Journal of Comparative Physiology A

, Volume 155, Issue 5, pp 649–659 | Cite as

Miniature end plate currents from teleost extraocular muscle

  • John A. Macdonald
  • Ron J. Balnave


Miniature end plate currents (MEPCs) were recorded with focal extracellular electrodes from white extraocular muscle fibres of a marine teleost fish,Trachurus novaezelandiae, over a temperature range of 5 °C to 27 °C.
  1. 1.

    Teleost MEPCs rose rapidly, attaining a maximum amplitude of 250–500 μV, withTGof about 150 μs at 15 °C (Figs. 1, 2).

  2. 2.

    Decay of MEPCs was exponential, with τ=1 ms at 15 °C (Figs. 3, 5). τ was an exponential function of absolute temperature, withEa=70 kJ (Fig. 5).

  3. 3.

    τ ofTrachurus MEPCs was consistently smaller than values of τ reported for other vertebrate end plates (Table 1). Low τ is correlated with a high degree of lipid unsaturation in teleosts, and may be caused by increased membrane fluidity.

  4. 4.

    Frequency distributions ofTG(Fig. 2) and τ (Fig. 4) at a single recording site appear to represent one population of events, skewed toward smaller values.

  5. 5.

    Teleost MEPCs also appeared to be normal cholinergic MEPCs in that their rates of decay were decreased by neostigmine, ethanol and membrane hyperpolarization.



Lipid Exponential Function Maximum Amplitude Membrane Fluidity Neostigmine 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.





Arrhenius activation energy


membrane potential


miniature end plate current


growth time of MEPC (time elapsed between 20% and 80% of peak voltage)


time constant of exponential decay of MEPC


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Copyright information

© Springer-Verlag 1984

Authors and Affiliations

  • John A. Macdonald
    • 1
    • 2
  • Ron J. Balnave
    • 1
    • 2
  1. 1.Department of ZoologyUniversity of AucklandAucklandNew Zealand
  2. 2.Department of Biological SciencesCumberland College of Health SciencesLidcombeAustralia

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