Zigmond R E, Chalazonitis A
Brain Res. 1979 Mar 23;164:137-52. doi: 10.1016/0006-8993(79)90011-8.
The effects of increased synaptic stimulation of sympathetic neurons on the tyrosine hydroxylase activity of these cells were studied. Seventy-two hours after unilateral stimulation of the preganglionic cervical sympathetic trunk at 10 Hz for 30 min tyrosine hydroxylase activity was 32% higher in stimulated than in control superior cervical ganglia. Stimulation at 10 Hz for only 10 min increased enzyme activity by 25% when measured 72 h later, while stimulation for 60 min increased activity by 73%. No further change in enzyme activity was found after 90 min of stimulation although electrophysiological recordings from the ganglion demonstrated that synaptic transmission was maintained throughout the period of stimulation. Ganglionic neurons also follow high frequency trains of stimuli when they are interrupted by silent periods. Stimulation with 40 Hz trains (250 msec on/500 msec off) for 30 min and 90 min produced a 50% and a 92% increase in tyrosine hydroxylase activity, respectively. Stimulation of ganglia with the same number of pulses administered either continuously or in trains produced the same size increase in enzyme activity. The relationship between preganglionic nerve activity and tyrosine hydroxylase activity may represent an adaption of sympathetic neurons to situations requiring increased transmitter release.
研究了增加交感神经元的突触刺激对这些细胞酪氨酸羟化酶活性的影响。在以10Hz频率单侧刺激颈上交感干节前纤维30分钟后72小时，受刺激的颈上神经节中酪氨酸羟化酶活性比对照神经节高32%。当在72小时后测量时，以10Hz频率刺激仅10分钟可使酶活性增加25%，而刺激60分钟可使活性增加73%。在刺激90分钟后未发现酶活性有进一步变化，尽管神经节的电生理记录表明在整个刺激期间突触传递一直维持。当神经节神经元的高频刺激序列被静息期打断时，它们也会跟随这种刺激。以40Hz序列（250毫秒开启/500毫秒关闭）刺激30分钟和90分钟分别使酪氨酸羟化酶活性增加50%和92%。以相同数量的脉冲连续或成串刺激神经节，酶活性增加的幅度相同。节前神经活动与酪氨酸羟化酶活性之间的关系可能代表交感神经元对需要增加递质释放的情况的一种适应。
