Meyer G, Bottà G, Fedele G, Cremaschi D
Dipartimento di Fisiologia e Biochimica Generali, Università degli Studi di Milano, Italy.
Experientia. 1995 Nov 15;51(11):1045-51. doi: 10.1007/BF01946913.
In intact tissue, [D-Ala2,MePhe4,Gly-ol5]enkephalin (10(-5) M; mu-ligand), diminished short-circuit current (Isc) and increased water, Na+ and Cl- net fluxes in vitro under open circuit conditions; it also inhibited L-valine absorption and L-valine-dependent variations of short-circuit current (delta Isc,val). Naloxone (10(-6) M) antagonized these effects. In the absence of the muscularis and myenteric plexus this enkephalin or morphine (mu-ligand) reduced Isc and delta Isc,val. These enkephalin effects occurred at different times. Different concentrations of enkephalin were tested for their effects on delta Isc,val. [D-Ala2,D-Leu5]enkephalin (mainly a delta-ligand) significantly decreased Isc but not delta Isc,val. The reduction of L-valine absorption does not depend on the effects on basal ion transport. Interaction of opioids with mu-receptors located in the submucosal plexus and/or in the epithelial cell accounts for this reduction. This enkephalin effect seems to be at least partially under the control of the myenteric plexus.
在完整组织中，[D - Ala2，MePhe4，Gly - ol5]脑啡肽（10⁻⁵ M；μ配体）在开路条件下体外可降低短路电流（Isc），并增加水、Na⁺和Cl⁻的净通量；它还抑制L - 缬氨酸吸收以及L - 缬氨酸依赖性的短路电流变化（δIsc,val）。纳洛酮（10⁻⁶ M）可拮抗这些作用。在没有肌层和肌间神经丛的情况下，这种脑啡肽或吗啡（μ配体）可降低Isc和δIsc,val。这些脑啡肽的作用发生在不同时间。测试了不同浓度脑啡肽对δIsc,val的影响。[D - Ala2，D - Leu5]脑啡肽（主要是δ配体）可显著降低Isc，但对δIsc,val无影响。L - 缬氨酸吸收的降低并不依赖于对基础离子转运的影响。阿片类药物与位于黏膜下神经丛和/或上皮细胞中的μ受体相互作用导致了这种降低。这种脑啡肽的作用似乎至少部分受肌间神经丛的控制。
