Vesicle size and transmitter release at the frog neuromuscular junction when quantal acetylcholine content is increased or decreased
نویسندگان
چکیده
منابع مشابه
Vesicle size and transmitter release at the frog neuromuscular junction when quantal acetylcholine content is increased or decreased.
We investigated whether the synaptic vesicles at the neuromuscular junction change size when their acetylcholine (ACh) content is altered. The size of the miniature endplate potential (MEPP) increased 3- or 4-fold in preparations pre-treated in a hypertonic solution in which the anion was gluconate. We measured the dimensions of synaptic vesicles in such preparations and in controls. The size o...
متن کاملNon-quantal acetylcholine release at the neuromuscular junction.
There are two principal mechanisms of acetylcholine (ACh) release from the resting motor nerve terminal: quantal and non-quantal (NQR); the former being only a small fraction of the total, at least at rest. In the present article we summarize basic research about the NQR that is undoubtedly an important trophic factor during endplate development and in adult neuromuscular contacts. NQR helps to...
متن کاملStructural 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 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 کاملInteraction of glutamate- and adenosine-induced decrease of acetylcholine quantal release at frog neuromuscular junction.
In a frog neuromuscular preparation of m. sartorius, glutamate had a reversible dose-dependent inhibitory effect on both spontaneous miniature endplate potentials (MEPP) and nerve stimulation-evoked endplate potentials (EPP). The effect of glutamate on MEPP and EPP is caused by the activation of metabotropic glutamate receptors, as it was eliminated by MCPG, an inhibitor of group I metabotropic...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Journal of Physiology
سال: 2002
ISSN: 0022-3751,1469-7793
DOI: 10.1113/jphysiol.2001.014407