Related Experiment Video
Updated: Aug 10, 2026

Isolation and Functional Characterization of Human Ventricular Cardiomyocytes from Fresh Surgical Samples
Published on: April 21, 2014
The inotropic agents DPI 201-106 and BDF 9148 differentially affect potassium currents of guinea-pig ventricular
Abstract:
The inotropic agents DPI 201-106 and BDF 9148 increase action potential duration (APD) of heart muscle. This effect can be explained by inhibition of inactivation of sodium current, which is affected by both agents to a similar extent (Ravens et al. 1991, Br J Pharmacol 104:1019-1023). However, as DPI 201-106 prolongs APD of guinea-pig ventricle to a larger extent than BDF 9148, other currents may also be involved. The aim of the present study was to measure the effects of DPI 201-106 and BDF 9148 on the inward rectifier IK1, and the two components of the delayed rectifier, IKs and IKr. The methyl-for-carbonitrile-substituted derivative BDF 8784 was included to study structure-activity relationships. Single-electrode whole-cell voltage-clamp technique was used to measure membrane currents of guinea-pig ventricular myocytes. Only DPI 201-106 reduced IK1 at potentials both negative and positive to the reversal potential. Three microM of DPI 201-106 reduced IKs, whereas 1 microM of BDF 9148 had no effect on this current. These concentrations were equieffective with respect to positive inotropic action (Ravens et al. 1991, Br J Pharmacol 104:1019-1023). BDF 9148 did however block IKs at higher concentrations, as did BDF 8784. It is concluded that block of outward current by DPI 201-106, but insignificant effects of BDF 9148, are responsible for the differential effects of these compounds on APD at equieffective concentrations with respect to inotropy.
More Related Videos
Related Concept Videos
G-Protein Gated Ion Channels
Sensory organs,...
Depolarizing Blockers: Mechanism of Action
Succinylcholine is the most commonly used depolarizing blocker. Chemically, it constitutes two molecules of acetylcholine joined together by an acetate methyl group. They act on the receptors in the same way as acetylcholine. Because succinylcholine...
Depolarizing Blockers: Pharmocokinetics
Antiarrhythmic Drugs: Class I Agents as Sodium Channel Blockers
Class 1A Antiarrhythmic Drugs: These drugs work by moderately blocking sodium channels,...
Heart Failure Drugs: Inotropic Agents

