Peculiarities of the influence of mitochondrial ATP-dependent K+ channels activation on the function of external respiration under experimental pneumonia

Abstract

The studies were performed on male Wistar rats weighing 250-270 with experimental pneumonia (EP) induced by the method of A.M. Kulik. The animals were divided into the following groups: 1 – control; 2 - experimental pneumonia; 3 (first experimental group) - animals, which in parallel with the simulation of pneumonia were intraperitoneally administered uridine at a dose of 0.3 mg/100 g of body weight (daily within 1 week); 4 (second experimental group) - animals in which uridine was administered daily starting from day 4 (at the peak of pneumonia). Animals with EP were examined at 5th (n = 10), 9th (n = 8) and 12th (n = 6) days of the disease development, as well as 1 (n = 5) and 2 (n = 5) months after EP modeling. It was shown that in the first experimental group on the 5th day of EP development, an isoventilator restructuring of respiration was observed. In this group, from day 12 to the end of the study, there was a stenoventilator restructuring of breathing, which was characterized by an increase in tidal volume, alveolar ventilation, oxygen consumption and, accordingly, an increase in oxygen extraction from the alveoli and in the oxygen effect of the respiratory cycle. It can be assumed that in this group, an increase in the intensity of metabolism is provided by the effective activity of the respiratory system. In the second experimental group, isoventilator changes in respiration were observed with a gradual decrease in oxygen consumption and other indicators of the respiratory system efficiency. After 2 months, these changes became significant. Thus, we can talk about significant differences in the effect of uridine on the function of external respiration (i.e., apparently, on the activity of the mitochondrial ATP-dependent K+ channel) during EP, which depended on the period of onset of uridine administration. Application of uridine immediately (1st experimental group) looks more effective and even has a stimulating effect on the respiratory function over a long period of experiment. The administration of uridine starting from the 4 partially normalizes the respiration parameters. However, after 1 month there is a depression of the functions of the respiratory system, which, probably, may further worsen. The reasons for the differences in the identified dynamics require further investigation.