Department of Psychology, University of Roehampton, London, UK.
Combined Universities Brain Imaging Centre, Department of Psychology, Royal Holloway, University of London, Surrey, UK.
Addict Biol. 2021 Jul;26(4):e12986. doi: 10.1111/adb.12986. Epub 2020 Dec 3.
Cigarette smoking is still the largest contributor to disease and death worldwide. Successful cessation is hindered by decreases in prefrontal glutamate concentrations and gray matter volume due to daily smoking. Because nondaily, intermittent smoking also contributes greatly to disease and death, understanding whether infrequent tobacco use is associated with reductions in prefrontal glutamate concentrations and gray matter volume may aid public health. Eighty-five young participants (41 nonsmokers, 24 intermittent smokers, 20 daily smokers, mean age ~23 years old), underwent H-magnetic resonance spectroscopy of the medial prefrontal cortex, as well as structural magnetic resonance imaging (MRI) to determine whole-brain gray matter volume. Compared with nonsmokers, both daily and intermittent smokers exhibited lower concentrations of glutamate, creatine, N-acetylaspartate, and myo-inositol in the medial prefrontal cortex, and lower gray matter volume in the right inferior frontal gyrus; these measures of prefrontal metabolites and structure did not differ between daily and intermittent smokers. Finally, medial prefrontal metabolite concentrations and right inferior frontal gray matter volume were positively correlated, but these relationships were not influenced by smoking status. This study provides the first evidence that both daily and intermittent smoking are associated with low concentrations of glutamate, creatine, N-acetylaspartate, and myo-inositol and low gray matter volume in the prefrontal cortex. Future tobacco cessation efforts should not ignore potential deleterious effects of intermittent smoking by considering only daily smokers. Finally, because low glutamate concentrations hinder cessation, treatments that can normalize tonic levels of prefrontal glutamate, such as N-acetylcysteine, may help intermittent and daily smokers to quit.
吸烟仍然是全球疾病和死亡的最大元凶。由于每天吸烟会导致前额叶谷氨酸浓度和灰质体积减少，成功戒烟受到阻碍。由于非每日、间歇性吸烟也对疾病和死亡有很大贡献，因此了解偶尔吸烟是否与前额叶谷氨酸浓度和灰质体积减少有关，可能有助于公共卫生。85 名年轻参与者（41 名不吸烟者、24 名间歇性吸烟者、20 名每日吸烟者，平均年龄约 23 岁）接受了内侧前额叶皮质的 H 磁共振波谱分析，以及结构磁共振成像（MRI）以确定全脑灰质体积。与不吸烟者相比，每日吸烟者和间歇性吸烟者的内侧前额叶谷氨酸、肌酸、N-乙酰天冬氨酸和肌醇浓度均较低，右侧额下回灰质体积较低；这些前额叶代谢物和结构的测量值在每日吸烟者和间歇性吸烟者之间没有差异。最后，内侧前额叶代谢物浓度和右侧额下回灰质体积呈正相关，但这些关系不受吸烟状况的影响。这项研究首次提供了证据，表明每日和间歇性吸烟都与前额叶谷氨酸、肌酸、N-乙酰天冬氨酸和肌醇浓度降低以及前额叶灰质体积减少有关。未来的烟草戒烟工作不应忽视间歇性吸烟的潜在有害影响，只考虑每日吸烟者。最后，由于低谷氨酸浓度会阻碍戒烟，因此使用 N-乙酰半胱氨酸等可以使前额叶谷氨酸正常化的治疗方法，可能有助于间歇性和每日吸烟者戒烟。
