Anesthesia analgesia in the amygdala

Abstract

General anesthetics during surgery are presumed to block pain by dampening brain activity and promoting loss-of-consciousness. A new study shows that anesthetics activate an endogenous analgesia neural ensemble in the central nucleus of the amygdala.

Fig. 1 |. Anesthesia co-opts amygdalar analgesia ensembles.

a, Anesthesia induces sleep through activation of the supraoptic nucleus of the hypothalamus and inhibits pain through the CeA. b, Anesthesia-active neurons in the CeA lateral capsule region express enkephalin and PKCδ, but not CGRP-R. The anesthesia ensemble projects to several brain regions, notably pain-associated regions such as the insula, bed nucleus of the stria terminalis (BNST), PBN (parabrachial nucleus) and PAG, among others. c, Anesthesia neurons respond to various general anesthetics with dynamic and stable activities. d, Left: activation of the CeA anesthesia ensemble reduces reflexive and recuperative pain behaviors with no effect of sleep. Right: inhibition of the ensemble exacerbates reflexive and recuperative pain behaviors and blocks low-dose ketamine analgesia.