Boyajian R A, Otis S M
Division of Neurology, Department of Medicine, Scripps Clinic, La Jolla, CA 92037, USA.
J Neuroimaging. 2000 Oct;10(4):204-8. doi: 10.1111/jon2000104204.
Middle cerebral artery (MCA) flow velocity was continuously monitored during smoking in an observational study (n = 14) using transcranial Doppler (TCD) ultrasonography. Cerebral autoregulatory vasodilator capacitance under inspired CO2 challenge was also measured before smoking and at peak smoking effect. Several puffs on a single lighted cigarette over a period of five minutes acutely increased MCA mean flow velocity in every subject (group mean increase: 19%, individual increases ranged 2-64%) with a response onset and offset detectable within several seconds of beginning and ending smoking. The mechanism for the increase in MCA flow velocities appeared to be independent of the CO2 autoregulatory mechanism. Gender subgroup analysis showed smoking acutely suppressed the CO2 vasodilator capacitance by 56% in men but only by 5% in women (p = 0.05). The magnitude of the acute smoking-induced increases in MCA flow velocities appeared to be independent of the estimated cigarette yields for nicotine, carbon monoxide, and "tar." Smoking in healthy subjects acutely increased MCA mean flow velocity, which may reflect a global increase in cerebral blood flow via complex influences on the cerebral autoregulation.
在一项观察性研究（n = 14）中，使用经颅多普勒（TCD）超声在吸烟过程中持续监测大脑中动脉（MCA）的血流速度。在吸烟前和吸烟效果达到峰值时，还测量了在吸入二氧化碳刺激下的脑自动调节血管舒张能力。在五分钟内对一支点燃的香烟吸几口，会使每个受试者的MCA平均血流速度急剧增加（组平均增加：19%，个体增加范围为2 - 64%），在开始和结束吸烟的几秒钟内即可检测到反应的开始和结束。MCA血流速度增加的机制似乎与二氧化碳自动调节机制无关。性别亚组分析显示，吸烟会使男性的二氧化碳血管舒张能力急性降低56%，而女性仅降低5%（p = 0.05）。急性吸烟引起的MCA血流速度增加的幅度似乎与尼古丁、一氧化碳和“焦油”的估计香烟产量无关。健康受试者吸烟会使MCA平均血流速度急性增加，这可能反映了通过对脑自动调节的复杂影响导致脑血流量的整体增加。
