ATP-dependent potassium channels contribute to motor regulation of esophageal striated muscle in rats

Abstract

The aim of the present study was to clarify roles of ATP-dependent potassium channels (KATP channels) in motility of the striated muscle portion in the esophagus. An isolated segment of the rat esophagus was placed in an organ bath and mechanical responses were recorded using a force transducer. Electrical stimulation of the vagus nerve evoked contractile response of striated muscle in the esophageal segment. Application of glibenclamide, an antagonist of KATP channels, increased amplitude of vagally mediated twitch contractions of the rat esophagus. On the other hand, minoxidil, an agonist of KATP channels, decreased amplitude of twitch contractions. RT-PCR revealed the expression of subunits of KATP channels in esophageal tissue. In addition, immunopositivity for subunits of KATP channels was observed in the striated muscle cells of the esophageal muscle layer. These findings indicate that KATP channels contribute to motor regulation of striated muscle in the rat esophagus.

Purinergic inhibitory regulation of esophageal smooth muscle is mediated by P2Y receptors and ATP-dependent potassium channels in rats

“…On the basis of the findings presented here, we consider that P2Y receptors and K ATP channels are localized on smooth muscle cells of muscularis mucosae and are involved in the regulation of esophageal motility. In accordance with this, we have shown localization of K ATP channels on smooth muscle cells of muscularis mucosae of rat esophagi [ 55 , 56 ]. However, it should be noted that P2Y receptors might be located on interstitial cells of Cajal (ICCs).…”

“…In accordance with this, nicorandil, an agonist of K ATP channels, causes relaxation of smooth muscle in the lower esophageal sphincter of the rat [ 58 ]. We previously demonstrated that K ATP channels also contribute to motor regulation of striated muscle in the rat esophagus [ 55 , 56 ]. We think that elucidation of the coordination between striated muscle and smooth muscle is an important issue in studies on esophageal motor regulation.…”

Motor Dysfunction of Gastric Antral Smooth Muscle in Diabetic Rats: Contribution of ATP-Dependent Potassium Channels

“…[ 18 ] Moreover, a dose-dependent inhibition of smooth muscle contraction by K ATP channel activators such as minoxidil, cromakalim, and diazoxide has been demonstrated in the stomach and other regions of the GI tract, including the esophagus, ileum, and colon. [ 19 20 ] The activation of K ATP channel increases potassium conductance, leading to cell membrane hyperpolarization and subsequent inhibition of extracellular Ca 2+ influx and Ca 2+ release from intracellular storage organelles. [ 21 ] Studies have also demonstrated that K ATP channel opener-induced hyperpolarization is responsible for its relaxing action on ACh- and KCl-induced contractions in the smooth muscle of rat and the gastric antrum of guinea pig.…”

“…For example, Horii et al . [ 19 ] showed a dose-dependent effect of glibenclamide on esophagus muscle contractions in rat. In this study, glibenclamide increased vagally induced contractions of the rat esophagus at an effective dose of more than 500 μM, while glibenclamide at a dose of 50 μM did not affect esophageal muscle motility.…”

Mineral Deficiencies: A Root Cause for Reduced Longevity in Mammals

“…It helps regulate fluid balance, nerve signals and muscle contractions and beneficial aspects include reduction in blood pressure, water retention; prevention of kidney stones, osteoporosis, and protection against strokes. It functions to maintain intracellular osmotic known to play a role in Na + -K+ ATPase for effective muscle contraction [40] and motor regulation is by ATP driven potassium channels [41]. ATP driven potassium channel deficiency affected resting tension of skeletal muscle [42] deficiency of potassium ions alters sodium potassium pump of skeletal muscle and augments its contraction in ageing [43].…”