Co-localization of NMDA receptors and AMPA receptors in neurons of the vestibular nuclei of rats.
We are interested in studying the co-localization of NMDA glutamate receptor subunits (NR1, NR2A/B) and AMPA glutamate receptor subunits (GluR1, GluR2, GluR2/3 and GluR4) in individual neurons of the rat vestibular nuclei. Immunoreactivity for NR1, NR2A/B, GluR1, GluR2, GluR2/3 and GluR4 was found in the somata and dendrites of neurons in the four major subdivisions (superior, medial, lateral, and spinal vestibular nuclei) and in two minor groups (groups x and y) of the vestibular nuclei. Double immunofluorescence showed that all the NR1-containing neurons exhibited NR2A/B immunoreactivity, indicating that native NMDA receptors are composed of NR1 and NR2A/B in a hetero-oligomeric configuration. Co-expression of NMDA receptor subunits and AMPA receptor subunits was demonstrated by double labeling of NR1/GluR1, NR1/GluR2/3, NR1/GluR4 and NR2A/B/GluR2 in individual vestibular nuclear neurons. All NR1-containing neurons expressed GluR2/3 immunoreactivity, and all NR2A/B-containing neurons expressed GluR2 immunoreactivity. However, only about 52% of NR1-immunoreactive neurons exhibited GluR1 immunoreactivity and 46% of NR1-containing neurons showed GluR4 immunoreactivity. The present data reveal that NMDA receptors are co-localized with variants of AMPA receptors in a large proportion of vestibular nuclear neurons. These results suggest that cross-modulation between NMDA receptors and AMPA receptors may occur in individual neurons of the vestibular nuclei during glutamate-mediated excitatory neurotransmission and may in turn contribute to synaptic plasticity within the vestibular nuclei.
Chen
L W
LW
Department of Physiology, Faculty of Medicine, The University of Hong Kong, 5 Sassoon Road, Hong Kong, China.
Yung
K K
KK
Chan
Y S
YS
D000818:Animals; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology; D014726:Vestibular Nuclei / Q000166:cytology / Q000378:metabolism*; D003689:Vestibular Nucleus, Lateral / Q000166:cytology / Q000378:metabolism
D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; C409466:NR1 NMDA receptor; C120997:NR2A NMDA receptor; C121001:NR2B NMDA receptor; C104723:glutamate receptor ionotropic, AMPA 3; C104724:glutamate receptor ionotropic, AMPA 4; C104722:glutamate receptor ionotropic, AMPA 2