Modification of creatine kinase by S-nitrosothiols: S-nitrosation vs. S-thiolation.

Creatine kinase is reversibly inhibited by incubation with S-nitrosothiols. Loss of enzyme activity is associated with the depletion of 5,5'-dithiobis (2-nitrobenzoic acid)-accessible thiol groups, and is not due to nitric oxide release from RSNO. Full enzymatic activity and protein thiol content are restored by incubation of the S-nitrosothiol-modified protein with glutathione. S-nitroso-N-acetylpenicillamine, which contains a more sterically hindered S-nitroso group than S-nitrosoglutathione, predominantly modifies the protein thiol to an S-nitrosothiol via a transnitrosation reaction. In contrast, S-nitrosoglutathione modifies creatine kinase predominantly by S-thiolation. Both S-nitroso-N-acetylpenicillamine and S-nitrosoglutathione modify bovine serum albumin to an S-nitroso derivative. This indicates that S-thiolation and S-nitrosation are both relevant reactions for S-nitrosothiols, and the relative importance of these reactions in biological systems depends on both the environment of the protein thiol and on the chemical nature of the S-nitrosothiol.

Rapid and irreversible inhibition of creatine kinase by peroxynitrite.

We examined the ability of peroxynitrite and other .NO-derived oxidants to inhibit creatine kinase (CK). Peroxynitrite potently inhibited CK activity and depleted protein thiols. The rate constant for this reaction was 8.85x10(5) M(-1) s(-1). Glutathione did not reactivate CK activity nor did it regenerate protein thiol content. In contrast, glutathione reactivated CK, and regenerated protein thiols, after inhibition by either .NO or oxidized glutathione (GSSG). Peroxynitrite did not irreversibly inhibit CK after it had been treated with GSSG to block protein thiols. We conclude that thiol oxidation is a critical event leading to inactivation of CK by peroxynitrite.

S-nitrosoglutathione induces formation of nitrosylmyoglobin in isolated hearts during cardioplegic ischemia--an electron spin resonance study.

Previously, it has been shown that *NO donor S-nitrosoglutathione (GSNO) improves the postischemic functional recovery in crystalloid buffer-perfused isolated rat hearts subjected to cardioplegic ischemia. Supplementation of cardioplegic solution with nitronyl nitroxide, a scavenger of *NO, antagonized this protective effect. Using low temperature ESR, we have detected nitrosylmyoglobin (MbNO) in rat hearts subjected to cardioplegic ischemia in the presence of GSNO (20-200 mumol/l). During aerobic reperfusion MbNO signal intensity gradually decreased, but persisted for up to 30 min of aerobic reperfusion. We conclude that MbNO is an endogenous marker of *NO release in myocardial tissues. Implications of MbNO formation are discussed with respect to cardioprotection during ischemia- and reperfusion-induced myocardial injury.

Vasodilatory and toxic effects of spin traps on aerobic cardiac function.

The objective of this study was to compare the effect of several structurally related nitrone and nitroso spin traps on the function of the isolated bicarbonate-buffer perfused rat heart model. Spin traps investigated were alpha-phenyl-tert-butyl N-nitrone (PBN), alpha-(4-pyridyl-1-oxide)-N-tert-butyl nitrone (POBN), 2-methyl-2-nitroso propane (MNP), 2-hydroxymethyl-2-nitroso propane (MNP/OH), nitrosobenzene (NB), dibromonitrosobenzene-sulfonic acid (DBNBS), and 5,5'-dimethyl-1-pyrroline-N-oxide (DMPO). During perfusion of hearts with increasing concentrations of spin traps, ventricular pressure, coronary flow rate, and heart rate were continuously recorded. The extent of contractile recovery was subsequently measured upon return to spin-trap free perfusion. The percentage of maximum increase in coronary flow with PBN, POBN, MNP, MNP-OH, NB, DBNBS, and DMPO were 11, 40, 45, 66, 28, 28, and 29%, respectively. Thus, all nitroso and nitrone spin traps studied acted as vasodilators. Over the dose range studied, POBN, MNP, MNP/OH, and DMPO did not exert any chronotropic effect. PBN, NB, and DBNBS exerted a negative chronotropic effect at higher concentrations. All spin traps studied, with the exception of DMPO, exerted a negative inotropic effect at the higher concentrations studied. We conclude that all spin traps examined acted as coronary vasodilators. Their negative chronotropic and inotropic effects were minimal in comparison and only manifest at the higher concentrations studied.

