UMLS:C0030567 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030567 (Parkinson's disease)
63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The overactivity of subthalamopallidal and corticostriatal glutamatergic neurons observed in Parkinson's disease (PD) suggests that antagonists of glutamate receptor could be used to alleviate the motor symptoms of the disease. In this study, we analysed two features of the striatopallidal complex: (1) the distribution of alpha-amino-3 hydroxy-5-methyl-4-isoxasol-propionate (AMPA) and kainate receptors and their corresponding mRNA by immunohistochemistry and in situ hybridisation and (2) the effect of dopaminergic denervation on AMPA receptor gene expression in PD patients and rats with 6-hydroxydopamine (6-OHDA)-induced degeneration of the nigrostriatal dopaminergic system. All AMPA receptor mRNAs and proteins (GluR1-4) were detected in the internal segment of the globus pallidus (GPi). Among kainate receptors, only KA1 and KA2 were detectable and only at a low level. Only GluR4 protein was detected in the neuropil of the GPi. In the striatum, GluR1, GluR2, and GluR3 were detected in about 70% of medium-sized and large neurons. By contrast, GluR4 mRNA was detected in only a small number of large and medium-sized neurons. Among kainate receptors, GluR6, GluR7, and KA2 were detected in about 50-60% of medium-sized neurons, whereas GluR5 and KA1 were restricted to 1-2% and 20-30% of these neurons, respectively. These results suggest that antagonists of AMPA and kainate receptors could be effective in alleviating motor symptoms in Parkinson's disease by blocking the overstimulation of pallidal and striatal neurons by glutamate. A significant decrease in GluR1 gene expression (-33%) was observed in the neurons of the GPi in PD patients and in rat entopeduncular nucleus ipsilateral to the 6-OHDA lesion (-20%). GluR2, GluR3, and GluR4 mRNA levels in the GPi and GluR1-4 levels in the striatum were unchanged in PD patients and 6-OHDA-lesioned rats compared with their respective controls. These data suggest that dopamine positively regulates only GluR1 gene expression in the GPi.
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PMID:Expression of glutamate receptors in the human and rat basal ganglia: effect of the dopaminergic denervation on AMPA receptor gene expression in the striatopallidal complex in Parkinson's disease and rat with 6-OHDA lesion. 874 43

The objective of the present study was to analyze the cellular and subcellular localization of ionotropic glutamate receptor subunits in midbrain dopaminergic neurons in the squirrel monkey. This was achieved by means of immunohistochemistry at light and electron microscopic levels and in situ hybridization histochemistry. Colocalization studies show that nearly all dopaminergic neurons in both the ventral and dorsal tiers of the substantia nigra compacta (SNc-v, SNc-d) and the ventral tegmental area (VTA) are immunoreactive for AMPA (GluR1, GluR2/3, and GluR4) and NMDAR1 receptor subunits, but not for NMDAR2A/B subunits. The immunoreactivity of the receptor subunits is associated mainly with perikarya and dendritic shafts. Apart from the intensity of immunolabeling for the GluR4 subunit, which is quite similar for the different groups of midbrain dopaminergic neurons, the overall intensity of immunostaining for the other subunits is higher in the SNc-v and SNc-d than in the VTA. In line with these observations, in situ hybridization shows that the average level of labeling for the GluR2 and NMDAR1 subunit mRNAs is significantly higher in the SNc-v than in the VTA, and for the NMDAR1 subunit, higher in the SNc-v than in the SNc-d. In contrast, no significant difference was found for the level of GluR1 mRNA labeling among the three groups of midbrain dopaminergic neurons. At the subcellular level in the SNc-v, AMPA (GluR1 and GluR2/3) and NMDAR1 receptor subunit immunoreactivity is preferentially associated with the postsynaptic densities of asymmetric synapses, but occasionally some immunoreactivity is found along nonsynaptic portions of plasma membranes of dendrites. A small number of preterminal axons, axon terminals, and glial cell processes are also immunoreactive. Our observations indicate that the different groups of midbrain dopaminergic neurons in primates exhibit a certain degree of heterogeneity with regard to the level of expression of some ionotropic glutamate receptor subunits. The widespread neuronal and glial localization of glutamate receptor subunits suggests that excitatory amino acids may act at different levels to control the basal activity and, possibly, to participate in the degeneration of midbrain dopaminergic neurons in Parkinson's disease.
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PMID:AMPA and NMDA glutamate receptor subunits in midbrain dopaminergic neurons in the squirrel monkey: an immunohistochemical and in situ hybridization study. 900 80

