Teixeira Cleber E, Priviero Fernanda B M, Webb R Clinton
Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil.
J Pharmacol Exp Ther. 2007 Sep;322(3):1093-102. doi: 10.1124/jpet.107.124594. Epub 2007 Jun 27.
We aimed to characterize the relaxation induced by the soluble guanylyl cyclase (sGC) stimulator 5-cyclopropyl-2-[1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-yl]pyrimidin-4-ylamine (BAY 41-2272) and its pharmacological interactions with nitric oxide (NO) in the corpus cavernosum (CC) from wild-type (WT), endothelial nitric-oxide synthase (eNOS)(-/-), and neuronal (n)NOS(-/-) mice. The effect of BAY 41-2272 on superoxide formation and NADPH oxidase expression was also investigated. Tissues were mounted in myographs for isometric force recording. Enzyme immunoassay kits were used for cGMP determination. sGC activity was determined in the supernatant fractions of the cavernosal samples by the conversion of GTP to cGMP. Superoxide formation and expression of NADPH oxidase subunits were studied using the reduction of ferricytochrome c and Western blot analysis, respectively. BAY 41-2272 (0.01-10 microM) relaxed CC with pEC(50) values of 6.36 +/- 0.07 (WT), 6.27 +/- 0.06 (nNOS(-/-)), and 5.88 +/- 0.07 (eNOS(-/-)). The relaxations were accompanied by increases in cGMP levels. N(omega)-Nitro-L-arginine methyl ester inhibited BAY 41-2272-evoked responses in CC from WT and nNOS(-/-), but not eNOS(-/-).1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one reduced and sildenafil potentiated the relaxations induced by BAY 41-2272 in all groups. BAY 41-2272 enhanced NO (endogenous and exogenous)-induced relaxations in a concentration-dependent manner. Expression and activity of sGC was similar among the different groups. Superoxide formation was reduced by BAY 41-2272 (0.1-1 microM). The compound also inhibited p22(phox) and gp91(phox) expression induced by 9,11-dideoxy-11 alpha,9 alpha-epoxymethanoprostaglandin F(2 alpha (U46619). Our results demonstrated that sGC activation in the penis by BAY 41-2272 directly or via enhancement of NO effects may provide a novel treatment for erectile dysfunction, particularly in the event of an increased intrapenile oxidative stress.
我们旨在表征可溶性鸟苷酸环化酶（sGC）刺激剂5-环丙基-2-[1-(2-氟苄基)-1H-吡唑并[3,4-b]吡啶-3-基]嘧啶-4-胺（BAY 41-2272）诱导的舒张作用及其在野生型（WT）、内皮型一氧化氮合酶（eNOS）基因敲除（-/-）和神经元型（n）NOS基因敲除（-/-）小鼠阴茎海绵体（CC）中与一氧化氮（NO）的药理相互作用。还研究了BAY 41-2272对超氧化物生成和NADPH氧化酶表达的影响。将组织安装在肌张力测定仪中进行等长力记录。使用酶免疫分析试剂盒测定cGMP。通过将GTP转化为cGMP来测定海绵体样品上清液中的sGC活性。分别使用高铁细胞色素c还原法和蛋白质印迹分析研究超氧化物生成和NADPH氧化酶亚基的表达。BAY 41-2272（0.01 - 10 microM）使CC舒张，WT小鼠的pEC(50)值为6.36±0.07，nNOS(-/-)小鼠为6.27±0.06，eNOS(-/-)小鼠为5.88±0.07。舒张伴随着cGMP水平的升高。N(ω)-硝基-L-精氨酸甲酯抑制WT和nNOS(-/-)小鼠CC中BAY 41-2272诱发的反应，但不抑制eNOS(-/-)小鼠的反应。1H-[1,2,4]恶二唑并[4,3-a]喹喔啉-1-酮减弱而西地那非增强所有组中BAY 41-2272诱导的舒张。BAY 41-2272以浓度依赖性方式增强内源性和外源性NO诱导的舒张。不同组之间sGC的表达和活性相似。BAY 41-2272（0.1 - 1 microM）减少超氧化物生成。该化合物还抑制9,11-二脱氧-11α,9α-环氧甲烯前列环素F2α（U46619）诱导的p22(phox)和gp91(phox)表达。我们的结果表明，BAY 41-2272直接或通过增强NO作用激活阴茎中的sGC可能为勃起功能障碍提供一种新的治疗方法，特别是在阴茎内氧化应激增加的情况下。
