Zawia N H, Mattia C J, Bondy S C
Department of Pharmacology, University of California, Irvine 92717.
Neuropharmacology. 1991 Apr;30(4):337-43. doi: 10.1016/0028-3908(91)90058-j.
The induction of the activity of cerebral ornithine decarboxylase (EC 4.1.1.17) and mRNA by electrical stimulation exhibits regional differences. The effects of the enzyme inhibitor difluoromethylornithine on these regional variations was examined. Administration of this inhibitor resulted in pronounced depression of both basal and induced activity of ornithine decarboxylase in the hippocampus. Basal activity of the enzyme in the neocortex and the cerebellum appeared to be resistant to difluoromethylornithine but the induced enzyme activity was sensitive to the effects of this inhibitor. Susceptibility to difluoromethylornithine may be directly correlated with a slower turnover rate for ornithine decarboxylase. These results suggest that ornithine decarboxylase in the hippocampus may possess a longer half-life than its counterparts in other regions of the brain. Pretreatment with difluoromethylornithine had no effect on the induced ornithine decarboxylase mRNA in the neocortex. Thus, elevated activity of ornithine decarboxylase enzyme, due to electrical stimulation, appears to not have any effect on either the transcription or the decay rate of the induced ornithine decarboxylase mRNA. These findings support the concept of region-specific regulation of cerebral ornithine decarboxylase.
电刺激诱导大脑鸟氨酸脱羧酶（EC 4.1.1.17）活性和mRNA表达呈现出区域差异。研究了酶抑制剂二氟甲基鸟氨酸对这些区域差异的影响。给予该抑制剂导致海马体中鸟氨酸脱羧酶的基础活性和诱导活性均显著降低。新皮层和小脑中该酶的基础活性似乎对二氟甲基鸟氨酸有抗性，但诱导的酶活性对该抑制剂的作用敏感。对二氟甲基鸟氨酸的敏感性可能与鸟氨酸脱羧酶较慢的周转率直接相关。这些结果表明，海马体中的鸟氨酸脱羧酶可能比大脑其他区域的对应酶具有更长的半衰期。用二氟甲基鸟氨酸预处理对新皮层中诱导的鸟氨酸脱羧酶mRNA没有影响。因此，电刺激导致鸟氨酸脱羧酶活性升高似乎对诱导的鸟氨酸脱羧酶mRNA的转录或降解速率均无影响。这些发现支持大脑鸟氨酸脱羧酶区域特异性调节的概念。
