The vasodilatory effect of Apium graveolens L (celery) seed in isolated rat aorta: The roles of endothelium, calcium and potassium channels

OBJECTIVE: Apium graveolens L. (celery) seed has been used for hypertension treatment. To provide a pharmacological basis, the vasorelaxant effect of celery seed extract was investigated in isolated rat aorta. MATERIALS AND METHODS: Wistar male rats (200-250 g) were divided into 15 groups (n=7 for each group). The vasorelaxant response of different concentrations of celery seed extract (0.05, 0.1, 0.25, 0.5, 1, and 2 mg/ml) on isolated aorta precontracted with phenylephrine (PE) or KCl was evaluated by organ bath technique. The role of endothelium, extracellular calcium influx, intracellular sources of calcium, and potassium channels in vasorelaxant effect of celery seed extract was investigated. RESULTS: The extract showed a concentration-dependent relaxation in the isolated aorta contracted with PE and KCl that was endothelium-dependent at lower concentrations. Pretreatment of aortic rings with indomethacin or L-NAME, did not affect the vasorelaxation induced by celery seed extract. The extract inhibited KCl and PE-induced contractions in cumulative calcium concentrations as well as after incubation with diltiazem in denuded aortic rings of endothelium. The relaxation induced by celery seed extract was inhibited by 4-aminopyridine. CONCLUSION: This relaxation was mediated by inhibiting calcium influx into vascular smooth muscle cells. Also, voltage-dependent potassium channels were involved in inducing the vasorelaxant effect of celery seed extract.