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 o...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.展开更多
Direct observation was made by using the patch-clamp technique with a specially designed microperfusion system to investigate the effect of acetylcholine (Ach 10<sup>-6</sup> mol/L) elicited endothelium-de...Direct observation was made by using the patch-clamp technique with a specially designed microperfusion system to investigate the effect of acetylcholine (Ach 10<sup>-6</sup> mol/L) elicited endothelium-derived relaxing factor （EDRF） on the calcium-activated potassium channel （IK（Ca））in the smooth muscle cells of mesenteric resistance vessels in Wistar rats. Activation of IK（Ca） was firstly observed by inducing the elicited EDRF or sodium nitroprusside (SNP 10<sup>-8</sup> mol/L) under various clamping voltages in cell-attached configuration. While the pipette solution contained KCl 126 mmol/L and the bath solution contained KCl 5.9 mmol/L, two types of conductances of calcium-activated potassium current being 76.4±2.3 pS（mean±S.E. n = 7） and 160.3±7.5 pS （mean±S.E. n= 7） were recorded during the EDRF activation, one type of conductance being 100.5±2.8 pS （mean±S.E. n = 6） was activated by nitric oxide （NO） which is an effective component from SNP. Differences in kinetic characteristics of these channels展开更多
文摘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.
基金Project supported by the National Natural Science Foundation of China.
文摘Direct observation was made by using the patch-clamp technique with a specially designed microperfusion system to investigate the effect of acetylcholine (Ach 10<sup>-6</sup> mol/L) elicited endothelium-derived relaxing factor （EDRF） on the calcium-activated potassium channel （IK（Ca））in the smooth muscle cells of mesenteric resistance vessels in Wistar rats. Activation of IK（Ca） was firstly observed by inducing the elicited EDRF or sodium nitroprusside (SNP 10<sup>-8</sup> mol/L) under various clamping voltages in cell-attached configuration. While the pipette solution contained KCl 126 mmol/L and the bath solution contained KCl 5.9 mmol/L, two types of conductances of calcium-activated potassium current being 76.4±2.3 pS（mean±S.E. n = 7） and 160.3±7.5 pS （mean±S.E. n= 7） were recorded during the EDRF activation, one type of conductance being 100.5±2.8 pS （mean±S.E. n = 6） was activated by nitric oxide （NO） which is an effective component from SNP. Differences in kinetic characteristics of these channels
