Avila Matthew T, Sherr Jay D, Hong Elliot, Myers Carol S, Thaker Gunvant K
Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD 21228, USA.
Neuropsychopharmacology. 2003 Dec;28(12):2184-91. doi: 10.1038/sj.npp.1300265.
Several studies have shown that schizophrenic patients and their biological relatives generate a greater number of leading saccades during smooth pursuit eye movement (SPEM) tasks. This abnormality may reflect a failure of cortical and/or cerebellar areas to coordinate saccadic and pursuit eye movements during visual tracking. The pharmacology of this phenomenon is not known. Here, we sought to replicate and extend the findings of Olincy et al (1998), who found that nicotine transiently reduced the number of leading saccades during SPEMs. A total of 27 subjects with schizophrenia (17 males; 14 smokers), and 25 healthy comparison subjects (nine males; 14 smokers) completed an eye-tracking task after receiving a 1.0 mg nasal spray of nicotine and during drug-free conditions. Results confirm that nicotine reduces the number of leading saccadic eye movements during visual tracking in schizophrenic patients. Baseline impairments and the beneficial effects of nicotine were not restricted to patient smokers, as nonsmoker patients exhibited the greatest number of leading saccades in the no drug condition and exhibited the most pronounced improvements after nicotine administration. Improvement in patient nonsmokers was not a function of previous smoking history. No effect of nicotine was observed in control nonsmokers. In contrast to the previous study, nicotine appeared to improve performance in control smokers. Overall, the study results support a functional role of nACh receptors in improving eye-tracking performance, and are consistent with the hypothesis, articulated by several investigators, that nACh receptor system abnormalities are responsible for a number of schizophrenia-related neurophysiological deficits.
多项研究表明，精神分裂症患者及其生物学亲属在平稳跟踪眼球运动（SPEM）任务中产生的起始性扫视次数更多。这种异常可能反映出在视觉跟踪过程中，皮质和/或小脑区域在协调扫视和跟踪眼球运动方面存在功能障碍。这种现象的药理学机制尚不清楚。在此，我们试图重复并扩展奥林西等人（1998年）的研究结果，他们发现尼古丁能短暂减少SPEM期间的起始性扫视次数。共有27名精神分裂症患者（17名男性；14名吸烟者）和25名健康对照者（9名男性；14名吸烟者）在接受1.0毫克尼古丁鼻喷雾剂后以及在无药物状态下完成了一项眼球跟踪任务。结果证实，尼古丁可减少精神分裂症患者在视觉跟踪期间的起始性扫视眼球运动次数。基线损伤和尼古丁的有益作用并不局限于患者吸烟者，因为不吸烟的患者在无药物状态下起始性扫视次数最多，而在给予尼古丁后改善最为明显。不吸烟患者的改善与既往吸烟史无关。在对照不吸烟者中未观察到尼古丁的作用。与先前的研究不同，尼古丁似乎改善了对照吸烟者的表现。总体而言，研究结果支持了烟碱型乙酰胆碱受体（nACh）在改善眼球跟踪表现方面的功能作用，并且与一些研究者提出的假说一致，即nACh受体系统异常是导致一些与精神分裂症相关的神经生理缺陷的原因。
