10.26091/ESRNZ.8062103.v1
Penelope Truman
Penelope
Truman
Peter Grounds
Peter
Grounds
Katharine A. Brennan
Katharine A.
Brennan
Monoamine oxidase inhibitory activity in tobacco particulate matter: Are harman and norharman the only physiologically relevant inhibitors?
Institute of Environmental Science and Research
2019
Tobacco Dependence
Monoamine Oxidase Inhibitors
Tobacco Particulate Matter
MOA Inhibition
Nicotine
Smoke
Rats
Dependence
Potent
Medical and Health Sciences not elsewhere classified
2019-05-02 04:23:09
Journal contribution
https://research.esr.cri.nz/articles/journal_contribution/Monoamine_oxidase_inhibitory_activity_in_tobacco_particulate_matter_Are_harman_and_norharman_the_only_physiologically_relevant_inhibitors_/8062103
Monoamine oxidase inhibition is significant in smokers, but it is still unclear how the inhibition that is seen in the brains and bodies of smokers is brought about. Our aim was to test the contribution of the harman and norharman in tobacco smoke to MAO-A inhibition from tobacco smoke preparations, as part of a re-examination of harman and norharman as the cause of the inhibition of MAO-A inhibition in the brain. Tobacco smoke particulate matter and cigarette smoke particulate matter were prepared and the amounts of harman and norharman measured. The results were compared with the total monoamine oxidase-A inhibitory activity. At a nicotine concentration of 0.6,M (a "physiological" concentration in blood) the total monoamine oxidase-A inhibitory activity measured in these samples was sufficient to inhibit the enzyme by approximately 10%. Of this inhibitory activity, only a small proportion of the total was found to be due to harman and norharman. These results show that harman and norharman provide only a moderate contribution to the total monoamine oxidase-A inhibitory activity of tobacco smoke, perhaps under 10%. This suggests that other inhibitors (either known or unknown) may be more significant contributors to total inhibitory activity than has yet been established, and deserve closer examination.