GABAergic and glycinergic inhibition in pain pathways

Abstract

GABA and glycine are the fast inhibitory neurotransmitters in the spinal dorsal horn. They inhibit neuronal excitation by opening chloride channels on the somata and dendrites of intrinsic dorsal horn neurons, and on the spinal terminals of peripheral sensory neurons. They are released from interneurons and from neurons descending from higher CNS areas. They limit nociceptive input to the dorsal horn, control the output of dorsal horn projection neurons, and separate non-nociceptive signaling from nociceptive dorsal horn circuits. Peripheral inflammation and nerve injury reduce neuronal inhibition in the dorsal horn through various mechanisms that contribute to hyperalgesia and allodynia. © 2020 Elsevier Inc.