TY - JOUR
T1 - Kainate-receptor-mediated sensory synaptic transmission in mammalian spinal cord
AU - Li, Ping
AU - Wilding, Timothy J.
AU - Kim, Susan J.
AU - Calejesan, Amelita A.
AU - Huettner, James E.
AU - Zhuo, Min
PY - 1999/1/14
Y1 - 1999/1/14
N2 - Glutamate, the major excitatory neurotransmitter in the central nervous system, activates three different receptors that directly gate ion channels, namely receptors for AMPA (α-amino-3-hydroxy-5-methyl isoxozole propionic acid), NMDA (N-methyl-D-aspartate), and kainate, a structural analogue of glutamate. The contribution of AMPA and NMDA receptors to synaptic transmission and plasticity is well established. Recent work on the physiological function of kainate receptors has focused on the hippocampus, where repetitive activation of the mossy-fibre pathway generates a slow, kainate-receptor-mediated excitatory postsynaptic current (EPSC). Here we show that high-intensity single-shock stimulation (of duration 200 microseconds) of primary afferent sensory fibres produces a fast, kainate- receptor-mediated EPSC in the superficial dorsal horn of the spinal cord. Activation of low-threshold afferent fibres generates typical AMPA-receptor- mediated EPSCs only, indicating that kainate receptors may he restricted to synapses formed by high-threshold nociceptive (pain-sensing) and thermoreceptive primary afferent fibres. Consistent with this possibility, kainate-receptor-mediated EPSCs are blocked by the analgesic μ-opiate- receptor agonist Damgo and spinal blockade of both kainate and AMPA receptors produces antinociception. Thus, spinal kainate receptors contribute to transmission of somatosensory inputs from the periphery to the brain.
AB - Glutamate, the major excitatory neurotransmitter in the central nervous system, activates three different receptors that directly gate ion channels, namely receptors for AMPA (α-amino-3-hydroxy-5-methyl isoxozole propionic acid), NMDA (N-methyl-D-aspartate), and kainate, a structural analogue of glutamate. The contribution of AMPA and NMDA receptors to synaptic transmission and plasticity is well established. Recent work on the physiological function of kainate receptors has focused on the hippocampus, where repetitive activation of the mossy-fibre pathway generates a slow, kainate-receptor-mediated excitatory postsynaptic current (EPSC). Here we show that high-intensity single-shock stimulation (of duration 200 microseconds) of primary afferent sensory fibres produces a fast, kainate- receptor-mediated EPSC in the superficial dorsal horn of the spinal cord. Activation of low-threshold afferent fibres generates typical AMPA-receptor- mediated EPSCs only, indicating that kainate receptors may he restricted to synapses formed by high-threshold nociceptive (pain-sensing) and thermoreceptive primary afferent fibres. Consistent with this possibility, kainate-receptor-mediated EPSCs are blocked by the analgesic μ-opiate- receptor agonist Damgo and spinal blockade of both kainate and AMPA receptors produces antinociception. Thus, spinal kainate receptors contribute to transmission of somatosensory inputs from the periphery to the brain.
UR - http://www.scopus.com/inward/record.url?scp=0033552931&partnerID=8YFLogxK
U2 - 10.1038/16469
DO - 10.1038/16469
M3 - Article
C2 - 9923678
AN - SCOPUS:0033552931
VL - 397
SP - 161
EP - 164
JO - Nature
JF - Nature
SN - 0028-0836
IS - 6715
ER -