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. 1981 Feb;311:307–324. doi: 10.1113/jphysiol.1981.sp013586

Non-linear summation of end-plate potentials in the frog and mouse.

E M McLachlan, A R Martin
PMCID: PMC1275411  PMID: 6267255

Abstract

1. End-plate potentials (e.p.p.s) and end-plate currents (e.p.c.s) were recorded intracellularly from muscle fibres of frog and mouse at various levels of curarization to determine the relation between the potential change and the underlying synaptic conductance change over a wide range of e.p.p. amplitudes. 2. In frog muscle fibres the e.p.p.-e.p.c. relation was linear for e.p.p. amplitudes up to about 10 mV, beyond which the rate of increase of e.p.p. amplitude became progressively smaller as the e.p.c. amplitude increased. The equation proposed by Martin (1955) to correct for this non-linearity consistently over-corrected the e.p.p. amplitudes. 3. When synaptic potentials and currents of long duration were produced by ionophoresis of ACh onto the end-plate, the voltage-current relation showed greater non-linearity than with nerve-evoked responses, and correction of the synaptic potential amplitudes resulted in a linear relation. 4. The relation between e.p.p. and e.p.c. amplitudes in mouse muscle showed a greater non-linearity than in frog muscle and over-correction by the equation was correspondingly smaller. Theoretical voltage-current relations were calculated for various membrane models and compared with the relations observed experimentally. The results from mouse muscle agreed with those expected for a point synaptic contact on an infinite cable; those from from muscle were consistent with simple resistive-capacitative model with no cable extending from the synaptic region. 6. The applicability to the experimental results of several correction factors for non-linear summation is discussed.

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Selected References

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

  1. Adams W. B. Upper and lower bounds on the non-linearity of summation of end-plate potentials. J Theor Biol. 1976 Nov;63(1):217–224. doi: 10.1016/0022-5193(76)90093-x. [DOI] [PubMed] [Google Scholar]
  2. Bennett M. R., Florin T., Pettigrew A. G. The effect of calcium ions on the binomial statistic parameters that control acetylcholine release at preganglionic nerve terminals. J Physiol. 1976 Jun;257(3):597–620. doi: 10.1113/jphysiol.1976.sp011387. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Colquhoun D., Dreyer F., Sheridan R. E. The actions of tubocurarine at the frog neuromuscular junction. J Physiol. 1979 Aug;293:247–284. doi: 10.1113/jphysiol.1979.sp012888. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. DEL CASTILLO J., KATZ B. Quantal components of the end-plate potential. J Physiol. 1954 Jun 28;124(3):560–573. doi: 10.1113/jphysiol.1954.sp005129. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. DEL CASTILLO J., KATZ B. The membrane change produced by the neuromuscular transmitter. J Physiol. 1954 Sep 28;125(3):546–565. doi: 10.1113/jphysiol.1954.sp005180. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Dionne V. E., Stevens C. F. Voltage dependence of agonist effectiveness at the frog neuromuscular junction: resolution of a paradox. J Physiol. 1975 Oct;251(2):245–270. doi: 10.1113/jphysiol.1975.sp011090. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Edwards F. R., Hirst G. D., Silinsky E. M. Interaction between inhibitory and excitatory synaptic potentials at a peripheral neurone. J Physiol. 1976 Aug;259(3):647–663. doi: 10.1113/jphysiol.1976.sp011487. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. FALK G., FATT P. LINEAR ELECTRICAL PROPERTIES OF STRIATED MUSCLE FIBRES OBSERVED WITH INTRACELLULAR ELECTRODES. Proc R Soc Lond B Biol Sci. 1964 Apr 14;160:69–123. doi: 10.1098/rspb.1964.0030. [DOI] [PubMed] [Google Scholar]
  9. FATT P., KATZ B. An analysis of the end-plate potential recorded with an intracellular electrode. J Physiol. 1951 Nov 28;115(3):320–370. doi: 10.1113/jphysiol.1951.sp004675. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. KARNOVSKY M. J., ROOTS L. A "DIRECT-COLORING" THIOCHOLINE METHOD FOR CHOLINESTERASES. J Histochem Cytochem. 1964 Mar;12:219–221. doi: 10.1177/12.3.219. [DOI] [PubMed] [Google Scholar]
  11. Katz B., Miledi R. The binding of acetylcholine to receptors and its removal from the synaptic cleft. J Physiol. 1973 Jun;231(3):549–574. doi: 10.1113/jphysiol.1973.sp010248. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Linder T. M., Quastel D. M. A voltage-clamp study of the permeability change induced by quanta of transmitter at the mouse end-plate. J Physiol. 1978 Aug;281:535–558. doi: 10.1113/jphysiol.1978.sp012438. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. MARTIN A. R. A further study of the statistical composition on the end-plate potential. J Physiol. 1955 Oct 28;130(1):114–122. doi: 10.1113/jphysiol.1955.sp005397. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Magleby K. L., Stevens C. F. The effect of voltage on the time course of end-plate currents. J Physiol. 1972 May;223(1):151–171. doi: 10.1113/jphysiol.1972.sp009839. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Magleby K. L., Terrar D. A. Factors affecting the time course of decay of end-plate currents: a possible cooperative action of acetylcholine on receptors at the frog neuromuscular junction. J Physiol. 1975 Jan;244(2):467–495. doi: 10.1113/jphysiol.1975.sp010808. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Mallart A., Dreyer F., Peper K. Current-voltage relation and reversal potential at junctional and extrajunctional ACh-receptors of the frog neuromuscular junction. Pflugers Arch. 1976 Mar 11;362(1):43–47. doi: 10.1007/BF00588679. [DOI] [PubMed] [Google Scholar]
  17. Martin A. R. The effect of membrane capacitance on non-linear summation of synaptic potentials. J Theor Biol. 1976 Jun;59(1):179–187. doi: 10.1016/s0022-5193(76)80031-8. [DOI] [PubMed] [Google Scholar]
  18. Stevens C. F. A comment on Martin's relation. Biophys J. 1976 Aug;16(8):891–895. doi: 10.1016/S0006-3495(76)85739-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. TAKEUCHI A., TAKEUCHI N. Active phase of frog's end-plate potential. J Neurophysiol. 1959 Jul;22(4):395–411. doi: 10.1152/jn.1959.22.4.395. [DOI] [PubMed] [Google Scholar]
  20. TAKEUCHI A., TAKEUCHI N. Further analysis of relationship between end-plate potential and end-plate current. J Neurophysiol. 1960 Jul;23:397–402. doi: 10.1152/jn.1960.23.4.397. [DOI] [PubMed] [Google Scholar]

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