Zawia N H, Bondy S C
Department of Pharmacology, University of California, Irvine.
J Neurochem. 1992 Feb;58(2):736-9. doi: 10.1111/j.1471-4159.1992.tb09779.x.
Ornithine decarboxylase (ODC; EC 4.1.1.17) is a highly inducible, rate-limiting enzyme of the polyamine pathway. We have studied the mechanisms that lead to the induction of ODC activity in response to electrical stimulation in three brain regions. Hippocampal ODC activity was found to exhibit much larger elevations than that of the neocortex and the cerebellum. The levels of ODC gene expression were also followed to examine its relationship to the existing regional differences in ODC activity. In the neocortex, there was an elevation of both the ODC mRNA and enzyme activity. However, the hippocampal ODC mRNA level was not increased by electroconvulsive shock. Furthermore, the effects of hormonal changes and seizures on these regional differences in ODC induction were also examined. Adrenalectomy did not affect ODC activity, but pretreatment with the anticonvulsant MK-801 caused a depression of the induced levels of enzyme activity. Our data suggest that ODC activity in all the brain regions studied is directly elevated by electrically stimulated seizures. However, this induced ODC activity may or may not involve enhanced gene expression.
鸟氨酸脱羧酶（ODC；EC 4.1.1.17）是多胺途径中一种高度可诱导的限速酶。我们研究了在三个脑区中响应电刺激导致ODC活性诱导的机制。发现海马体中的ODC活性升高幅度比新皮层和小脑大得多。还跟踪了ODC基因表达水平，以检查其与ODC活性中现有区域差异的关系。在新皮层中，ODC mRNA和酶活性均升高。然而，电惊厥休克并未使海马体ODC mRNA水平升高。此外，还研究了激素变化和癫痫发作对这些ODC诱导区域差异的影响。肾上腺切除术不影响ODC活性，但用抗惊厥药MK-801预处理会导致诱导的酶活性水平降低。我们的数据表明，在所有研究的脑区中，ODC活性都通过电刺激癫痫发作直接升高。然而，这种诱导的ODC活性可能涉及也可能不涉及基因表达增强。