Nitronyl nitroxides as probes to study the mechanism of vasodilatory action of nitrovasodilators, nitrone spin traps, and nitroxides: role of nitric oxide.

Nitronyl nitroxides have been used to trap nitric oxide (.NO) produced during visible irradiation of nitrovasodilators such as sodium nitroprusside (Joseph et al., Biochem. Biophys. Res. Commun. 192:926-934; 1993). We have also shown that nitrone and nitroso spin traps exert a potent vasodilatory effect in the isolated perfused rat heart (Konorev et al., Free Radic. Biol. Med. 14:127-137, 1993). The objective of this study was to investigate the effect of nitronyl nitroxides on the vasodilatory action of sodium nitroprusside (SNP), S-nitroso-N-acetylpenicillamine (SNAP), alpha-(4-pyridyl-1-oxide)-N-tert-butyl nitrone (POBN) and 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy free radical (TEMPOL) in the isolated perfused rat heart model. In this study, we have used the following nitronyl nitroxides as nitric oxide traps: 2-(p-carboxyphenyl)-4,4,5,5-tetramethyl imidazoline-3-oxide 1-oxyl (SLI) and 2(1',1'-dimethyl-2'-hydroxyethyl)-4,4,5,5-tetramethyl imidazoline-3-oxide 1-oxyl (SLII). Under in vitro conditions, both SLI and SLII trapped .NO released from SNP/light treatment and from spontaneous decomposition of SNAP, forming the corresponding imino nitroxides, which were characterized by electron spin resonance (ESR) technique. In isolated hearts, SNP (2 mumol/l) and SNAP (20 mumol/l) increased coronary flow rate to a maximum of 185% and 190%, respectively. SNP-induced vasodilation was inhibited by SLI (0.05-3 mmol/l) from 162% to 131% of baseline, and SNAP-induced vasodilation was inhibited by SLII (0.05-1.2 mmol/l) from 190% to 136% of baseline. In contrast, neither SLI nor SLII inhibited the vasodilatory action elicited by POBN or TEMPOL.(ABSTRACT TRUNCATED AT 250 WORDS)

The mechanism of cardioprotection by S-nitrosoglutathione monoethyl ester in rat isolated heart during cardioplegic ischaemic arrest.

1. This study was designed (i) to assess the effect of S-nitrosoglutathione monoethyl ester (GSNO-MEE), a membrane-permeable analogue of S-nitrosoglutathione (GSNO), on rat isolated heart during cardioplegic ischaemia, and (ii) to monitor the release of nitric oxide (.NO) from GSNO-MEE in intact hearts using endogenous myoglobin as an intracellular .NO trap and the hydrophilic N-methyl glucamine dithiocarbamate-iron (MGD-Fe2+) complex as an extracellular .NO trap. 2. During aerobic perfusion of rat isolated heart with GSNO-MEE (20 mumol 1(-1), there was an increase in cyclic GMP from 105 +/- 11 to 955 +/- 193 pmol g-1 dry wt. (P < 0.05), and a decrease in glycogen content from 119 +/- 3 to 96 +/- 2 mumol g-1 dry wt. (P < 0.05), and glucose-6-phosphate concentration from 258 +/- 22 in control to 185 +/- 17 nmol g-1 dry wt. (P < 0.05). During induction of cardioplegia, GSNO-MEE caused the accumulation of cyclic GMP (100 +/- 6 in control vs. 929 +/- 168 pmol g-1 dry wt. in GSNO-MEE-treated group, P < 0.05), and depletion of glycogen from 117 +/- 3 to 103 +/- 2 mumol g-1 dry wt. (P < 0.05) in myocardial tissue. 3. Inclusion of GSNO-MEE (20 mumol l-1) in the cardioplegic solution improved the recovery of developed pressure (46 +/- 8 vs. 71 +/- 3% of baseline, P < 0.05), and rate-pressure product from 34 +/- 6 to 63 +/- 5% of baseline (P < 0.05), and reduced the diastolic pressure during reperfusion from 61 +/- 7 in control to 35 +/- 5 mmHg (P < 0.05) after 35 min ischaemic arrest. GSH-MEE (20 mumol l-1) in the cardioplegic solution did not elicit the protective effect. 4. During cardioplegic ischaemia, GSNO-MEE (20-200 mumol l-1) induced the formation of nitrosylmyoglobin (MbNO), which was detected by electron spin resonance (ESR) spectroscopy. Inclusion of MGD-Fe2+ (50 mumol l-1 Fe2+ and 500 mumol l-1 MGD) in the cardioplegic solution along with GSNO-MEE yielded an ESR signal characteristic of the MGD-Fe2+ -NO adduct. However, the MGD-Fe2+ trap did not prevent the formation of the intracellular MbNO complex in myocardial tissue. During aerobic reperfusion, denitrosylation of the MbNO complex slowly occurred as shown by the decrease in ESR spectral intensity. GSNO-MEE treatment did not affect ubisemiquinone radical formation during reperfusion. 5. GSNO-MEE (20 microliters l-1) treatment elevated the myocardial cyclic GMP during ischaemia (47 +/- 3 in control vs. 153 +/- 34 pmol g-1 dry wt. after 35 min ischaemia, P < 0.05). The cyclic GMP levels decreased in the control group during ischaemia from 100 +/- 6 after induction of cardioplegia to 47 +/- 3 pmol g-1 dry wt. at the end of ischaemic duration. 6. Glycogen levels were lower in GSNO-MEE (20 mumol l-1)-treated hearts throughout the ischaemic duration (26.7 +/- 3.1 in control vs. 19.7 +/- 2.4 mumol g dry-t wt. in GSNO-MEE-treated group at the end of ischaemic duration), because of rapid depletion of glycogen during induction of cardioplegia. During ischaemia, the amounts of glycogen consumed in both groups were similar. Equivalent amounts of lactate were produced in both groups (148 +/- 4 in control vs. 141 +/- 4 mumol g-1 dry wt. in GSNO-MEE-treated group after 35 min in ischaemia). 7. The mechanism(s) of myocardial protection by GSNO-MEE against ischaemic injury may involve preischaemic glycogen reduction and/or elevated cyclic GMP levels in myocardial tissue during ischaemia.

