Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
This figure shows schematically the descending inhibitory pathways. Areas shaded grey display a high expression of opioid receptors and their endogenous ligands. MOP agonists produce analgesia either by indirectly increasing neuronal traffic through the descending pathway at the NRPG and PAG, or by directly inhibiting nociceptive afferents in the periphery.
PAG = Periaqueductal grey
NRPG = Nucleus reticularis paragigantocellularis
NRM = Nucleus raphe magnus
LC = Locus cereleus
