AIMS ATP-sensitive potassium (K(ATP)) channels in the heart are critical regulators of cellular excitability and action potentials during ischaemia. However, little is known about subcellular localization of these channels and their regulation. The present study was designed to explore the potential role of caveolae in the regulation of K(ATP) channels in cardiac ventricular myocytes. METHODS...

there are many reports for involvement of atp-sensitive potassium channels in pancreatic, cardiac and vascular smooth muscle cells. this study examined the effect of single doses of k+ channel openers diazoxide, minoxidil and k+ channel blockers chlorpropamide, glibenclamide on serum concentration of aldosterone in male rats. blood samples were obtained 60 minutes after drug treatment and serum...

ATP-sensitive potassium (K(ATP)) channels regulate insulin release, vascular tone, and neuronal excitability. Whether these channels are modulated by NO, a membrane-permeant messenger in various physiological and pathological processes, is not known. The possibility of NO signaling via K(ATP) channel modulation is of interest because both NO and K(ATP) have been implicated in physiological func...

The K’ activation profile of the (Cap+ + My’+)-dependent ATPase of sarcoplasmic reticulum vesicles is markedly changed by the free magnesium concentration. At 0.2 mM Mg’+, a complex dependence on the K+ concentration is observed which changes to a simple hyperbolic dependence when Mg’+ is raised to 3 mM. The degree of activation by K+ is always higher at 0.2 rnH than at 3 mM MgY+. At 0.2 mM Mg”...

The heart is richly endowed with K(ATP) channels, which function as biological sensors, regulating membrane potentials and electrical excitability in response to metabolic alterations. We recently reported that the cytochrome P450 metabolites of arachidonic acid, epoxyeicosatrienoic acids (EETs), potently activate cardiac K(ATP) channels by reducing channel sensitivity to ATP. In the present st...

Measurements have been made of K influx in squid giant axons under internal solute control by dialysis. With [ATP](i) = 1 microM, [Na](i) = 0, K influx was 6 +/- 0.6 pmole/cm(2) sec; an increase to [ATP](i) = 4 mM gave an influx of 8 +/- 0.5 pmole/cm(2) sec, while [ATP](i) 4, [Na](i) 80 gave a K influx of 19 +/- 0.7 pmole/cm(2) sec (all measurements at approximately 16 degrees C). Strophanthidi...