Search

This work is based on the hypothesis that it is possible to characterize the cardiovascular system just from the detailed shape of the arterial pulse waveform (APW). Since H 2 S, NO donor S-nitrosoglutathione (GSNO) and their H 2 S/GSNO products (SSNO - -mix) have numerous biological actions, we aimed to compare their effects on APW and to find characteristic "patterns" of their actions. The right jugular vein of anesthetized rats was cannulated for i.v. administration of the compounds. The left carotid artery was cannulated to detect APW. From APW, 35 hemodynamic parameters (HPs) were evaluated. H 2 S transiently influenced all 35 HPs and from their cross-relationships to systolic blood pressure "patterns" and direct/indirect signaling pathways of the H 2 S effect were proposed. The observed "patterns" were mostly different from the published ones for GSNO. Effect of SSNO - -mix (≤32 nmol kg -1 ) on blood pressure in the presence or absence of a nitric oxide synthase inhibitor (L-NAME) was minor in comparison to GSNO, suggesting that the formation of SSNO - -mix in blood diminished the hemodynamic effect of NO. The observed time-dependent changes of 35 HPs, their cross-relationships and non-hysteresis/hysteresis profiles may serve as "patterns" for the conditions of a transient decrease/increase of blood pressure caused by H 2 S.

We characterized modes of action of NO-donor S-nitrosoglutathione (GSNO) and NO-synthase inhibitor l-NAME derived from dicrotic (DiN) and anacrotic (AnN) notches of rat arterial pulse waveform (APW) in the condition of increased/decreased NO bioavailability. The cross-relationship patterns of DiN and AnN with 34 hemodynamic parameters (HPs) induced by GSNO and l-NAME are presented. After GSNO bolus administration, approximate non-hysteresis relationships were observed in the difference between DiN-AnN (mmHg) blood pressure (BP) and other 19 HPs, suggesting that these HPs, i.e., their signaling pathways, responding to NO concentration, are directly connected. Hysteresis relationships were observed between DiN-AnN (mmHg) and other 14 HPs, suggesting that signaling pathways of these HPs are indirectly connected. The hysteresis relationships were only observed between the time interval DiN-AnN (ms) and other 34 HPs, indicating no direct connection of signaling pathways. The cross-relationship patterns of DiN-AnN (mmHg), but not DiN-AnN (ms), induced by l-NAME were in accordance to the increased NO bioavailability induced by GSNO. In conclusion, we found the non-hysteresis/hysteresis cross-relationship "patterns" of DiN-AnN intervals to other HPs in the presence of GSNO that revealed their direct or indirect signaling pathways connections. This may contribute to our understanding of biological effects of natural substances that modulate NO production and/or NO signaling pathways.

Aim: To study "patterns" and connections of signaling pathways derived from the rat arterial pulse waveform (APW) under the condition of transient NO increase., Methods and Results: The right jugular vein of anesthetized Wistar rats was cannulated for administration of NO donor S-nitrosoglutathione. The left carotid artery was cannulated to detect APW. From rat APW, 35 hemodynamic parameters (HPs) and several their crossrelationships were evaluated. We introduced a new methodology to study "patterns" and connections of different signaling pathways, which are suggested from hysteresis and nonhysteresis crossrelationships of 35 rat HPs. Here, we show parallel time-dependent patterns of 35 HPs and some of their crossrelationships under the condition of transient increase of NO bioavailability by administration of S-nitrosoglutathione. Approximate nonhysteresis relationships were observed between systolic blood pressure and at least 11 HPs suggesting that these HPs, i.e., their signaling pathways, responding to NO concentration, are directly connected. Hysteresis relationships were observed between systolic blood pressure and at least 14 HPs suggesting that the signaling pathways of these HPs are indirectly connected. Totally, from the crossrelationships of 35 HPs, one can obtain 595 "patterns" and indication of direct or indirect connections between the signaling pathways., Conclusion: We described the procedure leading virtually to 595 relationships, from which "patterns" for transient NO increase and direct or indirect connections of signaling pathways can be suggested. From a clinical perspective, this approach may be used in animal models and in humans to create a data bank of patterns of crossrelationships of HPs for different cardiovascular conditions. By comparison with unknown patterns of studied APW with the data bank patterns, it would be possible to determine cardiovascular conditions of the studied subject from the recorded arterial blood pressure. Additionally, it can help to find molecular mechanism of particular (patho-) physiological conditions or drug action and may have predictive or diagnostic value., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Anton Misak et al.)

