Salvador M T, Rodriguez-Yoldi M C, Alcalde A I, Marco R, Rodríguez-Yoldi M J
Departamento de Fisiología, Facultad de Veterinaria, Zaragoza, Spain.
Life Sci. 1996;59(15):1269-81. doi: 10.1016/0024-3205(96)00450-x.
The aim of the present study has been to determine the effect of serotonin (5-HT) on the absorption of L-leucine across the rabbit jejunum. The results show that serotonin significantly diminishes the uptake and steady-state tissue accumulation and the mucosal to serosal flux of L-leucine. This effect does not change with previous intestinal exposure of the mucosa to the 5-HT. Serotonin does not seem to modify amino acid simple diffusion across the intestinal epithelium. The effect on the amino acid uptake is due to an inhibition of the Na(+)-dependent system of transport, mainly through a reduction of the apparent Vmax. Moreover, this hormone, added to the incubation solution, does not affect the L-leucine uptake across brush border membrane vesicles. In presence of trifluoroperazine, TMB-8 and staurosporine, the serotonin effect disappears. These results suggest an effect mediated by intracellular processes related to protein kinase C which inhibit the intestinal absorption of L-leucine.
本研究的目的是确定血清素（5-羟色胺，5-HT）对L-亮氨酸跨兔空肠吸收的影响。结果表明，血清素显著减少L-亮氨酸的摄取、稳态组织蓄积以及从黏膜到浆膜的通量。先前将黏膜暴露于5-HT不会改变这种效应。血清素似乎不会改变氨基酸跨肠上皮的简单扩散。对氨基酸摄取的影响是由于抑制了Na(+)依赖性转运系统，主要是通过降低表观最大转运速率（Vmax）。此外，添加到孵育溶液中的这种激素不会影响L-亮氨酸跨刷状缘膜囊泡的摄取。在存在三氟拉嗪、TMB-8和星形孢菌素的情况下，血清素的效应消失。这些结果表明，这是一种由与蛋白激酶C相关的细胞内过程介导的效应，该过程抑制L-亮氨酸的肠道吸收。
