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

Donald W. Hilgemann

doi:10.1007/BF00370601

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

Donald W. Hilgemann

Research output: Contribution to journal › Article › peer-review

47 Scopus citations

Abstract

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 <0.1 μM internal free, calcium. Maximum exchange current density is >20 μA/cm².

Original language	English (US)
Pages (from-to)	247-249
Number of pages	3
Journal	Pflügers Archiv European Journal of Physiology
Volume	415
Issue number	2
DOIs	https://doi.org/10.1007/BF00370601
State	Published - Nov 1 1989

Keywords

Patch clamp
cardiac myocytes
sodium current
sodium-calcium exchange current

ASJC Scopus subject areas

Physiology
Clinical Biochemistry
Physiology (medical)

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10.1007/BF00370601

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title = "Giant excised cardiac sarcolemmal membrane patches: sodium and sodium-calcium exchange currents",

abstract = "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 <0.1 μM internal free, calcium. Maximum exchange current density is >20 μA/cm2.",

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

Abstract

Keywords

ASJC Scopus subject areas

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