霍乱毒素、不耐热和耐热大肠杆菌肠毒素对猪和兔小肠黏膜中环磷酸腺苷浓度的影响。
The effect of cholera toxin and heat labile and heat stable Escherichia coli enterotoxin on cyclic AMP concentrations in small intestinal mucosa of pig and rabbit.
作者信息
Hamilton D L, Johnson M R, Forsyth G W, Roe W E, Nielsen N O
出版信息
Can J Comp Med. 1978 Jul;42(3):327-31.
The effect of cholera toxin, heat labile and heat stable Escherichia coli enterotoxin on mucosal cyclic AMP concentrations was determined on the proximal jejunum of weanling pigs and young rabbits. Ligated loops were injected with solutions containing no enterotoxin for control and either cholera toxin, heat labile or heat stable E. coli enterotoxin. The loops were drained after either two, four or six hours incubation at which time accumulated fluid was recorded and mucosal samples removed for determination of cyclic AMP concentration. In the rabbit, cholera toxin and heat labile, but not heat stable E. coli enterotoxin stimulated intestinal secretion while in the pig all three enterotoxins induced net fluid accumulation. Cholera toxin and heat labile, but not heat stable E. coli enterotoxin elevated rabbit mucosal cyclic AMP concentrations. In the pig these enterotoxins had no significant effect on mucosal cyclic AMP concentrations. The results are inconsistent with the hypothesis that the adenyl cyclase system is an essential step for enterotoxin induced intestinal secretion. The activation of intestinal adenyl cyclase by bacterial enterotoxins may only be an associated and not a necessary event for the stimulation of intestinal secretion.
研究了霍乱毒素、不耐热和耐热大肠杆菌肠毒素对断奶仔猪和幼兔空肠近端黏膜环磷酸腺苷（cAMP）浓度的影响。将结扎肠袢分别注射不含肠毒素的溶液作为对照，以及霍乱毒素、不耐热或耐热大肠杆菌肠毒素。在孵育两小时、四小时或六小时后，排出肠袢内液体，记录积聚的液体量，并取黏膜样本测定cAMP浓度。在兔中，霍乱毒素和不耐热大肠杆菌肠毒素可刺激肠道分泌，但耐热大肠杆菌肠毒素无此作用；而在猪中，这三种肠毒素均能诱导液体净积聚。霍乱毒素和不耐热大肠杆菌肠毒素可提高兔黏膜cAMP浓度，但在猪中这些肠毒素对黏膜cAMP浓度无显著影响。这些结果与“腺苷酸环化酶系统是肠毒素诱导肠道分泌的关键步骤”这一假说不一致。细菌肠毒素激活肠道腺苷酸环化酶可能只是刺激肠道分泌的一个相关而非必要事件。
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