| Inhibition of cytochrome P-450 (CYP450)ω-hydroxylase markedly decreases 20-HETE production, produces profound reduction in myocardial infarct size. However, the action of 20-HETE on cardiomyotyes is poorly understood. Thus, the objective of current study is to examine the effect of 20-HETE on intracellular calcium levels and reactive oxygen species (ROS) generation in cardiomyocytes. Calcium concentration were measured using confocal microscope and calcium-sensitive fluo 3-AM in cardiac cells cultured from neonatal rats. Incubation of cardiomyotyes with 20-HETE significantly increased calcium concentration and calcium transient by 44 % and 33% respectively. This effect of 20-HETE was abolished by a ROS scavenger tempol (100μM) and a NADPH oxidase inhibitor apocynin(1μM). In addition, 20-HETE significantly elevated intracellular ROS levels by 23% and increased NADPH oxidase activity by 27 % in cultured cardiac cells. These observations provide the first evidence that 20-HETE, the product of CYP450ω-hydroxylase, stimulates NADPH oxidase-derived ROS production and elevates intracellular calcium. The action of 20-HETE could contribute to the cardiac injury during myocardial ischemia.
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