Karakullukçu Y E, Ozçelik T, Gökhan N
Department of Physiology, Istanbul Faculty of Medicine, University of Istanbul, Turkey.
Pflugers Arch. 1987 Dec;410(6):657-63. doi: 10.1007/BF00581328.
Reperfusion of hearts with a Ca2+-containing medium after a perfusion period in Ca2+-free medium results in irreversible cell damage (calcium paradox). In this investigation we have studied coronary flow and cyclic AMP and cyclic GMP levels after several periods of Ca2+-free perfusion in isolated rat hearts. We also investigated the effects of papaverine (Pap), noradrenaline (NA), acetylcholine (ACh) and absence of inorganic phosphate during Ca2+-free perfusion on coronary flow (CF) and cyclic nucleotide levels. Inability of the heart to recover contractile activity with development of contracture during the reperfusion period was accepted as indicative of the calcium paradox. Ca2+-free perfusion alone and NA and absence of inorganic phosphate during the Ca2+-free perfusion period increased CF, whereas Pap and ACh decreased it. However, only Ca2+-free perfusion and NA elevated cyclic AMP. On the other hand, Pap and ACh increased cyclic GMP (with a transient rise of cyclic AMP in Pap infusion), and absence of inorganic phosphate decreased both cyclic AMP and cyclic GMP. Pap, ACh and absence of phosphate prevented the calcium paradox. Our study suggests that increased cyclic AMP during the Ca2+-free perfusion may contribute, with the other factors, to the occurrence of the calcium paradox.
在无钙培养基中灌注一段时间后，用含钙培养基对心脏进行再灌注会导致不可逆的细胞损伤（钙反常）。在本研究中，我们研究了离体大鼠心脏在经历几个无钙灌注期后的冠脉流量以及环磷酸腺苷（cAMP）和环磷酸鸟苷（cGMP）水平。我们还研究了罂粟碱（Pap）、去甲肾上腺素（NA）、乙酰胆碱（ACh）以及无钙灌注期间无机磷酸盐缺乏对冠脉流量（CF）和环核苷酸水平的影响。在再灌注期心脏无法恢复收缩活动并出现挛缩被视为钙反常的指标。单独的无钙灌注以及无钙灌注期间的NA和无机磷酸盐缺乏会增加冠脉流量，而Pap和ACh则会使其降低。然而，只有无钙灌注和NA会升高cAMP。另一方面，Pap和ACh会增加cGMP（在注入Pap时cAMP会有短暂升高），而无机磷酸盐缺乏会降低cAMP和cGMP。Pap、ACh和磷酸盐缺乏可预防钙反常。我们的研究表明，无钙灌注期间cAMP的增加可能与其他因素一起促成了钙反常的发生。