Parkinson's disease (PD) is characterized by the destruction of dopaminergic cells in the substantia nigra (SN). The cause of the cell death and the development of Parkinsonism is however unknown. There are increasing evidences to suggest the involvement of glutamate mediated by its receptors. Using immunohistochemistry and cell counting, the present study investigated whether the numbers of neurons immunostained with glutamate alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor subunits GluR1, GluR2/3 and GluR4 in the SN of rats would change after the injection of 6-hydroxydopamine (6-OHDA) into the SN. The results showed that the numbers of GluR1 positive cells were significantly decreased in the substantia nigra pars compacta (SNc), pars reticulata (SNr) and pars lateralis (SNl) from 3 days (13.7%) to 3 months (40.3%) and of GluR2/3 cells, from 1 week (17.6%) to 3 months (19.1%) after 6-OHDA injection, compared to those in the contralateral non-injected side. There was, however, no significant difference in the number of GluR4 positive cells between the injected and non-injected SN. The results were discussed.
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PMID:Effect of 6-OHDA injection on the AMPA glutamate receptor subunits in the substantia nigra of Sprague-Dawley rats. 950 1

Glutamatergic neurotransmission in the subthalamic nucleus (STN) and in the output nuclei of the basal ganglia is critical in the expression of basal ganglia function, and increased glutamate transmission in these nuclei has been implicated in the pathology of Parkinson's disease. In order to determine the precise spatial relationship of subunits of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) and N-methyl-D-aspartate (NMDA) glutamate receptors to nerve terminals enriched in glutamate or gamma-aminobutyric acid (GABA) in one of the output nuclei, the entopeduncular nucleus (EP), and the STN, postembedding immunolabelling for glutamate receptor subunits and for glutamate and GABA was carried out in the rat. Immunolabelling for the AMPA glutamate receptor subunits 1, 2/3, and 4 (GluR1, GluR2/3, and GluR4) and the NMDA receptor subunit 1 (NR1) was localized predominantly within asymmetrical synapses in both the EP and STN. Quantitative analysis revealed that, on average for the whole population, each of the receptor subunits was evenly distributed along the synaptic specialization. Multiple AMPA receptor subunits and the GluR2/3 and NMDA (NR1) subunits were co-localized within individual synapses. The combination of immunolabelling for glutamate and GABA with the receptor immunolabelling revealed that the majority of axon terminals presynaptic to the receptor-immunoreactive synapses were enriched in glutamate immunoreactivity and were GABA-immunonegative. However, at some NR1- and GluR2/3-positive synapses, the level of glutamate immunoreactivity was low in the presynaptic terminal and, in the STN, some of them were GABA-immunopositive. It is concluded that glutamatergic transmission at individual synapses of different origins in the EP and STN is mediated by a combination ofAMPA and NMDA glutamate receptors.
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PMID:Distribution of glutamate receptor subunits at neurochemically characterized synapses in the entopeduncular nucleus and subthalamic nucleus of the rat. 967 65

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: mGluR1alpha, mGluR2/3). When compared to the localization of tyrosine hydroxylase immunoreactivity, immunoreactivity for GluR1, GluR2/3 and NMDARI 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, mGluR1alpha. 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 mGluR1alpha-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.
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PMID:Localization of ionotropic and metabotropic glutamate receptors in distinct neuronal elements of the rat substantia nigra. 984 Feb 22

