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The involvement of basolateral potassium channels in the intestinal response to secretagogues in the rat.
Author(s) -
Hardcastle J,
Hardcastle P T
Publication year - 1986
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1986.sp016256
Subject(s) - acetylcholine , chemistry , tetraethylammonium , endocrinology , tetraethylammonium chloride , medicine , apamin , secretagogue , stimulation , potassium , potassium channel , biophysics , biology , organic chemistry
The possible involvement of basolateral K+ channels in the intestinal response to secretagogues was investigated using stripped sheets of rat mid‐intestine. Increasing the serosal K+ concentration reduced the rise in short‐circuit current induced by acetylcholine, 5‐hydroxytryptamine, theophylline and prostaglandin E2 (PGE2) without affecting the change caused by glucose. The secretagogue‐induced rise in short‐circuit current was inhibited by quinine, but not by tetraethylammonium chloride, apamin or 3,4‐diaminopyridine. Acetylcholine stimulated 86Rb efflux into the serosal fluid from pre‐loaded intestinal sheets and a smaller response was observed with PGE2. The acetylcholine‐induced stimulation of 86Rb efflux was inhibited by serosal quinine and lack of serosal Ca2+. Furosemide in the serosal fluid reduced the electrical response to acetylcholine without affecting the increase in 86Rb efflux. It is concluded that as well as increasing luminal Cl‐ permeability, intestinal secretagogues also enhance the basolateral K+ conductance by activating Ca2+‐dependent K+ channels.