Potassium (K+) channels mediate numerous electrical events in excitable cells, including cellular membrane potential repolarization. The hERG K+ channel plays an important role in myocardial repolarization, and inhibition of these K+ channels is associated with long QT syndromes that can cause fatal cardiac arrhythmias. In this study, we identify saxitoxin (STX) as a hERG channel modifier and i...

BACKGROUND Volatile anesthetics can protect the myocardium against ischemic injury by opening the adenosine triphosphate (ATP)-sensitive potassium (K(atp)) channels. However, direct evidence for anesthetic-channel interaction is still limited, and little is known about the role K(atp) channel modulators play in this effect. Because pH is one of the regulators of K(atp) channels, the authors tes...

In a recent study (Leroy C, Dagenais A, Berthiaume Y, and Brochiero E. Am J Physiol Lung Cell Mol Physiol 286: L1027-L1037, 2004), we identified an ATP-sensitive K(+) (K(ATP)) channel in alveolar epithelial cells, formed by inwardly rectifying K(+) channel Kir6.1/sulfonylurea receptor (SUR)2B subunits. We found that short applications of K(ATP), voltage-dependent K(+) channel KvLQT1, and calciu...

Calcium-sensitive potassium (K(Ca)) channels play a critical role in mediating perinatal pulmonary vasodilation. Because infants with persistent pulmonary hypertension of the newborn (PPHN) have blunted vasodilator responses to birth-related stimuli, we hypothesized that lung K(Ca) channel gene expression is decreased in PPHN. To test this hypothesis, we measured K(Ca) channel gene expression i...

The mechanism by which ATP-sensitive K 1 (K ATP ) channels open in the presence of inhibitory concentrations of ATP remains unknown. Herein, using a four-state kinetic model, we found that the nucleotide diphosphate UDP directed cardiac K ATP channels to operate within intraburst transitions. These transitions are not targeted by ATP, nor the structurally unrelated sulfonylurea glyburide, which...

The basolateral membrane of human colonic crypt cells contains Ca2+ and cAMP activated, Ba2+ blockable, low conductance (23 pS) K+ channels, which probably play an important part in intestinal Cl- secretion. This study has defined more clearly the basolateral K+ conductive properties of human colonic crypts using patch clamp recording techniques. High conductance (138 pS) K+ channels were seen ...

Metabolic regulation of pancreatic beta-cell ATP-sensitive K+ channel (K(ATP) channel) function plays a key role in the process of glucose-stimulated insulin secretion (GSIS). Modulation of K(ATP) channel activity by long-chain acyl CoAs represents an important endogenous regulatory mechanism. Elevated acyl CoA levels have been reported in obese and type 2 diabetic individuals and may contribut...

BACKGROUND Adenosine can initiate ischemic preconditioning, and mitochondrial ATP-sensitive potassium (K(ATP)) channels have emerged as the likely effectors. We sought to determine the mechanistic interactions between these 2 observations. METHODS AND RESULTS The mitochondrial flavoprotein oxidation induced by diazoxide (100 micromol/L) was used to quantify mitochondrial K(ATP) channel activi...

Potassium ion (K(+)) channel activity is a major regulator of vascular muscle cell membrane potential (E(m)) and is therefore an important determinant of vascular tone. There is growing evidence that the function of several types of vascular K(+) channels is altered during major cardiovascular diseases, such as chronic hypertension, diabetes, and atherosclerosis. Vasoconstriction and the compro...

Channels formed by the co-assembly of the KCNQ1 subunit and the mink (KCNE1) subunit underline the slowly activating delayed rectifier K(+) channels (IKs ) in the heart. This K(+) channel is one of the main pharmacological targets for the development of drugs against cardiovascular disease. Panax ginseng has been shown to exhibit beneficial cardiovascular effects. In a previous study, we showed...