Alla Silkina

An evolutionary development of the rheological characteristics of blood in the capillary blood flow is one of indicator of fishes’ adaptation for the changing temperature conditions. Our earlier studies showed that large, nucleated erythrocytes of the Black Sea thornback ray (Raja clavata L.) and scorpionfish (Scorpaena porcus L.) had high ecto-ATPase activity. This activity varied from 3.0 to 3.9 and 6.0 to 10.0 nmol Fn/min/µL RBC in rays and scorpionfish, respectively. The use of thermal energy of ATP in the hydrolysis process made by ecto-ATPases in fish erythrocytes provided a heating of the plasma cells’ membrane and the near-wall plasma layer with an aim to improve the rheological characteristics of blood in the capillary blood flow. To confirm the proposed assumption, we studied thermal phenomena in erythrocytes suspensions of fishes by continuous recording of temperature changes in the experimental cell with fishes’ erythrocytes suspension with the addition of ATP (1 mg/mL) in vitro. A higher “thermal” activity of scorpionfish erythrocytes was established in comparison with erythrocytes of the thornback ray, which had the multiplicity of activity of ecto-ATPase in the plasma membranes of erythrocytes of the studied fishes. The presence of heat-producing activity of suspensions of erythrocytes of thornback ray and scorpionfish is evidence of the possible use of thermal energy of ATP hydrolysis by fish erythrocytes, both to maintain the functional state of the plasma membrane of red blood cells and to improve the rheological characteristics of blood in the capillary section of blood flow.