Domino E F, Kadoya C, Matsuoka S
Department of Pharmacology, University of Michigan, Ann Arbor 48109-0626.
Eur J Clin Pharmacol. 1994;46(6):527-32. doi: 10.1007/BF00196110.
Ten normal adult tobacco smokers and 10 nonsmoking volunteers 20-31 years of age were the subjects of this study. The tobacco smokers all had a history of daily tobacco smoking. They were asked to stop smoking for 12 hours prior to testing. The Hoffmann (H) reflex and its recovery cycle were measured on different days before and just after smoking one nonfiltered 0 mg, low (0.27 mg), or high (2.16 mg) nicotine containing cigarette in a randomized order. Blood samples were drawn immediately after the H reflex recordings in the tobacco smokers. The blood samples were centrifuged, the plasma removed, frozen, and later assayed for nicotine and cotinine levels. Nonsmokers compared to tobacco smokers before smoking only had a tendency for enhanced amplitude of the recovery cycle. After smoking the nicotine containing cigarettes, the tobacco smokers had a depression of the amplitude of the H reflex recovery cycle. The amplitude of the H reflex recovery cycle at 160 ms was reduced. This decreased significantly with increasing plasma nicotine and cotinine concentrations. Individual differences were marked. The data obtained are consistent with evidence in animals that nicotine and tobacco smoke stimulate Renshaw inhibitory neurons in the spinal cord, either directly or indirectly which leads to a skeletal muscle relaxant effect.
本研究的对象为10名成年正常吸烟男性和10名年龄在20至31岁之间的非吸烟志愿者。所有吸烟男性均有每日吸烟史。他们被要求在测试前12小时停止吸烟。按照随机顺序，在吸烟前及刚吸完一支未过滤的含0毫克、低（0.27毫克）或高（2.16毫克）尼古丁香烟后的不同日期测量霍夫曼（H）反射及其恢复周期。在吸烟男性完成H反射记录后立即采集血样。将血样离心，分离出血浆，冷冻，随后检测尼古丁和可替宁水平。与仅在吸烟前的吸烟男性相比，非吸烟者的恢复周期振幅有增加的趋势。吸含尼古丁香烟后，吸烟男性的H反射恢复周期振幅降低。160毫秒时H反射恢复周期的振幅减小。随着血浆尼古丁和可替宁浓度的增加，这种减小显著。个体差异明显。所获得的数据与动物实验证据一致，即尼古丁和烟草烟雾直接或间接刺激脊髓中的闰绍抑制性神经元，从而产生骨骼肌松弛作用。
