Smith S S, Woodward D J, Chapin J K
Hahnemann University, Department of Anatomy, Philadelphia, PA 19102-1192.
Brain Res. 1989 Jan 9;476(2):307-16. doi: 10.1016/0006-8993(89)91251-1.
Adult female rats implanted with a microelectrode drive unit were trained to walk on a computer-controlled treadmill apparatus (10 s on every 20 s for 2 h) during recording of single Purkinje neurons in the paravermal area of the anterior cerebellum. Vigorous increases in the firing rate of individual units were found to be correlated with movement of specific limbs in particular stages of the step cycle during treadmill locomotion. Both spontaneous and motor-evoked discharge of individual Purkinje neurons were monitored before and after s.c. injection of either 17 beta estradiol (E2, 100 ng/kg) or progesterone (P, 50 micrograms). The percent increase in firing rate during locomotion versus rest was determined as a measure of the evoked:spontaneous discharge ratio. Drug-induced changes in this ratio indicate differential effects on the individual parameters, rather than simple excitatory or inhibitory effects. For all neurons tested, E2 augmented the movement-evoked discharge over pre-E2 control levels. The onset for this effect occurred at 15 min post-steroid, with a peak response noted at 30-35 min post-steroid. By 60-90 min, a partial recovery of the evoked:spontaneous ratio was noted, although absolute increases in both parameters were still observed, indicating long-term effects on neuronal activity. These effects were independent of the stage of the estrous cycle. In contrast, P decreased absolute firing rates of Purkinje cells during stationary and locomotor phases. However, the evoked:spontaneous ratio was decreased to an even greater degree. The latency for this effect was 9-12 min, with recovery to control levels of response seen at 30 min post-steroid. This response was typical of cells tested on estrus and diestrus 1. Cells tested on proestrus or diestrus 2, when E2 levels are increasing, were not modulated by P using the above paradigm.
将微电极驱动单元植入成年雌性大鼠体内，在记录小脑前叶蚓旁区域单个浦肯野神经元活动时，训练这些大鼠在计算机控制的跑步机装置上行走（每20秒行走10秒，共2小时）。研究发现，在跑步机运动的特定步周期阶段，单个神经元放电频率的剧烈增加与特定肢体的运动相关。在皮下注射17β-雌二醇（E2，100 ng/kg）或孕酮（P，50 μg）之前和之后，监测单个浦肯野神经元的自发放电和运动诱发放电。将运动期间与休息期间放电频率增加的百分比确定为诱发放电与自发放电比率的衡量指标。药物引起的该比率变化表明对各个参数有不同影响，而非简单的兴奋或抑制作用。对于所有测试的神经元，E2使运动诱发放电比注射E2前的对照水平有所增加。这种效应在注射类固醇后15分钟开始出现，在注射类固醇后30 - 35分钟达到峰值反应。到60 - 90分钟时，诱发放电与自发放电比率部分恢复，尽管两个参数的绝对值仍有增加，表明对神经元活动有长期影响。这些效应与发情周期阶段无关。相比之下，P降低了浦肯野细胞在静止和运动阶段的绝对放电频率。然而，诱发放电与自发放电比率下降得更为明显。这种效应的潜伏期为9 - 12分钟，在注射类固醇后30分钟恢复到对照反应水平。这种反应在发情期和动情间期1测试的细胞中很典型。在发情前期或动情间期2测试的细胞，此时E2水平正在升高，使用上述范式未受P的调节。
