Adrenergic stimulation of sea bream (Sparus aurata) red blood cells in normoxia and anoxia: effects on metabolism and on the oxygen affinity of haemoglobin
The metabolic response of sea bream (Sparus aurata) red blood cells to adrenergic stimulation was determined in normoxia and anoxia. In the presence of oxygen, red blood cells swelled and then recovered their resting volume. Continuous monitoring of oxygen uptake displayed the kinetics of the increase in the oxygen affinity of haemoglobin. Cell volume recovery correlated with an activation of ATP consumption, and the energy equilibrium was restored by increasing the rates of respiration and glycolysis. When the respiratory chain was blocked, adrenergic stimulation increased the rates of ATP consumption and glycolysis of red blood cells. Moreover, adrenergic stimulation of deoxygenated erythrocytes also increased cell volume but did not enhance glycolysis or ATP consumption, and the cells remained swollen. Our results suggest that there is an oxygen-linked signal transducer that activates ATP-consuming processes, provided that the adrenergic stimulation occurs in the presence of oxygen.
Roig
T
S&Aacute;Nchez
J
Tort
L
Altimiras
J
Berm&Uacute;Dez
J