Slow calcium and potassium currents across frog muscle membrane: measurements with a vaseline‐gap technique.

W. Almers, P. T. Palade

Research output: Contribution to journalArticle

103 Scopus citations

Abstract

1. A vaseline‐gap voltage‐clamp technique was used to record slow Ca2+ and K+ currents from frog skeletal muscle fibres loaded with the Ca2+ chelator EGTA. 2. K+ currents were increased when Mg2+ replaced external Ca2+, and they were abolished when internal K+ was replaced by tetraethylammonium (TEA+). Ca2+ currents could be studied in isolation in fibres loaded with (TEA)2EGTA. 3. Under maintained depolarization, Ca2+ currents slowly increase (half‐time of 35 msec or more at 25 mV) and then decline to a steady value. Decline under repolarization is rapid (half‐time of 6‐7 msec) and complete. During an action potential, the Ca2+ influx through this system is probably less than the influx observed with tracers. 4. Ba2+, Sr2+, Ca2+, Mn2+ and Mg2+ can carry current across the membrane; Ni2+ and Co2+ cannot. Ca2+ currents are weakly blocked by external Mg2+.

Original languageEnglish (US)
Pages (from-to)159-176
Number of pages18
JournalThe Journal of Physiology
Volume312
Issue number1
DOIs
StatePublished - Mar 1 1981

ASJC Scopus subject areas

  • Physiology

Fingerprint Dive into the research topics of 'Slow calcium and potassium currents across frog muscle membrane: measurements with a vaseline‐gap technique.'. Together they form a unique fingerprint.

  • Cite this