scholarly journals Org NC 45 Reduces Quantal Release of Acetylcholine (a Preliminary Communication)

1982 ◽  
Vol 10 (2) ◽  
pp. 127-129 ◽  
Author(s):  
T. A. Torda ◽  
N. Kiloh
Keyword(s):  
Neuromuscular Blocker ◽  
Variance Ratio ◽  
Muscle Preparation ◽  
Quantal Release ◽  
End Plate ◽  
Release Of Acetylcholine ◽  
Preliminary Communication ◽  
Nerve Muscle

The new neuromuscular blocker, Org NC 45 was applied to the toad sartorius nerve-muscle preparation. Measurement of the variance ratio of end-plate potentials recorded by micro-electrodes demonstrated that in concentrations greater than that required to block myoneural transmission, Org NC 45 reduced the quantal release of acetylcholine.

scholarly journals Measurement of quantal secretion induced by ouabain and its correlation with depletion of synaptic vesicles.

1985 ◽  
Vol 101 (5) ◽  
pp. 1953-1965 ◽  
Author(s):  
C Haimann ◽  
F Torri-Tarelli ◽  
R Fesce ◽  
B Ceccarelli
Keyword(s):  
Synaptic Vesicles ◽  
Time Course ◽  
Neuromuscular Junctions ◽  
Power Spectra ◽  
Peak Frequency ◽  
Fluctuation Analysis ◽  
Experimental Conditions ◽  
Quantal Release ◽  
Release Of Acetylcholine ◽  
Nerve Muscle

Ouabain (0.1 and 0.05 mM) was applied to frog cutaneous pectoris nerve-muscle preparations bathed in modified Ringer's solution containing either 1.8 mM Ca2+ (and 4 mM Mg2+) or no added Ca2+ (4 mM Mg2+ and 1 mM EGTA). During the intense quantal release of acetylcholine (ACh) induced by ouabain, the parameters of the miniature endplate potentials (mepps) were deduced from the variance, skew, and power spectra of the endplate recordings by applying a recently described modification of classical fluctuation analysis. Often the high frequency of mepps is not stationary; therefore, the signal was high-pass filtered (time constant of the resistance-capacitance filter of 2 ms) to remove the errors introduced by nonstationarity. When ouabain was applied in the presence of Ca2+, mepp frequency started to rise exponentially after a lag of 1.5-2 h, reached an average peak frequency of 1,300/s in approximately 30 min, and then suddenly subsided to low level (10/s). In Ca2+-free solution, after a shorter lag (1-1.5 h), mepp frequency rose to peak rate of 700/s in approximately 20 min and then gradually subsided. In spite of the different time course of secretion in the two experimental conditions, the cumulative quantal release was not significantly different (7.4 +/- 1.3 X 10(5) in Ca2+-containing and 8.8 +/- 2.7 X 10(5) in Ca2+-free solutions). 60 min after the peak secretion, the muscles were fixed for observation in the electron microscope. Morphometric analysis on micrographs of neuromuscular junctions revealed in both cases a profound depletion of synaptic vesicles and deep infoldings of presynaptic membrane. This rapid depletion and the lack of uptake of horseradish peroxidase suggest that ouabain impairs the recycling process that tends to conserve the vesicle population during intense secretion of neurotransmitter. The good correlation observed between the reduction in the store of synaptic vesicles and the total number of quanta of ACh secreted in the absence of a vigorous membrane recycling strongly supports the view that the secretion of a quantum of ACh requires the fusion of a synaptic vesicle with the axolemma.

Effect of armin on synaptic transmission in the frog nerve-muscle preparation

1981 ◽  
Vol 91 (6) ◽  
pp. 774-777 ◽  
Author(s):  
I. I. Krivoi ◽  
V. I. Kuleshov ◽  
D. P. Matyushkin ◽  
V. I. Sanotskii ◽  
I. A. Shabunova
Keyword(s):  
Synaptic Transmission ◽  
Muscle Preparation ◽  
Nerve Muscle

Effect of Bothrops insularis venom on the mouse and chick nerve-muscle preparation

Toxicon ◽  
1993 ◽  
Vol 31 (10) ◽  
pp. 1237-1247 ◽  
Author(s):  
J.C. Cogo ◽  
J. Prado-Franceschi ◽  
M.A. Cruz-Hofling ◽  
A.P. Corrado ◽  
L. Rodrigues-Simioni
Keyword(s):  
Muscle Preparation ◽  
Nerve Muscle

scholarly journals I. Croonian Lecture .—Observations on isolated nerve (with particular reference to carbon dioxide)

1897 ◽  
Vol 188 ◽  
pp. 1-101 ◽  
Keyword(s):  
Weak Link ◽  
Nerve Degeneration ◽  
Muscle Preparation ◽  
Marked Contrast ◽  
Functional Failure ◽  
Du Bois ◽  
Motor End Plates ◽  
Nerve Muscle ◽  
Long Endurance ◽  
Experimental Disturbance

As was pointed out ten years ago by Wedenski, from telephone observations of the negative variation, by Waller, from galvanometric observations of the same, and by Bowditch from the observation of long-persisting excitability in the nerves of temporarily curarised mammals, nerve is now admitted to be practically inexhaustible. The apparent exhaustion of nerve when a nerve-muscle preparation is submitted to prolonged excitation is, as was first demonstrated in Bernstein’s experiment, not an exhaustion of nerve, but an exhaustion of the organ of intermediation between nerve and muscle, which, as pointed out by Waller, is the weak link in the neuro-muscular chain, being the point at which functional failure is first manifested, in fatigue, in nerve degeneration, in intoxication by curare (Bernard), and at death. Taking as the sign of action artificially excited in a nerve, the negative variation of its current of rest (du Bois-Reymond) or current of injury (Hermann), the long endurance by nerve of excitation excessive in strength and in length, is well shown by prolonged photographic records of the galvanometric indications, which exhibit little or no decline, in marked contrast with similar records of the negative variation of muscle which declines pari passu with the declining contraction due to fatigue of the motor end plates. This steady regularity of response renders nerve pre-eminently suitable to the systematic study of its experimental disturbance.

Varespladib (LY315920) inhibits neuromuscular blockade induced by Oxyuranus scutellatus venom in a nerve-muscle preparation

Toxicon ◽  
2020 ◽  
Vol 187 ◽  
pp. 101-104
Author(s):  
Isadora Caruso Fontana Oliveira ◽  
José María Gutiérrez ◽  
Matthew R. Lewin ◽  
Yoko Oshima-Franco
Keyword(s):  
Neuromuscular Blockade ◽  
Muscle Preparation ◽  
Nerve Muscle
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