Coupling of membrane and metabolic functions in nucleated erythrocytes of Scorpaena porcus L. Under hypoxia in vivo and in vitro

The in vivo and in vitro effect of hypoxia (0.57–8.17 mg O2l−1) on functional characteristics of nucleated erythrocytes of the benthic scorpionfish Scorpaena porcus L. was studied. The cellular systems in this species were established to be characterized by a balanced suppression of membrane and metabolic functions in conditions of external oxygen deficit (in vivo experiments). It manifests itself in the capacity of cells to maintain the intracellular ATP concentration and transmembrane Na+ and K+ gradients within the norm at low activity of Na+, K+-ATPase and hexokinase. This phenomenon appears to be underlain by the reduction in the number of active plasma membrane ion channels diminishing energetic costs of cationic gradient maintenance (metabolic arrest phenomenon). The same is also evidenced by the rise in FDA and R123 fluorescence intensity in erythrocyte suspensions under hypoxia (in vitro experiments). The mechanisms underlying this phenomenon are discussed.