Pflügers Archiv

, Volume 390, Issue 2, pp 156–160 | Cite as

Neuromuscular transmission in experimental autoimmune myasthenia gravis (EAMG)

Quantitative ionophoresis and current fluctuation analysis at normal and myasthenic rat end-plates
  • Reinhard Hohlfeld
  • Raimund Sterz
  • Inge Kalies
  • Klaus Peper
  • Hartmut Wekerle
Excitable Tissues and Central Nervous Physiology

Abstract

Chronic experimental autoimmune myasthenia gravis (EAMG) was induced in rats by immunization with acetylcholine receptor (AChR) purified from the electroplax of Torpedo californica. 35–40 days after immunization, serum anti-AChR antibody titers were about 40 nM. At this stage, electrophysiology was performed on isolated M. omohyoideus muscle-preparations from myasthenic and from normal (control) rats.

For the study of the equilibrium interaction between acetylcholine (ACh) and AChR, dose-response curves were obtained by quantitative ionophoretic application of ACh to voltage-clamped end-plates. Analysis of dose-response curves yielded the following parameters: maximum end-plate conductance per unit surfacegmax (EAMG)=10.3±1.1 nS/μm2,gmax (normal)=20.2±1.8 nS/μm2; apparent dissociation constant K (EAMG)=96±5 μM, K (normal)=58±6 μM; Hill-coefficient nH (EAMG)=2.3±0.1, nH (normal)=2.3±0.1. Single channel properties were derived from an analysis of ACh-induced end-plate current noise: the mean single channel conductance was γ(EAMG)=29.1±2.2 pS, γ(normal)=27.6±1.8 pS and the mean channel life-time τ(EAMG)=1.39±0.09 ms, τ(normal)=1.32±0.08 ms (T=22°C).

The electrophysiological data are interpreted as follows: (1) At myasthenic end-plates there is a 50–60% reduction of functioning AChR (decrease ofgmax). A total number of about 2×106 (1×106) channels per end-plate was calculated for control (myasthenic) rats. (2) The affinity of AChR for ACh is reduced and/or there is an impediment of the conformational change from the closed- to the open-channel configuration (increase of K). (3) Single channel properties are essentially unaffected.

