Pflügers Archiv

, Volume 408, Issue 2, pp 146–152 | Cite as

Effects of external cations and calcium-channel blockers on depolarization-contraction coupling in denervated rat twitch skeletal muscles

  • C. Léoty
  • J. Noireaud
Article

Abstract

In the double mannitol gap arrangement the contraction was estimated in single fibres isolated from rat extensor digitorum longus (e.d.l.) muscles that had been denervated for 2–48 days. Denervation induced large changes in the characteristics of the action potential and of the twitch. Up to 15–20 days after denervation the contraction-depolarization curve was sigmoidal and the maximum amplitude of the contraction was not modified by variation of [Ca]o or [Na]o. After 15–20 days of denervation a bell-shaped curve described the relation between contraction and potential. The maximum amplitude was dependent upon the [Ca]o. In Ca-free solution no contractile response was obtained. In Na-free, Ca-containing solution the relationship between contraction and potential was not modified by the addition of divalent cations Co2+, Cd2+, Mg2+, Mg2+, Ni2+, or Ba2+. The contraction, which appeared in Ca-free solution, was restored by adding Sr2+. D600, verapamil and bepridil failed to change the amplitude of the contraction while a marked reduction was found with dihydropyridines. The reduction was overcome by increasing [Ca]o. The present results suggest that the slow calcium current is not involved in the generation of the contractile responses developed by denervated muscles in Na-free (TEA) solution.

Key words

Skeletal muscle Denervation Contraction Calcium channel inhibitors 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Beam KG, Knudson CM, Powell JA (1986) A lethal mutation in mice eliminates the slow calcium current in skeletal muscle cells. Nature 320:168–170Google Scholar
  2. Bolaños P, Caputo C, Velaz L (1986) Effects of calcium, barium and lanthanum on depolarization-contraction coupling in skeletal muscle fibres ofRana pipiens. J Physiol 370:39–60Google Scholar
  3. Caillé J, Ildefonse M, Rougier O (1985) Excitation-contraction coupling in skeletal muscle. Prog Biophys Mol Biol 46:185–239Google Scholar
  4. Cota G, Stefani E (1986) A fast-activated inward calcium current in twitch muscle fibres of the frog (Rana montezume). J Physiol 370:151–164Google Scholar
  5. Donaldson PL, Beam KG (1983) Calcium current in a fast-twitch skeletal muscle of the rat. J Gen Physiol 82:449–468Google Scholar
  6. Duval A, Léoty C (1978) Ionic currents in mammalian fast skeletal muscle. J Physiol 278:403–423Google Scholar
  7. Duval A, Léoty C (1985) Changes in the ionic currents sensitivity to inhibitors in twitch rat skeletal muscles following denervation. Pflügers Arch 403:407–414Google Scholar
  8. Edwards C, Lorković H, Weber A (1966) The effect of the replacement of calcium by strontium on excitation-contraction coupling in frog skeletal muscle. J Physiol 186:295–306Google Scholar
  9. Finol HJ, Lewis DM, Owens R (1981) The effect of denervation on contractile properties of rat skeletal muscle. J Physiol 319:81–92Google Scholar
  10. Gallant EM, Goettl VM (1985) Effects of calcium antagonists on mechanical responses of mammalian skeletal muscles. Eur J Pharmacol 117:259–265Google Scholar
  11. Hoar PE, Kerrick WGL (1979) Rabbit diaphragm: two types of fibres determined by calcium/strontium activation and protein content. J Physiol 295:345–352Google Scholar
  12. Ildefonse M, Jacquemond V, Rougier O, Renaud JF, Fosset M, Lazdunski M (1985) Excitation contraction coupling in skeletal muscle: evidence for a role of slow Ca2+ channels using Ca2+ channels activators and inhibitors in the dihydropyridine series. Biochem Biophys Res Com 129:904–909Google Scholar
  13. Kotsias BA, Muchnik S, Paz CAO (1986) Co2+, low Ca2+, and verapamil reduce mechanical activity in rat skeletal muscles. Am J Physiol 250:C40-C46Google Scholar
  14. Léoty C (1984) Sodium withdrawal contractures in rat slow twitch skeletal muscle. Gen Physiol Biophys 5:413–429Google Scholar
  15. Léoty C, Alix J (1976) Some technical improvements for the voltage clamp with the double sucrose gap. Pflügers Arch 365:95–97Google Scholar
  16. Léoty C, Léauté M (1982) Membrane potential and contractures in segments cut from rat fast and slow twitch muscles. Pflügers Arch 395:42–48Google Scholar
  17. Lee KS, Tsien RW (1982) Reversal of current through calcium channels in dialysed single heart cells. Nature 297:498–501Google Scholar
  18. Lewis DM (1972) The effect of denervation on the mechanical and electrical properties of fast and slow mammalian twitch muscle. J Physiol 222:51–75Google Scholar
  19. Lüttgau HC (1963) The action of calcium ions on potassium contractures of single muscle fibres. J Physiol 168:679–697Google Scholar
  20. McCleskey EW (1985) Calcium channels and intracellular calcium release are pharmacologically different in frog skeletal muscle. J Physiol 361:231–249Google Scholar
  21. Miledi R, Parker I, Zhu PH (1984) Extracellular ions and excitationcontraction coupling in frog twitch muscle fibres. J Physiol 351:687–710Google Scholar
  22. Paponne PA (1980) Voltage-clamp experiments in normal and denervated mammalian skeletal muscle fibres. J Physiol 306:377–410Google Scholar
  23. Pellegrino C, Franzini C (1963) An electron microscope study of denervation atrophy in red and white skeletal muscle fibers. J Cell Biol 17:327–349Google Scholar
  24. Schwartz LM, McCleskey EW, Almers W (1985) Dihydropyridine receptors in muscle are voltage-dependent but most are not functional calcium channels. Nature 314:747–751Google Scholar
  25. Walsh KB, Bryant SH, Schwartz A (1986) Effect of calcium antagonist drugs on calcium currents in mammalian skeletal muscle fibers. J Pharmacol Exp Therap 236:403–407Google Scholar

Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • C. Léoty
    • 1
  • J. Noireaud
    • 1
  1. 1.Laboratory of General Physiology, National Veterinary SchoolUniversity of NantesNantes CedexFrance

Personalised recommendations