EFFECT OF THE LOCAL-ANESTHETIC BUPIVACAINE ON THE ENERGY-METABOLISM OF EHRLICH ASCITES TUMOR-CELLS

The effect of the local anesthetic bupivacaine on the energy metabolis m of Ehrlich ascites tumor cells has been investigated. Even at low co ncentrations, bupivacaine decreased the oxygen uptake rate, but its ef fect was remarkably higher on the uncoupled respiration. Experiments o n specific segments of the respiratory chain have shown that bupivacai ne did not inhibit electron transport from Q to oxygen. Spectroscopic evidences demonstrated a NAD(P)H oxidation in bupivacaine-treated cell s respiring on endogenous substrates, indicating that the inhibition o f oxygen depended on a reduced electron transport from site 1-entering substrates to respiratory chain. The aerobic glycolysis was stimulate d by low and inhibited by high bupivacaine concentrations. The increas ed lactate production rate was due to an activation of mitochondrial A TPase, whereas its decrease was related to an inhibition of the hexoki nase activity.