Quinidine blocks adenosine 5'-triphosphate-sensitive potassium channels in heart.

Published

Journal Article

The ATP-sensitive potassium channel current (IK-ATP) was studied in excised inside-out patches from rat ventricular cells at 20-23 degrees C. The bath solution contained 140 mM KF, and the pipette solution contained 140 mM KCl and 1.2 mM MgCl2. ATP (0.5 mM) in the bath inhibited IK-ATP. In the absence of ATP, 10 microM quinidine decreased open probability 67 +/- 1% (n = 6) at -50 mV and 28 +/- 12% at -130 mV (n = 5) without affecting single channel conductance (48-52 pS). The block increased with 25 and 50 microM quinidine and could be reversed on washing quinidine for several minutes. Interburst (closed) intervals were increased by quinidine, whereas open and closed time distributions within bursts were not changed. We conclude that quinidine blocks IK-ATP in a "slow" and voltage-dependent manner in clinically relevant concentrations. Because of the postulated role for IK-ATP in cardiac ischemia, quinidine block of this channel may play a role in ischemic arrhythmias.

Full Text

Duke Authors

Cited Authors

  • Undrovinas, AI; Burnashev, N; Eroshenko, D; Fleidervish, I; Starmer, CF; Makielski, JC; Rosenshtraukh, LV

Published Date

  • November 1990

Published In

Volume / Issue

  • 259 / 5 Pt 2

Start / End Page

  • H1609 - H1612

PubMed ID

  • 2240258

Pubmed Central ID

  • 2240258

Electronic International Standard Serial Number (EISSN)

  • 2163-5773

International Standard Serial Number (ISSN)

  • 0002-9513

Digital Object Identifier (DOI)

  • 10.1152/ajpheart.1990.259.5.h1609

Language

  • eng