Salvador M T, Rodríguez-Yoldi M C, Alcalde A I, Rodríguez-Yoldi M J
Departamento de Fisiología, Facultad de Veterinaria, Zaragoza, Spain.
Life Sci. 1997;61(3):309-18. doi: 10.1016/s0024-3205(97)00387-1.
The aim of the present study was to determine the 5-HT receptor subtypes involved in the serotonin-induced inhibition of L-leucine absorption across rabbit jejunum in vitro. A number of agonists and antagonists were used to characterize the receptors through which serotonin inhibits this absorption. The results show that 2.5x10(-6) M 5-HT inhibits the amino acid absorption by about 20%. The 5-HT receptor agonists, alpha-methyl-5-HT (5-HT2), 2-methyl-5-HT (5-HT3) and zacopride (5-HT4) at concentrations 2.5x10(-6) and 2.5x10(-5) M produced 10-30% inhibition on L-leucine intestinal absorption. 5-carboxyamidotryptamine (5-HT1) did not produce any inhibition. The 5-HT antagonists, GR 113808A (5-HT4) at 2.5x10(-6) M and ritanserin (5-HT2) and ondansetron (5-HT3) at 2.5x10(-5) M completely blocked the effect of 5-HT. However, methiothepin (5-HT1) did not produce any effect on serotonin action in the intestinal absorption of amino acid. It can be concluded that 5-HT2, 5-HT3 and 5-HT4 receptors could mediate inhibition of L-leucine absorption across rabbit jejunum.
本研究的目的是确定参与5-羟色胺（5-HT）诱导的体外抑制兔空肠L-亮氨酸吸收的5-HT受体亚型。使用了多种激动剂和拮抗剂来表征5-HT抑制这种吸收所通过的受体。结果表明，2.5×10⁻⁶ M的5-HT可使氨基酸吸收抑制约20%。浓度为2.5×10⁻⁶和2.5×10⁻⁵ M的5-HT受体激动剂α-甲基-5-HT（5-HT2）、2-甲基-5-HT（5-HT3）和扎考必利（5-HT4）对L-亮氨酸肠道吸收产生10%-30%的抑制作用。5-羧基酰胺色胺（5-HT1）未产生任何抑制作用。5-HT拮抗剂，2.5×10⁻⁶ M的GR 113808A（5-HT4）、2.5×10⁻⁵ M的利坦色林（5-HT2）和昂丹司琼（5-HT3）完全阻断了5-HT的作用。然而，甲硫哒嗪（5-HT1）对氨基酸肠道吸收中5-HT的作用未产生任何影响。可以得出结论，5-HT2、5-HT3和5-HT4受体可能介导兔空肠L-亮氨酸吸收的抑制作用。
