WATER AND ELECTROLYTE TRANSPORT BY THE INTESTINE

在第一部分中建议进行研究，以确定 肠道神经系统对电解质和水的运输 通过兔的小肠和大肠。之前的研究已经 显示刺激肠神经(可能是粘膜下神经) 神经元)减少人回肠和乙状结肠对氯的吸收 结肠，并导致空肠和盲肠分泌氯化物。 将继续对3个假设进行测试：1)刺激(化学或 机械)在一定程度上引起了运输方面的变化， 通过肠神经反射；2)通过这种反射， 某些粘膜刺激可以改变局部的离子和液体运输。 远离刺激部位；3)离子反应 运输方式会有所不同，这取决于所研究的区段 是刺激节段的Orad或Aborad。刺激因素是 所研究的是机械(膨胀)和化学(胆盐， 5-羟色胺、大肠杆菌ST毒素和茶碱)。交通将会是 在麻醉兔身上用标准方法进行研究，并通过 在专门设计的仪器中测量离子通量和电学指数 磁通室。 在第二部分中，我们将确定多肽是否对 人体小肠和大肠粘膜的转运 是由肠细胞上的受体直接或间接介导的 通过释放次级神经递质。这些多肽是 存在于静脉曲张或神经末梢中，这些神经末梢来自 肌间神经丛将被研究，因为它们可能 生理上的相关性。在手术中获得的组织中，剥离 并安装在标准的通量室中，我们 将评估神经调节，通过确定 减少由多肽引起的短路电流变化 神经毒素河豚毒素。如果是这样的话，我们会尝试确定 具有特定拮抗剂的递质，例如阿托品，推定 VIP拮抗剂，或通过脱敏。这样的研究应该 监测递质释放的补充性研究 (由他人)通过展示一种生物的 这种释放的效果。对人体组织的研究是必要的，因为 物种的可变性。

Studies are proposed in Part I to determine the influence of the enteric nervous system on the transport of electrolytes and water by the small and large intestine of rabbit. Previous studies have shown that stimulation of the enteric nerves (probably submucous neurons) reduces chloride absorption in human ileum and sigmoid colon, and causes secretion of chloride in jejunum and cecum. Tests of 3 hypotheses will be continued: 1) Stimuli (chemical or mechanical) that evoke changes in transport do so, in part, through enteric neural reflexes; 2) By means of such reflexes, some mucosal stimuli can alter ion and fluid transport at sites remote from the site of stimulation; and 3) A response in ion transport will differ depending upon whether the segment studied is orad or aborad from the stimulated segment. The stimuli to be studied are mechanical (distension) and chemical (bile salts, serotonin, E. coli ST toxin and theophylline). Transport will be studied by standard methods in anesthetized rabbits and by measuring ion fluxes and electrical indices in a specially-designed flux chamber. In part II, we will determine whether the effects of peptides on transport by the mucosa of the human small and large intestine are mediated directly by receptors on enterocytes, or indirectly by release of secondary neurotransmitters. Peptides that are present in varicosities or nerve endings arising from fibers of the myenteric plexus will be studied because of their probable physiological relevance. In tissues obtained at surgery, stripped of muscularis propria and mounted in a standard flux chamber, we will asssess the neural mediation by determining whether the short-circuit current change induced by the peptide is reduced with the neurotoxin, tetrodotoxin. If it is, we will try to identify the transmitter with specific antagonists, e.g., atropine, putative VIP antagonists, or by desensitization. Such studies should complement studies of transmitter release monitored immunochemically (by others) by demonstrating a biological effect of such release. Study of human tissues is required because of species variability.