Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/197106
Type: Artigo de periódico
Title: [influence Of Nifedipine On The Neuromuscular Block Produced By Atracurium And Cistracurium: Study In Rat Phrenic-diaphragmatic Nerve Preparation.].
Author: Sousa, Silmara Rodrigues de
Braga, Angélica de Fátima de Assunção
Potério, Glória Maria Braga
Braga, Franklin Sarmento da Silva
Loyola, Yolanda Christina S
Fernandes, Samanta Cristina Antoniassi
Abstract: Calcium channel blockers may interact with neuromuscular blockers, increasing its effects. Research studies about this interaction display controversial results. In some studies these drugs produced neuromuscular blockage, or contracture, or no effect at all was proved over skeletal neuromuscular response. This study assessed the nifedipine effects over muscular responses and its possible interaction with neuromuscular blockers in rat diaphragm. A number of 25 rats were used, weighing between 250 and 300 g and sacrificed under anesthesia with intraperitoneal pentobarbital (40 mg.kg-1). Preparation was mounted according to the technique described by Bulbring. Diaphragm was kept under tension, connected to an isometric transducer and subjected to an indirect stimulation of 0.1 Hz frequency. Diaphragm contractions were registered on a physiograph. In order to evaluate the effect of these drugs on neuromuscular transmission, they were added separately or associated to the preparation, on the following concentrations: nifedipine (4 microg.mL-1); atracurium (20 microg.mL-1); cistracurium (3 microg.mL-1). On phrenic-nerve preparation, the assessed items were: 1) the extent of diaphragm muscle response to indirect stimulation, before and 45 minutes after adding nifedipine and neuromuscular blockers separately and after the association of both drugs; 2) nifedipine effects on membrane potentials (MP) and miniature end-plate potentials (MEPP). Employed separately, nifedipine did not alter the extent of muscular responses, but it did significantly increase the neuromuscular blocking activity of atracurium and cistracurium. Nifedipine did not alter the membrane potential and caused an initial increase on MEPP frequencies, followed by a blockage. Nifedipine, on the employed concentration, increased the neuromuscular blockage produced by atracurium and cistracurium. Electrophysiological studies demonstrate the existence of presynaptic action and absence of depolarizing action over the muscle fiber.
Rights: fechado
Identifier DOI: 
Address: http://www.ncbi.nlm.nih.gov/pubmed/19468562
Date Issue: 2006
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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