Related Experiment Video
Updated: Sep 29, 2026

Contractions of Human-iPSC-derived Cardiomyocyte Syncytia Measured with a Ca-sensitive Fluorescent Dye in Temperature-controlled 384-well Plates
Published on: October 18, 2018
Sodium channel blocking and antiarrhythmic actions of the novel arylpiperazine rsd992
Eric S Hayes1, Michael K Pugsley, Alan L Goldin
1Department of Pharmacology and Therapeutics, The University of British Columbia, Room 413, 2176 Health Sciences Mall, Vancouver, Canada V8V 3L2. ehayes@bart.rprc.washington.edu
Abstract:
Bolus doses (4-128 micromolkg(-1)) and infusions (2-32 micromolkg(-1)min(-1)) of the novel arylpiperazine drug RSD992 produced bradycardia in rats and guinea pigs but had minimal effect on ECG variables. RSD992 (2-32 micromolkg(-1)min(-1)) increased threshold current (I(T)) for induction of extra-systoles and induction of sustained ventricular fibrillation (VF(T)) and also increased the effective refractory period (ERP) and decreased the maximum following frequency (MFF) in rat and guinea pig hearts. RSD992 (32-512 microM) significantly increased PR and QRS intervals in isolated rat hearts subjected to conditions that mimic ischaemia (pH 6.4, K(+) 11mM) but not in isolated hearts under normal perfusion conditions (pH 7.4, K(+) 3mM). RSD992 (0.1-3.0mM) reduced peak sodium current in rat cardiac (rNa(v)1.5) sodium channels more potently than neuronal (rNa(v)1.2a) sodium channels expressed in Xenopus oocytes. The voltage-dependence of sodium channel activation was unaffected whereas inactivation was shifted in a hyperpolarized direction thus suggesting RSD992 may preferentially interact with the inactive state of the sodium channel, a state usually associated with myocardial cell depolarization in ischaemic myocardium. RSD992 (2-24 micromolkg(-1)min(-1)) decreased the incidence of ventricular arrhythmias and mortality in rats subject to coronary artery ligation. RSD992 exhibits frequency- and ischaemia-selective actions on myocardial sodium currents and antiarrhythmic actions in ischaemic rat myocardium.
More Related Videos
Related Concept Videos
Antiarrhythmic Drugs: Class I Agents as Sodium Channel Blockers
Class 1A Antiarrhythmic Drugs: These drugs work by moderately blocking sodium channels,...
Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers
Antiarrhythmic Drugs: Class IV Agents as Calcium Channel Blockers
Verapamil, a calcium channel blocker, inhibits calcium movement across myocardial cell membranes and vascular smooth muscle. This results in the dilation of coronary and...
Antianginal Drugs: Calcium Channel Blockers and Ranolazine
CCBs, a diverse class that includes dihydropyridines (nifedipine) and diphenylalkylamines (verapamil and diltiazem), exert their effect by blocking calcium channels in cardiac and smooth muscle cells. This...
Antiarrhythmic Drugs: Class II Agents as β-Adrenergic Blockers
Antiepileptic Drugs: Sodium Channel Blockers
Sodium channel blockers modulate ion channels, particularly voltage-gated sodium channels. They block only sodium ion movement.
Among the most commonly prescribed antiepileptic drugs are...

