Loiselle J, Wollin A
Department of Physiology, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
Gastroenterology. 1993 Apr;104(4):1013-20. doi: 10.1016/0016-5085(93)90268-h.
Rapid elimination of histamine near the oxyntic cells is important in the termination of the secretory response when the signal for histamine release is discontinued. The mechanism of this local process is still unclear.
Gastric mucosal histamine elimination was, therefore, examined in fundic mucosa mounted in flux chambers and in dispersed mucosal cells.
[3H]histamine placed into the serosal chamber medium was transported across the mucosal tissue into the lumen, but a greater quantity was methylated to an inactive metabolite, Nt-methylhistamine, and preferentially released to the serosal chamber, the interstitial medium. Both processes were enhanced by increased substrate concentration. They were reduced by lowering the temperature and by sodium replacement. Inhibition of histamine methyltransferase suppressed histamine uptake and methylation and significantly increased histamine-stimulated acid secretion in the tissue preparation and in dispersed mucosal cells. The augmentation was reduced by an H2-receptor blocker.
Mucosal histamine methylation and the secretion of histamine into the gastric lumen removes histamine from the extracellular space effectively, reducing the histamine concentration near the oxyntic cell surface.
当组胺释放信号终止时，胃壁细胞附近组胺的快速清除对于分泌反应的终止很重要。这一局部过程的机制仍不清楚。
因此，在置于通量室的胃底黏膜和分散的黏膜细胞中研究了胃黏膜组胺清除情况。
置于浆膜腔培养基中的[³H]组胺穿过黏膜组织进入管腔，但更多的组胺被甲基化形成无活性代谢物Nτ-甲基组胺，并优先释放到浆膜腔即间质介质中。这两个过程都因底物浓度增加而增强。它们因温度降低和钠替代而减少。组胺甲基转移酶的抑制抑制了组胺摄取和甲基化，并显著增加了组织制剂和分散黏膜细胞中组胺刺激的酸分泌。H₂受体阻滞剂可减少这种增加。
黏膜组胺甲基化以及组胺分泌到胃腔中可有效清除细胞外空间中的组胺，降低胃壁细胞表面附近的组胺浓度。
