The effects of the local anesthetics, procaine and mepivacaine, on rat liver Mitochondria

The effects of local anesthetics, procaine and mepivacaine, were examined using isolated rat liver mitochondria as a model membrane system. The effects of procaine and mepivacaine were studied on mitochondrial respiration, calcium stimulated respiration and gramicidin-induced K+ efflux and swelling. High concentrations (about 10^-3 and 10^-4 M) of procaine and mepivacaine were found to stimulate the respiratory rates and decrease the RCRs of mitochondria. High concentrations of procaine and mepivacaine also inhibited the rate of Ca++-stimulated respiration, induced by the presence of both limited and massive amounts of Ca++, under both normel stoichiometric and "superstoichiometric” conditions. High concentrations of mepivacaine inhibited gramicidin-induced K+ efflux and gramicidin-induced swelling