Asymmetry of the acetylcholine channel revealed by quaternary anesthetics.
Tissue-cultured rat myoballs were examined electrophysiologically with a suction pipette, which was used for voltage clamping and internal perfusion. The lidocaine derivative QX-314 caused a time- and membrane potentia-dependent block of acetylcholine-induced current only when applied from the extracellular membrane surface. The same compounds caused a use-dependent block of the sodium channel only from the intracellular membrane surface. These experiments demonstrate a fundamental asymmetry of the acetylcholine receptor-channel complex.
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D007473:Ion Channels / Q000187:drug effects; D008012:Lidocaine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D008565:Membrane Proteins; D009045:Motor Endplate / Q000648:ultrastructure*; D009469:Neuromuscular Junction / Q000648:ultrastructure*; D051381:Rats; D011950:Receptors, Cholinergic; D012964:Sodium / Q000378:metabolism; D013329:Structure-Activity Relationship
D007473:Ion Channels; D008565:Membrane Proteins; D011950:Receptors, Cholinergic; C006072:QX-222; C012647:QX-314; D008012:Lidocaine; D012964:Sodium; D000109:Acetylcholine