Key words

Myasthenia gravis Experimental autoimmune myasthenia gravis Acetylcholine receptor Quantitative ionophoresis Neuromuscular junction 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Albuquerque EX, Rash JE, Mayer RF, Satterfield JR (1976) An electrophysiological and morphological study of the neuromuscular junction in patients with myasthenia gravis. Exp Neurol 51:536–563Google Scholar
  2. Almon RR, Andrew CG, Appel SH (1974) Serum globulin in myasthenia gravis: Inhibition of α-bungarotoxin binding to acetylcholine receptors. Science 186:55–57Google Scholar
  3. Anderson CR, Stevens CF (1973) Voltage clamp analysis of acetylcholine produced end-plate current fluctuations at frog neuromuscular junction. J Physiol 235:655–691Google Scholar
  4. Appel SH, Anwyl R, McAdams MW, Elias S (1977) Accelerated degradation of acetylcholine receptor from cultured rat myotubes with myasthenia gravis sera and globulins. Proc Natl Acad Sci 74:2130–2134Google Scholar
  5. Bevan S, Kullberg RW, Rice J (1978) Acetylcholine-induced conductance fluctuation in cultured human myotubes. Nature 273:469–470Google Scholar
  6. Cull-Candy SG, Miledi R, Trautmann A (1979) End-plate currents and acetylcholine noise at normal and myasthenic human end-plates. J Physiol 287:247–265Google Scholar
  7. Dionne VE, Steinbach JH, Stevens CF (1978) An analysis of the dose-response relationship at voltage-clamped frog neuromuscular junctions. J Physiol (Lond) 281:421–444Google Scholar
  8. Drachman DB (1978) Myasthenia Gravis. N Engl J Med 298:136–142, 186–193Google Scholar
  9. Dreyer F, Müller KD, Peper K, Sterz R (1976a) The M. omohyoideus of the mouse as a convenient mammalian muscle preparation. A study of junctional and extrajunctional acetylcholine receptors by noise analysis and cooperativity. Pflügers Arch 367:115–122Google Scholar
  10. Dreyer F, Walther C, Peper K (1976b) Junctional and extrajunctional acetylcholine receptors in normal and denervated frog muscle fibres. Pflügers Arch 366:1–9Google Scholar
  11. Dreyer F, Peper K, Sterz R (1978) Determination of dose-response curves by quantitative ionophoresis at the frog neuromuscular junction. J Physiol 281:395–419Google Scholar
  12. Engel AG, Lindstrom JM, Lambert EH, Lennon VA (1977) Ultrastructural localization of the acetylcholine receptor in myasthenia gravis and its experimental autoimmune model. Neurology 27:307–315Google Scholar
  13. Fambrough DM (1979) Control of acetylcholine receptors in skeletal muscle. Physiol Rev 59:165–227Google Scholar
  14. Fambrough DM, Drachman DB, Satyamurti S (1973) Neuromuscular junction in myasthenia gravis: Decreased acetylcholine receptors. Science 182:293–295Google Scholar
  15. Green DPL, Miledi R, Vincent A (1975) Neuromuscular transmission after immunization against acetylcholine receptors. Proc R Soc Lond B 189:57–68Google Scholar
  16. Heidmann T, Changeux JP (1978) Structure and functional properties of the acetylcholine receptor protein in its purified and membranebound states. Ann Rev Biochem 47:317–357Google Scholar
  17. Heinemann S, Bevan S, Kullberg R, Lindstrom SJ, Rice J (1977) Modulation of acetylcholine receptor by anti-receptor antibody. Proc Natl Acad Sci 74:3090–3094Google Scholar
  18. Hohlfeld R, Kalies I, Heinz F, Kalden JR, Wekerle H (in press) Autoimmune rat T-lymphocytes monospecific for acetylcholine receptors: Purification and fine specificity. J ImmunolGoogle Scholar
  19. Kalies I, Kalden JR, Heinz F, Janzen RWCh, Lachenmayer L (1979) Nachweis von Acetylcholin-Rezeptor-Antikörpern im Serum von Myasthenia-Gravis-Patienten unter Verwendung affinitätschromatographisch gereinigter humaner Acetylcholin-Rezeptor-Präparationen. Klin Wochenschr 57:875–881Google Scholar
  20. Kao I, Drachman DB (1977) Myasthenic immunoglobulin accelerates acetylcholine receptor degradation. Science 196:527–529Google Scholar
  21. Katz B, Miledi R (1972) The statistical nature of the acetylcholine potential and its molecular components. J Physiol 224:665–699Google Scholar
  22. Lambert EH, Lindstrom JM, Lennon VA (1976) End-plate potentials in experimental autoimmune myasthenia gravis in rats. Ann NY Acad Sci 274:300–318Google Scholar
  23. Lennon VA, Lindstrom JM, Seybold ME (1975) Experimental autoimmune myasthenia: A model of myasthenia gravis in rats and guinea pigs. J Exp Med 141:1365–1375Google Scholar
  24. Lindstrom J (1979) Autoimmune response to acetylcholine receptors in myasthenia gravis and its animal model. Adv Immunol 27:1–50Google Scholar
  25. Lindstrom J, Einarson B (1979) Antigenic modulation and receptor loss in EAMG. Muscle Nerve 2:173–179Google Scholar
  26. Lindstrom J, Lambert EH (1978) Content of acetylcholine receptor and antibodies bound to receptor in myasthenia gravis, experimental autoimmune myasthenia gravis and in Eaton-Lambert syndrome. Neurology 28:130–138Google Scholar
  27. Lindstrom JM, Einarson B, Lennon VA, Syybold ME (1976a) Pathological mechanisms in EAMG. I. Immunogenicity of syngeneic muscle acetylcholine receptor and quantitative extraction of receptor and antibody-receptor and quantitative extraction of receptor and antibody-receptor complexes from muscles of rats with experimental autoimmune myasthenia gravis. J Exp Med 144:726–738Google Scholar
  28. Lindstrom J, Lennon VA, Seybold M, Whittingham S (1976b) Experimental autoimmune myasthenia gravis and myasthenia gravis: Biochemical and immunochemical aspects. Ann NY Acad Sci 274:254–274Google Scholar
  29. Lindstrom JM, Seybold ME, Lennon VA, Whittingham S, Duane DD (1976c) Antibody to acetylcholine receptor in myasthenia gravis: Prevalence, clinical correlates, and diagnostic value. Neurology 26:1054–1059Google Scholar
  30. Patrick J, Lindstrom J (1973) Autoimmune response to acetylcholine receptor. Science 180:871–872Google Scholar

Copyright information

© Springer-Verlag 1981

Authors and Affiliations

  • Reinhard Hohlfeld
    • 1
  • Raimund Sterz
    • 2
  • Inge Kalies
    • 3
  • Klaus Peper
    • 2
  • Hartmut Wekerle
    • 1
  1. 1.Max-Planck-Institut für ImmunbiologieFreiburg
  2. 2.II. Physiologisches InstitutHomburg/Saar
  3. 3.Zentrum BiochemieHannoverFederal Republic of Germany

Personalised recommendations