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. 1988 Aug;402:595–603. doi: 10.1113/jphysiol.1988.sp017224

Estimating the timing of quantal releases during end-plate currents at the frog neuromuscular junction.

W Van der Kloot 1
PMCID: PMC1191911  PMID: 2466987

Abstract

1. Following motor nerve stimulation there is a period of greatly enhanced quantal release, called the early release period or ERP (Barrett & Stevens, 1972b). Until now, measurements of the probability of quantal releases at different points in the ERP have come from experiments in which quantal output was greatly reduced, so that the time of release of individual quanta could be detected or so that the latency to the release of the first quantum could be measured. 2. A method has been developed to estimate the timing of quantal release during the ERP that can be used at much higher levels of quantal output. The assumption is made that each quantal release generates an end-plate current (EPC) that rises instantaneously and then decays exponentially. The peak amplitude of the quantal currents and the time constant for their decay are measured from miniature end-plate currents (MEPCs). Then a number of EPCs are averaged, and the times of release of the individual quanta during the ERP estimated by a simple mathematical method for deconvolution derived by Cohen, Van der Kloot & Attwell (1981). 3. The deconvolution method was tested using data from preparations in high-Mg2+ low-Ca2+ solution. One test was to reconstitute the averaged EPCs from the estimated times of quantal release and the quantal currents, by using Fourier convolution. The reconstructions fit well to the originals. 4. Reconstructions were also made from averaged MEPCs which do not rise instantaneously and the estimated times of quantal release.(ABSTRACT TRUNCATED AT 250 WORDS)

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Selected References

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

  1. Baldo G. J., Cohen I. S., Van der Kloot W. Estimating the time course of evoked quantal release at the frog neuromuscular junction using end-plate current latencies. J Physiol. 1986 May;374:503–513. doi: 10.1113/jphysiol.1986.sp016094. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Barrett E. F., Stevens C. F. Quantal independence and uniformity of presynaptic release kinetics at the frog neuromuscular junction. J Physiol. 1972 Dec;227(3):665–689. doi: 10.1113/jphysiol.1972.sp010053. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Barrett E. F., Stevens C. F. The kinetics of transmitter release at the frog neuromuscular junction. J Physiol. 1972 Dec;227(3):691–708. doi: 10.1113/jphysiol.1972.sp010054. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Cohen I., van der Kloot W., Attwell D. The timing of channel opening during miniature end-plate currents. Brain Res. 1981 Oct 26;223(1):185–189. doi: 10.1016/0006-8993(81)90821-0. [DOI] [PubMed] [Google Scholar]
  5. Datyner N. B., Gage P. W. Phasic secretion of acetylcholine at a mammalian neuromuscular junction. J Physiol. 1980 Jun;303:299–314. doi: 10.1113/jphysiol.1980.sp013286. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Dempster J. The use of the driving function in the analysis of endplate current kinetics. J Neurosci Methods. 1986 Nov;18(3):277–285. doi: 10.1016/0165-0270(86)90014-2. [DOI] [PubMed] [Google Scholar]
  7. Gage P. W., Armstrong C. M. Miniature end-plate currents in voltage-clamped muscle fibre. Nature. 1968 Apr 27;218(5139):363–365. doi: 10.1038/218363b0. [DOI] [PubMed] [Google Scholar]
  8. Hartzell H. C., Kuffler S. W., Yoshikami D. Post-synaptic potentiation: interaction between quanta of acetylcholine at the skeletal neuromuscular synapse. J Physiol. 1975 Oct;251(2):427–463. doi: 10.1113/jphysiol.1975.sp011102. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. KATZ B., MILEDI R. THE MEASUREMENT OF SYNAPTIC DELAY, AND THE TIME COURSE OF ACETYLCHOLINE RELEASE AT THE NEUROMUSCULAR JUNCTION. Proc R Soc Lond B Biol Sci. 1965 Feb 16;161:483–495. doi: 10.1098/rspb.1965.0016. [DOI] [PubMed] [Google Scholar]
  10. 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]
  11. Land B. R., Salpeter E. E., Salpeter M. M. Acetylcholine receptor site density affects the rising phase of miniature endplate currents. Proc Natl Acad Sci U S A. 1980 Jun;77(6):3736–3740. doi: 10.1073/pnas.77.6.3736. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Lederer W. J., Spindler A. J., Eisner D. A. Thick slurry bevelling: a new technique for bevelling extremely fine microelectrodes and micropipettes. Pflugers Arch. 1979 Sep;381(3):287–288. doi: 10.1007/BF00583261. [DOI] [PubMed] [Google Scholar]
  13. Marnay A., Nachmansohn D. Choline esterase in voluntary muscle. J Physiol. 1938 Feb 16;92(1):37–47. doi: 10.1113/jphysiol.1938.sp003582. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Simonneau M., Tauc L., Baux G. Quantal release of acetylcholine examined by current fluctuation analysis at an identified neuro-neuronal synapse of Aplysia. Proc Natl Acad Sci U S A. 1980 Mar;77(3):1661–1665. doi: 10.1073/pnas.77.3.1661. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Van der Kloot W., Cohen I. S. Temperature effects on spontaneous and evoked quantal size at the frog neuromuscular junction. J Neurosci. 1984 Sep;4(9):2200–2203. doi: 10.1523/JNEUROSCI.04-09-02200.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Van der Kloot W. The kinetics of quantal releases during end-plate currents at the frog neuromuscular junction. J Physiol. 1988 Aug;402:605–626. doi: 10.1113/jphysiol.1988.sp017225. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Wathey J. C., Nass M. M., Lester H. A. Numerical reconstruction of the quantal event at nicotinic synapses. Biophys J. 1979 Jul;27(1):145–164. doi: 10.1016/S0006-3495(79)85208-X. [DOI] [PMC free article] [PubMed] [Google Scholar]

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