Mizuno T, Endo Y, Arita J, Kimura F
Department of Physiology, Yokohama City University School of Medicine, Japan.
Neuroscience. 1991;44(3):607-12. doi: 10.1016/0306-4522(91)90081-x.
Extracellular levels of acetylcholine were measured by the microdialysis method coupled to high performance liquid chromatography in the dorsal hippocampus of freely moving rats over a period of 24 h to examine whether the acetylcholine release in the hippocampus exhibited a diurnal variation. Spontaneous motor activity was simultaneously measured with an automatic animal activity monitor. The amount of acetylcholine collected per 20-min sample varied markedly, in a range from about 5 to 90 pmol. There appeared to be variations in the amount with a 2-4 h periodicity as well as an apparent diurnal periodicity. In all five rats studied, the overall mean value for the dark cycle (11.1-34.5, average 20.9 pmol/20 min) was significantly greater than that for the light cycle (5.1-21.3, average 12.3 pmol/20 min), showing a 70% average increase. Cross-correlation analysis performed between the amount of acetylcholine and the motor activity count for the animal during the sampling revealed a significant positive correlation coefficient in four rats studied. The present study demonstrates for the first time that the acetylcholine release shows a diurnal variation.
采用微透析法结合高效液相色谱法，对自由活动大鼠背侧海马在24小时内的细胞外乙酰胆碱水平进行测定，以研究海马中乙酰胆碱释放是否呈现昼夜变化。同时用自动动物活动监测仪测量自发运动活动。每20分钟样本收集的乙酰胆碱量变化显著，范围约为5至90皮摩尔。似乎存在2 - 4小时周期性变化以及明显的昼夜周期性变化。在所有研究的五只大鼠中，暗周期的总体平均值（11.1 - 34.5，平均20.9皮摩尔/20分钟）显著高于光周期（5.1 - 21.3，平均12.3皮摩尔/20分钟），平均增加70%。对采样期间动物的乙酰胆碱量与运动活动计数进行的交叉相关分析显示，在四只研究大鼠中相关系数显著为正。本研究首次证明乙酰胆碱释放呈现昼夜变化。
