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Background and Objective: Tangeretin is a flavonoid compound found in citrus fruits. Several biological activities of tangeretin have been revealed including; anti-neurodegeneration, anti-inflammation, and anti-oxidation. This study was to investigate the effects of tangeretin on vascular function in L-NAME-treated rats.
Methods: Rats were divided into 4 groups. Groups I; rats treated with L-NAME (40 mg/kg) in drinking water only, Groups II and III; rats treated with L-NAME together with tangeretin (15 and 30 mg/kg, respectively), Groups IV; control rats were received only distilled water (n=7/each group). At the end of experiment, vascular responses to electrical field stimulation (EFS) and vasoactive agents in mesenteric vascular beds and aortic rings were evaluated.
Results: A significant increase in contractile response to electrical EFS was observed in the mesenteric vascular bed isolated from L-NAME-treated rats (p<0.05). Tangeretin reduced the augmented response to EFS in L-NAME-treated rats comparing to those of untreated rats (p<0.05). However, the contractile response to exogenous norepinephrine was not different among groups. Vasorelaxation responses to acetylcholine (ACh) in the mesenteric vascular beds and aortic rings were significantly blunted in L-NAME-treated rats compared to control rats (p<0.05). Treatment with tangeretin improved the vasorelaxation response to ACh in L-NAME-treated rats compared to untreated rats (p<0.05). There was no significant difference in the
vasorelaxation responses to sodium nitroprusside among groups.
Conclusions: The results of this study indicated that tangeretin suppresses sympathetic nerve mediated contractile response and improves endothelium-dependent vasorelaxtion in L-NAME-treated rats.
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