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Endogenous opioids produce the same effects as the chemicals known as classic alkaloid opiates, which include morphine and heroin. Endogenous opioid peptides function both as hormones and as neuromodulators. The aim of the present study was to analyze the results of docking of ligands with MOR to identify the key elements required for selectivity. Many of the ligands have been synthesized and biologically tested by our colleagues. The other part is compounds known in the literature. The analysis of the obtained ligand-receptor complexes makes it possible to determine the key structural elements associated with the manifestation of specificity with respect to the receptor. These results will assist in the design of new compounds with potential MOR agonistic or antagonistic effects. In order to be active and effective, a ligand must have certain properties. First, it must be stable in a biological environment so that it can reach the place where it will manifest its action. Second, be of a suitable structure to allow it to reach and interact with the receptor's binding site. Third, upon binding, the resulting ligand-receptor complex should be stable, i.e. its energy to be small. Fourth, the ligand induces the appropriate conformations in the receptor molecule upon interaction, i.e. to bind to precisely defined amino acid residues. Therefore, the present study aims to analyze the docking results of dalargine derivatives with MOR and determine the necessary conditions for the manifestation of the biological effect. [ABSTRACT FROM AUTHOR]

Blood pressure and fluid balance are regulated hormonally by renin-angiotensin system (RAS). Influence on this system could be achieved by different compounds that act as angiotensin-converting enzyme inhibitors (ACE inhibitors), angiotensin receptor blockers and renin inhibitors. The purpose of the present study is to predict the structures of the potent ACE inhibitors on the base of His-Leu peptide structural element of angiotensine I using computational methods. Different modifications were made in the structure of this dipeptide and the energy of binding with the enzyme were calculated. The docking results were analyzed and it was found that along with the important amino acid residue of the receptor molecule Arg167, the Tyr residues (35, 87, 88 and 92) as well as Cys180 are extremely important for the strong binding to the receptor and, accordingly, the manifestation of antagonistic action by the analogues. To block the receptor, the ligand molecule must have an intact terminal carboxyl group and an imidazole nucleus to participate in appropriate interactions. The inclusion of functional groups in the side chains of the amino acid residues of the dipeptide create an additional site for binding to the receptor. With the help of docking, the ligand molecule can be optimized, and this process is fast, saving the synthesis of many compounds and their biological testing. And finally, the most potent analogues will be synthesized and biologically tested. [ABSTRACT FROM AUTHOR]

The present study was designed to investigate the structure-activity relationship between cannabinoid and opioid ligands with models of cannabinoid and opioid receptors. There are differences in the mechanisms of pain control for these two types of receptors, but targeting the creation of compounds that bind to both opioid and cannabinoid receptors lead to more effective solving of this problem. This will lead to the development of new and improved strategies to prevent opiate addiction and its consequences. [ABSTRACT FROM AUTHOR]

Artistic swimming is a sport that requires combination of aerobic and anaerobic power. There is little data in the literature on the anaerobic capacity of synchronized swimmers. This study aimed to track the observed changes in the anthropometric and anaerobic parameters among young female synchronized swimmers over a one-year period. The study included 9 female artistic swimmers with average values for age 11 ± 2 years, height 148.2 ± 11.1 cm and weight 39.5 ± 9.2 kg at the initial measurement. Measurements were conducted twice within a period of 1 year. The measurements take place in late April, before the participation of the athletes in important key competitions. Body composition assessment, somatotyping, Wingate and Sargent test were performed. Results indicated an increase in the body mass index over the year, attributed to enhanced muscle mass as a result of from training. Their somatotype varied little in the two measurements, but the variations were minor, a statistically insignificant decrease in the mesomorphic component and an increase in the ectomorphic component shows that as a result of synchronized swimming training, female athletes form suggested the formation of a characteristic sports somatotype. Maximum power of the studied group of artistic swimmers progressively increased over the study period and after 12 months was significantly higher than at the beginning of the study. A statistically significant difference between two measurements was observed in vertical jump and calculated peak power (Wilcoxon signed rank test, P value = 0.0039 and P value = 0.0039, respectively). These results are further evidence that finding underscore the profound impact of artistic swimming training has a strong impact on increasing the anaerobic capacity of athletes. Tracking the anthropometric and anaerobic characteristics enables the analysis of changes in artistic swimming athletes allows for the analysis of their changes. Targeted training guided by these observations can contribute to the improvement of specific qualities, in the case of desired changes in body composition and anaerobic capacity. Ultimately, this approach enhances sports form and increasing sports improves athletic performance. [ABSTRACT FROM AUTHOR]

