title: Potency of nondepolarizing muscle relaxants on muscle-type acetylcholine receptors in denervated mouse skeletal muscle.
abstract: OBJECTIVE
  to investigate the changing resistance to nondepolarizing muscle relaxants (NDMRs) during the first month after denervation.
  
  
  METHODS
  the denervated and innervated skeletal muscle cells were examined on days 1, 4, 7, 14, 21, and 28 after denervation. Individual denervated and innervated cells were prepared from the flexor digitorum brevis of the surgically denervated and contralateral hind feet, respectively. Nicotinic acetylcholine receptors (nAChRs) in the cells were activated with 30 micromol/L acetylcholine, either alone or in combination with various concentrations of vecuronium. Currents were recorded using a whole-cell patch-clamp technique.
  
  
  RESULTS
  the concentrations of vecuronium resulting in half-maximal inhibitory responses (IC(50)) increased 1.2- (P>0.05), 1.7-, 3.7-, 2.5-, 1.9-, and 1.8-fold (P<0.05) at Days 1, 4, 7, 14, 21, and 28 after denervation, respectively, compared to the innervated control. Resistance to vecuronium appeared at Day 4, peaked at Day 7, and declined at Day 14 after denervation. Nevertheless, IC(50) values at Day 28 remained significantly higher than those for the innervated control, suggesting that the resistance to vecuronium had not disappeared at Day 28.
  
  
  CONCLUSIONS
  The NDMR doses required to achieve satisfactory clinical effects differ at different times after muscle denervation.
authors.affiliation: Department of Anesthesiology, First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China.
authors.forename: Hong
authors.initials: H
authors.lastname: WANG
authors.forename: Bin
authors.initials: B
authors.lastname: YANG
authors.forename: Guang-wei
authors.initials: GW
authors.lastname: HAN
authors.forename: Shi-tong
authors.initials: ST
authors.lastname: LI
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D051379:Mice; D008807:Mice, Inbred BALB C; D009121:Muscle Denervation; D018485:Muscle Fibers, Skeletal / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000166:cytology / Q000187:drug effects* / Q000294:innervation; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D011950:Receptors, Cholinergic / Q000378:metabolism*; D014673:Vecuronium Bromide / Q000494:pharmacology*
chemical_list: D003473:Neuromuscular Nondepolarizing Agents; D011950:Receptors, Cholinergic; D014673:Vecuronium Bromide; D000109:Acetylcholine