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. 1985 Nov;368:379–392. doi: 10.1113/jphysiol.1985.sp015863

Biochemical separation of delayed rectifier currents in frog short skeletal muscle fibres.

C Lynch 3rd
PMCID: PMC1192602  PMID: 2416917

Abstract

Frog short (1-1.5 mm) skeletal muscle fibres in sucrose hypertonic Ringer at 5 degrees C were voltage clamped employing a two-electrode technique. Decreasing pH from 7.0 to 5.0 dramatically increased the rate of turn on of the slow delayed rectifier (GK,s) current, so that it became similar to the rapidly activated form. The accelerating effects of decreased pH upon slow current kinetics had a pKa of 5.8. Decreased pH also appeared to shift the voltage dependence of fast and GK,s gating to more positive potentials. In addition, a decrease in pH from 7.0 to 5.0 shifted the reversal potential of GK,s by over 11 mV in the positive direction. GK,s was selectively and irreversibly abolished by applying 1 mM-diethylpyrocarbonate (DEP), a histidine reagent. This effect occurred even after GK,s had been accelerated by low pH. DEP had no effect upon fast delayed rectifier current except for a small positive shift in voltage dependence. Application of 1 or 2 mM-N-ethylmaleimide, a sulphydryl reagent, depressed the fast delayed rectifier while sparing the GK,s currents. However, the muscle fibres also developed markedly increased leakage currents.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Adrian R. H., Chandler W. K., Hodgkin A. L. Slow changes in potassium permeability in skeletal muscle. J Physiol. 1970 Jul;208(3):645–668. doi: 10.1113/jphysiol.1970.sp009140. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Adrian R. H., Chandler W. K., Hodgkin A. L. Voltage clamp experiments in striated muscle fibres. J Physiol. 1970 Jul;208(3):607–644. doi: 10.1113/jphysiol.1970.sp009139. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. FRANKENHAEUSER B., HODGKIN A. L. The action of calcium on the electrical properties of squid axons. J Physiol. 1957 Jul 11;137(2):218–244. doi: 10.1113/jphysiol.1957.sp005808. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Fedorcsák I., Ehrenberg L. Effects of diethyl pyrocarbonate and methyl methanesulfonate on nucleic acids and nucleases. Acta Chem Scand. 1966;20(1):107–112. doi: 10.3891/acta.chem.scand.20-0107. [DOI] [PubMed] [Google Scholar]
  5. Hille B. Potassium channels in myelinated nerve. Selective permeability to small cations. J Gen Physiol. 1973 Jun;61(6):669–686. doi: 10.1085/jgp.61.6.669. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Hutter O. F., Warner A. E. The effect of pH on the 36-Cl efflux from frog skeletal muscle. J Physiol. 1967 Apr;189(3):427–443. doi: 10.1113/jphysiol.1967.sp008177. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Hutter O. F., Warner A. E. The pH sensitivity of the chloride conductance of frog skeletal muscle. J Physiol. 1967 Apr;189(3):403–425. doi: 10.1113/jphysiol.1967.sp008176. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Keana J. F., Stämpfli R. Effect of several "specific" chemical reagents on the Na+, K+ and leakage currents in voltage-clamped single nodes of Ranvier. Biochim Biophys Acta. 1974 Nov 27;373(1):18–33. doi: 10.1016/0005-2736(74)90101-1. [DOI] [PubMed] [Google Scholar]
  9. Lynch C., 3rd Ionic conductances in frog short skeletal muscle fibres with slow delayed rectifier currents. J Physiol. 1985 Nov;368:359–378. doi: 10.1113/jphysiol.1985.sp015862. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Sanchez J. A., Stefani E. Inward calcium current in twitch muscle fibres of the frog. J Physiol. 1978 Oct;283:197–209. doi: 10.1113/jphysiol.1978.sp012496. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Shrager P. Ionic conductance changes in voltage clamped crayfish axons at low pH. J Gen Physiol. 1974 Dec;64(6):666–690. doi: 10.1085/jgp.64.6.666. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Shrager P. Slow sodium inactivation in nerve after exposure to sulhydryl blocking reagents. J Gen Physiol. 1977 Feb;69(2):183–202. doi: 10.1085/jgp.69.2.183. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Spalding B. C. Properties of toxin-resistant sodium channels produced by chemical modification in frog skeletal muscle. J Physiol. 1980 Aug;305:485–500. doi: 10.1113/jphysiol.1980.sp013377. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Stanfield P. R. The differential effects of tetraethylammonium and zinc ions on the resting conductance of frog skeletal muscle. J Physiol. 1970 Jul;209(1):231–256. doi: 10.1113/jphysiol.1970.sp009164. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Stanfield P. R. The effect of the tetraethylammonium ion on the delayed currents of frog skeletal muscle. J Physiol. 1970 Jul;209(1):209–229. doi: 10.1113/jphysiol.1970.sp009163. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Woodhull A. M. Ionic blockage of sodium channels in nerve. J Gen Physiol. 1973 Jun;61(6):687–708. doi: 10.1085/jgp.61.6.687. [DOI] [PMC free article] [PubMed] [Google Scholar]

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