Zigmond R E
Fed Proc. 1980 Oct;39(12):3003-8.
The role of neural activity in the long-term regulation of tyrosine hydroxylase in peripheral adrenergic neurons had been studied by electrically stimulating the preganglionic nerves innervating the superior cervical ganglion. Tyrosin hydroxylase activity was elevated maximally 3 days after stimulation. The magnitude of the increase varied from 25 to 120% depending on the frequency and duration of the stimulation. Dopamine-beta-hydroxylase activity was also increased after preganglionic nerve stimulation, but there was no change in dopa decarboxylase activity or in the ganglion protein content. The increase in tyrosine hydroxylase activity is paralleled by a comparable increase in the amount of immunoreactive tyrosine hydroxylase in the ganglia. This increase in enzyme activity could be prevented by pretreating animals with the ganglion-blocking drugs hexamethonium or chlorisondamine but was unaffected by administration of atropine or dihydroergotamine. Antidromic stimulation did not mimic the effects of orthodromic stimulation indicating that an increase in the firing rate of the neurons was not a sufficient condition for the long-term elevation of tyrosine hydroxylase activity. These studies demonstrate that periods of increased synaptic stimulation can alter the protein composition of sympathetic neurons, increasing the specific activity of the key enzyme involved in their transmitter biosynthesis.
通过电刺激支配颈上神经节的节前神经，研究了神经活动在外周肾上腺素能神经元中酪氨酸羟化酶长期调节中的作用。刺激后3天，酪氨酸羟化酶活性最大程度升高。增加的幅度在25%至120%之间，具体取决于刺激的频率和持续时间。节前神经刺激后多巴胺-β-羟化酶活性也增加，但多巴脱羧酶活性或神经节蛋白含量没有变化。神经节中免疫反应性酪氨酸羟化酶量的相应增加与酪氨酸羟化酶活性的增加平行。用神经节阻断药物六甲铵或氯异吲哚铵预处理动物可防止酶活性的增加，但阿托品或双氢麦角胺的给药对此没有影响。逆向刺激不能模拟顺向刺激的效果，这表明神经元放电频率的增加不是酪氨酸羟化酶活性长期升高的充分条件。这些研究表明，突触刺激增加的时期可以改变交感神经元的蛋白质组成，增加参与其递质生物合成的关键酶的比活性。