Lack of protection of PBN in isolated heart during ischemia and reperfusion: implications for radical scavenging mechanism.

We evaluated the ability of alpha-phenyl-tert-butyl nitrone (PBN) to trap free radicals and to protect the rat myocardium during ischemia and reperfusion. Isolated bicarbonate buffer-perfused hearts (n = 8) were subjected to 20 min global ischemia (37 degrees C) followed by reperfusion with 0.4 to 4.0 mM PBN. Coronary effluent containing the PBN adduct was extracted in toluene. Electron spin resonance analysis of the toluene extract revealed a PBN-hydroxyl adduct. To verify this assignment, a Fenton system was used to generate an authentic PBN-hydroxyl adduct (n = 8), which yielded the same ESR spectra as the reperfusion-derived adduct. The structure of the adduct formed in the Fenton system was confirmed by gas chromatography-mass spectrometry. The ESR parameters of the PBN-hydroxyl adduct were exquisitely sensitive to solvent polarity during extraction of the adduct. Extraction of an authentic PBN-hydroxyl adduct into chloroform, chloroform:methanol, and toluene closely matched the ESR parameters obtained during reperfusion of ischemic myocardium in other animal models. To determine whether PBN could confer any protective effect during ischemia or reperfusion, hearts (n = 8/group) were subjected to 35 min global ischemia at 37 degrees C with the St. Thomas' II cardioplegic solution followed by 30 min reperfusion. Percent recovery (mean +/- SEM) of developed pressure, rate pressure product, and leakage of lactate dehydrogenase during reperfusion in control hearts were 58 +/- 3%, 48 +/- 4% and 3.2 +/- 0.5 IU/15 min/g wet wt. PBN at a concentration of 0.4 mM or 4.0 mM when present either during ischemia alone or reperfusion alone did not exert any effect upon recovery of developed pressure, rate pressure product or post-ischemic enzyme leakage. We conclude that PBN fails to improve contractile recovery and reduce enzyme leakage during reperfusion of myocardium subjected to global ischemia.

[Diagnosis and prevention of myocardial reperfusion injury in experimental myocardial infarction]. / Diagnostika i profilaktika reperfuzionnogo povrezhdeniia miokarda v usloviiakh eksperimental'nogo infarkta miokarda.

