Meyer-Overton Correlation

The Meyer-Overton correlation ( Meyer-Overton hypothesis , Meyer-Overton rule ) is the correlation between the effect of anesthetics and their lipophilicity . For a long time it was used to explain the effects of anesthesia, which is now largely considered out of date.

Developing the theory

The Meyer-Overton relationship of some anesthetically effective substances.

Horst Meyer, one of the namesake of the correlation

The pharmacologists Charles Ernest Overton in Zurich and Hans Horst Meyer in Marburg independently developed the hypothesis that arose from observations of anesthetics on tadpoles and the solubility of the substances in olive oil:

“The relative potency of such narcotics must depend on their mechanical affinity to fat-like substances on the one hand, to the other body components, ie mainly water on the other; hence on the partition coefficient which determines their distribution in a mixture of water and fat-like substances. "

- Meyer : 1899

Subsequently, various lipid theories (also: lipoid theories ) of the anesthetic effect were derived from the relationship described. They postulated that anesthetics act on the lipid bilayer of the cell membranes of nerve cells in the brain and that more fat-soluble agents therefore have a stronger effect. Various mechanisms, such as changes in the flow behavior or the permeability of the membranes, have been discussed over time. The lipid-based anesthesia theories dominated most of the 20th century.

Today's meaning

Although the anesthetics used today can also be described according to the Meyer-Overton correlation, theories about the mechanisms of action of anesthetics that are based on them can no longer be upheld. The idea of a uniform mechanism ( unitarity principle ) is now viewed as outdated and has been replaced by the concept of multiple mechanisms and sites of action . Effects on a number of ( protein- based) receptors and ion channels ( opioid receptor , GABA _A receptor , NMDA receptor , sodium and potassium channels ) and other modification of synaptic signal transmission in different areas of the central nervous system that are relevant for individual Anesthetics exist in varying degrees, but based on current knowledge, they are held responsible for the various dimensions of anesthesia. However, there is no comprehensive anesthesia theory that can be explained by the known mechanisms, so that an effect according to the Meyer-Overton hypothesis (influence on the lipid components of the central nervous system) cannot be ruled out and is sometimes controversial.

Individual evidence

^ E. Overton: Studies on anesthesia. Gustav Fischer Verlag, Jena 1901.
↑ H. Meyer: On the theory of alcohol anesthesia. In: Arch Exp Pathol Pharmakol. , 42, 1899, pp. 109-118.
^ ^A ^b N. P. Franks: Molecular targets underlying general anesthesia . In: Br J Pharmacol . , 147, Suppl 1, Jan 2006, pp. S72-S81. Review. PMID 16402123
^ C. Lynch: Meyer and Overton revisited. In: Anesth Analg. , 107 (3), Sep 2008, pp. 864-867. PMID 18713897
^ JG Bovill: Mechanisms of anesthesia: time to say farewell to the Meyer-Overton rule. In: Curr Opin Anaesthesiol. , 13 (4), Aug 2000, pp. 433-436. PMID 17016337

[1] E. Overton: Studies on anesthesia. Gustav Fischer Verlag, Jena 1901.

[2] H. Meyer: On the theory of alcohol anesthesia. In: Arch Exp Pathol Pharmakol. , 42, 1899, pp. 109-118.

[franks-3] A ^b N. P. Franks: Molecular targets underlying general anesthesia . In: Br J Pharmacol . , 147, Suppl 1, Jan 2006, pp. S72-S81. Review. PMID 16402123

[4] C. Lynch: Meyer and Overton revisited. In: Anesth Analg. , 107 (3), Sep 2008, pp. 864-867. PMID 18713897

[5] JG Bovill: Mechanisms of anesthesia: time to say farewell to the Meyer-Overton rule. In: Curr Opin Anaesthesiol. , 13 (4), Aug 2000, pp. 433-436. PMID 17016337