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Local and general anesthetics work by blocking nerve transmission to pain centers in the central nervous system, although the exact mechanisms for general anesthetics are not well understood, despite use of such pharmacological agents for more than 150 years.

Local anesthetics, such as Novocain, bind to and inhibit the function of the sodium channel in the nerve cell membrane, a type of ion channel required for the propagation of nerve impulses. This action obstructs the movement of nerve impulses from tissue innervated by nerves at the site of local anesthetic injection but causes no changes in awareness and sense perception elsewhere in the body.