THE FEATURES OF MELATONIN INFLUENCE ON THE CHRONORHYTHMIC ORGANIZATION OF THE ACID-REGULATING FUNCTION OF THE KIDNEY UNDER THE INFLUENCE OF THE BLOCKADE OF NITROGEN MONOXIDE SYNTHESIS UNDER THE CONDITION OF THE PINEAL GLAND HYPOFUNCTION

The doctors have known about the rhythmic organization of individual body functions for a long time. Rhythm is considered as the decapitating ability of living matter at all levels of the organization, and the study of the rhythms of the functioning of various body systems, factors that affect their formation is of immediate interest to modern biology and medicine. The purpose of this study is to evaluate the effects of melatonin on the chronorhythmic organization of the acid-regulating function of the kidneys under the influence of a blockade of nitrogen monoxide synthesis under conditions of hypofunction of the pineal gland. Materials and methods. Studies were per-formed on 72 sexually mature non-linear male white rats weighing 0.15-0.18 kg. The animals were kept in vivari-um at a constant temperature and humidity in a standard diet. The control group consisted of animals (n=36), which were under normal light conditions (12.00L: 12.00D) for seven days.The study group consisted of animals (n=36), which were injected with N-nitro-L-arginine (L-NNA) at a dose of 20 mg/kg for 7 days under the condition of constant clarification (12.00L: 12.00L) and parallel to melatonin (MT) at a dose of 0.5 mg/kg for 7 days. On the 8th day, the animals were treated with a 5% water load of running water heated to room temperature and the parameters of acid-regulating function of the kidneys were examined under the condition of forced diuresis. The experiments were carried out at 4-hour intervals throughout the day. We studied the pH level of urine, the excretion of hydrogen ions, the acids that are titrated, ammonia, and the ammonium coefficient. The results were processed statistically by the method of "Cosinor analysis", as well as a parametric method of variation statistics. Diagnostics of functional features was based on the analysis of changes in the characteristics of the mesor (daily average level), amplitude, acrophase, and the shape of the circadian rhythm curve. The obtained individual chronograms for each animal were grouped according to the principle of maximum acrophase identity and calculated by the “Cosinor analysis” method, the mesor, amplitude, and phase structure intersecting for each group of chronograms (according to the time interval between acro- and bathyphase). All stages of the experiment were carried out in compliance with the basic requirements of the Europe-an Convention for the Humane Treatment of Animals Results of the research and their discussion. The elucidation of the features of chronorhythmic rearrangements of the acid-regulating function of the kidneys under the condition of nitrogen monoxide (NO) synthesis and the introduction of MT against the background of inhibition of the activity of the pineal gland (PG) is important for understanding the mechanisms of the onset and development of pathologi-cal conditions, which makes it possible to improve early diagnosis, improve treatment of renal pathology, and timely carry out preventive measures. Conclusions. Thus, under the condition of L-NNA blockade of the synthesis of nitrogen monoxide and the introduction of melatonin under conditions of hypofunction of the pineal gland, chronorhythmic rearrangements of the architectonics and phase structure of the rhythms of most indicators of acid-regulating function of the kidneys were observed. Thus, blockade of synthesis NO under condi-tions of MT correction brings the average daily excretion level of hydrogen ions to the control. The introduction of L-NNА against the background of hypofunction PG, and the correction of MT changed the structure of the excre-tion chronorhythms of the titrated acids, and led to a significant increase in this indicator, and ammonia excre-tion during the observation period.