White A M, Best P J
Department of Psychology and Center for Neuroscience, Miami University, Oxford, OH 45056, USA.
Brain Res. 2000 Sep 8;876(1-2):154-65. doi: 10.1016/s0006-8993(00)02629-9.
Mounting evidence suggests that ethanol exerts effects on learning and memory by altering cellular activity in the hippocampus and related structures. However, little is actually known regarding ethanol's effects on hippocampal function in awake, freely-behaving animals. The present study examines the effects of ethanol on hippocampal place-cell and interneuron activity in freely-behaving rats. Signals from individual hippocampal neurons were isolated while subjects traversed a symmetric Y-maze for food reward. Following 15 min of baseline recording, subjects were injected with one of four doses of ethanol (0.0, 0.5, 1.0 and 1.5 g/kg), and cellular activity was monitored for a 1-h time period. Following sufficient time for recovery (minimum of 3 h post injection), cellular activity was monitored for an additional 15-min period. Both 1.0 and 1.5 g/kg ethanol potently suppressed the firing of hippocampal place-cells without altering place-field locations. Ethanol did not significantly suppress out-of-field firing rates, leading to a decrease in spatial specificity (i.e. the ratio of in-field/out-of-field firing rates). Interneuron activity was not altered by 1.0 g/kg ethanol, but was occasionally suppressed by 1.5 g/kg ethanol. Results are interpreted in light of recent behavioral and electrophysiological studies examining the effects of ethanol on hippocampal function.
越来越多的证据表明，乙醇通过改变海马体及相关结构中的细胞活动来影响学习和记忆。然而，对于乙醇在清醒、自由活动的动物体内对海马体功能的影响，实际了解甚少。本研究考察了乙醇对自由活动大鼠海马体位置细胞和中间神经元活动的影响。在实验对象穿过对称的Y型迷宫以获取食物奖励时，分离出单个海马体神经元发出的信号。在进行15分钟的基线记录后，给实验对象注射四种剂量乙醇（0.0、0.5、1.0和1.5克/千克）中的一种，然后在1小时内监测细胞活动。在有足够的恢复时间（注射后至少3小时）后，再额外监测15分钟的细胞活动。1.0克/千克和1.5克/千克的乙醇均能有效抑制海马体位置细胞的放电，同时不改变位置野的位置。乙醇并未显著抑制野外放电率，导致空间特异性降低（即野内/野外放电率之比）。1.0克/千克的乙醇未改变中间神经元的活动，但1.5克/千克的乙醇偶尔会抑制其活动。结合近期研究乙醇对海马体功能影响的行为学和电生理学研究结果对本研究结果进行了解释。
