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Citation
Tags
HERO ID
2283536
Reference Type
Journal Article
Title
Etomidate evokes synaptic vesicle exocytosis without increasing miniature endplate potentials frequency at the mice neuromuscular junction
Author(s)
Valadão, PA; Naves, LA; Gomez, RS; Guatimosim, C
Year
2013
Is Peer Reviewed?
1
Journal
Neurochemistry International
ISSN:
0197-0186
EISSN:
1872-9754
Volume
63
Issue
6
Page Numbers
576-582
Language
English
PMID
24044896
DOI
10.1016/j.neuint.2013.09.008
Web of Science Id
WOS:000327232300006
Abstract
Etomidate is an intravenous anesthetic used during anesthesia induction. This agent induces spontaneous movements, especially myoclonus after its administration suggesting a putative primary effect at the central nervous system or the periphery. Therefore, the aim of this study was to investigate the presynaptic and postsynaptic effects of etomidate at the mouse neuromuscular junction (NMJ). Diaphragm nerve muscle preparations were isolated and stained with the styryl dye FM1-43, a fluorescent tool that tracks synaptic vesicles exo-endocytosis that are key steps for neurotransmission. We observed that etomidate induced synaptic vesicle exocytosis in a dose-dependent fashion, an effect that was independent of voltage-gated Na(+) channels. By contrast, etomidate-evoked exocytosis was dependent on extracellular Ca(2+) because its effect was abolished in Ca(2+)-free medium and also inhibited by omega-Agatoxin IVA (30 and 200nM) suggesting the participation of P/Q-subtype Ca(2+) channels. Interestingly, even though etomidate induced synaptic vesicle exocytosis, we did not observe any significant difference in the frequency and amplitude of miniature end-plate potentials (MEPPs) in the presence of the anesthetic. We therefore investigated whether etomidate could act on nicotinic acetylcholine receptors labeled with α-bungarotoxin-Alexa 594 and we observed less fluorescence in preparations exposed to the anesthetic. In conclusion, our results suggest that etomidate exerts a presynaptic effect at the NMJ inducing synaptic vesicle exocytosis, likely through the activation of P-subtype voltage gated Ca(2+) channels without interfering with MEPPs frequency. The present data contribute to a better understanding about the effect of etomidate at the neuromuscular synapse and may help to explain some clinical effects of this agent.
Tags
IRIS
•
n-Butanol
Database searches
Pubmed
Database Searches - March 2014 (private)
Pubmed - 3/2014
Excluded (not pertinent)
Not chemical specific
PFAS
•
PFAS 150
Literature Search August 2019
Web of Science
Not prioritized for screening
Sevoflurane
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