The introduction of general anesthetics into clinical practice more than 150 years ago stands as one of the seminal innovations of medicine. It facilitated the development of modern surgery and spawned the specialty of anesthesiology (Crowder CM, Palanca BJ, Evers AS. Mechanisms of anesthesia and consciousness. In: Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Ortega R, Stock MC, eds.Clinical Anesthesia. Philadelphia: Lippincott Williams & Wilkins; 2013: 105–129). Despite the importance of general anesthetics and more than 100 years of active research, the molecular mechanisms responsible for anesthetic action remain one of the unsolved mysteries of science (Table 5-1: Why are Mechanisms of Anesthesia so Difficult to Elucidate?).

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