title: Association between levobupivacaine and pancuronium. Interference in neuromuscular transmission and blockade in rats.
abstract: OBJECTIVE
  To evaluate the effects of levobupivacaine on neuromuscular transmission and neuromuscular blockade produced by pancuronium in vitro.
  
  
  METHODS
  Thirty rats were distributed into groups (n = 5) according to the drug used alone or in combination: Group I - levobupivacaine (5 µg.mL-1); Group II - pancuronium (2 µg.mL-1); Group III - pancuronium (2 µg.mL-1) + levobupivacaine (5µg.mL-1). The following parameters were evaluated: 1) amplitude of diaphragmatic response to indirect stimulation, before and 60 minutes after the addition of levobupivacaine and pancuronium alone, and after the addition of levobupivacaine combined with pancuronium; 2) membrane potentials (MP) and miniature endplate potentials (MEPP).
  
  
  RESULTS
  Levobupivacaine alone did not alter the amplitude of muscle response and MP. In preparations previoulsy exposed to levobupivacaine, the block with pancuronium was significantly denser (90.2 ± 15.2%), showing a significant difference (p=0.031) in comparison to the block produced by pancuronium alone (48.9% ± 9.8%). There was a decrease in the frequency and amplitude of MEPPs.
  
  
  CONCLUSIONS
  Levobupivacaine potentiated the neuromuscular blockade produced by pancuronium, confirming a presynaptic action by a decrease in miniature endplate potentials.
authors.affiliation: PhD, Department of Anesthesiology, Faculty of Medical Sciences, Universidade Estadual de Campinas (UNICAMP), Brazil. Intellectual, scientific and design of the study; acquisition and interpretation of data; technical procedures; manuscript preparation and writing, critical revision, supervised all phases of the study.
authors.forename: Vanessa Henriques
authors.initials: VH
authors.lastname: Carvalho
authors.affiliation: Associate Professor, Department of Anesthesiology, Faculty of Medical Sciences, UNICAMP, Campinas-SP, Brazil. Intellectual, scientific and design of the study; interpretation of data; technical procedures; manuscript preparation and writing, critical revision, supervised all phases of the study.
authors.forename: Angélica de Fátima de Assunção
authors.initials: Ade F
authors.lastname: Braga
authors.affiliation: PhD, Department of Anesthesiology, Faculty of Medical Sciences, UNICAMP, Campinas-SP, Brazil. Critical revision.
authors.forename: Franklin Sarmento da Silva
authors.initials: FS
authors.lastname: Braga
authors.affiliation: Associate Professor, Department of Anesthesiology, Faculty of Medical Sciences, UNICAMP, Campinas-SP, Brazil. Critical revision.
authors.forename: Gloria Maria Braga
authors.initials: GM
authors.lastname: Potério
authors.affiliation: MD, Department of Anesthesiology, School of Medicine, UNICAMP, Campinas-SP, Brazil. Acquisition of data.
authors.forename: Filipe Nadir Caparica
authors.initials: FN
authors.lastname: Santos
authors.affiliation: Resident, Department of Anesthesiology, School of Medicine, UNICAMP, Campinas-SP, Brazil. Acquisition of data.
authors.forename: Fernando Eduardo Féres
authors.initials: FE
authors.lastname: Junqueira
mesh_terms: D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D002045:Bupivacaine / Q000031:analogs & derivatives* / Q000494:pharmacology; D003964:Diaphragm / Q000187:drug effects / Q000294:innervation; D004359:Drug Therapy, Combination; D004558:Electric Stimulation / Q000379:methods; D000077554:Levobupivacaine; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D023421:Models, Animal; D019148:Neuromuscular Blockade; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology; D010197:Pancuronium / Q000494:pharmacology*; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology
chemical_list: D000779:Anesthetics, Local; D003473:Neuromuscular Nondepolarizing Agents; D000077554:Levobupivacaine; D010197:Pancuronium; D002045:Bupivacaine