Truman Penelope, Grounds Peter, Brennan Katharine A
Institute of Environmental Science and Research Ltd, Porirua, New Zealand; Massey University, Wellington, New Zealand.
Institute of Environmental Science and Research Ltd, Christchurch, New Zealand.
Neurotoxicology. 2017 Mar;59:22-26. doi: 10.1016/j.neuro.2016.12.010. Epub 2017 Jan 3.
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 0.6μM (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.
单胺氧化酶抑制作用在吸烟者中很显著，但目前仍不清楚吸烟者大脑和身体中所观察到的这种抑制作用是如何产生的。我们的目的是测试烟草烟雾中的哈尔满和去甲哈尔满对烟草烟雾制剂中MAO - A抑制作用的贡献，这是对哈尔满和去甲哈尔满作为大脑中MAO - A抑制作用原因进行重新审视的一部分。制备了烟草烟雾颗粒物和香烟烟雾颗粒物，并测量了哈尔满和去甲哈尔满的含量。将结果与总单胺氧化酶 - A抑制活性进行比较。在尼古丁浓度为0.6μM（血液中的“生理”浓度）时，这些样品中测得的总单胺氧化酶 - A抑制活性足以使该酶抑制约10%。在这种抑制活性中，发现只有一小部分总量是由哈尔满和去甲哈尔满引起的。这些结果表明，哈尔满和去甲哈尔满对烟草烟雾的总单胺氧化酶 - A抑制活性的贡献仅为中等程度，可能低于10%。这表明其他抑制剂（无论是已知的还是未知的）可能是总抑制活性比目前所确定的更重要的贡献者，值得更深入的研究。
