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Regulation of slowly activating potassium current ( I Ks ) by secretin in rat pancreatic acinar cells
Author(s) -
Kim Sung Joon,
Kim Jin Kyoung,
Pavenstädt Hermann,
Greger Rainer,
Hug Martin J.,
Bleich Markus
Publication year - 2001
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 - 10.1111/j.1469-7793.2001.00349.x
Subject(s) - secretin , forskolin , vasoactive intestinal peptide , medicine , secretagogue , endocrinology , carbachol , ibmx , chemistry , isoprenaline , stimulation , depolarization , patch clamp , potassium channel , acinus , secretion , biophysics , biology , pancreas , neuropeptide , electrophysiology , receptor
1 The secretagogue‐activated K + conductance is indispensable for the electrogenic Cl − secretion in exocrine tissue. In this study, we investigated the effect of secretin and other cAMP‐mediated secretagogues on the slowly activating voltage‐dependent K + current ( I Ks ) of rat pancreatic acinar cells (RPAs) with the whole‐cell patch clamp technique. 2 Upon depolarization, RPAs showed I Ks superimposed upon the instantaneous background outward current. Secretin (5 n m ), vasoactive intestinal peptide (5 n m ), forskolin (5 μ m ), isoprenaline (10 μ m ) or 3‐isobutyl‐1‐methylxanthine (IBMX, 0.1 m m ) increased the amplitude of I Ks two‐ to fourfold. 3 The physiological concentration of secretin (50 p m ) had a relatively weak effect on I Ks (160 % increase), which was significantly enhanced by transient co‐stimulation with carbachol (CCh) (10 μ m ). However, the secretin‐induced production of cAMP, which was measured by enzyme‐linked immunosorbent assay, was not augmented by co‐stimulation with CCh. 4 This study is the first to demonstrate the regulation of K + channels in RPAs by cAMP‐mediated agonists. The I Ks channel is a common target for both Ca 2+ and cAMP agonists. The vagal stimulation under the physiological concentration of secretin facilitates I Ks , which provides an additional driving force for Cl − secretion.