Repaske D R, Corbin J G, Conti M, Goy M F
Division of Endocrinology, Children's Hospital Medical Center, Cincinnati, OH 45229.
Neuroscience. 1993 Oct;56(3):673-86. doi: 10.1016/0306-4522(93)90364-l.
Cyclic AMP and cyclic GMP serve as second messengers in a variety of neural cells, modulating their metabolic and electrical activity. The cyclic GMP-stimulated cyclic nucleotide phosphodiesterase, an enzyme whose hydrolytic activity is allosterically regulated by cyclic GMP in peripheral tissues, could play an important role in the regulation of cyclic nucleotide levels in the brain. To study the presence and distribution of cyclic GMP-stimulated phosphodiesterase in the rat brain, we cloned a portion of rat liver cyclic GMP-stimulated phosphodiesterase complementary DNA by polymerase chain reaction, using degenerate phosphodiesterase-specific oligonucleotide primers. Northern blot analysis of rat tissues reveals abundant expression of cyclic GMP-stimulated phosphodiesterase messenger RNA in the brain. Northern blot analysis of brain subregions shows especially strong expression in hippocampus and cortex, modest expression in the remainder of the forebrain and in the midbrain, and little expression in cerebellum and hindbrain. In situ hybridization studies with cyclic GMP-stimulated phosphodiesterase riboprobes confirm these northern blot results, and delineate cell groups with high levels of expression. Medial habenular nucleus is intensely labeled, as is hippocampus in the vicinity of pyramidal and granule cell bodies in areas CA1, CA2, CA3, and dentate gyrus. Other elements of the limbic system also contain cyclic GMP-stimulated phosphodiesterase messenger RNA, including olfactory and entorhinal cortices, subiculum, and amygdala. Additional cortical regions show more diffuse expression of cyclic GMP-stimulated phosphodiesterase messenger RNA, as do the basal ganglia. Cerebellum, thalamus, and hypothalamus do not show appreciable specific labeling. These studies demonstrate the presence of cyclic GMP-stimulated phosphodiesterase messenger RNA in specific regions of the rat brain, and suggest that the cyclic GMP-stimulated phosphodiesterase might modulate neuronal activity by regulating intracellular cyclic AMP levels in response to changes in intracellular cyclic GMP levels.
环磷酸腺苷（cAMP）和环磷酸鸟苷（cGMP）在多种神经细胞中作为第二信使，调节它们的代谢和电活动。环磷酸鸟苷刺激的环核苷酸磷酸二酯酶，一种其水解活性在周围组织中受环磷酸鸟苷变构调节的酶，可能在调节脑中的环核苷酸水平中起重要作用。为了研究环磷酸鸟苷刺激的磷酸二酯酶在大鼠脑中的存在和分布，我们使用简并的磷酸二酯酶特异性寡核苷酸引物，通过聚合酶链反应克隆了大鼠肝脏环磷酸鸟苷刺激的磷酸二酯酶互补DNA的一部分。对大鼠组织的Northern印迹分析显示，环磷酸鸟苷刺激的磷酸二酯酶信使核糖核酸（mRNA）在脑中大量表达。对脑亚区域的Northern印迹分析表明，在海马体和皮质中表达特别强烈，在前脑其余部分和中脑中表达适中，而在小脑和后脑几乎没有表达。用环磷酸鸟苷刺激的磷酸二酯酶核糖探针进行的原位杂交研究证实了这些Northern印迹结果，并描绘了高表达水平的细胞群。内侧缰核被强烈标记，海马体中CA1、CA2、CA3区的锥体细胞和颗粒细胞体附近以及齿状回也被强烈标记。边缘系统的其他成分也含有环磷酸鸟苷刺激的磷酸二酯酶mRNA，包括嗅觉皮质和内嗅皮质、下托和杏仁核。其他皮质区域显示环磷酸鸟苷刺激的磷酸二酯酶mRNA表达更弥散，基底神经节也是如此。小脑、丘脑和下丘脑没有显示明显的特异性标记。这些研究证明了环磷酸鸟苷刺激的磷酸二酯酶mRNA在大鼠脑的特定区域中存在，并表明环磷酸鸟苷刺激的磷酸二酯酶可能通过响应细胞内环磷酸鸟苷水平的变化调节细胞内环磷酸腺苷水平来调节神经元活动。
