title: Studies on the mechanism of action of local anesthetics on proton translocating ATPase from Mycobacterium phlei.
abstract: We have measured the inhibitory potencies of local anesthetics (procaine, lidocaine, tetracaine and dibucaine) on ATP-mediated H+-translocation, Ca2+-transport and ATPase activity in membrane vesicles from Mycobacterium phlei. Procaine and lidocaine up to 1 mM concentration did not inhibit ATP-dependent H+-translocation, Ca2+-transport and ATPase activity. However, tetracaine and dibucaine at 0.2 mM concentration caused dissipation of the proton gradient, measured by the reversal of the quenching of fluorescence of quinacrine, and inhibition of active Ca2+-transport. Tetracaine (1 mM) inhibited membrane-bound ATPase activity without affecting solubilized F1-ATPase activity. Studies show that these local anesthetics do not prevent the inactivation of F0-F1 ATPase by dicyclohexylcarbodiimide (DCCD). Binding of [14C]DCCD to F0-proteolipid component remained unchanged in the presence of tetracaine indicating that DCCD and tetracaine do not share common binding sites on the F0-proteolipid sector. The inhibition of H+-translocation and membrane-bound ATPase activity by tetracaine was substantially additive in the presence of vanadate.
mesh_terms: D000779:Anesthetics, Local / Q000494:pharmacology*; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D007700:Kinetics; D009161:Mycobacterium / Q000201:enzymology*; D009168:Mycobacterium phlei / Q000201:enzymology* / Q000378:metabolism; D010101:Oxygen Consumption; D006180:Proton-Translocating ATPases / Q000378:metabolism*
chemical_list: D000779:Anesthetics, Local; D004024:Dicyclohexylcarbodiimide; D006180:Proton-Translocating ATPases; D002118:Calcium