Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2545664 | Journal of Ethnopharmacology | 2010 | 7 Pages |
Aim of the studyDanshen (root of Salvia miltiorrhiza) and Gegen (root of Pueraria lobata) are two herbs used in traditional Chinese medicine, most commonly for their putative cardioprotective and anti-atherosclerotic effects. In this study, the actions of a Danshen and Gegen formulation (DG; ratio 7:3) were investigated on rat-isolated cerebral basilar artery.Materials and methodsRat basilar artery rings were precontracted with 100 nM U46619. Involvement of endothelium-dependent mechanisms was investigated by mechanical removal of the endothelium; K+ channels were investigated by pretreatment of the artery rings with various K+ channel inhibitors, and Ca2+ channels were investigated in artery rings incubated with Ca2+-free buffer and primed with 100 nM U46619 for 5 min prior to adding CaCl2 to elicit contraction.ResultsDG produced concentration-dependent relaxation of the artery rings with an IC50 of 895 ± 121 μg/ml. Mechanical removal of the endothelium or pretreatment with the BKCa channel inhibitor iberiotoxin (100 nM), the KV channel inhibitor 4-aminopyridine (1 mM), or the KIR channel inhibitor barium chloride (100 μM), all had no effect on the DG-induced response (P > 0.05 for all). However, pretreatment with the KATP channel inhibitor glibenclamide (1 μM), the non-selective K+ channel inhibitor tetraethylammonium (TEA, 100 mM), or a combination of all the K+ channel inhibitors (iberiotoxin + 4-aminopyrindine + barium chloride + glibenclamide + TEA) produced significant inhibition on the DG-induced response (P < 0.01 for all); its maximum vasorelaxant effect (Imax) was reduced by 37, 24, and 30%, respectively. Preincubation of the artery rings with DG for 10 min produced concentration-dependent (1, 3 and 7 mg/ml) and total inhibition on the CaCl2-induced vasoconstriction.ConclusionsThese findings suggest the vasorelaxant effect of DG on rat basilar artery is independent of endothelium-derived mediators, whereas, inhibition of Ca2+ influx in the vascular smooth muscle cells is important, and a minor component is mediated by the opening of KATP channels. DG could be a useful cerebroprotective agent in some patients with occlusive cerebrovascular disease.
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