Hutchison K E, Niaura R, Swift R
University of Colorado, Department of Psychology, Boulder, 80309-0345, USA.
Psychopharmacology (Berl). 2000 Jun;150(3):244-52. doi: 10.1007/s002130000399.
Several previous investigations with animals and humans have suggested that nicotine enhances prepulse inhibition of the startle reflex (PPI). However, the administration of nicotine activates mesolimbic dopamine, and activation of mesolimbic dopamine is known to attenuate prepulse inhibition of the startle reflex (PPI), which might suggest that nicotine would decrease PPI.
The primary aim of this study was to test rigorously the effects of smoking high nicotine cigarettes on PPI and other measures (e.g., heart rate, craving, and mood) when the concentration of nicotine peaks in the brain (i.e., immediately after smoking).
Thirty smokers participated in two experimental sessions 1 week apart. Two high nicotine cigarettes were smoked in one session, and two control cigarettes were smoked in the other session after overnight deprivation.
The results indicated that smoking the high nicotine cigarettes decreased PPI and that PPI increased across trials in both conditions. The interaction between nicotine dose and trial was not significant, although it appeared that high nicotine may have reversed an increase in PPI across trials in the control condition. High nicotine cigarettes also significantly increased heart rate, decreased the latency to peak startle response on control trials, but did not alter the magnitude of the startle response.
The findings suggest that either high nicotine cigarettes reduced PPI, or possibly, that high nicotine cigarettes may have reversed an increase in PPI across trials as evident in the control condition.
先前针对动物和人类的多项研究表明，尼古丁可增强惊吓反射的前脉冲抑制（PPI）。然而，尼古丁的给药会激活中脑边缘多巴胺，而中脑边缘多巴胺的激活已知会减弱惊吓反射的前脉冲抑制（PPI），这可能表明尼古丁会降低PPI。
本研究的主要目的是在大脑中尼古丁浓度达到峰值时（即吸烟后立即），严格测试吸高尼古丁香烟对PPI及其他指标（如心率、渴望和情绪）的影响。
30名吸烟者参加了相隔1周的两次实验。在一次实验中吸两支高尼古丁香烟，在另一次实验中，经过一夜禁食后吸两支对照香烟。
结果表明，吸高尼古丁香烟会降低PPI，且在两种情况下PPI在各试验中均增加。尼古丁剂量与试验之间的交互作用不显著，尽管在对照条件下，高尼古丁似乎可能逆转了PPI在各试验中的增加。高尼古丁香烟还显著提高了心率，缩短了对照试验中惊吓反应峰值的潜伏期，但未改变惊吓反应的幅度。
研究结果表明，要么是高尼古丁香烟降低了PPI，要么可能是高尼古丁香烟逆转了对照条件下各试验中PPI的增加。
