Research Article

Different magnitude of resistance to non-depolarizing muscle relaxants in dexamethasone-treated rat diaphragm associated with altered acetylcholine receptor expression

Published: August 07, 2014
Genet. Mol. Res. 13 (3) : 5892-5900 DOI: 10.4238/2014.August.7.4

Abstract

The aim of this study was to investigate the influence of chronic dexamethasone (Dex) administration on rat diaphragm sensitivity to non-depolarizing muscle relaxants (NDMRs) and muscular nicotinic acetylcholine receptor (nAChR) expression, which may help direct future administration of NDMRs. Adult male Sprague-Dawley rats were randomized to receive a daily intraperitoneal injection of Dex (600 μg/kg body mass) or an equivalent volume of saline (N = 20 in each group) for 14 days. We evaluated isometric twitch tensions of nerve-hemidiaphragm preparations elicited by indirect supramaximal stimulation at 0.1 Hz. Real-time quantitative PCR was performed to determine the mRNA expression of two nAChR subunits (ε-subunit and γ-subunit) in the diaphragm. Dex administration markedly (P 50) of the three NDMRs. The IC50 ratio, which standardized the magnitudes of the resistance, was the largest for atracurium, with the second largest for vecuronium and the smallest for rocuronium (P

The aim of this study was to investigate the influence of chronic dexamethasone (Dex) administration on rat diaphragm sensitivity to non-depolarizing muscle relaxants (NDMRs) and muscular nicotinic acetylcholine receptor (nAChR) expression, which may help direct future administration of NDMRs. Adult male Sprague-Dawley rats were randomized to receive a daily intraperitoneal injection of Dex (600 μg/kg body mass) or an equivalent volume of saline (N = 20 in each group) for 14 days. We evaluated isometric twitch tensions of nerve-hemidiaphragm preparations elicited by indirect supramaximal stimulation at 0.1 Hz. Real-time quantitative PCR was performed to determine the mRNA expression of two nAChR subunits (ε-subunit and γ-subunit) in the diaphragm. Dex administration markedly (P 50) of the three NDMRs. The IC50 ratio, which standardized the magnitudes of the resistance, was the largest for atracurium, with the second largest for vecuronium and the smallest for rocuronium (P