Problem Statement and Purpose: Soccer is a sport characterized by high intensity and duration. The energy needed to play a soccer match is provided by aerobic metabolism. Therefore, it is important to determine such parameters as oxygen consumption and maximal oxygen consumption in soccer players. The aim of the study is to track the changes in the functional indicators of professional soccer players during the spring half-season and to give recommendations for changes in the training plan to increase their performance and reduce fatigue at the end of the season. Approach: The study involved 13 professional soccer players and was conducted in the period January - June. Functional examination of respiration - spirometry and determination of gas exchange parameters during exercise - spiroergometry were performed twice at the beginning and at the end of the period. Results: The spirometry data of the subjects showed values close to the predicted values. The decrease in values at the end of the spring half-season is probably due to the fatigue accumulated during this period. Although the values show a decrease in the parameters, there is no statistically significant difference in the two measurements of the Tifno index, but there is a statistically significant difference in the decrease in VC (Wilcoxon signed rank test, p value = 0.04) and FEO1 (Wilcoxon signed rank test, p value = 0.0002). The fact that even the indicators at the beginning of the study are to some extent underestimated, shows the accumulation of fatigue in the players and the need to rethink the overall training plan with corresponding individual approaches to each soccer player in order to optimize the training-recovery ratio. There was a slight increase (statistically insignificant) in mean VO2max and VO2max/kg during the spring half-season, indicating that training resulted in an increase in aerobic capacity. This is an indication that conditioning training is producing the desired result and can be carried out without any major changes. Conclusions: The benefit of periodic medical and functional examinations of football players is mainly in two directions. First, it provides information about the current state of health of the athlete under study and his fitness to participate in training and sports competitions. And, secondly, it enables the coach, analyzing the results, to assess the specific functional capabilities of the football players, to make changes in the training schedule and specific exercises, to pay attention to recovery and to apply an individual approach to each specific case in order to improve specific indicators. [ABSTRACT FROM AUTHOR]

Cannabinoid receptors are important class of receptors as they are involved in various physiological processes such as appetite, pain-sensation, mood, and memory. It is important to design receptor-selective ligands in order to treat a particular disorder. The aim of the present study is to model the structure of cannabinoid receptor CB1 and to perform docking between obtained models and known ligands. Two models of CBR1 were prepared with two different methods (Modeller of Chimera and MOE). They were used for docking with GOLD 5.2. It was established a high correlation between inhibitory constant Ki of CB1 cannabinoid ligands and the ChemScore scoring function of GOLD, which concerns both models. This suggests that the models of the CB1 receptors obtained could be used for docking studies and in further investigation and design of new potential, selective and active cannabinoids with the desired effects.

The bioactive peptides are specific protein fragments which have a positive effect on the body functions and conditions. These peptides have a hormone- or a drug like activity and play an important role. The antihypertensive peptides are a significant group of these peptides, which are used as angiotensin-converting enzymes inhibitors, because they are associated with the high blood pressure decrease and play an important role in cardiovascular diseases. Angiotensin-I Converting Enzyme (ACE) is one of the major components of the so-called Renin-Angiotensin System (RAS). Renin is responsible for the release of Angiotensin I (AI) in blood because of its catalytic action on angiotensinogen. The role of ACE connected with the inhibition of ACE enzymatic activity against AI is considered one of the major challenges in case of a hypertensive disease and a congestive heart failure. The present investigation is focused on the synthesis of His-Leu and Val-Trp peptide analogues using well know procedures. The intermediates and the dipeptide analogues are characterized by TLC and spectral methods. The computer modeling and the docking studies are performed to determine the structure-activity relationship and to synthesize new potential ACE inhibitors. [ABSTRACT FROM AUTHOR]

The endocannabinoid system consists of endocannabinoids, cannabinoid receptors and enzymes that synthesise and degrade the endocannabinoids. The cannabinoid receptors (CBR) are an important class of receptors participating in various physiological processes. Many of their effects are mediated by two G protein-coupled receptors (GPCRs), (CB1) and (CB2), although additional receptors may be involved. The purpose of this paper is to present a computer modelling of the CBR and several known cannabinoid ligands aiming to determine the structure-activity relationship by using molecular docking with GOLD software. Four scoring functions provided by GOLD are used for molecular docking of the models of CBR1, its crystal structure and the known cannabinoid ligands. Significant correlations between the biological activity of the ligands and the ChemScore optimization function are established. The results obtained could be further used for in silico experiments of the interaction between CBR and cannabinoid ligands. [ABSTRACT FROM AUTHOR]

