Chlopicki Stefan, Olszanecki Rafal, Marcinkiewicz Ewa, Lomnicka Magdalena, Motterlini Roberto
Department of Experimental Pharmacology, Chair of Pharmacology, Jagiellonian University Medical College, 31-531 Krakow 16 Grzegorzecka, Poland.
Cardiovasc Res. 2006 Jul 15;71(2):393-401. doi: 10.1016/j.cardiores.2006.03.011. Epub 2006 Mar 22.
Carbon monoxide (CO) modulates several physiological functions through activation of a cGMP-dependent pathway similar to that of nitric oxide (NO). Here we investigated the possible involvement of soluble guanylate cyclase in the anti-aggregatory effect of micromolar concentrations of CO released by a novel, water-soluble, CO releasing molecule (CORM) in human platelets.
Human platelet aggregation was induced by collagen or thrombin, and the effects of CO releasing molecule (CORM-3) and an NO donor on platelet aggregation were compared.
CORM-3 liberated CO in a time- and concentration-dependent manner as evidenced by the formation of carbon monoxy myoglobin (MbCO) using a spectrophotometric assay. When added to washed platelets, CORM-3 (10-300 microM) inhibited collagen- and thrombin-induced aggregation in a concentration-dependent manner. The anti-aggregatory effect of CORM-3 was reversed by deoxy-Mb (50 microM). Interestingly, in the presence of an inhibitor of guanylate cyclase (ODQ, 5 microM), inhibition of collagen-induced aggregation by CORM-3 was not blocked but potentiated. Under the same experimental conditions, inhibition of platelet aggregation by an NO donor (SNAP, 1 microM) was prevented by ODQ. In collagen-induced or thrombin-induced platelet aggregation, a stimulator of guanylate cyclase (YC-1, 0.3 microM) did not alter the effect of CORM-3, whereas it markedly potentiated the inhibition of platelet aggregation mediated by SNAP. Notably, CORM-3-induced inhibition of platelet aggregation was of similar degree when platelets were activated by a low (20 mU/ml) or by high concentration of thrombin (100-200 mU/ml), whereas NO donors (SNP and SNAP)- or carbaprostacylin (cPGI(2))-induced effects were considerably attenuated when platelets were activated by high concentrations of thrombin.
Inhibition of platelet aggregation by CO released by a novel, water-soluble CORM is not mediated by activation of soluble guanylate cyclase. In contrast to NO and PGI(2), CO effectively inhibits platelets even when cells are activated excessively. We suggest that despite the fact that CO is not a potent inhibitor of platelet activation, it may gain importance when NO and PGI(2) alone are insufficient to overcome excessive platelet activation.
一氧化碳（CO）通过激活一条类似于一氧化氮（NO）的环磷酸鸟苷（cGMP）依赖性途径来调节多种生理功能。在此，我们研究了可溶性鸟苷酸环化酶是否可能参与了一种新型水溶性一氧化碳释放分子（CORM）释放的微摩尔浓度CO对人血小板的抗聚集作用。
用胶原蛋白或凝血酶诱导人血小板聚集，并比较一氧化碳释放分子（CORM-3）和一氧化氮供体对血小板聚集的影响。
通过分光光度法检测碳氧肌红蛋白（MbCO）的形成证明，CORM-3以时间和浓度依赖性方式释放CO。当添加到洗涤过的血小板中时，CORM-3（10 - 300微摩尔）以浓度依赖性方式抑制胶原蛋白和凝血酶诱导的聚集。脱氧肌红蛋白（50微摩尔）可逆转CORM-3的抗聚集作用。有趣的是，在存在鸟苷酸环化酶抑制剂（ODQ，5微摩尔）的情况下，CORM-3对胶原蛋白诱导聚集的抑制作用未被阻断反而增强。在相同实验条件下，ODQ可阻止一氧化氮供体（SNAP，1微摩尔）对血小板聚集的抑制作用。在胶原蛋白诱导或凝血酶诱导的血小板聚集中，鸟苷酸环化酶刺激剂（YC-1，0.3微摩尔）不会改变CORM-3的作用，而它能显著增强SNAP介导的血小板聚集抑制作用。值得注意的是，当血小板被低浓度（20毫单位/毫升）或高浓度凝血酶（100 - 200毫单位/毫升）激活时，CORM-3诱导的血小板聚集抑制程度相似，而当血小板被高浓度凝血酶激活时，一氧化氮供体（SNP和SNAP）或卡前列素（cPGI₂）诱导的作用则明显减弱。
新型水溶性CORM释放的CO对血小板聚集的抑制作用不是由可溶性鸟苷酸环化酶的激活介导的。与NO和PGI₂不同，即使细胞被过度激活，CO也能有效抑制血小板。我们认为，尽管CO不是血小板激活的强效抑制剂，但当单独的NO和PGI₂不足以克服过度的血小板激活时，它可能会变得重要。
