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The Effect of Carbachol and α‐Bungarotoxin on the Frequency of Miniature Endplate Potentials at the Frog Neuromuscular Junction
Author(s) -
Bukharaeva Ela,
Ipatova Tania,
Nikolsky E. E.,
Vyskocil F.
Publication year - 2000
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1111/j.1469-445x.2000.01949.x
Subject(s) - carbachol , neuromuscular junction , chemistry , acetylcholine , acetylcholine receptor , nicotinic agonist , antagonist , bungarotoxin , biophysics , endocrinology , medicine , receptor , neuroscience , biochemistry , biology
The effects of an acetylcholine analogue, carbachol (CCh), and a purified irreversible nicotinic antagonist, α‐bungarotoxin (BTX), on the frequency of the miniature endplate potentials (mEPPs) at the neuromuscular junction of the frog were tested at 20 and 10°C. CCh (5 ± 10‐6 m) reduced the frequency of mEPPs to about 60%; this reduction was not affected by 1 ± 10‐7 g ml‐1 BTX. BTX also reversibly decreased the mEPP frequency by 40%, but not in the presence of CCh or in Ringer solution with 0 or 8 mM Ca 2+ . The present data show that BTX, which inhibits a class of nicotinic ACh receptors, does not block the decrease of mEPP frequency evoked by CCh and can itself suppress the frequency of spontaneous quantal release.