Related Experiment Video
Updated: May 12, 2026

Exploring Arterial Smooth Muscle Kv7 Potassium Channel Function using Patch Clamp Electrophysiology and Pressure Myography
Published on: September 14, 2012
The cardiac K+ channel KCNQ1 is essential for gastric acid secretion
F Grahammer1, A W Herling, H J Lang
1Institute of Physiology, Albert-Ludwigs-University, Freiburg, Germany.
Background & Aims:
Gastric H+ secretion via the H+/K+-adenosine triphosphatase is coupled to the uptake of K+. However, the molecular identity of luminal K+ channels enabling K+ recycling in parietal cells is unknown. This study was aimed to investigate these luminal K+ channels.
Methods:
Acid secretion was measured in vivo and in vitro; KCNQ1 protein localization was assessed by immunofluorescence, and acid-sensitivity of KCNQ1 by patch-clamp.
Results:
We identified KCNQ1, which is mutated in cardiac long QT syndrome, as a K+ channel located in tubulovesicles and apical membrane of parietal cells, where it colocalized with H+/K+-adenosine triphosphatase. Blockade of KCNQ1 current by 293B led to complete inhibition of acid secretion. The putative KCNQ1 subunits, KCNE2 and KCNE3, were abundant in human stomach; KCNE1, however, was absent. Coexpression of KCNE3/KCNQ1 in COS cells led to an acid-insensitive current; KCNE2/KCNQ1 was activated by low extracellular pH.
Conclusions:
We identified KCNQ1 as the missing luminal K+ channel in parietal cells and characterized its crucial role in acid secretion. Because KCNE3 and KCNE2 are expressed in human stomach, one or both are candidates to coassemble with KCNQ1 in parietal cells. Thus, stomach- and subunit-specific inhibitors of KCNQ1 might offer new therapeutical perspectives for peptic ulcer disease.
Related Concept Videos
Stomach pH Regulation
The acid-secreting gastric mucosal epithelial cells (parietal cells) lining the stomach lumen maintain the low pH in the lumen. Numerous ion transporters and channels on these parietal...
Voltage-gated Ion Channels
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
G-Protein Gated Ion Channels
Sensory organs,...
Pathophysiology of Peptic Ulcer Disease: Injurious Factors
In the antrum region, G cells secrete the gastrin hormone that binds to gastrin-cholecystokinin-B (CCK2) receptors on parietal and enterochromaffin-like (ECL) cells in the fundic glands. Simultaneously, the vagus nerve releases acetylcholine, which binds to M3...
Mucosal Barrier of the Stomach
Within parietal cells, carbonic acid is first formed through the reaction of water and carbon dioxide. The dissociation of carbonic acid releases bicarbonate and hydrogen ions. The bicarbonate...
Cardiac Action Potential
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials

