Human heart mitochondria and nitric oxide production: hard work

attilaexperimentI’ve almost missed the publication of an article by our group back home, in Budapest which is my first real first author peer-review article published in Life Sciences, impact factor, 2.512 as of 2005. The peer-review process was hard (illustration: me under the hood) and bloody, because it is a negative result, so you have to be more careful and logically step-by-step. We’ve eventually showed that Human heart mitochondria do not produce physiologically relevant quantities of nitric oxide. Take care, it is hardcore science without any popular tone. đŸ™‚ Abstract here:

Previous studies raised the possibility that nitric oxide synthase is present in heart mitochondria (mtNOS) and the existence of such an enzyme became generally accepted. However, original experimental evidence is rather scarce and positive identification of the enzyme is lacking. We aimed to detect an NOS protein in human and mouse heart mitochondria and to measure the level of NO released from the organelles. Western blotting with 7 different anti-NOS antibodies failed to detect a NOS-like protein in mitochondria. Immunoprecipitation or substrate-affinity purification of the samples concentrated NOS in control preparations but not in mitochondria. Release of NO from live respiring human mitochondria was below 2 ppb after 45 min of incubation. In a bioassay system, mitochondrial suspension failed to cause vasodilation of human mammary artery segments. These results indicate that mitochondria do not produce physiologically relevant quantities of NO in the heart and are unlikely to have any physiological importance as NO donors, nor do they contain a recognizable mtNOS enzyme.

One thought on “Human heart mitochondria and nitric oxide production: hard work

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