Reinke Yvonne, Gross Stefan, Eckerle Lars G, Hertrich Isabel, Busch Mathias, Busch Raila, Riad Alexander, Rauch Bernhard H, Stasch Johannes-Peter, Dörr Marcus, Felix Stephan B
Department of Internal Medicine B, Cardiology, University Medicine Greifswald, Germany; DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Germany.
Department of Internal Medicine B, Cardiology, University Medicine Greifswald, Germany.
Eur J Pharmacol. 2015 Nov 15;767:1-9. doi: 10.1016/j.ejphar.2015.09.022. Epub 2015 Sep 25.
In cardiovascular diseases, reduced responsiveness of soluble guanylate cyclase (sGC) to nitric oxide (NO) upon long-term application has led to the development of NO-independent sGC stimulators (heme-dependent) and sGC activators (heme-independent). Any direct inotropic or lusitropic effects of these compounds on isolated cardiac myocytes, however, remain to be elucidated. Here, we analyzed the dose-dependent effects of clinical relevant concentrations (10(-10)-10(-5) M) of the sGC activator cinaciguat and the sGC stimulator riociguat on the contraction, relaxation, and calcium transients of isolated field-stimulated cardiac myocytes from healthy rats. For comparison, we used isoproterenol, which induced a dose-dependent significant increase in cell contractility, relaxation, and calcium transients, verapamil that significantly decreased these parameters (both at 10(-9)-10(-5) M) and 8-(4-Chlorophenylthio)-guanosine 3',5'-cyclic monophosphate (8-pCPT-cGMP) that induced a negative inotropic effect at 10(-5) M accompanied by a slight increase in relaxation. In contrast, neither cinaciguat nor riociguat significantly influenced any measured parameters. Furthermore, isoproterenol significantly increased intracellular cAMP levels that were not influenced by cinaciguat or riociguat (all at 10(-6) M). Otherwise, riociguat and cinaciguat (both at 10(-6) M) significantly enhanced intracellular cGMP generation. This accumulation was significantly augmented by cinaciguat in the presence of the sGC inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 25 µM), whereas ODQ blocked cGMP generation by riociguat. However, blocking of sGC did not influence cell contractility. Our results demonstrate that, in isolated cardiac myocytes from healthy rats, the increase in cGMP levels induced by cinaciguat and riociguat at clinical relevant concentrations is not associated with acute direct effects on cell contraction and relaxation.
在心血管疾病中，长期应用时可溶性鸟苷酸环化酶（sGC）对一氧化氮（NO）的反应性降低，导致了不依赖NO的sGC刺激剂（血红素依赖性）和sGC激活剂（血红素非依赖性）的研发。然而，这些化合物对分离的心肌细胞的任何直接正性肌力或舒张期肌力作用仍有待阐明。在此，我们分析了sGC激活剂西那吉特和sGC刺激剂利奥西呱临床相关浓度（10^(-10)-10^(-5) M）对健康大鼠分离的场刺激心肌细胞收缩、舒张和钙瞬变的剂量依赖性影响。为作比较，我们使用了异丙肾上腺素，其可诱导细胞收缩性、舒张和钙瞬变呈剂量依赖性显著增加；维拉帕米可显著降低这些参数（均在10^(-9)-10^(-5) M）；8-(4-氯苯硫基)-鸟苷3',5'-环磷酸酯（8-pCPT-cGMP）在10^(-5) M时可诱导负性肌力作用，同时舒张略有增加。相比之下，西那吉特和利奥西呱均未显著影响任何测量参数。此外，异丙肾上腺素显著增加细胞内cAMP水平，而西那吉特或利奥西呱（均在10^(-6) M）对此无影响。另外，利奥西呱和西那吉特（均在10^(-6) M）显著增强细胞内cGMP生成。在存在sGC抑制剂1H-[1,2,4]恶二唑并[4,3-a]喹喔啉-1-酮（ODQ，25 μM）的情况下，西那吉特可显著增强这种积累，而ODQ可阻断利奥西呱诱导的cGMP生成。然而，阻断sGC并不影响细胞收缩性。我们的结果表明，在健康大鼠分离的心肌细胞中，临床相关浓度的西那吉特和利奥西呱诱导的cGMP水平升高与对细胞收缩和舒张的急性直接作用无关。
