Site and mechanisms of action of kinins in rat ileal mucosa.
Site and mechanisms of action of kinins in rat ileal mucosa.
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激肽在大鼠回肠粘膜中的作用位点和机制。
DOI：
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发表时间：
1987
影响因子：
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通讯作者：
L. Turnberg
中科院分区：
文献类型：
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作者：
G. Warhurst;M. Lees;N. Higgs;L. Turnberg
肠内激肽诱导的分泌伴随着粘膜腺苷3 '，5'-环磷酸（cAMP）和前列腺素类的显著增加，这无疑有助于整体分泌反应。尽管最近的一个假说认为上皮细胞是激肽作用的靶点，但这些作用起始的细胞部位尚不清楚（6）。我们已经研究了胰激肽对磷脂酶-前列腺素-cAMP途径在整个回肠粘膜和上皮细胞分离自同一组织在大鼠。胰激肽（1 μ M）刺激PG（前列腺素）E2释放的显着上升（24至30倍）从剥离回肠粘膜的serenum表面在1-2分钟内，这与粘膜短路电流的上升密切相关。胰激肽还使粘蛋白cAMP水平增加2至3倍。然而，在相同的条件下，在活的上皮细胞悬浮液中，激肽不能引起效果。PGE 2释放不受激肽或缓激肽在浓度高达100 μ M，而cAMP水平可以刺激毛喉素和PGE 2，但不是由激肽。肠磷脂酶A2（PLA 2）活性的研究也表明非上皮网站激肽行动。这种酶负责从细胞磷脂中释放花生四烯酸，并已被证明在几种组织中被激肽激活。在肠道中，PLA 2活性被发现集中在subepithelium与显着较低的水平在上皮本身。此外，胰激肽不能影响与[14 C]花生四烯酸孵育的细胞中的磷脂标记（PLA 2活性的间接测量）。（250字处删节）
Kinin-induced secretion in the intestine is accompanied by marked increases in mucosal adenosine 3', 5'-cyclic monophosphate (cAMP) and prostanoids that undoubtedly contribute to the overall secretory response. The cellular site at which these effects are initiated is unclear although a recent hypothesis has suggested the epithelial cell as the target for kinin action (6). We have investigated the effects of kallidin on the phospholipase-prostanoid-cAMP pathway in whole ileal mucosa and in epithelial cells isolated from the same tissue in the rat. Kallidin (1 microM) stimulated a marked rise (24 to 30-fold) in PG (prostaglandin) E2 release from the serosal surface of stripped ileal mucosa within 1-2 min, which correlated closely with the rise in mucosal short-circuit current. Mucosal cAMP levels were also increased two to threefold by kallidin. However, kinins were unable to elicit effects under the same conditions in suspensions of viable epithelial cells. PGE2 release was unaffected by kallidin or bradykinin at concentrations up to 100 microM, whereas cAMP levels could be stimulated by forskolin and PGE2 but not by kinin. Studies of intestinal phospholipase A2 (PLA2) activity also suggest a nonepithelial site for kinin action. This enzyme is responsible for liberating arachidonic acid from cellular phospholipids and has been shown to be activated by kinins in several tissues. In the intestine, PLA2 activity was found to be concentrated within the subepithelium with significantly lower levels in the epithelium itself. In addition, kallidin was unable to influence phospholipid labeling (an indirect measure of PLA2 activity) in cells incubated with [14C]arachidonic acid.(ABSTRACT TRUNCATED AT 250 WORDS)