Participation of nitric oxide in regional coronary bloodflow regulation during myocardial ischemia in the canine heart (part 10)

9 Sep

Other substances such as adenosine, a metabolite that is produced during myocardial ischemia , has been proposed as mediator for the release of nitric oxide in the endothelium; however, in isolated canine coronary microvessels, Jones et al showed that inhibition of nitric oxide synthesis does not affect the dilation of isolated arterioles by adenosine, suggesting that adenosine does not act by releasing nitric oxide.
Our results agree with reports supporting the participation of nitric oxide in the regulation of coronary flow during myocardial hypoxia and ischemia . Thus, Smith and Canty showed in conscious dogs that the coronary autoregulatory pressure-flow curve is not affected by inhibition of nitric oxide synthesis except for very low coronary perfusion pressures in the ischemic range. Besides, Kitakaze et al recently reported the participation of nitric oxide in coronary flow regulation in the ischemic myocardium.

Because inhibition of nitric oxide synthesis seems to produce constriction mainly in small arteries larger than 100 |j.m in diameter, and the metabolic regulation of coronary flow occurs predominantly in vessels smaller than 100 |j.m in diameter , we interpret our results as the constriction of small arteries in the presence of maximal dilation of the microvessels induced by ischemia. You will appreciate this opportunity to have a trusted pharmacy at your service, available round the clock and offering buy levlen birth control with fast delivery to any country of the world, which will sure make it a lot easier for you as a patient.