N-METHYL-D-ASPARTATE (NMDA) AND NON-NMDA GLUTAMATE-RECEPTOR ANTAGONISTS DIFFERENTIALLY SUPPRESS DORSAL HORN NEURON RESPONSES TO MECHANICAL STIMULI IN RATS WITH PERIPHERAL-NERVE INJURY
Jw. Leem et al., N-METHYL-D-ASPARTATE (NMDA) AND NON-NMDA GLUTAMATE-RECEPTOR ANTAGONISTS DIFFERENTIALLY SUPPRESS DORSAL HORN NEURON RESPONSES TO MECHANICAL STIMULI IN RATS WITH PERIPHERAL-NERVE INJURY, Neuroscience letters, 211(1), 1996, pp. 37-40
The effects of iontophoretically ejected glutamate receptor antagonist
s on mechanically evoked responsiveness were examined on wide dynamic
range (WDR) dorsal horn neurons in anesthetized rats that received a u
nilateral ligation of the L5 and L6 spinal nerves 10-15 days previousl
y. Both brush- and pinch-evoked responses of dorsal horn neurons on th
e nerve-injured side were enhanced. N-Methyl-D-aspartate (NMDA) recept
or antagonist, 2-amino-5-phosphonopentanoic acid (AP5), preferentially
suppressed the enhanced pinch-evoked response, whereas ha-amino-3-hyd
roxy-5-methyl-4-isoxazole-propionate (AMPA) receptor selective antagon
ist, 6-nitro-7-sulphamoylbenzo(f)quinoxaline-2,3 (NBQX), preferentiall
y attenuated the enhanced brush-evoked response. The results indicate
that the enhanced responses to noxious and non-noxious peripheral inpu
ts induced in WDR dorsal horn neurons following the nerve injury are m
ediated by activation of NMDA and AMPA receptors, respectively.