Faculty Collaboration Database

Delayed-rectifier potassium channel activity in isolated membrane patches of guinea pig ventricular myocytes. Am J Physiol 1991 Apr;260(4 Pt 2):H1390-3

Date

04/01/1991

Pubmed ID

1849375

DOI

10.1152/ajpheart.1991.260.4.H1390

Scopus ID

2-s2.0-0025874842 (requires institutional sign-in at Scopus site)   36 Citations

Abstract

When the patch-clamp technique was used, a slowly activating, time-dependent outward current was identified in both cell-attached and excised membrane patches obtained from guinea pig ventricular myocytes. This macroscopic patch current was present in approximately 50% of patches studied and could be observed both in the presence and absence of unitary single channel activity (i.e., ATP-sensitive K+ channels). The time course of activation of the patch current resembled that of the whole cell delayed-rectifier K+ current (IK) recorded under similar ionic conditions, and the patch current and IK were activated over a similar membrane potential range. The time-dependent patch current could be eliminated when the Nernst potential for K+ equaled that of the pulse voltage. The patch current was inhibited by external addition of the tertiary ammonium compound LY 97241 (50 microM) and was augmented after internal application of the catalytic subunit of adenosine 3',5'-cyclic monophosphate-dependent protein kinase (500 nM). Deactivating tail currents with kinetics similar to those of IK could be recorded to cell-attached and excised patches. Unitary single channel events underlying the time-dependent patch current could not be resolved despite various attempts to increase single channel conductance. Thus our results suggest that a major component of delayed rectification in guinea pig ventricular cells is due to the activity of a high-density, extremely low conductance K+ channel.

Author List

Walsh KB, Arena JP, Kwok WM, Freeman L, Kass RS

Author

Wai-Meng Kwok PhD Professor in the Anesthesiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adenosine Triphosphate
Animals
Cell Membrane
Cyclic AMP
Electric Conductivity
Guinea Pigs
Heart
Kinetics
Potassium Channels
Protein Kinases
Quaternary Ammonium Compounds
Ventricular Function