Author/Authors :
Carvalho, Vanessa Henriques Department of Anesthesiology - Faculty of Medical Sciences - Universidade Estadual de Campinas (UNICAMP), Brazil , Braga, Angélica de Fátima de Assunção Department of Anesthesiology - Faculty of Medical Sciences - Universidade Estadual de Campinas (UNICAMP), Brazil , Braga, Franklin Sarmento da Silva Department of Anesthesiology - Faculty of Medical Sciences - Universidade Estadual de Campinas (UNICAMP), Brazil , Potério, Gloria Maria Braga Department of Anesthesiology - Faculty of Medical Sciences - Universidade Estadual de Campinas (UNICAMP), Brazil , Santos, Filipe Nadir Caparica Department of Anesthesiology - School of Medicine - Universidade Estadual de Campinas (UNICAMP), Brazil , Junqueira, Fernando Eduardo Féres Department of Anesthesiology - School of Medicine - Universidade Estadual de Campinas (UNICAMP), Brazil
Abstract :
PURPOSE:
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.
CONCLUSION:
Levobupivacaine potentiated the neuromuscular blockade produced by pancuronium, confirming a presynaptic action by a decrease in miniature endplate potentials.
