Prolonged nerve stimulation causes changes in transmitter release at the frog neuromuscular junction.
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چکیده
منابع مشابه
Structural changes after transmitter release at the frog neuromuscular junction
The sequence of structural changes that occur during synaptic vesicle exocytosis was studied by quick-freezing muscles at different intervals after stimulating their nerves, in the presence of 4-aminopyridine to increase the number of transmitter quanta released by each stimulus. Vesicle openings began to appear at the active zones of the intramuscular nerves within 3-4 ms after a single stimul...
متن کاملA quantitative description of stimulation-induced changes in transmitter release at the frog neuromuscular junction
Endplate potentials were recorded from frog sartorius neuromuscular junctions under conditions of greatly reduced quantal contents to develop a quantitative description of stimulation-induced changes in transmitter release. Four general models relating potentiation, augmentation, and the first and second components of facilitation to transmitter release were developed. These models were then te...
متن کاملPhenobarbital Increases Spontaneous Transmitter Release at the Frog Neuromuscular Junction
Phenobarbital (1-2 × 10(-4)M) markedly increases the frequency of miniature end-plate potentials at the neuromuscular synapse of the frog. This effect was seen in calcium free media containing EGTA. The drug probably acts presynaptically at an intracellular locus to increase the presynaptic free calcium concentration.
متن کاملRole of intracellular Ca2+ in stimulation-induced increases in transmitter release at the frog neuromuscular junction
Under conditions of reduced quantal content, repetitive stimulation of a presynaptic nerve can result in a progressive increase in the amount of transmitter released by that nerve in response to stimulation. At the frog neuromuscular junction, this increase in release has been attributed to four different processes: first and second components of facilitation, augmentation, and potentiation (e....
متن کاملEffects of changes in motor unit size on transmitter release at the frog neuromuscular junction.
The dependence of transmitter release and synaptic effectiveness on the size of a neuron's peripheral field was studied using neuromuscular junctions in sartorius muscles of adult frogs (Rana pipiens). The size of the peripheral field (motor unit size) was reduced by crushing the sartorius nerve and surgically removing half of the muscle fibers. Synapses thus formed were compared with those for...
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ژورنال
عنوان ژورنال: The Journal of Physiology
سال: 1988
ISSN: 0022-3751
DOI: 10.1113/jphysiol.1988.sp017179