Ugolev A M, Zaripov B Z, Iezuitova N N, Nikitina A A, Voloshenovich M I, Rybin I S, Gurman E G, Mamatakhunov A I
Gen Physiol Biophys. 1985 Jun;4(3):287-99.
A technique to study membrane digestion and transport in the small intestine under physiological conditions has been developed. The technique is based on a continuous perfusion of a chronically isolated loop of the rat small intestine. Membrane hydrolysis and transport of some nutrients in the rat small intestine in chronic, as well as in acute (in situ) experiments was investigated. The absorption of hexoses and amino acids has been found to be 2.5-4 times higher under physiological conditions than in acute in situ experiments. Both the active transport of glucose released from maltose hydrolysis and the hydrolysis of the latter is increased under physiological conditions. A coupling between the final stages of hydrolysis and the initial stages of transport in chronic experiments was shown to be highly efficient; practically all or nearly all glucose released is being transported without entering the luminal phase. The hydrolysis rate of starch during the perfusion of a small intestinal segment in chronic experiments is many times higher than that in acute experiments or under anaesthesia. The enzymatic and transport activities revealed using a widely accepted technique in situ, the more so, in vitro account for only a small fraction of those which are typical of undisturbed processes under conditions close to the physiological. The levels of functioning of the digestive-transport systems of the small intestine considered as natural levels developed in the process of evolution, actually reflect only residual processes and, in most cases, they account for 1/3 to 1/10 of the true level of an actual physiological process.
已开发出一种在生理条件下研究小肠膜消化和转运的技术。该技术基于对大鼠小肠慢性分离肠袢的连续灌注。研究了慢性以及急性（原位）实验中大鼠小肠膜水解和某些营养物质的转运情况。已发现己糖和氨基酸在生理条件下的吸收比急性原位实验中高2.5至4倍。在生理条件下，麦芽糖水解释放的葡萄糖的主动转运以及后者的水解均增加。慢性实验中水解的最后阶段与转运的初始阶段之间的偶联显示效率很高；实际上，几乎所有或几乎所有释放的葡萄糖都在不进入肠腔相的情况下被转运。慢性实验中小肠段灌注期间淀粉的水解速率比急性实验或麻醉状态下高许多倍。使用广泛接受的原位技术，更不用说体外技术所揭示的酶活性和转运活性，仅占接近生理条件下未受干扰过程中典型活性的一小部分。小肠消化 - 转运系统的功能水平被视为在进化过程中形成的自然水平，实际上仅反映残余过程，并且在大多数情况下，它们仅占实际生理过程真实水平的三分之一至十分之一。
