Tetzlaff W, Kreutzberg G W
Exp Neurol. 1985 Sep;89(3):679-88. doi: 10.1016/0014-4886(85)90016-0.
The activity of ornithine decarboxylase, the rate-limiting enzyme in polyamine synthesis, was assayed in the isolated facial nucleus of the rat at various times after axotomy of the facial nerve. In addition, it was measured 24 h after the second of a series of two lesions (conditioning lesion design) with various times between the first and second operations. Ornithine decarboxylase activity was found to increase 8 h after nerve transection and was maximum after 24 h (300% of control). Thereafter the activity declined to subnormal levels where it remained for several weeks. Ornithine decarboxylase activity did not increase again when a second axotomy was made 2 weeks after the first lesion. However, ornithine decarboxylase did respond to the second axotomy if it was carried out 3 weeks after the first lesion. Histochemical localization of ornithine decarboxylase demonstrated that the increase in enzyme activity was mainly confined to the perikarya of the motoneurons. These data suggest that this enzyme is somehow involved in triggering the "regeneration program" and clearly indicate that at least some aspects of the neuronal response to axotomy are not further stimulated by a conditioning lesion.
在大鼠面神经切断后的不同时间，对其分离出的面神经核中鸟氨酸脱羧酶（多胺合成中的限速酶）的活性进行了测定。此外，在一系列两次损伤（条件性损伤设计）中的第二次损伤24小时后进行测量，第一次和第二次手术之间有不同的时间间隔。发现鸟氨酸脱羧酶活性在神经切断后8小时增加，24小时后达到最大值（为对照的300%）。此后，活性下降至低于正常水平，并持续数周。在第一次损伤2周后进行第二次轴突切断时，鸟氨酸脱羧酶活性没有再次增加。然而，如果在第一次损伤3周后进行第二次轴突切断，鸟氨酸脱羧酶确实会对第二次轴突切断做出反应。鸟氨酸脱羧酶的组织化学定位表明，酶活性的增加主要局限于运动神经元的胞体。这些数据表明，这种酶以某种方式参与触发“再生程序”，并清楚地表明，至少神经元对轴突切断反应的某些方面不会因条件性损伤而进一步受到刺激。
