Molecular biologocal studies on the regulation of neuropeptide synthesis by dopamine

多巴胺对神经肽合成的调节被认为是由受体的刺激引发的，并且作为各种细胞内生化事件的结果，观察到神经肽基因的翻译速率的变化。虽然这些机制的细节是未知的，第二信使系统，如环核苷酸和磷脂酰肌醇周转已被报道参与调控。在本研究中，获得了以下几种在第二信使系统中起重要作用的蛋白激酶的分子结构和组织分布的结果.我们从大鼠脑cDNA文库中克隆了一个含有环腺苷酸依赖性蛋白激酶I型调节亚基的cDNA克隆，并根据该cDNA克隆的核苷酸序列推导出其氨基酸序列。通过与其他环核苷酸结合蛋白的同源性确定了该亚基的分子量.蛋白激酶C的各种亚型的存在已被分子克隆技术所证实。蛋白<gamma>激酶C的γ亚型主要分布于中枢神经系统，小脑浦肯野细胞和海马锥体细胞呈强阳性反应。此外，<beta><beta>选择性剪接机制产生的_1和_2亚型在神经元和神经末梢中也表现出特异性的不同定位。这些结果表明，不同亚型的蛋白激酶C可能与不同的神经元功能有关。

Regulation of the neuropeptide synthesis by dopamine is thought to be initiated by the stimulation of the receptor,and as a result of various intracellular biochemical events,the change in the translation rate of the neuropeptide gene is observed. Althogh details of these mechanisms are unknown, second messenger systems such as cyclic nucleotides and phosphatidylinositol turnover have been reported to be involved in the regulation. In the present study, following results were obtained on the molecular structures and tissue distributions of several protein kinases which seem to play important roles in the these second messenger systems.1. We obtained the cDNA clone which contains the entire coding regoin of the type I regulatory subnit of syclic AMP-dependent protein kinase from a rat brain cDNA library by a homology proding method based on the amino acid sequence was deduced by the nucleotide sequence of the cDNA clone. Molecular weight of the subunit was determined by the homology with other cyclic nucleotide binding proteins.2. The presence of various subtypes of protein kinase C has been shown by molecular cloning techniques. Gamma<gamma>subtype of the protein kinase C mainly localizans in the central nervous system, and Purkinje cells in the cerebellum and pyramidal cells in the hippocampus showed strong immunoreactivities. Furthermore, <beta>_1 and <beta>_2 subtypes which are produced by alternative splicing mechanism also showed specific distinct localization in the neurons and nerve terminals. These results indicate that different subtypes of protein kinase C may be crrelated with different neuronal functions.