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Updated: Jul 7, 2026

Stimulated Single Fiber Electromyography (SFEMG) for Assessing Neuromuscular Junction Transmission in Rodent Models
Published on: March 8, 2024
Influence of stimulus frequency on blockade induced by pancuronium and rocuronium: study on rats phrenic
Angélica de Fátima de Assunção Braga1, Derli Conceição Munoz, Franklin Sarmento da Silva Braga
1Department of Anesthesiology, Faculty of Medical Sciences, UNICAMP, São Paulo, Brazil. franklinbraga@terra.com.br
Purpose:
To evaluate the influence of two stimulation frequencies on the installation of neuromuscular blockade produced by pancuronium and rocuronium on the rat diaphragm.
Methods:
Diaphragms were submitted to an indirect frequency stimulation of 0.1 and 1 Hz (Groups I and II, respectively). Subgroups were formed (n=5) according to the neuromuscular blocker employed (pancuronium-2 microg/ml and rocuronium-4 microg/ml). The twitch height depression was evaluated at 5, 15 and 30 minutes after adding the neuromuscular blocker.
Results:
The decrease in twitch height was greater (p<0.01) with a frequency of 1 Hz at all time periods studied both in preparations that are blocked with pancuronium and in those that are blocked with rocuronium.
Conclusion:
The frequency of stimulation interferes significantly with the installation of neuromuscular blockade produced by pancuronium and rocuronium, since the reduction in amplitude of the rat diaphragm response was greater for 1 Hz frequencies, at all periods studied.
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