Bupivacaine is a sodium channel blocker and local anesthetic. It inhibits sodium currents in rat dorsal horn neurons in a concentration-dependent manner and inhibits synaptic transmission in rat sympathetic ganglia, increasing the firing threshold when used at a concentration of 200 nM. Bupivacaine (10 µM) blocks cardiac sodium channels in a use-dependent manner and inhibits respiration in cardiac cell mitochondria when palmitoyl-carnitine or acetyl-carnitine are used as substrates (IC50s = 0.78 and 0.37 mM, respectively). It also reduces thermal hyperplasia in a rat model of sciatic ligation injury when 0.6 ml of a 0.5% solution is administered into the perinerve space, and the duration of this effect is extended by co-administration of the NMDA receptor antagonist MK-801 . Formulations containing bupivacaine have been used as local anesthetics for surgery, oral surgery, and dental procedures and for anesthetic purposes in research studies using animals.