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Summary: The glutamate-receptor ion channels (iGluRs), namely AMPA, kainate
and NMDA receptors, are the major mediators of excitatory synaptic
transmission in the central nervous system13
. Each subtype has a unique
role. NMDA receptors, which have attracted enormous interest, act as
coincidence detectors. These monitor changes in membrane potential
and the presence of glutamate in the synaptic cleft4
. AMPA receptors
have key roles in mediating the rapid excitatory synaptic current, the
kinetics of which is tuned over about a fivefold range in different struc-
tures of the brain5
. Kainate receptors have a major modulatory role at
both presynaptic and postsynaptic sites, and kainate-receptor agonists
have long been known to be potent convulsants and environmental
toxins in the food supply6,7
. These receptors were identified through
traditional pharmacological approaches, and their naming reflects
this: AMPA, kainate and NMDA are synthetic agonists and naturally
occurring toxins not found in the brain8
.
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