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. 1980 Oct;307:43–57. doi: 10.1113/jphysiol.1980.sp013422

Comparison between the delayed outward current in slow and fast twitch skeletal muscle in the rat.

A Duval, C Léoty
PMCID: PMC1283032  PMID: 7205672

Abstract

1. A comparison of the delayed outward current of isolated fibres from rat soleus and iliacus muscle has been made using a double sucrose-gap voltage-clamp method. 2. The fast and slow components of the outward current were separated using time constants of the tail currents. The results indicate that in both iliacus and soleus fibres there is a shift in reversal potential which depends on the quantity of current that flows during depolarization. 3. The shift is larger in iliacus than in soleus; it is absent in glycerol-treated muscles. 4. The results obtained in normal and in detubulated fibres show that the shift is due to an accumulation process of potassium ions in the lumen of the T-tubules. 5. In detubulated soleus fibres the outward current is composed of a fast and a slow component, each with the same reversal potential; in detubulated iliacus the slow component is absent. 6. In both types of muscles TEA produces a dose-dependent block of the total outward current. 4-aminopyridine has different effects; it inhibits the total outward current in iliacus fibres and only the fast component in soleus fibres. 7. These results show that in soleus fibres a fast and a slow component participate in the potassium outward current, while only a fast component is present in iliacus muscle.

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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., Freygang W. H. The potassium and chloride conductance of frog muscle membrane. J Physiol. 1962 Aug;163(1):61–103. doi: 10.1113/jphysiol.1962.sp006959. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Almers W. Potassium conductance changes in skeletal muscle and the potassium concentration in the transverse tubules. J Physiol. 1972 Aug;225(1):33–56. doi: 10.1113/jphysiol.1972.sp009928. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Barry P. H., Adrian R. H. Slow conductance changes due to potassium depletion in the transverse tubules of frog muscle fibers during hyperpolarizing pulses. J Membr Biol. 1973;14(3):243–292. doi: 10.1007/BF01868081. [DOI] [PubMed] [Google Scholar]
  5. Duval A., Leoty C. Voltage-clamp experiments in mammalian slow twitch skeletal muscle [proceedings]. J Physiol. 1979 Apr;289:37P–37P. [PubMed] [Google Scholar]
  6. Duval A., Léoty C. Ionic currents in mammalian fast skeletal muscle. J Physiol. 1978 May;278:403–423. doi: 10.1113/jphysiol.1978.sp012312. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Duval A., Léoty C. Ionic currents in slow twitch skeletal muscle in the rat. J Physiol. 1980 Oct;307:23–41. doi: 10.1113/jphysiol.1980.sp013421. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Eisenberg B. R., Kuda A. M. Discrimination between fiber populations in mammalian skeletal muscle by using ultrastructural parameters. J Ultrastruct Res. 1976 Jan;54(1):76–88. doi: 10.1016/s0022-5320(76)80010-x. [DOI] [PubMed] [Google Scholar]
  9. FRANKENHAEUSER B., HODGKIN A. L. The after-effects of impulses in the giant nerve fibres of Loligo. J Physiol. 1956 Feb 28;131(2):341–376. doi: 10.1113/jphysiol.1956.sp005467. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Gillespie J. I., Hutter O. F. Proceedings: The actions of 4-aminopyridine on the delayed potassium current in skeletal muscle fibres. J Physiol. 1975 Nov;252(2):70P–71P. [PubMed] [Google Scholar]
  11. Gillespie J. I. Voltage-dependent blockage of the delayed potassium current in skeletal muscle by 4-aminopyridine [proceedings]. J Physiol. 1977 Dec;273(2):64P–65P. [PubMed] [Google Scholar]
  12. Kirsch G. E., Nichols R. A., Nakajima S. Delayed rectification in the transverse tubules: origin of the late after-potential in frog skeletal muscle. J Gen Physiol. 1977 Jul;70(1):1–21. doi: 10.1085/jgp.70.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Noble S. J. Potassium accumulation and depletion in frog atrial muscle. J Physiol. 1976 Jul;258(3):579–613. doi: 10.1113/jphysiol.1976.sp011436. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. 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]

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