Stimulation of oxyntic and histaminergic cells in gastric mucosa by gastrin C-terminal tetrapeptide.
Stimulation of oxyntic and histaminergic cells in gastric mucosa by gastrin C-terminal tetrapeptide.
复制标题
胃泌素 C 末端四肽刺激胃粘膜中的泌酸细胞和组胺能细胞。
DOI：
10.1152/ajpgi.1986.251.4.g529
复制
发表时间：
1986
期刊：
影响因子：
--
通讯作者：
F. Michelangeli
中科院分区：
文献类型：
--
作者：
M. Ruiz;F. Michelangeli
在离体两栖动物胃粘膜上观察了胃泌素四肽（TG）对H+分泌和组胺释放的刺激作用及其相互关系。TG释放组胺，刺激H+分泌。TG的剂量-反应曲线显示两个参数的非平行增加。在快速耐受实验中，组胺释放和H+分泌之间没有相关性。西咪替丁抑制最大TG或组胺刺激的剂量-反应曲线的比较表明，TG刺激的H+分泌的敏感性要高得多。这表明TG释放的细胞周围组胺浓度低于最大反应所需的浓度。在组胺最大刺激的粘膜中，TG诱导H+分泌进一步增加。在西咪替丁的存在下，有增强TG和二丁酰cAMP依赖于细胞外钙的存在。结果表明，TG（或胃泌素）刺激H+分泌通过不同的机制：1）直接刺激依赖于细胞外钙的泌酸细胞，2）胃泌素和组胺之间的增强作用，和3）从旁分泌细胞释放组胺。TG对泌酸细胞的直接刺激不足以触发H+分泌。TG和组胺在泌酸细胞之间的增强作用可能是由于TG诱导的细胞内Ca 2+增加和组胺诱导的细胞内cAMP增加之间的相互作用。
Gastrin tetrapeptide (TG) stimulation of H+ secretion and histamine release and their relationship were characterized in isolated amphibian gastric mucosa. TG released histamine and stimulated H+ secretion. Dose-response curves to TG showed nonparallel increases in both parameters. In tachyphylaxis experiments, there was no correlation between histamine release and H+ secretion. Comparison of cimetidine inhibitory dose-response curves of maximal TG or histamine stimulation showed a much higher sensitivity for TG-stimulated H+ secretion. This suggests that the pericellular histamine concentration released by TG was lower than that needed for maximal response. In mucosae maximally stimulated by histamine, TG induced a further increase in H+ secretion. In the presence of cimetidine, there was potentiation between TG and dibutyryl cAMP that was dependent on the presence of extracellular calcium. The results are interpreted to indicate that TG (or gastrin) stimulates H+ secretion through different mechanisms: 1) direct stimulation of the oxyntic cell dependent on extracellular calcium, 2) potentiation between gastrin and histamine, and 3) release of histamine from paracrine cells. Direct stimulation of the oxyntic cell by TG is not sufficient to trigger H+ secretion. Potentiation between TG and histamine at the oxyntic cell may result from interaction between TG-induced increases in intracellular Ca2+ and histamine-induced increases in intracellular cAMP.