压力（p<0.05），而D-色氨酸无此作用。相反，L-色氨酸和D-色氨酸均刺激（p<0.05）局部阶段性幽门压力波，且反应无显著差异。输注L-色氨酸期间十二指肠压力波的数量多于输注D-色氨酸期间（p<0.05）。
我们得出结论，十二指肠内色氨酸对幽门和十二指肠运动有立体特异性作用。尽管这些差异效应对胃排空的确切贡献仍有待阐明，但它们可能部分解释了D-色氨酸和L-色氨酸胃排空差异的原因。
