TY - JOUR
T1 - Localization of ionotropic and metabotropic glutamate receptors in distinct neuronal elements of the rat substantia nigra
AU - Yung, K. K.L.
N1 - Funding Information:
The author would like to thank Miss L. S. Tai and Mr Y. C. Tse for assistance in the present work and Miss Lousie L. H. Ng for technical assistance. The present work was supported by the Faculty Research Grants, FRG/95-96/I-17 and FRG/95-96/II-73, Hong Kong Baptist University and HKBU2006/97M, Hong Kong Research Grant Council.
PY - 1998/10/1
Y1 - 1998/10/1
N2 - The localization of glutamate receptors in the substantia nigra is of critical importance since glutamate receptor-mediated excitotoxicity is implied in the cause for the neuronal degeneration in Parkinson's disease. The major glutamatergic synaptic inputs to the substantia nigra originate in the subthalamic nucleus, in which hyperactivity is reported in Parkinson's disease. In order to compare directly the localization of different ionotropic and metabotropic glutamate receptors in the substantia nigra of the same animals, rats were perfuse-fixed under deep anesthesia. Sections of the substantia nigra were obtained and receptor immunocytochemistry was performed using commercially available antibodies (against subunits of ionotropic glutamate receptors: GluR1, GluR2/3, GluR4, NMDAR1, NMDAR2A/B; and subtypes of metabotropic glutamate receptors: mGluR1α, mGluR2/3). When compared to the localization of tyrosine hydroxylase immunoreactivity, immunoreactivity for GluR1, GluR2/3 and NMDAR1 was mainly localized in the perikarya and proximal dendrites of the compacta neurons and only in a few reticulata neurons. In contrast, GluR4 immunoreactivity was only detected in the reticulata neurons. Consistent results were obtained by double labeling experiments that revealed tyrosine hydroxylase and GluR1, GluR2/3, GluR4 or NMDAR1 immunoreactivity in the same sections. Immunoreactivity for NMDAR2A/B, mGluR1α and mGluR2/3 was detected in the neuropil of the substantia nigra pars reticulata. No NMDAR2A/B- and mGluR2/3-immunoreactive perikarya were detected. However, a few neurons in the reticulata were found to be mGluR1α- immunoreactive. The present results indicate there is a differential localization of different subunits and subtypes of glutamate receptors in the substantia nigra and there may be functional implications in different neuronal elements in the substantia nigra in normal and in Parkinson's disease.
AB - The localization of glutamate receptors in the substantia nigra is of critical importance since glutamate receptor-mediated excitotoxicity is implied in the cause for the neuronal degeneration in Parkinson's disease. The major glutamatergic synaptic inputs to the substantia nigra originate in the subthalamic nucleus, in which hyperactivity is reported in Parkinson's disease. In order to compare directly the localization of different ionotropic and metabotropic glutamate receptors in the substantia nigra of the same animals, rats were perfuse-fixed under deep anesthesia. Sections of the substantia nigra were obtained and receptor immunocytochemistry was performed using commercially available antibodies (against subunits of ionotropic glutamate receptors: GluR1, GluR2/3, GluR4, NMDAR1, NMDAR2A/B; and subtypes of metabotropic glutamate receptors: mGluR1α, mGluR2/3). When compared to the localization of tyrosine hydroxylase immunoreactivity, immunoreactivity for GluR1, GluR2/3 and NMDAR1 was mainly localized in the perikarya and proximal dendrites of the compacta neurons and only in a few reticulata neurons. In contrast, GluR4 immunoreactivity was only detected in the reticulata neurons. Consistent results were obtained by double labeling experiments that revealed tyrosine hydroxylase and GluR1, GluR2/3, GluR4 or NMDAR1 immunoreactivity in the same sections. Immunoreactivity for NMDAR2A/B, mGluR1α and mGluR2/3 was detected in the neuropil of the substantia nigra pars reticulata. No NMDAR2A/B- and mGluR2/3-immunoreactive perikarya were detected. However, a few neurons in the reticulata were found to be mGluR1α- immunoreactive. The present results indicate there is a differential localization of different subunits and subtypes of glutamate receptors in the substantia nigra and there may be functional implications in different neuronal elements in the substantia nigra in normal and in Parkinson's disease.
KW - AMPA receptors
KW - Basal ganglia
KW - Immunocytochemistry
KW - Light microscopy
KW - NMDA receptors
UR - http://www.scopus.com/inward/record.url?scp=0032192440&partnerID=8YFLogxK
U2 - 10.1016/S0197-0186(98)00034-5
DO - 10.1016/S0197-0186(98)00034-5
M3 - Journal article
C2 - 9840222
AN - SCOPUS:0032192440
SN - 0197-0186
VL - 33
SP - 313
EP - 326
JO - Neurochemistry International
JF - Neurochemistry International
IS - 4
ER -