The physiological requirements for practicing alpine skiing are both aerobic and anaerobic power, as well as muscle strength and a complex of motor abilities. Alpine skiing competitions consist of four separate disciplines: downhill -- duration of 2-3 minutes at a speed of over 90 km / h; super giant slalom - shorter than the downhill -- 1-2 minutes; giant slalom - is held on very steep terrain with a duration of 60 to 90 seconds; slalom - includes very fast turns on steep terrain, consists of two attempts lasting 45-60 seconds for attempt. The purpose of this study is to track the changes of anaerobic capacity of adolescent alpine skiers during competition season using the Wingate test and the Sargent test. As a result of the study, several major conclusions could be drawn: - As a result of the training and competitions during the period between the two tests, the participants in the study increased their average power (p = 0.02); - there were significant correlations between muscle mass and maximum power ( December - 0.93 ***, April - 0.84 **), average power (December - 0.90 **, April - 0.87 **) and relative power (m December - 0.73 *, April - 0.62 *; *** - p <0.001; ** - p <0.03; * - p <0.05; ns - p> 0.05); - moderate correlations were found between the maximum and average power of the Wingate test and the ranking on the national level of the subjects; - the fatigue index of the athletes increased on the second measurement, probably as a result of the busy training and competition program. The research shows that training and competitions in alpine skiing disciplines allow the development of anaerobic capacity of athletes, which are extremely important for better performance during a race. [ABSTRACT FROM AUTHOR]

Cannabinoid receptor type 2 (CB2) is a member of the G protein-coupled receptor superfamily. CB2 plays an important role in regulating receptor desensitization and internalization. It has protective effects in chronic degenerative diseases. 3D homology models of different templates in absence of CB2 receptor crystal structures are reported in the literature, but their wide use is limited. The aims of the present study are: 1) to choose among the published crystallographic structures templates for CB2 receptor homology modelling and to evaluate them with different computational tools; 2) to investigate the interaction between the developed model of CB2 and several known cannabinoid ligands aiming to determine the structure-activity relationship by molecular docking with GOLD 5.2 software. A significant correlation between the docking results (ChemScore function) and the ligands biological activity is found. The results obtained could be further used in silico experiments of the cannabinoid receptor-ligand interactions. [ABSTRACT FROM AUTHOR]

Basketball is a sport in which the development of anaerobic power is of great importance as short intense workouts are part of the game. The purpose of this study is to determine the anaerobic capacity of adolescent basketball players. The study involved 15 basketball players aged 15.5 ± 1.2 years. The anaerobic test used is the Wingate test. The test results indicate that athletes have high peak power (522.9 ± 113.3 W) and high relative peak power (7.1 ± 0.5 W / kg). Blood lactate concentrations after Wingate anaerobic test significantly differ from those before the test (11.35 ± 1.62 mmol/l on the 1st min as compared with 2.57 ±0.30 mmol/l before the test). These results make it possible to conclude that training with adolescents is conducted properly in the direction of anaerobic capacity development. The study is the beginning of a longitudinal tracking on the development of these basketball players and will be used for tracking the changes every six months, which will allow the coaches to make appropriate changes in the training sessions. [ABSTRACT FROM AUTHOR]

Bioactive peptides are protein fragments that have a positive impact on body functions and may ultimately influence health. Angiotensin-converting enzyme plays an important role in the control of arterial blood pressure. The main action of Angiotensin II is to maintain blood pressure and fluid balance in the body. It is obtained from the precursor under catalytic action of angiotensin-converting enzyme (ACE). In order to control (inhibit) the action of the ACE different inhibitors were proposed and some of them are already in use in the clinic. In the present investigation we design and docking studies of fife new potential ACE inhibitors. Three of the proposed analogues have a potential to be ACE inhibitors, as they bind to the enzyme stronger than His-Leu. The studied peptides may form as a basis for the design of new compounds and will be synthesized and biologically tested. [ABSTRACT FROM AUTHOR]

Leu-Arg is a kyotorphin receptor antagonist. It is very important to control antinociception and this could be achieved by modifications in agonist's or antagonist's molecules. Two analogues of Leu-Arg were synthesized, their IR- spectral characteristics were defined, and preliminary docking studies were performed. The results show that new analogues bind receptor thus they could be used for further analysis and their biological activity could be tested in vitro and in vivo. [ABSTRACT FROM AUTHOR]