In an experimental study in 69 dogs with the occluded anterior descending branch of the left coronary artery, dibunol, an antioxidant, and isoptin, a Ca2+ antagonist reduced myocardial infarction area, prolonged survival time and brought down mortality rate, in spite of an increase in reperfusion-related arrhythmias. The value of various electrocardiographic parameters for the diagnosis of ischemized-myocardium reperfusion and the severity of reperfusion-related heart damage in relation to the type of preventive medication, as compared to postmortem findings, are discussed.

[Prevention of myocardial damage during reperfusion of the coronary artery in dogs using dibunol combined with verapamil]. / Ogranichenie povrezhdeniia miokarda pri reperfuzii koronarnoi arterii u sobak s pomoshch'iu dibunola i ego kombinatsii s verapamilom.

An experimental study in 69 dogs examined the effect of isolated and combined use of dibunol and verapamil (isoptin) on the course of reperfusion of ischemized myocardium after 180 minutes' coronary occlusion. Verapamil alone had no protective effect on reperfused myocardium, whereas dibunol, and particularly its combination with verapamil, essentially limited the size of necrosis, reduced plasma CPK activity and animal mortality rate and maintained ultrastructural integrity of cardiomyocytes, which was accompanied by a decrease of plasma lipid peroxidation products and a stabilization of cardiomyocyte sarcolemma. The significance of membrane damage and uncontrolled calcium entrance into cardiomyocytes for the mechanism of myocardial damage at the recovery of coronary circulation is discussed.

Doxorubicin-induced apoptosis in endothelial cells and cardiomyocytes is ameliorated by nitrone spin traps and ebselen. Role of reactive oxygen and nitrogen species.

Doxorubicin (DOX) is a broad spectrum anthracycline antibiotic used to treat a variety of cancers. Redox activation of DOX to form reactive oxygen species has been implicated in DOX-induced cardiotoxicity. In this work we investigated DOX-induced apoptosis in cultured bovine aortic endothelial cells and cardiomyocytes isolated from adult rat heart. Exposure of bovine aortic endothelial cells or myocytes to submicromolar levels of DOX induced significant apoptosis as measured by DNA fragmentation and terminal deoxynucleotidyltransferase-mediated nick-end labeling assays. Pretreatment of cells with 100 microm nitrone spin traps, N-tert-butyl-alpha-phenylnitrone (PBN) or alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) dramatically inhibited DOX-induced apoptosis. Ebselen (20-50 microm), a glutathione peroxidase mimetic, also significantly inhibited apoptosis. DOX (0.5-1 microm) inactivated mitochondrial complex I by a superoxide-dependent mechanism. PBN (100 microm), POBN (100 microm), and ebselen (50 microm) restored complex I activity. These compounds also inhibited DOX-induced caspase-3 activation and cytochrome c release. PBN and ebselen also restored glutathione levels in DOX-treated cells. We conclude that nitrone spin traps and ebselen inhibit the DOX-induced apoptotic signaling mechanism and that this antiapoptotic mechanism may be linked in part to the inhibition in formation or scavenging of hydrogen peroxide. Therapeutic strategies to mitigate DOX cardiotoxicity should be reexamined in light of these emerging antiapoptotic mechanisms of antioxidants.

Cell-permeable superoxide dismutase and glutathione peroxidase mimetics afford superior protection against doxorubicin-induced cardiotoxicity: the role of reactive oxygen and nitrogen intermediates.

The use of the potent antitumor antibiotic doxorubicin (DOX) is hampered because of its severe cardiac toxicity that leads to the development of cardiomyopathy and heart failure. In this study, we have developed a cell culture model for DOX-induced myocardial injury using primary adult rat cardiomyocytes that were cultured in serum-free medium and exposed to 1 to 40 microM DOX. DOX caused a dose-dependent release of sarcosolic enzyme lactate dehydrogenase (LDH) from cultured myocytes. The release of LDH was prevented by the cell-permeable superoxide dismutase (SOD) mimetic (MnTBAP), but was unaffected by either cell-impermeable SOD enzyme, or manganese (II) sulfate. Ebselen, a glutathione peroxidase (GPx) mimetic, enhanced the protection of cardiomyocytes afforded by MnTBAP. DOX caused the increased formation of oxidants in cardiomyocytes, and MnTBAP lowered the amount of intracellular oxidants induced by DOX. In addition, DOX selectively inactivated aconitase in cardiomyocytes, and MnTBAP partially reversed this inactivation. Ebselen further amplified the protective effect of MnTBAP on aconitase activity. These results suggest that the SOD mimetic MnTBAP prevents DOX-induced damage to cardiomyocytes and that the GPx mimetic ebselen synergistically enhanced the cardioprotection afforded by MnTBAP. Relevance of these findings to minimizing cardiotoxicity in cancer treatment is discussed.

