Effect of local anesthetic ropivacaine on the energy metabolism of Ehrlichascites tumor cells

The effect of local anesthetic ropivacaine on the energy metabolism of Ehrl ich ascites tumor cells has been investigated. Ropivacaine impaired energy metabolism of Ehrlich ascites tumor cells by affecting primarily mitochondr ial metabolism. Even at low concentrations ropivacaine decreased the rate o f oxygen uptake, but its effect was remarkably higher on the uncoupled resp iration and, in both cases, it was strongly enhanced by hydrophobic anion t etraphenylboron (TPB-). The decrease of oxygen uptake was ascribed to an im pairment of electron transport from site 1- and 2-entering substrates to re spiratory chain. The inhibition of respiration, coupled to a true uncouplin g mechanism by an electrophoretic mechanism, impaired ADP phosphorylation, decreased ATP content, and collapsed mitochondrial membrane potential. Ropi vacaine, at all concentrations tested, stimulated aerobic lactate productio n, and this increase, in addition to the inhibition of respiration, was als o due to an activation of mitochondrial ATPase.