Literature DB >> 6603514

The calcium dependence of spontaneous and evoked quantal release at the frog neuromuscular junction.

S B Barton, I S Cohen, W van der Kloot.   

Abstract

1. The quantal output from stimulated nerve terminals in the frog sciatic nerve-sartorius muscle preparation in low-Ca(2+) Ringer solution was measured by the coefficient of variation and the failures methods. Adding sucrose to the Ringer to increase the tonicity or adding ethanol increased miniature end-plate potential (m.e.p.p.) frequency and also the end-plate potential (e.p.p.) amplitude. Earlier reports suggested that increases in tonicity did not increase evoked quantal release.2. Concanavalin A has been reported to block the increase in m.e.p.p. frequency caused by increasing the tonicity of the Ringer (Gorio & Mauro, 1979). This effect was confirmed. The lectin-treated preparations also failed to show an increase in evoked quantal release when the tonicity was increased.3. A model in which both spontaneous and evoked quantal releases depend on some power of the intracellular [Ca(2+)] is presented. The model predicts that rises in m.e.p.p. frequency will be accompanied by increased quantal output from stimulated nerve terminals. The maximum slope of the relationship between log (evoked quantal output) and log ([Ca(2+)](out)) will be less than the true power. A theoretical analysis shows that, as the true power approaches infinity, the maximum slope will be slightly above 4. The value for the slope usually found experimentally at the frog neuromuscular junction is also about 4.4. The model does not fit the experimental data. The observed increases in evoked quantal release are higher than those predicted for the observed increases in spontaneous release. There are several possible explanations for the discrepancy. Treatments that increase m.e.p.p. frequency may also increase Ca(2+) influx into the stimulated terminal. However, we prefer the explanation that there is a fraction of spontaneous release that is independent of the [Ca(2+)] in the terminal; if this is true the model might account for the data.5. The model can account for a variety of puzzling experimental observations, including: (a) the effect of hypertonic solutions and of diamine in decreasing the slope in the relation between log (evoked quantal output) and log ([Ca(2+)](out)); (b) the slope of near 1 observed at the crustacean neuromuscular junction; (c) the decrease in the slope produced by treatment with botulinum toxin.

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Year:  1983        PMID: 6603514      PMCID: PMC1199135          DOI: 10.1113/jphysiol.1983.sp014652

Source DB:  PubMed          Journal:  J Physiol        ISSN: 0022-3751            Impact factor:   5.182


  40 in total

1.  Evoked transmitter release at the frog neuromuscular junction in very low calcium solutions.

Authors:  A C Crawford
Journal:  J Physiol       Date:  1973-05       Impact factor: 5.182

2.  The quantitative relation between extracellular calcium and acetylcholine release at the frog neuromuscular junction.

Authors:  H Kita; W van der Kloot
Journal:  Brain Res       Date:  1973-01-15       Impact factor: 3.252

3.  Effect of the thiol-oxidizing agent, diamide, on acetylcholine release at the frog endplate.

Authors:  R Werman; P L Carlen; M Kushnir; E M Kosower
Journal:  Nat New Biol       Date:  1971-09-22

4.  Effects of lanthanum ions on function and structure of frog neuromuscular junctions.

Authors:  J Heuser; R Miledi
Journal:  Proc R Soc Lond B Biol Sci       Date:  1971-12-14

5.  Effects of alcohols and acetone on the neuromuscular junction of frog.

Authors:  K Okada
Journal:  Jpn J Physiol       Date:  1967-06

6.  Effects of sodium pump inhibitors on spontaneous acetylcholine release at the neuromuscular junction.

Authors:  D Elmqvist; D S Feldman
Journal:  J Physiol       Date:  1965-12       Impact factor: 5.182

7.  Co-operative action a calcium ions in transmitter release at the neuromuscular junction.

Authors:  F A Dodge; R Rahamimoff
Journal:  J Physiol       Date:  1967-11       Impact factor: 5.182

8.  The effects of hypoxia on neuromuscular transmission in a mammalian preparation.

Authors:  J I Hubbard; Y Loyning
Journal:  J Physiol       Date:  1966-07       Impact factor: 5.182

9.  Calcium: is it required for transmitter secretion?

Authors:  D M Quastel; J T Hackett; J D Cooke
Journal:  Science       Date:  1971-06-04       Impact factor: 47.728

10.  The effect of noradrenaline on the end-plate potential in twitch fibres of the frog.

Authors:  D H Jenkinson; B A Stamenović; B D Whitaker
Journal:  J Physiol       Date:  1968-04       Impact factor: 5.182

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  13 in total

1.  Biphasic modulation of synaptic transmission by hypertonicity at the embryonic Drosophila neuromuscular junction.

Authors:  Kazuhiro Suzuki; Tomonori Okamoto; Yoshiaki Kidokoro
Journal:  J Physiol       Date:  2002-11-15       Impact factor: 5.182

2.  Ca(2+) influx and neurotransmitter release at ribbon synapses.

Authors:  Soyoun Cho; Henrique von Gersdorff
Journal:  Cell Calcium       Date:  2012-07-08       Impact factor: 6.817

3.  Presynaptic calcium diffusion from various arrays of single channels. Implications for transmitter release and synaptic facilitation.

Authors:  A L Fogelson; R S Zucker
Journal:  Biophys J       Date:  1985-12       Impact factor: 4.033

4.  Relationship between transmitter release and presynaptic calcium influx when calcium enters through discrete channels.

Authors:  R S Zucker; A L Fogelson
Journal:  Proc Natl Acad Sci U S A       Date:  1986-05       Impact factor: 11.205

5.  Stimulation of spontaneous transmitter release at the frog neuromuscular junction by 12-O-tetradecanoylphorbol-13-acetate occurs in the absence of extracellular Ca2+ and is enhanced by depolarization.

Authors:  P E Light; Z Y Sahaf; S J Publicover
Journal:  Naunyn Schmiedebergs Arch Pharmacol       Date:  1988-10       Impact factor: 3.000

6.  Calcium dependence of quantal release triggered by graded depolarization pulses to nerve terminals on crayfish and frog muscle.

Authors:  J Dudel
Journal:  Pflugers Arch       Date:  1989-12       Impact factor: 3.657

7.  Calcium dependence of presynaptic calcium current and post-synaptic response at the squid giant synapse.

Authors:  G J Augustine; M P Charlton
Journal:  J Physiol       Date:  1986-12       Impact factor: 5.182

8.  Hypertonic enhancement of transmitter release from frog motor nerve terminals: Ca2+ independence and role of integrins.

Authors:  A H Kashani; B M Chen; A D Grinnell
Journal:  J Physiol       Date:  2001-01-15       Impact factor: 5.182

9.  The calcium hypothesis and modulation of transmitter release by hyperpolarizing pulses.

Authors:  R S Zucker
Journal:  Biophys J       Date:  1987-08       Impact factor: 4.033

10.  The action of thallium acetate on spontaneous transmitter release in the rat neuromuscular junction.

Authors:  H Wiegand; R Papadopoulos; M Csicsaky; U Krämer
Journal:  Arch Toxicol       Date:  1984-10       Impact factor: 5.153

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