The septohippocampal system
participates in general anesthesia

by
Ma J, Shen B, Stewart LS,
Herrick IA, Leung LS.
Department of Physiology,
University of Western Ontario,
London, Ontario, Canada N6A 5A5.
J Neurosci. 2002 Jan 15;22(2):RC200


ABSTRACT

How the brain mediates general anesthesia is not known. We report that two interconnected structures in the forebrain, the medial septum and the hippocampus, participate in maintaining awareness and movements during general anesthesia. In the awake, freely behaving rat, inactivation of the medial septum or the hippocampus by local injection of a GABA(A) receptor agonist, muscimol, decreased the dose of a general anesthetic needed to induce a loss of the tail-pinch response or a loss of righting reflex. Septohippocampal inactivation also suppressed the behavioral hyperactivity or the delirium stage associated with general anesthesia. An increase and decrease of 30-50 Hz (gamma) waves in the hippocampus correlated with an increase and decrease in behavioral activity, respectively. Similar results were found for both volatile (halothane and isoflurane) and nonvolatile (propofol and pentobarbital) anesthetics. We conclude that the behavioral hyperactivity induced by a general anesthetic is mediated in part by the septohippocampal system, and that depression of the septohippocampal system increases the potency of a general anesthetic. It is suggested that more potent general anesthetics or adjuvants may be developed by maximizing the pharmacological depression of the septohippocampal system.
People
Anaesthesia
Nitrous oxide
Inhaled anaesthetics
Obstetric anaesthesia
Molecular mechanisms
Chloroform anaesthesia
A thalamocortical switch?
Anaesthesia and the spinal chord
History of anaesthesia apparatus
Consciousness, anaesthesia and anaesthetics
Anaesthesia: mutants in yeast, nematodes, fruit flies and mice



Refs
and further reading

general-anaesthesia.com
HOME
HedWeb
Nootropics
erythroxylum-coca.com
Future Opioids
BLTC Research
MDMA/Ecstasy
Superhappiness?
Utopian Surgery?
The Good Drug Guide
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World