Inhibition of ATP-sensitive K+ (KATP) channel activity has previously been demonstrated to result in coronary vasoconstriction with decreased myocardial blood flow and loss of phosphocreatine (PCr). This study was performed to determine whether the high-energy phosphate abnormality during KATP channel blockade can be ascribed to oxygen insufficiency. Myocardial blood flow and oxygen extraction ...

Ischemic preconditioning models have been characterized in brain, heart, and other tissues, and previous pharmacologic studies have suggested an involvement of adenosine and ATP dependent potassium (KATP) channels in such tolerance phenomena. This question was reexamined in a reproducible gerbil model in which the duration of ischemic depolarization defined the severity of preconditioning and t...

BACKGROUND AND PURPOSE The purpose of these experiments was to examine mechanisms by which hypercapnia produces vasodilatation in brain. We examined the hypothesis that dilatation of cerebral arterioles during hypercapnia is dependent on activation of ATP-sensitive potassium channels and formation of nitric oxide. METHODS Diameters of cerebral arterioles were measured using a closed cranial w...

The relaxing effects of the adenosine 5'-triphosphate (ATP)-sensitive K+ channel openers (K(ATP) openers; diazoxide, minoxidil, pinacidil, (+/-)-cromakalim, (+)-cromakalim and (-)-cromakalim) were investigated on the resting tone of pig proximal urethra. In addition, patch clamp techniques were utilized for recording cromakalim-induced ionic currents in cells dispersed from the same urethral re...

The extent to which ATP-sensitive K(+) channels contribute to reactive hyperemia in humans is unresolved. We examined the role of ATP-sensitive K(+) channels in regulating reactive hyperemia induced by 5 min of forearm ischemia. Thirty-one healthy subjects had forearm blood flow measured with venous occlusion plethysmography. Reactive hyperemia could be reproducibly induced (n = 9). The contrib...

The mechanism of reactive hyperemia remains unknown. We hypothesized that reactive hyperemia was related to the opening of ATP-sensitive potassium channels during coronary occlusion. The resulting hyperpolarization of the smooth muscle cell plasma membrane might reduce calcium influx through voltage-dependent calcium channels and result in relaxation of smooth muscle tone and vasodilation. In e...

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...

Experimental data suggest that vascular ATP-sensitive potassium (K(ATP)) channels may be an important determinant of functional hyperaemia, but the contribution of K(ATP) channels to exercise-induced hyperaemia in humans is unknown. Forearm blood flow was assessed in 39 healthy subjects (23 males/16 females; age 22+/-4 years) using the technique of venous occlusion plethysmography. Resting fore...