[Significance of sarcolemma damage in the pathogenesis of myocardial ischemia induced by pituitrin-isadrin and its correction using the antioxidant dibunol]. / Znachenie povrezhdenii sarkolemmy v patogeneze pituitrin-izadrinovoi ishemii miokarda i ikh korrektsiia s pomoshch'iu antioksidanta dibunola.

The elevation of cardiomyocyte membrane permeability has been demonstrated during pituitrin-isadrin-induced myocardial ischemia. Preventive 7-day oral administration of an antioxidant dibunol (30 and 120 mg/kg) preserved sarcolemmal integrity, decreased myocardial membrane permeability to sulfacetamide sodium, and reduced peroxide and mechanical erythrocyte hemolysis. Inhibition of lipid peroxidation with an antioxidant dibunol improved myocardial injury and decreased the death rate of animals with catecholamine-induced myocardial ischemia. These data suggest the involvement of lipid peroxidation in the development of ischemic myocardial injury.

Bicarbonate exacerbates oxidative injury induced by antitumor antibiotic doxorubicin in cardiomyocytes.

Doxorubicin, a broad-spectrum antitumor antibiotic, causes dose-dependent cardiomyopathy and heart failure. Although the exact molecular mechanisms of cardiotoxicity are not well established, oxidative mechanisms involving doxorubicin-induced superoxide anion production have been proposed. In this study, we show that bicarbonate, a physiologically relevant tissue component, greatly amplified doxorubicin-induced cardiomyocyte injury. Bicarbonate also enhanced inactivation of aconitase, a crucial tricarboxylic acid cycle enzyme, in cardiomyocytes exposed to doxorubicin. The cell-permeable superoxide dismutase mimetic, Mn(III)tetrakis (4-benzoic acid) porphyrin, reversed doxorubicin-induced cardiomyocyte injury. Bicarbonate enhanced the inactivation of purified mitochondrial aconitase in the xanthine/xanthine oxidase system, generating superoxide. The results suggest that bicarbonate amplifies the prooxidant effect of superoxide. Bicarbonate also caused an increased loading of cardiomyocytes with doxorubicin. We conclude that the bicarbonate-mediated increase in doxorubicin toxicity is due to increased intracellular loading of doxorubicin in cardiomyocytes and subsequent exacerbation of superoxide-mediated cardiomyocyte injury.

[Oxidative damage to the myocardium: the protective action of exogenous phosphocreatine]. / Okislitel'noe povrezhdenie miokarda: zashchitnoe deistvie ékzogennogo fosfokreatina.

Oxidative damage of the isolated perfused rat heart was caused by addition of 90 microM H2O into Krebs-Henseleit solution. After 20 min of H2O2 addition an elevation of diastolic pressure (irreversible contracture) was observed followed by decrease of developed tension and heart work. Addition of phosphocreatine (10 mM) at constant total sodium concentration prevented the development of contracture and diminished the decrease of cardiac work. This protective effect is probably related to the elevation of structural order of phospholipids by phosphocreatine.

S-nitrosoglutathione improves functional recovery in the isolated rat heart after cardioplegic ischemic arrest-evidence for a cardioprotective effect of nitric oxide.

The objective of this study was to assess the cardioprotective effect of the nitric oxide (.NO) donor, S-nitrosoglutathione (GSNO) and to investigate the mechanism of cardioprotection in a model of ischemia and reperfusion in isolated rat hearts. The role of .NO in myocardial protection was investigated by using nitronyl nitroxide as the .NO trap. Electron spin resonance spectroscopy was used to demonstrate that nitronyl nitroxide can trap .NO released from GSNO in a cardioplegic solution. .NO traps, oxyhemoglobin (4 mumol/l, n = 4) and nitronyl nitroxide (400 mumol/l, n = 5), inhibited the (2 mumol/l) GSNO-induced coronary vasodilation from the control value of 122% (n = 6) above base-line value to 73 and 60%, respectively. In the ischemia-reperfusion protocol, GSNO (20 mumol/l) was added to the cardioplegic solution during a 35-min ischemic arrest (n = 8). GSNO improved the functional recovery of ischemic hearts as compared to control (n = 6) as measured by the developed pressure (76 +/- 3 to 95 +/- 5% of base-line), rate pressure product (68 +/- 3 to 83 +/- 4% of base-line) and diastolic pressure (31 +/- 2 to 19 +/- 3 mm Hg). Reduction of coronary flow rate during reperfusion to control values in GSNO-treated hearts did not eliminate the improvement of functional recovery induced by GSNO. GSNO increased cyclic GMP production and slowed the accumulation of lactate (154 +/- 7 in control to 114 +/- 4 mumol/g dry wt.) and glucose-6-phosphate (3.66 +/- 0.19 in control to 2.18 +/- 0.10 mumol/g dry wt.) in myocardial tissue during ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

