OBJECTIVE To test the hypothesis that hypoxia activates ATP-sensitive K+ (KATP) channels in cremasteric arteriolar muscle cells, resulting in membrane hyperpolarization and inhibition of norepinephrine-induced contraction. METHODS Arteriolar muscle cells were isolated enzymatically from second- and third-order arterioles that were surgically removed from hamster cremaster muscles. The effects...

  Tolerance and dependence are two main problems that have limited morphine administration as an analgesic drug and they might be as a result of changes in the number and affinity of receptors, dysfunction of adenylate cyclase, impaired coupling between activated µ receptor and K+ channels, and changes in the K+ and Ca2+ channels. There are several reports concerning the role of some of these...

The -cell of the pancreatic islet modulates glucose homeostasis by secreting glucagon that acts primarily by driving hepatic glucose production. Glucose sensing of the -cell becomes defective in both type 1 and type 2 diabetes, resulting in hyperglucagonemia that likely contributes to hyperglycemia (1). Thus, it is important to elucidate the signals that trigger glucagon secretion and the trans...

Activation of ATP-sensitive potassium (KATP) channels in arterial smooth muscle (ASM) contributes to vasodilation evoked by a variety of endogenous and exogenous compounds. Although controversial, activation of KATP channels by neuropeptides such as calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase activating peptide (PACAP) in the trigeminovascular system, including the mi...

There is wide speculation that ATP-sensitive K+(KATP) channels serve a protective function in the mammalian brain, being activated during periods of energy failure. The aim of the present study was to determine if KATP channels also have a protective role in the anoxia-tolerant turtle brain. After ouabain administration, rates of change in extracellular K+ were measured in the telencephalon of ...

86Rb fluxes through ATP-regulated K+(KATP) channels in membrane vesicles derived from basolateral membranes of Necturus small intestinal epithelial cells as well as the activity of single KATP channels reconstituted into planar phospholipid bilayers are inhibited by the presence of ADP plus phospho enolpyruvate in the solution bathing the inner surface of these channels. This inhibition can be ...

Type 2 diabetes (T2D) is closely associated with obesity. Obesity features an abnormality in energy balance with excess energy stored in fat tissues. In T2D, the ability to regulate glucose homeostasis is compromised resulting in hyperglycemia (high levels of blood glucose). Central nervous system (CNS) plays an important role in energy and glucose homeostasis [1]. In normal situations, the neu...

Vascular ATP-sensitive potassium (KATP) channels have an important role in hypoxic vasodilation. Because KATP channel activity depends on intracellular nucleotide concentration, one hypothesis is that hypoxia activates channels by reducing cellular ATP production. However, this has not been rigorously tested. In this study we measured KATP current in response to hypoxia and modulators of cellul...

BACKGROUND Pancreatic beta cells express ATP-sensitive potassium (KATP) channels that are needed for normal insulin secretion and are targets for drugs that modulate insulin secretion. The KATP channel is composed of two subunits: a sulfonylurea receptor (SUR 1) and an inward rectifying potassium channel (Kir6.2). KATP channel activity is influenced by the metabolic state of the cell and initia...

Cardiac KATP channels link metabolism with electrical activity. They are implicated in arrhythmias, secretion of atrial natriuretic peptide and protection of the heart from hypertrophy and failure. These processes may involve mechanosensitivity. KATP channels can be activated by mechanical stimulation and disrupting the cortical actin increases the activity. We propose that KATP channels are mo...