Ask the Brains; February/March 2007; Scientific American Mind; by William J. Perkins; 1 Page(s)

Anesthetics work by blocking transmission of nerve signals to pain centers in the central nervous system. The exact mechanisms for general anesthetics are not completely understood.

In 1846 physician Oliver Wendell Holmes, Sr., coined the term "anaesthesia" for drug-induced inability to experience sensation (particularly pain) after the first publicized demonstration of inhaled ether rendered a patient unresponsive during a surgical procedure. Today two broad classes of such agents, called local and general, can induce anesthesia.