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An analysis of the dose‐response relationship at voltage‐clamped frog neuromuscular junctions.
Author(s) -
Dionne V E,
Steinbach J H,
Stevens C F
Publication year - 1978
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1978.sp012431
Subject(s) - agonist , chemistry , receptor , carbachol , biophysics , dissociation constant , neuromuscular junction , biology , neuroscience , biochemistry
1. Frog neuromuscular junctions were viewed with Nomarski optics and voltage clamped. Agonist was applied ionophoretically and agonist concentrations were measured using a micro‐electrode sensitive to quaternary amines. 2. The dose‐response relationship was studied using the agonists carbamylcholine, suberyldicholine and hydroxyphenyl‐propyltrimethylammonium. 3. With all of these agonists, it appeared that the ACh receptor could be active when either one or two agonist binding sites were occupied. The receptor was much more likely to be active when both sites were occupied. Agonist dissociation constants and receptor activation probabilities were estimated by non‐linear regression techniques for several possible receptor activation schemes.