Kishi Y, Ashikaga T, Watanabe R, Numano F
Third Department of Medicine, Tokyo Medical and Dental University, Japan.
J Cardiovasc Pharmacol. 1994 Sep;24(3):351-7. doi: 10.1097/00005344-199409000-00001.
Bovine aortic endothelial cells contain cyclic GMP-stimulated phosphodiesterase (PDE) regulating intracellular cyclic AMP and cyclic GMP levels. To investigate the roles of this PDE isoform for cyclic AMP hydrolysis in intact endothelial cells (EC), we used an adenine prelabeling method to determine cyclic AMP accumulation in response to agents that might produce effects that increase cyclic GMP levels. Atrial natriuretic peptide (ANP), which dramatically increased cyclic GMP accumulation, reduced cyclic AMP in cultured EC from bovine aorta with or without addition of L-isoproterenol (L-ISO), whereas sodium nitroprusside (SNP) and 8-bromo cyclic GMP had no effect. The reduction in cyclic AMP by ANP was dose dependent (> or = 1.0 nM) and rapid (significant reduction was induced in < or = 15 s) and was abolished when EC were preincubated with 3-isobutyl-1-methylxanthine (IBMX) and HL-725, both nonselective PDE inhibitors. ANP had no effects on adenylate cyclase activity, nor any direct effects on the activities of partially purified cyclic GMP-stimulated PDE isoform or cyclic AMP-specific isoform. However, cyclic AMP hydrolyzing activities of EC were enhanced when EC were pretreated with 0.1 microM ANP. ANP activates cyclic GMP-stimulated PDE and induces reduction of cyclic AMP accumulation in intact EC, which may modify cyclic GMP-dependent endothelial function involved in ANP.
牛主动脉内皮细胞含有可调节细胞内环磷酸腺苷（cAMP）和环磷酸鸟苷（cGMP）水平的环磷酸鸟苷刺激的磷酸二酯酶（PDE）。为了研究这种PDE同工型在完整内皮细胞（EC）中对cAMP水解的作用，我们使用腺嘌呤预标记法来测定cAMP的积累，以响应可能产生增加cGMP水平作用的试剂。心房利钠肽（ANP）可显著增加cGMP的积累，在添加或不添加L-异丙肾上腺素（L-ISO）的情况下，均可降低培养的牛主动脉EC中的cAMP，而硝普钠（SNP）和8-溴环磷酸鸟苷则无作用。ANP对cAMP的降低呈剂量依赖性（≥1.0 nM）且迅速（在≤15秒内即可诱导显著降低），当EC与3-异丁基-1-甲基黄嘌呤（IBMX）和HL-725（均为非选择性PDE抑制剂）预孵育时，这种降低作用被消除。ANP对腺苷酸环化酶活性无影响，对部分纯化的环磷酸鸟苷刺激的PDE同工型或环磷酸腺苷特异性同工型的活性也无直接影响。然而，当用0.1μM ANP预处理EC时，EC的cAMP水解活性增强。ANP激活环磷酸鸟苷刺激的PDE，并诱导完整EC中cAMP积累的减少，这可能会改变ANP所涉及的环磷酸鸟苷依赖性内皮功能。
