TITLE:
Endothelium derived relaxation factors reduce sulfur dioxide-induced aortic relaxation
AUTHORS:
Omar A. M. Al-Habib, Abbas B. Q. Salihi
KEYWORDS:
Sulfur Dioxide; Endothelium; Endothelium Derived-Relaxation Factors; Organ Bath; PowerLab System; Aorta
JOURNAL NAME:
Open Journal of Molecular and Integrative Physiology,
Vol.3 No.4,
November
14,
2013
ABSTRACT: The
endothelium plays a key role in the control of vascular patency and tone. Thus,
the main objective of the study was to determine the role of endothelium and
its derived relaxation factors in mediating relaxation of rat thoracic aorta,
in response to sulfur dioxide (SO2) derivatives “1:3 M/M sodium
bisulfite (NaHSO3) and sodium sulfite (Na2SO3)”
using PowerLab tissue bath system. Endothelial denudation enhanced
relaxation responses of SO2 derivatives with an IC50 of
6.11 mM as compared to control rings with an IC50 of 6.21 mM, as
well as the maximum relaxation (Emax)
was increased from 62.026% ± 6.527% to 83.13% ± 14.755%. Furthermore, the
relaxation responses to SO2 derivatives in aortic rings were significantly
enhanced by indomethacin, clotrimazole and methylene blue with IC50’s
of 4.8 mM, 5.33 mM and 4.01 mM, and Emax were raised to 101.1% ± 6.537%, 66.92 ± 7.538 and 104.68 ± 3.575, respectively.
Meanwhile, L-NAME did not alter dose-dependent relaxation of SO2 derivatives in comparison to control aortic rings. The results of this study
had shown that endothelium denudation and blocking of endothelium
derived-relaxation factors enhanced vasodilator effect of SO2; this
may clarify the role of endothelium in the vasodilatory mechanism of SO2.