title: The vasorelaxant effect and its mechanisms of sodium bisulfite as a sulfur dioxide donor.
abstract: To study the biological role of bisulfite on vascular contractility and its underlying cellular and molecular mechanisms, to explore whether bisulfite can be used as a sulfur dioxide (SO(2)) donor in the biological experiments, the vasorelaxant effects of sodium bisulfite and sodium sulfite on isolated rat thoracic aortic rings were compared; and the signal transduction pathways and the ion channels involved in the vascular effects of bisulfite were investigated. The results show that: (1) Sodium bisulfite relaxed rat thoracic aortic rings in a concentration-dependent manner (from 100 to 4000 μM); however, sodium sulfite at 500 and 1000 μM caused vasoconstriction, and only at higher concentrations (from 2000 to 4000 μM) it caused vasorelaxation in a concentration-dependent manner. (2) The vasorelaxation caused by the bisulfite at low concentrations (≤500 μM) was endothelium-dependent, but at high concentrations (≥1000 μM) it was endothelium-independent. (3) The vasorelaxation by the bisulfite at the low concentrations was partially mediated by the cGMP pathway and the vasorelaxation was related to big-conductance Ca(2+)-activated K(+) (BK(Ca)) channel, but not due to prostaglandin, protein kinase C (PKC) and cAMP pathways. (4) The vasorelaxation by the bisulfite at high concentrations was partially inhibited by tetraethylammonium (TEA) and glibenclamide, suggesting that the vasorelaxation was related to ATP-sensitive K(+) channel (K(ATP)) and L-type calcium-channel. These results led to the conclusion that bisulfite (HSO(3)(-)) might be a vasoactive factor and sodium bisulfite can be used as a SO(2) donor for the study of SO(2) biology.
authors: Institute of Environmental Medicine and Toxicology, Shanxi University, Taiyuan 030006, China. zqmeng@sxu.edu.cn
authors: Ziqiang
authors: Z
authors: Meng
authors: Zhenhua
authors: Z
authors: Yang
authors: Junling
authors: J
authors: Li
authors: Quanxi
authors: Q
authors: Zhang
mesh_terms: D000042:Absorption; D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D015221:Potassium Channels / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects; D013447:Sulfites / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D013458:Sulfur Dioxide / Q000737:chemistry / Q000378:metabolism*; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D014867:Water / Q000737:chemistry
chemical_list: D020746:Calcium Channels, L-Type; D015221:Potassium Channels; D013447:Sulfites; D014665:Vasodilator Agents; D014867:Water; D013458:Sulfur Dioxide; D006152:Cyclic GMP; C009279:sodium bisulfite; C025026:sodium sulfite