Heartburn: cardiac potassium channels involved in parietal cell acid secretion.

Hydrochloric acid is produced in parietal cells of the gastric glands by an H(+)/K(+)-ATPase. This proton pump couples the outwards movement of H(+) to the inwards movement of K(+) thus requiring the presence of luminal K(+) to operate. To maintain the activity of the pump, K(+) recirculates over the apical membrane via conductive pathways, the molecular nature of which has been identified in the past few years. This review gives a short overview about the recent advances in the understanding of the role of K(+) channels in the process of parietal cell H(+) secretion and focuses on the identification of KCNQ1/KCNE2 K(+) channel as the molecular correlate of the parietal cell apical potassium conductance.