Multiple molecular forms of cyclic nucleotide phosphodiesterase in cardiac and smooth muscle and in platelets. Isolation, characterization, and effects of various reference phosphodiesterase inhibitors and cardiotonic agents.
Multiple molecular forms of cyclic nucleotide phosphodiesterase in cardiac and smooth muscle and in platelets. Isolation, characterization, and effects of various reference phosphodiesterase inhibitors and cardiotonic agents.
复制标题
心肌、平滑肌和血小板中环核苷酸磷酸二酯酶的多种分子形式。
DOI：
10.1016/0006-2952(86)90247-9
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发表时间：
1986
影响因子：
5.8
通讯作者：
Dale B. Evans
中科院分区：
文献类型：
--
作者：
R. Weishaar;S. D. Burrows;D. Kobylarz;M. Quade;Dale B. Evans
以前已经使用各种不同的分离方法在几种组织和细胞类型中鉴定了多种分子形式的环核苷酸磷酸二酯酶。在本研究中，用相同的分离程序分别从心肌(豚鼠左心室)、血管平滑肌(牛冠状动脉)和人血小板中分离到不同分子形式的磷酸二酯酶(PDE)。然后对这些酶进行了动力学表征，并检测了各种参考PDE抑制剂和强心剂对每种形式的影响。在三种组织/细胞类型中均发现低Km、低Vmax形式的磷酸二酯酶(PDE I)。钙调素对心肌和平滑肌的PDE I活性有刺激作用，但对血小板无明显影响。在平滑肌和血小板中，PDE I优先水解环GMP，而在心肌中，PDE I同等地水解环AMP和环GMP。在心肌和血小板中发现高Km、高Vmax形式的磷酸二酯酶(PDE II)，而在平滑肌中未见。PDE II活性不受钙调蛋白刺激，且无底物特异性。在所有三种组织/细胞类型中都发现了一种低Km、低Vmax环AMP特异性形式的磷酸二酯酶(PDE III)。钙调素不能刺激PDE III的活性。参比抑制剂茶碱和罂粟碱对所有形式的磷酸二酯酶都有非特异性的抑制作用。其他参比抑制剂(M&B 22,948和双嘧达莫)和几种强心剂(AR-L 57、CI-914、CI-930、氨力农和MDL 17,043)仅对一种分子形式的磷酸二酯酶产生选择性抑制作用。选择性的程度通常取决于从中分离出磷酸二酯酶分子形式的组织或细胞。这些研究表明：(I)存在于不同组织/细胞类型中的磷酸二酯酶的数量、底物专一性以及它们被钙调蛋白刺激的能力存在异质性，以及(Ii)这些不同的分子形式的磷酸二酯酶可以被不同的药物选择性地抑制。存在这样一种可能性，即这种选择性抑制剂可能会导致环状AMP或环状GMP水平的离散变化，并且这些变化可能在特定的组织和/或细胞中产生。
Multiple molecular forms of cyclic nucleotide phosphodiesterase have been identified previously in several tissues and cell types using a variety of different isolation methods. In the present study, the different molecular forms of phosphodiesterase (PDE) were isolated from cardiac muscle (guinea pig left ventricle), vascular smooth muscle (bovine coronary arteries) and human platelets using the same isolation procedure in each instance. These enzymes were then characterized kinetically, and the effects of various reference PDE inhibitors and cardiotonic agents on each form were examined. A lowKm, lowVmaxform of phosphodiesterase (PDE I) was found in all three tissue/cell types. PDE I activity was stimulated by calmodulin in cardiac and smooth muscle, but not in platelets. In smooth muscle and platelets, PDE I preferentially hydrolyzed cyclic GMP, whereas cardiac muscle PDE I hydrolyzed cyclic AMP and cyclic GMP equally. A highKm, highVmaxform of phosphodiesterase (PDE II) was found in cardiac muscle and platelets, but not in smooth muscle. PDE II activity was not stimulated by calmodulin and there was no substrate specificity. A lowKm, lowVmaxcyclic AMP-specific form of phosphodiesterase (PDE III) was found in all three tissue/cell types. The activity of PDE III was not stimulated by calmodulin. The reference inhibitors theophylline and papaverine exerted nonspecific inhibitory effects on all forms of phosphodiesterase. Other reference inhibitors (M & B 22,948 and dipyridamole) and several cardiotonic agents (AR-L 57, CI-914, CI-930, amrinone, and MDL 17,043) exerted selective inhibitory effects on only one molecular form of phosphodiesterase. The degree of selectivity was often dependent upon the tissue or cell from which the molecular form of phosphodiesterase was isolated. These studies demonstrate that (i) there is heterogeneity regarding the number of phosphodiesterases present in various tissue/cell types, as well as their substrate specificity and their ability to be stimulated by calmodulin, and (ii) these different molecular forms of phosphodiesterase can be selectively inhibited by different pharmacological agents. The possibility exists that such selective inhibitors may produce discrete changes in cyclic AMP or cyclic GMP levels, and that these changes may be produced in specific tissues and/or cells.