Nitroglycerine (NG) affords cardioprotection via NO formation, but the impact of NG application on reactive nitrogen species (RNS) metabolism remains little studied yet. Mitochondrial NO synthase (mtNOS) is an important endogenous source of RNS. Our aim was to study the effect of NG application on mtNOS activity and RNS production in rat heart and liver mitochondria. Different regulation of mtNOS activity in the heart and liver under NG treatment was found. While in heart mitochondria it increased dose-dependently, in liver mitochondria only moderate elevation and bell-shaped dose dependence of mtNOS activity on NG was observed. Nitrite and nitrate, which are the end products of L-arginine transformation by NOS, showed similar dose dependence on NG. To find an explanation for the observed dependences, we studied the effects of NG administration on the activity of arginase which competes with NOS for physiological substrate, Larginine. A strong reciprocal dependence between mtNOS and arginase activities was found. As we observed, the arginase activity increased under NG application. However, while in heart mitochondria high mtNOS activity agreed with moderate arginase activation, in liver mitochondria high arginase activity coincided with suppression of mtNOS activity at high doses of NG. Low arginase and high mtNOS activities observed in heart mitochondria were consistent with high NO2 − and NO3 − production and low hydroperoxide (H2O2) formation, whereas high arginase activity in liver mitochondria was accompanied by the reduction of NO2− /NO3− formation and simultaneous elevation of H2O2 production. A linear correlation between the arginase activity and hydroperoxide formation was found. We came to the conclusion that under NG administration arginase activation resulted in reciprocal regulation of RNS and ROS production in mitochondria, dependent on the proportion of mtNOS to arginase activity. Suppression of RNS metabolism could be the cause of ROS overproduction caused by high arginase and low mtNOS activity.
Arterial hypertension (AH) is a multifactorial disease that is accompanied by the development of oxidative-nitrosative stress and insufficient production of hydrogen sulfide (H2S). We hypothesized that garlic bio supplement Full Spectrum Garlic (Swanson Health Product, USA) may be used as a potential H2S donor in treatment of AH in patients. The aim was to study the effect of garlic on blood pressure, ROS generation and cNOS/iNOS activity, biochemical in male 28-39 years old patients with grade II AH. It was found that 10 days of standard antihypertensive therapy (adrenoblockers, ACE inhibitors) with 30 days of garlic supplementation reduced mean systolic and diastolic pressures by 9 and 8 mm Hg respectively. Positive effects of garlic consumption on hemodynamic parameters were observed: enddiastolic volume increased by 8% and peripheral vascular resistance decreased by 11,3% . In the blood plasma of patients, H2S levels increased by 43,6% , the production of ROS and the content of lipid peroxidation products decreased significantly. It is important that the cNOS activity was increased by 130% and iNOS activity decreased by 38,3%. No significant changes in cholesterol, urea, creatinine, glucose, as well as erythrocyte parameters were observed, which indicates the tolerance of the garlic supplements. Thus, the hypotonic effect of garlic is realized by increasing endogenous H2S in plasma, improving endothelium-dependent relaxation of blood vessels and reducing the manifestations of oxidative stress, which makes it promising to use it in the complex therapy of hypertension.
The effects of a single injection of the reduced form of glutathione on the expression of the KCNJ8 and KCNJ11 genes encoding Kir6.1 and Kir6.2 subunits of ATP-sensitive potassium (KATP) channels and on Ca2+-induced nonspecific mitochondrial permeability transition pores (mPTP) opening in the heart of old rats were studied. Changes in biochemical parameters characterizing the intensity of oxidative processes in organelles at the action of glutathione were also studied. The expression levels of Kir6.1 і Kir6.2 subunits KATP channels were determined using reverse transcription and quantitative PCR. It was shown that after the administration of glutathione to old rats, the expression of KATP channel subunits significantly increased, namely for Kir6.1 9.3 times, for Kir6.2 2.6 times. The use of glutathione in older animals inhibited mPTP opening: reduced the amplitude of spontaneous and Ca2+-induced swelling of mitochondria. An important consequence of the action of glutathione during aging was a decrease in the rate of generation of superoxide (.О2-) and hydroxyl (.ОН) radicals, as well as the content of hydrogen peroxide respectively in 1.8, 2.5 and 3.2 times compared with these figures in older animals without treatment. Glutathione also reduced lipid peroxidation, particularly pools of diene conjugates (2.5-fold) and malonic dialdehyde (1.8-fold). Thus, glutathione significantly increases the expression of KCNJ8 and KCNJ11 genes encoding Kir6.1 and Kir6.2 subunits of KATP channels in the heart of rats, regulates MP, preventing its opening, and reduces oxidative stress, indicating its important role in myocardial protection.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.