Concentration-dependent effects of vecuronium (VEC) (A), atracurium (ATRA) (B), and rocuronium (ROC) (C) on the nicotinic acetylcholine receptors in innervated (INN) and denervated (DEN) skeletal muscle cells. Traces represent raw currents observed during the application of ACh 30 μmol/L for 10 s, either alone (control) or in combination with various concentrations of vecuronium, atracurium, or rocuronium, as indicated.