Pflügers Archiv

, Volume 415, Issue 2, pp 247–249

Giant excised cardiac sarcolemmal membrane patches: sodium and sodium-calcium exchange currents

  • Donald W. Hilgemann
Short Communication Heart, Circulation, Respiration and Blood; Environmental and Exercise Physiology

DOI: 10.1007/BF00370601

Cite this article as:
Hilgemann, D.W. Pflügers Arch (1989) 415: 247. doi:10.1007/BF00370601

Summary

A tightly-sealed cardiac sarcolemmal patch preparation of large diameter (10–16 μm with 5–25 GΩ seals) has been developed to study regulation of selected electrogenic mechanisms. Formation of a large readily accessible membrane surface area is achieved by incubating freshly isolated myocytes in a high KCl/zero calcium solution, which promotes separation of sarcolemma from myofilaments. The formation of large-diameter, high resistance seals is facilitated by depositing a neutral hydrocarbon film on electrode tips. Sodium currents in excised patches are stable for patch life-times of 15–40 min with peak current densities of 120 to 350 μA/cm2. Outward sodium-calcium exchange current is identified by its specific dependence on external calcium and internal sodium, inhibition by cobalt and dichlorobenzamil, and activation by <0.1μM internal free, calcium. Maximum exchange current density is >20 μA/cm2.

Key words

Patch clamp cardiac myocytes sodium current sodium-calcium exchange current 

Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • Donald W. Hilgemann
    • 1
  1. 1.Department of PhysiologyUniversity of Texas Southwestern Medical Center at DallasDallasUSA