Tag Archives: NO-synthase

The indices of nitrogen (II) oxide system in experimental hepatopulmonary syndrome

I. Ya. Krynytska, M. I. Marushchak

I. Horbachevsky Ternopil State Medical University, Ternopil, Ukraine;
e-mail: marushchak@tdmu.edu.ua

Hepatopulmonary syndrome (HPS) is a pulmonary complication of liver disease characterized by arterial hypoxemia. Altered nitrogen (II) oxide (NO) production has also been implicated in the pathogenesis of the HPS. The present study was designed to evaluate the indices of NO system in the blood serum and lung tissue of animals with different models of hepatopulmonary syndrome. The total NOS activity was performed by monitoring the rate of conversion of L-arginine into citrulline. The total contents of NO metabolites was assessed by evaluation of their amount, which included nitrite ions that were previously presented in the sample (NO2) and also nitrate ions reducted to nitrites (NO3). We found a significant increase in total NOS activity in the lung tissue of Rats of both experimental groups  as compared to control animals, but it was greater in the rats on the 28th day after the common bile duct ligation. The total concentration of NO2 + NO3 in the lung tissue of the rats in the experimental group N 1 also significantly increased (5.8 times) and in the rats of the experimental group with carbon – 4.5 times (P < 0.001) vs the control group. Thus, in rats with different models of hepatopulmonary syndrome the activation of nitroxydergic process by a significant increase in nitrogen (II) oxide metabolites contents and total NO synthases activity has been established. Herewith a more pronounced intensification of nitroxydergic processes was observed in rats on the 28th day after the common bile duct ligation.

The effect of agmatine on L-arginine metabolism in erythrocytes under streptozotocin-induced diabetes in rats

I. V. Ferents, I. V. Brodyak, M. Ya. Lyuta,
V. A. Burda, A. M. Fedorovych, N. O. Sybirna

Ivan Franko National University of Lviv, Ukraine;
e-mail: sybirna_natalia@yahoo.com

The effects of agmatine on oxidative and non-oxidative metabolic pathways of L-arginine were investigated both in plasma and erythrocytes under experimental diabetes mellitus. It was indicated, that agmatine prevents the development of oxidative-nitrosative stress in diabetic rats. After treatment of animals by agmatine NO-synthase methabolic pathway of L-arginine is depressed whereas arginase one increases in erythrocytes of rats with experimental diabetes mellitus.

Peculiarities of arginase and NO-synthase pathways of L-arginine metabolism in peripheral blood lymphocytes of patients with ovarian cancer

O. I. Yakubets, R. V. Fafula, D. Z. Vorobets, Z. D. Vorobets

Danylo Halytski Lviv National Medical University, Ukraine;
е-mail: vorobets@meduniv.lviv.ua

The peculiarities of arginase and NO-synthase pathways of L-arginine metabolism in peripheral blood lymphocytes of patients with ovarian cancer were studied. It was shown that the development of cancer pathology is associated with an imbalance in the NO synthesis in blood lymphocytes. The reason for such imbalance is the activation of arginase and inducible isoform of NO-synthase (iNOS) and significant inhibition of its constitutive isoform. The analysis of the kinetic properties of NOS of blood lymphocytes of patients with ovarian cancer was carried out. It was shown that the affinity constant of iNOS affinity for L-arginine is 5.4-fold lower than for eNOS of blood lymphocytes of persons in the control group. The inhibition of eNOS occurs via non-competitive type and is related to the reduction of maximum reaction rate.

Effect of anticonvulsants on the nitric oxide system

L. A. Gromov1, I. F. Belenichev2, L. G. Gonchar-Cherdakli1, G. A. Zhernovaja2

1SI Іnstitute of Pharmacology and Toxicology, National Academy of Medical Sciences of Ukraine, Kyiv;
2Zaporizhia State Medical University, Ukraine;
e-mail: llrr@ukr.net

The effect of phenobarbital, carbamazepine, valproate sodium, depakine, topiramate and lamotrigine on the content of NO and NO-synthase activity in white rat brain tissues has been studied. It was established that the action of carbamazepine, valproate sodium, topiramate and lamotrigine decreases the activity of NO-synthase and the level of NO in the brain tissues. The amount of NO does not change while NO-synthase activity increases with the introduction of phenobarbital. The involvement of nitric oxide in the mechanism of action of the studied anticonvulsant drugs is discussed.