青蛙光敏感松果体神经节细胞自发放电的昼夜节律变化

为了研究青蛙松果体的昼夜节律,本实验采用细胞外连续记录,研究了松果体内对光产生抑制反应的光敏神经节细胞放电的昼夜节律变化.结果表明(1)所有表现自发放电的细胞,其放电频率介于1-6Hz之间,脉冲发放特征有规则、不规则(或波动)和阵发等方式;(2)无论在持续黑暗(DD)、持续光照(LL)或在模拟自然光照周期(L-D-L)任何一种条件下所进行的昼夜连续记录都显示:有些细胞在白天放电频率低,在夜间放电增强;而另一些细胞则在整个记录过程中,其脉冲频率基本上保持不变.当用与昼夜光照颠倒的周期(D-L-D)作实验时,所有被检测的细胞都反映出夜间的放电活性受到了不同程度的抑制.

CIRCADIAN CHANGE OF THE MAINTAINED DISCHARGE OF PHOTORECEPTIVE PINEAL GANGLION CELLS IN THE FROG

In order to study the circadian changes of activity of the pineal organ, long-term recording was performed from light-sensitive ganglion cells of the frog's epiphysis cerebri responding inhibitory to light. Results show that (i) all cells exhibiting spontaneous electrical activity have firing frequen cies between 1 and 6 Hz, and their discharge patterns are characterized as regular, irregular (or oscillatory) and bursting; (ii) long-term recording across day- and night-time reveals some cells exhibiting lower firing rate during the day and increasing activity during the night and some units showing constant activity throughout the recording time, no matter what conditions of darkness (DD) and constant illumination(LL), as well as natural lightening period(L-D -L), takes place. With inverted periods of illumination(D-L-D) the firing rate of all tested cells are depressed in different degree at night period.