Fig. (1).

Diverse structures of general anesthetics. A: Volatile anesthetics including halothane, isoflurane, sevoflurane and desflurane. The chemical name of halothane is 2-bromo-2-chloro-1,1,1-trifluoroethane, belongs to a different class of compounds than fluorinated ether for isoflurane, sevoflurane and desflurane. But they produce similar pharmacological actions including amnesia, hypnosis, unconsciousness and immobility. B: Commonly used tool drug for anesthetic research F6. F6 has similar physicochemical properties to volatile anesthetics, but F6 cannot produce general anesthetic actions including unconsciousness and immobility. These facts indicate that physicochemical property (e.g. lipid solubility) is not the determined mechanism for general anesthesia. C: Commonly used intravenous general anesthetics, including propofol, etomidate, ketamine and phenobarbital. The structures of these intravenous general anesthetics are varied while all induce unconsciousness. Nevertheless, the discrepancy in structure determined various mechanisms of general anesthesia by enhancing inhibitory neuron or inhibiting excitatory neuron, and even might be associated with other effect, such as sympathetic suppression or activation.