Conductance of channels opened by acetylcholine-like drugs in muscle end-plate

• DOI: 10.1038/253204a0
• Publication Date: 2005-08-03T18:52:04Z
• Authors: D. COLQUHOUN; V. E. DIONNE; J. H. STEINBACH; C. F. STEVENS
• Keywords: 0303 health sciences; Rana pipiens; Molecular Conformation; Neuromuscular Junction; Biological Transport, Active; In Vitro Techniques; Motor Endplate; Acetylcholine; Choline; Membrane Potentials; Quaternary Ammonium Compounds; Structure-Activity Relationship; 03 medical and health sciences; Parasympathomimetics; Phenols; Benzene Derivatives; Animals; Dicarboxylic Acids; Caprylates

MOST recent views of the way in which acetylcholine (ACh) can cause ion channels to open postulate that the channel can exist only in one or other of two distinct conformations, open or shut1–4. In their simplest form, these theories predict that a channel, once it is open, will have the same conductance whichever drug caused it to open. We have estimated average single channel conductances for four cholinomimetic agonists, and find this prediction is not confirmed.