an-antegrade-perfusion-method-for-cardiomyocyte-isolation-from-mice

An Antegrade Perfusion Method for Cardiomyocyte Isolation from Mice

In basic research using mouse heart, isolating viable individual cardiomyocytes is a crucial technical step to overcome. Traditionally, isolating ...

Shiga University of Medical Science

The phenylalkylamine class of L-type Ca channel antagonist verapamil prolongs the effective refractory period (ERP) of human atrium, which appears to contribute to the efficacy of verapamil in preventing reentrant-based atrial arrhythmias including atrial fibrillation. This study was designed to investigate the molecular and electrophysiological mechanism underlying the action of verapamil on human Kv1.5 (hKv1.5) channel that determines action potential duration and ERP in human atrium.

Identification of Verapamil Binding Sites Within Human Kv1.5 Channel Using Mutagenesis and Docking Simulation.

Volatile anaesthetics have been shown to differentially modulate mammalian Shaker-related voltage-gated potassium (K 1.x) channels. This study was designed to investigate molecular and cellular mechanisms underlying the modulatory effects of desflurane or sevoflurane on human K 1.5 (hK 1.5) channels.

Open-channel blocking action of volatile anaesthetics desflurane and sevoflurane on human voltage-gated K 1.5 channel.

The organic anion transporter SLCO2A1 constitutes an essential core component of the ATP-conductive large-conductance anion (Maxi-Cl) channel. Our previous experiments using Langendorff-perfused mouse hearts showed that the Maxi-Cl channel contributes largely to the release of ATP into the coronary effluent observed during 10-min reperfusion following a short period (6 min) of oxygen-glucose deprivation. The present study examined the effect of endogenous ATP released  Maxi-Cl channels on the left ventricular contractile function of Langendorff-perfused mouse hearts, using a fluid-filled balloon connected to a pressure transducer. After the initial 30-min stabilization period, the heart was then perfused with oxygen-glucose-deprived Tyrode solution for 6 min, which was followed by a 10-min perfusion with oxygenated normal Tyrode solution in the absence and presence of an ATP-hydrolyzing enzyme, apyrase, and/or an adenosine A1 receptor antagonist, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). In the absence of apyrase and DPCPX, the left ventricular developed pressure (LVDP) decreased from a baseline value of 72.3 ± 7.1 to 57.5 ± 5.5 mmHg ( = 4) at the end of 6-min perfusion with oxygen-glucose-deprived Tyrode solution, which was followed by a transient increase to 108.5 ± 16.5 mmHg during subsequent perfusion with oxygenated normal Tyrode solution. However, in the presence of apyrase and DPCPX, the LVDP decreased to the same degree during 6-min perfusion with oxygen-glucose-deprived Tyrode solution, but failed to exhibit a transient increase during a subsequent perfusion with oxygenated normal Tyrode solution. These results strongly suggest that endogenous ATP released through Maxi-Cl channels contributes to the development of transient positive inotropy observed during reperfusion after short-period hypoxia/ischemia in the heart.

Positive Inotropic Effects of ATP Released  the Maxi-Anion Channel in Langendorff-Perfused Mouse Hearts Subjected to Ischemia-Reperfusion.

The slowly activating delayed rectifier K channel (I ), composed of pore-forming KCNQ1 α-subunits and ancillary KCNE1 β-subunits, regulates ventricular repolarization in human heart. Propofol, at clinically used concentrations, modestly inhibits the intact (wild-type) I channels and is therefore unlikely to appreciably prolong QT interval in ECG during anaesthesia. However, little information is available concerning the inhibitory effect of propofol on I channel associated with its gene variants implicated in QT prolongation. The KCNE1 single nucleotide polymorphism leading to D85N is associated with drug-induced QT prolongation and therefore regarded as a clinically important genetic variant. This study examined whether KCNE1-D85N affects the sensitivity of I to inhibition by propofol.

Article	Year
Identification of Verapamil Binding Sites Within Human Kv1.5 Channel Using Mutagenesis and Docking Simulation. Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology\| PubMed ID: 30816676	2019
Open-channel blocking action of volatile anaesthetics desflurane and sevoflurane on human voltage-gated K 1.5 channel. British journal of pharmacology\| PubMed ID: 32436224	2020
Positive Inotropic Effects of ATP Released the Maxi-Anion Channel in Langendorff-Perfused Mouse Hearts Subjected to Ischemia-Reperfusion. Frontiers in cell and developmental biology\| PubMed ID: 33553176	2021
Elevation of propofol sensitivity of cardiac I channel by KCNE1 polymorphism D85N. British journal of pharmacology\| PubMed ID: 33763865	2021

Xinya Mi

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