Abstract
Nociceptive primary afferents release glutamate, activating postsynaptic glutamate receptors on spinal cord dorsal horn neurons. Glutamate receptors, both ionotropic and metabotropic, are also expressed on presynaptic terminals, where they regulate neurotransmitter release. During the last two decades, a wide number of studies have characterized the properties of presynaptic glutamatergic receptors, particularly those expressed on primary afferent fibers. This review describes the subunit composition, distribution and function of presynaptic glutamate ionotropic (AMPA, NMDA, kainate) and metabotropic receptors expressed in rodent spinal cord dorsal horn. The role of presynaptic receptors in modulating nociceptive information in experimental models of acute and chronic pain will be also discussed.
Highlights
Glutamate receptors(GluRs) are widely expressed in the membrane of spinal neurons postsynaptic to nociceptive afferents
We have shown that presynaptic NMDARs could modulate glutamate release from primary afferent fibers (PAFs) in rat spinal cord slices [45]
The first issue is related to the physiological action of ionotropic GLURs expressed on PAF and interneuron terminals in spinal cord dorsal horn (DH)
Summary
Glutamate receptors(GluRs) are widely expressed in the membrane of spinal neurons postsynaptic to nociceptive afferents. Central terminals of primary afferent fibers (PAFs) express both ionotropic and metabotropic GluRs. Their activation modulates the release of glutamate and peptides in dorsal horn (DH). AMPARs on PAF central terminals mediate primary afferent depolarization and modulate glutamate release.
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