(Fig. 5-3: A multisite model for anesthesia)

1. It is clear that all anesthetic actions cannot be localized to a specific anatomic site in the CNS. (Considerable evidence supports the conclusion that different components of the anesthetic state are mediated by actions at disparate anatomic sites.)
2. The actions of anesthetics cannot be localized to a single physiologic process.
   1. At a molecular level, volatile anesthetics show some selectivity but still affect the function of multiple ion channels and synaptic proteins.
   2. The intravenous anesthetics, etomidate, propofol, and barbiturates are more specific with the GABA_A receptor as their major target.
3. Genetic data plainly demonstrate that the unitary theory of anesthesia is not correct.
4. No single mechanism is responsible for the effects of all general anesthetics, nor does a single mechanism account for all of the effects of a single anesthetic, at least where it has been examined.
5. The precise set of molecular interactions responsible for producing anesthesia have not been fully elucidated, but anesthetics do act via selective effects on specific molecular targets.

Mechanisms of Anesthesia and Consciousness

1. What is Anesthesia?
2. How is Anesthesia Measured?
3. What is the Chemical Nature of Anesthetic Target Sites?
4. How Do Anesthetics Interfere with the Electrophysiologic Function of the Nervous System?
5. Anesthetic Actions on Ion Channels
6. How are the Molecular Effects of Anesthetics Linked to Anesthesia in the Intact Organism?
7. Where in the Central Nervous System Do Anesthetics Work?
8. Conclusions