Comments on 'vascular effects of dietary nitrate (as found in green leafy vegetables and beetroot) via the nitrate-nitrite-nitric oxide pathway'.

摘要: It was our pleasure to read an excellent review by Lidder & Webb about the nitrate-nitrite-nitric oxide pathway 1. These authors summarized whole spectrum of nitrite and nitrate effects provided a clinical trials using dietary interventions as well suggesting nitrite/nitrate dose standardization. We would like comment on effect platelet function. In this part, older reports cited show that addition preparations had no We recently reported 2 is correct when only rich plasma or similar pure are used. However, we showed red blood cells such combined with hypoxia significant functioning inhibition aggregation observed upon addition. data in agreement hypothesis added reduced nitric hypoxic recent observation altered manipulation – mice fed low diet better than standard (Park JW, unpublished data). This could be important start for future investigations settings enhanced either required avoided. We also address one other point. Since neuroglobin cytoglobin were discovered, there has been intensive search their biological functions. Neuroglobin normally expressed brain at very levels both globins upregulated during hypoxia. They able bind oxygen, CO NO, so proposals function range from delivering oxygen detoxifying deleterious NO reperfusion. Several papers claim reductase 3–5. question physiological relevance based following considerations (i) Heme exists 5-coordinated 6-coordinated molecule. equilibrium shifted strongly towards conformation distal histidine bound heme position available binding ligands state. leads small fraction total possibly active conditions. All three used non-physiological conditions detect activity reactions carried out anaerobically. (ii) Only ferrous reduce NO. known oxidizes ferric state fairly easily have unsuccessful attempts find neuroglobin-associated Fe back its [see 6 example]. Similar explained apply under near-anoxic described cultured human aortic smooth muscle 7. (iii) Even these limitations it necessary introduce arbitrary structural mutations into achieve reduction 3, 4. For reasons, together abundance cytoglobin, believe reductases vivo physiologically irrelevant.