[Effects of stimulation and blockade of the synthesis of endogenous hydrogen sulfide at myocardial ischemia-reperfusion].

In experiments on isolated rat hearts, perfused according to Langendorff method, the effects of stimulation of the synthesis and blockade of endogenous hydrogen sulfide in myocardial ischemia-reperfusion (20 min/40 min) was studied. L-cysteine (121 mg/kg), precursor of endogenous hydrogen sulfide was injected intraperitoneally 30 minutes before the experiment without and within 10 minutes after administration of DL-propargylglycine (11.3 mg/kg) ("Sigma", USA)--inhibitor of cystathionine-gamma-lyase.

[Effect of hydrogen sulfide on isolated rat heart reaction under volume load and ischemia-reperfusion].

The present study was aimed to investigate the effect of H2S donor (NaHS) on heart function in conditions of functional loads and ischemia-reperfusion (I/R) injury by using Langendorf isolated heart perfusion. NaHS ("Sigma", 7,4 mg per kg) was dissolved in physiological solution and injected intraperitoneally 30 min before experiment. Rat isolated hearts were Langendorf-perfused and subjected to 20-minute non-flow ischemia followed by 40-minute reperfusion.

[Mitochondria permeability transition as a target for ischemic preconditioning].

The ischemic preconditioning (IPC) limits myocardial injury provoked by a subsequent prolonged ischemia-reperfusion (I/ R). The underlying mechanisms of enhanced resistance of heart are actively studied, but for sure it was established that mitochondria play a major role in IPC-stimulated adaptation to ischemia. In this article we present and discuss evidences that cardioprotective effect of IPC is mediated by inhibition of mitochondria permeability transition pore (MPTP) opening.

[Role of nitric oxide in the development of the myocardial contractile reactions in trained animals].

Intensive constitutive production of nitric oxide (NO) during physical training improves vasodilatation and heart function. However, it remains unclear how NO takes part in myocardial adaptation to workload, which is accompanied by an increased heart inflow and intracellular calcium content. Using isolated rat heart by Langendorf preparation, we studied myocardial response to gradually increased left ventricular volume (Frank-Starling low) and increasing concentration of Ca2+ in the perfusion solution (from 1.

[Genipin--uncoupling protein inhibitor--reduces the protective effect of ischemic preconditioning].

The functional significance of uncoupling proteins UCP2 and UCP3 in the cell and the organism remains unknown. There have been reports about their involvement in cellular protection mechanisms underlying the phenomenon of ischemic preconditioning. The purpose of this study was to elucidate the role of uncoupling proteins UCP2 and UCP3 in the formation of cardioprotective effect of ischemic preconditioning.

[Effect of UCP2 activity inhibitor genipin on heart function of aging rats].

To estimate the role of uncoupling proteins in aging rat heart recovery from prolonged ischemia we used genipin application during Langendorfpreparation. It was shown that genipin in dose-depended manner depressed coronary flow, heart rate and cardiac diastolic function. Such effect was similar to that observed during myocardial Ca2+ overload by gradually elevated CaCl2, in perfusion solution.

[UCP2 and UCP3 gene expression, heart function and oxygen cost of myocardial work changes during aging and ischemia-reperfusion].

To examine the effects of ischemia/reperfusion on UCPs genes expression, heart function and oxygen cost of myocardial work, hearts of adult (6 mo) and old (24 mo) rats were perfused by Langendorf preparation and subjected to 20 min ischemia followed by 40 min reperfusion. Mitochondrial permeability transition due to ischemic stimuli was evaluated by release of mitochondrial factor (lambda 250 nm) which was previously shown as a marker of MPTP opening. Expression of UCPs was detected by reverse transcriptional polymerase chain reaction.

[Effects of uncoupling proteins on nitric oxide synthesis and oxidative stress development in ishemia-reperfusion of old rat hearts].

Genipin is aglycone of geniposide, one of the active compounds of Gardenia gasminoides Ellis. The gardenia fruit extract has been used in traditional Chinese medicine to relieve the symptoms of type 2 diabetes that is accompanied with extensive oxidative stress and endothelial dysfunction of NO production. Besides, genipin was shown to inhibit UCP-depended proton leak through the inner mitochondrial membrane that leads to increased membrane potential and ATP production.

[Inhibition of mitochondrial permeability transition pore is one of the mechanisms of cardioprotective effect of coenzyme Q10].

Protective properties of coenzyme Q10 (CoQ10) on the: (i) Langendorff isolated guinea pig heart's function under ischemia and reperfusion (I/R) and on the isolated mitochondria (ii) the mitochondrial permeability transition pore (MPTP) opening under exposure to calcium as natural MPTP inductor and phenylarsine oxide as oxidant--were studied. Physiological characteristic of contractile function, myocardial oxygen consumption and mitochondrial factor release as index of MPTP opening were compared before and after ischemia of isolated heart in control animals and animals with preliminary administration of CoQ10 per os. It have been shown that I/R disturbances of heart function were decreased and oxygen metabolism was normalised in animals treated with CoQ10 in compare to non-treated control.

[Factor released during myocardial ischemia reperfusion may become a marker of opening of the mitochondrial permeability transition pore].

In experiments on isolated hearts of guinea-pigs, on a model of ischemia-reperfusion cardiac reperfusion has been shown to result in a constriction of coronary vessels, arrhythmia, an inhibition of the contractile activity of the myocardium, and an increase in an oxygen cost of the myocardial work. Apart from that, a stable agent was detected in a reperfusion solution by spectrophotometry on the wave length of 250 nM. Similar deterioration of the heart function and the availability of the stable agent in the solution were observed under influence of the known activators of mitochondrial permeability transition pore-phenilarsine oxide and antimycin A.

[Study of a factor released during myocardial ischemia reperfusion and its effects on myocardial, coronary and peripheral vessels].

The effect of reoxygenated coronary effluent of an isolated guinea-pig heart on a sequentially perfused second heart, right auricle trabecula and arterial vessel rings was studied after 20 min ischaemia of the first heart. It has been shown that a factor released after myocardial ischemia/reperfusion stimulates arrhythmia, decreases myocardial contractility of the second heart and depresses tonical tension of the right auricle trabecula and arterial vessel rings. Storage of the coronary effluent up to 24 h did not modify its effects.

[The role of nitric oxide in changes in the oxygen consumption and the oxygen cost of the work of the cardiac muscle].

In experiments on guinea-pig isolated hearts, perfused under Langendorff preparation, it has been shown that heart volume load and inotropic stimulation were accompanied with an increase of nitric oxide synthesis (by 46 and 51% accordingly) and with a decrease in an oxygen cost of myocardial work. L-arginine or sodium nitroprusside administration resulted in a reduce of the oxygen consumption by 29% and a decrease of oxygen cost of myocardial work. Inhibition of NO-synthase activity lead to an opposite effect--an increase in both--O2 consumption and an oxygen cost of the heart work by 15 and 19%.

[The effect of a grape extract on the contractile activity of the myocardium and on the coronary flow of the isolated guinea pig heart].

Effects of one of the fraction of grape extract on myocardial contractility and coronary flow of isolated guinea pig heart have been investigated. It was shown that the administration of grape extract led to myocardial contractility index is increase by 77%, coronary flow increase by 13% and oxygen consumption increase by 30%. Inhibition of nitric oxide synthesis by L-NMMA resulted in decrease of grape extract-induced coronary flow increase.