[Emoxipin in reperfusion of ischemic myocardium in dogs: effects on infarct size and plasma creatine kinase activity]. / Emoksipin pri reperfuzii ishemicheskogo miokarda u sobak: vliianie na razmer infarkta i kreatinkinaznuiu aktivnost' plazmy krovi.

The effects of synthetic antioxidant emoxypine on infarct size and plasma creatine kinase (CK) activity was studied on open-chest anesthetized dogs with 180-min myocardial ischemia followed by reperfusion. Emoxypine (10 and 40 mg/kg) was injected intravenously, beginning since 120th min of coronary artery occlusion. Emoxypine (10 mg/kg) resulted in infarct size limitation and reduction in plasma CK activity. An increase in dose of emoxypine to 40 mg/kg largely attenuated its protective effect on infarct size. CK activity during post-ischemic reperfusion was even higher in emoxypine (40 mg/kg) group compared with control. Augmented CK leakage from irreversibly injured myocardium to plasma under these experimental conditions may be owing to preservation of microvascular integrity and improving of drainage of infarcted tissue exerted by emoxypine.

[Improving the contractility and metabolism of the isolated rat heart during post-ischemia reperfusion with phosphocreatine, tocopheryl phosphate and their combination]. / Uluchshenie sokratimosti i metabolizma izolirovannogo serdtsa krysy pri postishemicheskoi reperfuzii s pomoshch'iu fosfokreatina, tokoferilfosfata i ikh sochetaniia.

Within the framework of the multifactor programme of ischemic heart disease (IHD) prevention, among the male population aged 40 to 59 years, the total mortality rate is shown to increase with elevation of blood pressure caused not only by cardiovascular disease but by other disease as well. The incidence of myocardial infarction and cerebral stroke is also shown to increase. Active complex therapeutic and preventive measures among the persons with arterial hypertension (AH) detected during a mass examination, have led to reduction of the prognostic value of AH for the total mortality rate and that in cardiovascular disease, in IHD in particular. Persons under 50 years with concurrent AH and IHD were found to have more pronounced changes.

[Molecular and cellular aspects of the cardioprotective mechanism of phosphocreatine]. / Molekuliarnye i kletochnye aspekty mekhanizma kardioprotektivnogo deistviia fosfokreatina.

The present state of investigations on molecular and cellular mechanisms of cardioprotective effects of phosphocreatine (PCr) is reviewed. The protective effect of PCr is manifested as significant improvement of heart contractile function recovery, lowering of diastolic pressure elevation and myocardial enzymes release during postischemic reperfusion as well as better preservation of high energy phosphates in comparison with control. Data from multidisciplinary studies using physico-chemical, physiological, pharmacological etc. approaches suggest that one of the key mechanisms of PCr action is its interaction with the sarcolemmal membrane. The authors own data obtained with the use of spin-labeled ESR-probe incorporated into the isolated sarcolemmal vesicles provide direct evidence in favor of the ordering effect of PCr sarcolemmal phospholipid packing with essential involvement of Ca2+ ions. PCr transform membrane phospholipids into more structured gel-like state. The results of biomedical studies suggest that the mechanism of this protective action is complex and includes at least four components: 1) inhibition of lysophosphoglyceride accumulation in the ischemic myocardium and preservation of cardiac cell sarcolemma structure via zwitterionic interaction with PCr molecules; ii) extracellular action consisting in inhibition of platelet aggregation via ADP removal in the extracellular creatine kinase reaction and increasing plasticity of red blood cells; iii) PCr penetration into cells maintenance of high local ATP levels is possible; iiii) inhibition of adenine nucleotide degradation at the step of 5'-nucleotidase reaction in cardiac cell sarcolemma.