EXPERIMENTAL RESEARCH
Endothelium-dependent relaxation induced by etomidate in the aortas of insulin-resistant rats
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Submission date: 2016-08-25
Final revision date: 2016-12-01
Acceptance date: 2016-12-15
Online publication date: 2018-08-13
Publication date: 2018-08-07
Arch Med Sci 2018;14(5):1155-1162
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ABSTRACT
Introduction:
Few reports have mentioned the effect of etomidate on the
aortas of insulin-resistant (IR) rats. In this study, we investigated the effect
of etomidate on isolated IR aortas of rats, and explored its underlying
mechanism.
Material and methods:
The IR rat model was established through feeding with
a high-fructose diet. The systolic blood pressure (SBP) was measured by the tailcuff
method before grouping and at the end of the 8-week feeding; blood samples
were also obtained for analysis. Thoracic aorta rings of IR rats were isolated
and suspended in a tissue bath. The tensile force was recorded isometrically.
The effect of etomidate on provoked contraction of the rings was assessed with
or without a potassium channel blocker or NO synthase inhibitor
Results:
Etomidate-induced relaxation in IR rings was greater than normal
control (NC) rings (all p < 0.001 with etomidate log M of –4 to –6). NG-nitro-
L-arginine methyl ester (L-NAME, an NO synthase inhibitors) inhibited
etomidate-induced relaxation in NC rings, but had no effect on the IR rings
(all p < 0.001 with etomidate log M of –4 to –6). Pre-incubation with glibenclamide
(Gli, a potassium channel blocker) significantly inhibited etomidate-
induced relaxation in NC and IR rings (all p < 0.001 with etomidate log M
of –4 to –6), and had no inhibited effect on endothelial denuded aortic rings.
Conclusions:
IR increased etomidate-induced relaxation in rat aortas. Etomidate
causes vasodilation in IR rat aortas via both endothelium-dependent
and independent ways; impaired NO-mediated relaxation was disrupted and
ATP-sensitive potassium (KATP) channel-mediated relaxation may be involved
in the endothelium-dependent relaxation of etomidate in IR rats.