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EN
Accumulating evidence suggests that the nongenomic cardiovascular actions of aldosterone are produced by varied cellular pathways and mediated by a multitude of messenger systems including the reactive oxygen and nitrogen species. Considering the involvement of the oxidative and nitrosative stress in the pathways leading to the activation of the angiotensin - aldosterone system, in the current study we tried to evaluate the functional interactions between aldosterone, angiotensin II and antioxidants in isolated vascular smooth muscle of aortic rings from rats. Our data provide additional arguments that the nongenomic actions of aldosterone on aortic smooth muscle cells of rats are a question of cross-talk and balance between its rapid vasoconstrictor and vasodilator effects, as result of the activation of reactive oxygen species in the first case and of nitrogen species in the second. In this way, it seems that at low ambient oxidative stress, aldosterone promotes nitric oxide (NO) production and vasodilatation, while in situations with increased oxidative stress the endothelial dysfunction and detrimental effects induced by vasoconstriction will prevail. Thus, aldosterone could be considered both “friend and foe”. This could be relevant for the ways in which aldosterone damages cardiovascular functions and could lead to significant therapeutic improvements.
EN
In addition to its known classical roles, the renin angiotensin system (RAS) has more subtle functions which include the regulation of emotional responses. Previous studies regarding the anxiety related behavior of RAS have showed controversial results. There is also evidence that oxidative stress accompanies angiotensin II infusion, but the role of AT1/AT2 specific receptors is not clear. The aim of this study was to evaluate the effects of central angiotensin II receptor blockers on anxiety state and oxidative stress. Behavioral testing included elevated plus maze, while oxidative stress status was measured though the extent of a lipid peroxidation product (malondialdehyde-MDA) and the specific activity of some defense antioxidant enzymes (superoxide dismutase-SOD and glutathione peroxidase-GPx). The rats treated with angiotensin II spent significantly less time in the open-arms of elevated-plus-maze, while the administration of losartan resulted in a significant increase of this time. We observed a significant increase of MDA concentration in the angiotensin II group and a decrease of MDA levels in both losartan and PD-123177 groups. In addition, a significant correlation was seen between the time spent in the open arms and oxidative stress markers. These findings could lead to important therapeutic aspects regarding the use of angiotensin II receptor blockers in anxiety-related disorders.
EN
Nucleus accumbens (NAcc) are a collection of neurons that form the main part of the ventral striatum, which is a significant dopaminergic structure. Also, NAcc is thought to play an important role in reward, pleasure, laughter, addiction, aggression, fear, and the placebo effect. In the present work we were interested in studying the effects of a 6-OHDA induced lesion in the nucleus accumbens (NAcc), which is known as an important dopaminergic structure, on a specific behavioral task that involves both short term and long term spatial memory (the radial-8-arm-maze task), as well as on the oxidative stress markers (two antioxidant enzymes: superoxide dismutase-SOD and glutathione peroxidase-GPX and a lipid peroxidation marker: malondialdehyde-MDA, as well as the total antioxidant status-TAS) from the temporal lobe, which is considered to be the most vulnerable cortical area to oxygen levels fluctuations and hypoxia. Our results showed some significant effects of this lesion on the reference memory errors and time necessary to finish the test in the radial-8-arm-maze task. Additionally, increased oxidative stress status was demonstrated in the temporal lobe of the lesioned rats, as demonstrated by the high levels of lipid peroxidation and decreased total antioxidant status. Moreover, significant correlations are reported here between the behavioral parameters which we studied in the radial-8-arm-maze task and the aforementioned oxidative stress markers.
EN
Although it is accepted that an important correlation exists between the physical exercise and the oxidative stress status, the data regarding the levels of the main oxidative stress markers after physical training have been difficult to interpret and a subject of many controversies. There are also very few studies regarding the effects of short-time exercise on the oxidative stress status modifications. Thus, in the present report we were interested in studying the modifications of some oxidative stress markers (two antioxidant enzymes-superoxide dismutase and glutathione peroxidase, a lipid peroxidation parameter - malondyaldehide, the total antioxidant status and protein carbonyl levels), from the serum of rats that were subject to one bout of five minutes exercise on a treadmill, when compared to a control sedentary group. In this way, we observed a decrease of superoxide dismutase specific activity in the rats which performed the exercises. Still, no modifications of glutathione peroxidase specific activity were found between groups. In addition, increased levels of malondyaldehide and protein carbonyls were observed in the rats subjected to exercises. In conclusion, our data provides new evidence regarding the increase of the oxidative stress status, as a result of a 5-minutes bout of treadmill exercising in rats, expressed through a decrease in the SOD specific activity and the total antioxidant status and also an increase of the lipid peroxidation and protein oxidation processes.
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