New Findings: What is the central question of this study? Can the cross-relationship between 35 rat arterial pulse waveform (APW) parameters be described by known mathematical functions and can mathematical parameters be obtained for conditions in a model of hypertension resulting from decreased NO bioavailability? What is the main finding and its importance? Mathematical functions and their parameters were obtained that approximate the cross-relationships of 35 APW parameters to systolic blood pressure and to the augmentation index in conditions of decreased NO bioavailability. The results enable APW parameters to be assigned to decreased NO bioavailability, which may have predictive or diagnostic value., Abstract: Information obtained from the arterial pulse waveform (APW) using haemodynamic parameters (HPs) is useful for characterization of the cardiovascular system in particular (patho)physiological conditions. Our goal was to find out whether the relationships between rat HPs could be described by simple mathematical functions and to find mathematical parameters for conditions of high blood pressure (BP) resulting from decreased NO bioavailability. The right jugular vein of anaesthetized Wistar rats was cannulated for i.v. administration of N ω -nitro-l-arginine methyl ester (l-NAME). The left common carotid artery was cannulated to detect the APW. From 10 points on the rat APW we defined 35 HPs (some were known already) and found 595 cross-relationships between HPs showing unique patterns for particular cardiovascular conditions. Here we show parallel time-dependent changes of 35 HPs and some of their cross-relationships in condition of high BP induced by l-NAME. We found that most of the time-dependent changes of 35 HPs and their relationships were very well fitted by simple mathematical functions, e.g. a linear function, exponential growth, exponential decay or exponential rise to maximum. The results may enable the mathematical functions to be assigned for decreased NO bioavailability, which may have predictive or diagnostic value for conditions of high BP. Using this approach, it may be possible to find unique cross-relationship patterns of HPs and mathematical functions between HPs for different cardiovascular (patho)physiological or drug-modulating conditions. This knowledge can be used in studying the molecular mechanisms of particular (patho)physiological conditions or drug actions and may have predictive or diagnostic value., (© 2019 Slovak Academy of Sciences, Slovak Republic. Experimental Physiology © 2019 The Physiological Society.)

Selenium (Se), an essential trace element, and hydrogen sulfide (H 2 S), an endogenously produced signalling molecule, affect many physiological and pathological processes. However, the biological effects of their mutual interaction have not yet been investigated. Herein, we have studied the biological and antioxidant effects of the products of the H 2 S (Na 2 S)/selenite (Na 2 SeO 3 ) interaction. As detected by the UV-VIS and EPR spectroscopy, the product(s) of the H 2 S-Na 2 SeO 3 and H 2 S-SeCl 4 interaction scavenged superoxide-derived radicals and reduced · cPTIO radical depending on the molar ratio and the preincubation time of the applied interaction mixture. The results confirmed that the transient species are formed rapidly during the interaction and exhibit a noteworthy biological activity. In contrast to H 2 S or selenite acting on their own, the H 2 S/selenite mixture cleaved DNA in a bell-shaped manner. Interestingly, selenite protected DNA from the cleavage induced by the products of H 2 S/H 2 O 2 interaction. The relaxation effect of H 2 S on isolated thoracic aorta was eliminated when the H 2 S/selenite mixture was applied. The mixture inhibited the H 2 S biphasic effect on rat systolic and pulse blood pressure. The results point to the antioxidant properties of products of the H 2 S/selenite interaction and their effect to react with DNA and influence cardiovascular homeostasis. The effects of the products may contribute to explain some of the biological effects of H 2 S and/or selenite, and they may imply that a suitable H 2 S/selenite supplement might have a beneficial effect in pathological conditions arisen, e.g., from oxidative stress., Competing Interests: The authors declare no conflict of interest., (Copyright © 2019 Marian Grman et al.)

Doxycycline (DOXY) is an antibiotic routinely prescribed in human and veterinary medicine for antibacterial treatment, but it has also numerous side effects that include oxidative stress, inflammation, cancer or hypoxia-induced injury. Endogenously produced hydrogen sulfide (H₂S) and polysulfides affect similar biological processes, in which reactive oxygen species (ROS) play a role. Herein, we have studied the interaction of DOXY with H₂S (Na₂S) or polysulfides (Na₂S₂, Na₂S₃ and Na₂S₄) to gain insights into the biological effects of intermediates/products that they generate. To achieve this, UV-VIS, EPR spectroscopy and plasmid DNA (pDNA) cleavage assay were employed. Na₂S or Na₂S₂ in a mixture with DOXY, depending on ratio, concentration and time, displayed bell-shape kinetics in terms of producing/scavenging superoxide and hydroxyl radicals and decomposing hydrogen peroxide. In contrast, the effects of individual compounds (except for Na₂S₂) were hardly observable. In addition, DOXY, as well as oxytetracycline and tetracycline, interacting with Na₂S or other studied polysulfides reduced the • cPTIO radical. Tetracyclines induced pDNA cleavage in the presence of Na₂S. Interestingly, they inhibited pDNA cleavage induced by other polysulfides. In conclusion, sulfide and polysulfides interacting with tetracyclines produce/scavenge free radicals, indicating a consequence for free radical biology under conditions of ROS production and tetracyclines administration.