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The interaction of the neuromuscular effects between mivacurium and esmolol in rats
1Department of Anesthesiology, Taipei Municipal Yang Ming Hospital, Taiwan, R.O.C.
Background:
To study the neuromuscular interaction between mivacurium and esmolol, we compared the neuromuscular actions of the ED90 dose of mivacurium both in the absence and presence of esmolol infusion.
Methods:
Twelve rats were anesthetized with urethane. Train-of-four stimulation was applied every 12 s to the sciatic nerve, and the electromyogram (EMG) response of the anterior tibial muscle was measured.
Results:
The ED50 and ED90 of mivacurium in rats were 144 +/- 7.3 micrograms/kg and 197 +/- 7.7 micrograms/kg, respectively. The maximal EMG depression produced by ED50 of mivacurium decreased significantly with esmolol treatment from 88.2 +/- 2.7% to 83.1 +/- 2.6% after esmolol infusion (p < 0.05). The onset time for 75% EMG depression was much shorter for control (44 +/- 6.3 s) than that of esmolol treatment (78.2 +/- 2.4 s; p < 0.05). There was no difference between their duration.
Conclusions:
The results of this study demonstrated that esmolol does not potentiate the neuromuscular effect of mivacurium but antagonize the maximal neuromuscular block and decrease its onset time in rats.
Insights
Esmolol does not potentiate mivacurium's neuromuscular effects. Instead, esmolol antagonizes maximal neuromuscular block and reduces its onset time when co-administered with mivacurium in rats.
Area of Science:
- Anesthesiology
- Pharmacology
- Neuroscience
Background:
- Investigating the neuromuscular interaction between mivacurium and esmolol.
- Comparing mivacurium's neuromuscular actions with and without esmolol infusion.
Purpose of the Study:
- To elucidate the interaction between mivacurium and esmolol on neuromuscular function.
- To determine if esmolol potentiates or antagonizes mivacurium's neuromuscular blockade.
Main Methods:
- Utilized a rat model anesthetized with urethane.
- Applied train-of-four stimulation to the sciatic nerve.
- Measured electromyogram (EMG) response of the anterior tibial muscle.
Main Results:
- Esmolol treatment significantly decreased maximal EMG depression from mivacurium (88.2% to 83.1%).
- The onset time for 75% EMG depression was significantly longer with esmolol (78.2 s) compared to control (44 s).
- No significant difference in the duration of neuromuscular block was observed between groups.
Conclusions:
- Esmolol does not potentiate the neuromuscular effects of mivacurium.
- Esmolol antagonizes the maximal neuromuscular block induced by mivacurium.
- Esmolol decreases the onset time of mivacurium-induced neuromuscular blockade in rats.