Intracellular mediators in the process of secretory diarrhea

测定了各种细菌毒素引起的分泌和出血性腹泻过程中细胞内介质的变化。得到以下结果：1)将霍乱毒素（CT）、大肠杆菌热不稳定毒素（LT）、艰难梭菌毒素（clostridium difficile toxin）注入大鼠空肠袢。CT和LT均激活肠上皮细胞中的a激酶，而梭状芽胞杆菌毒素通过Ca^<++>介导的过程诱导分泌性腹泻。但在ct诱导的分泌性腹泻过程中，a激酶被激活后，上皮细胞胞质游离Ca^<++>可能发挥了作用。2) ct诱导的分泌性腹泻可检测到刷边酶碱性磷酸酶（ALP）活性升高。为了观察被CT特异性磷酸化的膜组分与灌木边缘ALP之间的关系，我们将磷酸化部分与该BBM酶进行了比较。3)荧光显微镜下测定了肠上皮细胞、内皮细胞和白细胞Ca^<++>浓度的变化。Clostridium toxin and verotoxin （VT）可使白细胞游离Ca^<++>浓度升高，而CT对白细胞游离Ca^<++>浓度无影响。(4)活体显微镜下观察肠道微血管直径、流速和血管通透性。CT给药后，小静脉增大，血流增加，血管通透性增加。梭状芽孢杆菌毒素和VT均引起大鼠血流量减少，并引起小静脉内白细胞粘附和肠黏膜出血性病变。这些病变被PAF-和Ca^<++>-拮抗剂抑制，提示各种血管活性物质和白细胞在出血性腹泻的发生中起主要作用。少

Changes of intracellular mediators were determined in the process of secretory and hemorrhagic diarrhea induced by various kinds of bacterial toxins. The following results were obtained;1) Cholera toxin (CT), heat labile toxin (LT) from E. coli, clostridium difficile toxin were administered into the jejunal loop of rats. CT and LT both activated A-kinase in the intestinal epithelial cells, while clostridium toxin induced secretory diarrhea via mechanism of Ca^<++>-mediated processes. But there is possibility that cytosolic free Ca^<++> of epithelial cells may play a role after A-kinase was activated in the process of CT-induced secretory diarrhea.2) Increased activity of brush-border enzyme alkaline phosphatase (ALP) was recognized in CT-induced secretory diarrhea. In order to see the relation between membrane component which was specifically phosphorylated by CT and bush border ALP, phosphorylated fraction was compared with this BBM enzyme. The phosphorylated fraction was recognized t … More o be a 105KDa protein, which was different from ALP as determined by specific antibody against ALP.3) The alteration of Ca^<++> concentration was determined in intestinal epithelial cells, endothelial cells and leukocytes under fluorescence microscopy. Clostridium toxin and verotoxin (VT) was shown to increase free Ca^<++> concentration in leukocytes, while CT did not influence the Ca^<++> concentration of leukocytes.(4) Diameter, flow velocity and vascular permeability of intestinal microvessels were observed under intravital microscopy. After CT administration, enlargement of venules and increased blood flow were observed accompanying with the increased vascular permeability. Clostridium toxin and VT induced the decrease in blood flow and also induced leukocyte sticking in venules and hemorrhagic lesions in the intestinal mucosa. These lesions were inhibited by PAF- and Ca^<++>- antagonist suggesting that various vasoactive substances and leukocytes play major roles in the development of hemorrhagic diarrhea. Less