neurochemical mediators of pain

Etiology

• sensory neurons
  • glutamate
  • ATP
  • bradykinin
  • 5-hydroxytryptamine (5-HT)
  • histamine
  • arachidonic acid metabolites
  • nitric oxide
  • calcitonin gene-related peptide (CGRP)
  • mechanotransduction (mechanisms poorly understood)
• ascending pathway (dorsal horn neurons)
  • glutamate
  • substance P
  • neurotensin
  • cholecystokinin
  • somatostatin
• descending pathway (midbrain & spinal cord)
  • serotonin
  • norepinephrine
  • gamma-aminobutyric acid (GABA)
  • glycine
  • acetylcholine
• assorted areas (brain, spinal cord, nerves, ganglia)
  • dopamine
  • adenosine
  • neuropeptide Y
  • opioid receptors
    • mu receptor type most often associated with pain
  • endogenous opioids
    • endorphins
    • enkephalins
    • dynorphins