Where are ATP-sensitive potassium channel?

ATP-sensitive potassium channels are composed of Kir6. x-type subunits and sulfonylurea receptor (SUR) subunits, along with additional components. KATP channels are found in the plasma membrane; however some may also be found on subcellular membranes.

What do KATP channels do?

The ATP-sensitive K+ channel (K ATP channel) senses metabolic changes in the pancreatic beta-cell, thereby coupling metabolism to electrical activity and ultimately to insulin secretion. When K ATP channels open, beta-cells hyperpolarize and insulin secretion is suppressed.

Which of the following drugs acts blocking ATP-sensitive K+ channels in pancreas?

Sulphonylureas stimulate insulin secretion from pancreatic β-cells primarily by closing ATP-sensitive K+ channels in the β-cell plasma membrane. The mechanism of channel inhibition by these drugs is unusually complex.

How do potassium channels work?

Potassium channels function to conduct potassium ions down their electrochemical gradient, doing so both rapidly (up to the diffusion rate of K+ ions in bulk water) and selectively (excluding, most notably, sodium despite the sub-angstrom difference in ionic radius).

Where are the ATP sensitive potassium channels located?

ATP-sensitive potassium channels are composed of K ir6.x-type subunits and sulfonylurea receptor (SUR) subunits, along with additional components. K ATP channels are found in the plasma membrane; however some may also be found on subcellular membranes.

How are potassium channels activated in smooth muscle?

Adenosine triphosphate (ATP)–sensitive potassium channels in vascular smooth muscle are activated by ATP-dependent potassium channel openers. This process results in hyperpolarization of the plasma membrane and vasodilation of the blood vessel, probably by preventing opening of voltage-activated calcium channels.

Why are potassium channels always open in the pancreas?

In the pancreas, these channels were always open, but remained closed in the cardiac cells. Upon the onset of a cellular energy crisis, mitochondrial function tends to decline. This is due to alternating inner membrane potential, imbalanced trans-membrane ion transport, and an overproduction of free radicals, among other factors.

Why is potassium channel sensitive to magnesium salt?

These allow for nucleotide-mediated regulation of the potassium channel, and are critical in its roles as a sensor of metabolic status. These SUR subunits are also sensitive to sulfonylureas, MgATP (the magnesium salt of ATP), and some other pharmacological channel openers.