Opiate activity and transepithelial passage of intact beta-casomorphins in rabbit ileum.
Opiate activity and transepithelial passage of intact beta-casomorphins in rabbit ileum.
复制标题
兔回肠中完整β-酪啡肽的阿片活性和跨上皮通道。
DOI：
10.1152/ajpgi.1987.253.6.g737
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
J. Desjeux
中科院分区：
文献类型：
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作者：
D. Tomé;A. Dumontier;M. Hautefeuille;J. Desjeux
阿片肽在食物蛋白酶消化中的功能意义尚不确定。研究了天然β -casomorphins （β - cms）、β - cm -5和β - cm -4- nh2 （morphiceptine）及其类似物β -[D-Ala2,4，Tyr5]CM-5-NH2对兔离体回肠的影响。在组织浆膜侧添加浓度为10(-4)M的肽后，所有三种肽引起纳洛酮可逆的短路电流（Isc）减少。除粘膜侧外，只有类似物β -[D-Ala2,4，Tyr5]CM-5-NH2降低了Isc。天然β - cms可被肠粘膜降解，未检测到这些肽的完整的上皮通道，而β -[D-Ala2,4，Tyr5]CM-5-NH2在粘膜库中添加浓度为10(-3)M（粘膜-浆膜通量= 3.5 +/- 1.2 nmol.h-1 cm-2）时，可完整地穿过上皮。这些结果表明，天然β - cms和受保护的类似物对肠道电解质运输都具有阿片活性。它们在肠道管腔一侧的作用似乎取决于完整肽从管腔转移到阿片受体所在的组织血液一侧。这种作用是由天然多肽的腔内水解所阻止的。
The functional significance of the presence of opioid peptides in enzymatic digestion of food proteins remains uncertain. The effect of natural beta-casomorphins (beta-CMs), beta-CM-5 and beta-CM-4-NH2 (morphiceptine), and the analogue beta-[D-Ala2,4,Tyr5]CM-5-NH2 were studied in isolated rabbit ileum mounted in Ussing chambers. All three peptides caused a naloxone-reversible reduction in short-circuit current (Isc) after addition at a concentration of 10(-4) M to the serosal side of the tissue. After addition to the mucosal side, only the analogue beta-[D-Ala2,4,Tyr5]CM-5-NH2 reduced Isc. Natural beta-CMs were degraded by the intestinal mucosa, and no intact transepithelial passage was detected for these peptides, whereas beta-[D-Ala2,4,Tyr5]CM-5-NH2 was demonstrated to cross the epithelium intact when added at a concentration of 10(-3) M in the mucosal reservoir (mucosal-to-serosal flux = 3.5 +/- 1.2 nmol.h-1.cm-2). These results show that both natural beta-CMs and the protected analogue have an opiate activity on intestinal electrolyte transport. Their action from the luminal side of the intestine seems to depend on the transfer of the intact peptides from the luminal to the blood side of the tissue where opiate receptors are located. This action is prevented by luminal hydrolysis of the natural peptides.