We studied possible involvement of ATP in the influence of protein sensitization on contractile function and non-quantum secretion in the end-plate of isolated skeletal muscles from mouse leg. The dynamic vector of muscle contraction force was shown to correlate with changes in non-quantum secretion of acetylcholine under various conditions of experimental pathology. However, the degree of these changes was lower in sensitized animals. It can be hypothesized that the ATP-induced variability in functional properties of slow muscles during protein sensitization reflects the development of resistance to external loads. The adaptive changes in fast muscles during protein sensitization are not associated with the ATP-mediated mechanisms of excitation.
We estimated the count of pancreatic alpha- and beta-cells and blood glucose level at various stages of alloxan-induced diabetes in rats. Alloxan decreased the count of insulin-producing beta-cells, but increased the number of glucagon-secreting alpha-cells in the pancreas (week 1 of diabetes). These changes were accompanied by hyperglycemia. The decrease in blood glucose level in diabetic rats was associated with an increase in beta-cell count against the background of high density of pancreatic alpha-cells.
Low-intensity He-Ne laser radiation induces metabolic rearrangements in platelet lipids and activates some lipid-dependent systems of cell regulation as well as the synthesis of lipidlike second messengers. Modification of the lipid phase and physicochemical state of biological membranes are the molecular basis of biochemical adaptation of the platelets to laser radiation.
Changes in the mitochondrial potential, expression of phosphatidylserine, parameters of direct and lateral light scattering, and DNA fragmentation during spontaneous and induced apoptosis in peripheral blood lymphocytes were studied by flow cytofluorometry. Dexamethasone and Ca2+ ionophore A23187 served as inductors of apoptosis. A decrease in the mitochondrial potential is an early sign of spontaneous and induced apoptosis. Phosphatidylserine expression on the outer plasma membrane occurred later and inversely depended on the mitochondrial potential. Our results indicate that the involvement of mitochondria in spontaneous and induced apoptosis accompanied by a decrease in the mitochondrial potential is an early and key event of programmed lymphocyte death. The decrease in the mitochondrial potential of lymphocytes induced degradation of their nuclei (DNA fragmentation) and promoted elimination of apoptotic cells (phosphatidylserine expression).
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