单价阳离子在兔外分泌胰腺液体分泌中的作用。

Role of monovalent cations in fluid secretion from the exocrine rabbit pancreas.

作者信息

Kuijpers G A, Van Nooy I G, De Pont J J

机构信息

Department of Biochemistry, University of Nijmegen, The Netherlands.

出版信息

Biochim Biophys Acta. 1989 Aug 21;984(1):63-70. doi: 10.1016/0005-2736(89)90343-x.

DOI:10.1016/0005-2736(89)90343-x

PMID:2765540

Abstract

The role of Na+ in fluid secretion by the isolated rabbit pancreas was investigated. The fluid secretion rate is reduced upon replacement of Na+ in the bathing medium by Li+, K+ or choline. The inhibition depends on the nature of the substituting cation, and is largest with choline. Upon replacement, the substituent cation appears in the secreted fluid, and the Na+ concentration in the secreted fluid is decreased in a mirror-like fashion. When Na+ is replaced by Li+ or choline, the secretory Na+ concentration is decreased, although less than in the bathing medium, and the K+ concentration is increased. When Na+ is replaced by K+, the Na+ and the K+ concentration in the secreted fluid are approximately equal to their bathing medium concentrations. In the Li+ and choline medium, stimulation of the pancreas by carbachol or CCK-8 increases the fluid secretion rate. In addition, it increases the Li+ or choline concentration, and decreases the Na+ and K+ concentrations in the secreted fluid. In normal and K+ medium, stimulation causes only a slight increase in fluid secretion rate, with no change in the secretory Na+ concentration. In normal medium, stimulation leads to a decrease in the secretory K+ concentration. The effects of replacing Na+ appear to be the result of a direct inhibition of the active HCO3- transport underlying secretion, and an indirect inhibition related to the permeability of the pancreas for the various cations. The stimulants are likely to act by increasing the permeability of the tight junctions.

摘要

研究了Na⁺在离体兔胰腺液体分泌中的作用。当用Li⁺、K⁺或胆碱替代浴液中的Na⁺时，液体分泌速率降低。抑制作用取决于替代阳离子的性质，胆碱的抑制作用最大。替代后，替代阳离子出现在分泌液中，分泌液中的Na⁺浓度呈镜像下降。当Na⁺被Li⁺或胆碱替代时，分泌的Na⁺浓度降低，尽管低于浴液中的浓度，而K⁺浓度升高。当Na⁺被K⁺替代时，分泌液中的Na⁺和K⁺浓度大致等于其浴液中的浓度。在Li⁺和胆碱介质中，卡巴胆碱或CCK-8刺激胰腺会增加液体分泌速率。此外，它会增加Li⁺或胆碱浓度，并降低分泌液中的Na⁺和K⁺浓度。在正常和K⁺介质中，刺激只会使液体分泌速率略有增加，分泌的Na⁺浓度没有变化。在正常介质中，刺激会导致分泌的K⁺浓度降低。替代Na⁺的作用似乎是直接抑制分泌过程中潜在的主动HCO₃⁻转运以及与胰腺对各种阳离子通透性相关的间接抑制的结果。刺激剂可能通过增加紧密连接的通透性起作用。