To demonstrate the cellular distributions of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptor subunits (GluR1, GluR2/3, and GluR4) in the intrastriatal grafts of a rat model of Parkinson's disease, immunocytochemistry was performed in 6-hydroxydopamine rats with intrastriatal transplants of fetal ventral mesencephalon (VM). In the fetal VM (at embryonic day 15) in which the tyrosine hydroxylase (TH) immunoreactivity was intensely observed, no GluR subunit immunoreactivity was detected. Within the intrastriatal fetal VM grafts containing TH-positive cells, a large number of cells immunoreactive for GluR1 and GluR2/3 were observed. However, the GluR1- and GluR2/3-positive cells tended to locate homogeneously within the grafts and were composed of various cell sizes and shapes, mainly medium-sized and aspiny cells. Weak GluR4-positive cells were seen in the grafts, although in some cases the staining was too faint to see any immunoreactive cells at all. Double immunostaining revealed that a part of TH-positive cells in the grafts was also immunopositive for GluR1 or GluR2/3. Both dopaminergic neurons and nondopaminergic neurons in the VM transplants appear to be modified functionally by glutamatergic afferents via various glutamate receptors, including GluR1 and GluR2/3 and, to a lesser extent, GluR4.
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PMID:Cellular distributions of AMPA glutamate receptor subunits in fetal ventral mesencephalon transplants in the dopamine-depleted striatum of a rat. 988 83

We have examined the distribution of dopamine neurons expressing alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor subunits (glutamate receptors 1, 2/3 and 4) in the A8-A15 regions of the rat brain using double immunofluorescence. The distribution of glutamate receptor 1- or 2/3-like immunoreactive neurons completely overlapped that of tyrosine hydroxylase-like immunoreactive neurons in dopamine cell groups in the retrorubral field (A8), the substantia nigra (A9), the ventral tegmental area and the nucleus raphe linealis (A10), and the rostral hypothalamic periventricular nucleus (A14, A15). In the caudal hypothalamic periventricular nucleus (A11), arcuate nucleus (A12) and zona incerta (A13), the distribution was partially overlapping. Neurons double-labeled for tyrosine hydroxylase and glutamate receptor 1 or 2/3 immunoreactivities were, however, exclusively found in certain dopamine cell regions: in areas A14-A15, 85-88% of tyrosine hydroxylase-containing neurons expressed glutamate receptor 1 and 22-25% expressed glutamate receptor 2/3, while in areas A8-A10, 20-43% expressed glutamate receptor 1 and 63-84% expressed glutamate receptor 2/3. In contrast, the double-labeled neurons were hardly detected in the A11-A13 regions. No tyrosine hydroxylase-positive neurons displayed glutamate receptor 4 immunoreactivity, though a partially overlapping distribution of tyrosine hydroxylase- and glutamate receptor 4-immunopositive neurons was also seen in regions A8-10, A11 and A13. The present study has demonstrated the morphological evidence for direct modulation of dopamine neurons via AMPA receptors in rat mesencephalon and hypothalamus. This distribution may provide the basis for a selective dopamine neuron loss in neurodegenerative disorders, such as Parkinson's disease.
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PMID:Differential expression of AMPA receptor subunits in dopamine neurons of the rat brain: a double immunocytochemical study. 1156 25

In the present study, we attempted to address the modulation of the gene expression of N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) glutamate receptors in the neostriatum of the 6-hydroxydopamine (6-OHDA)-lesioned rat, an animal model of Parkinson's disease. After 2 weeks of lesion, reverse transcriptase-polymerase chain reactions (RT-PCRs) revealed significant reduction in GluR1 mRNA expression but a significant enhancement of NR1 mRNA expression in the striatal tissues of the lesioned side. No modulation in the mRNA expression of GluR2, GluR3, GluR4 and NR2B were found. Immunofluorescence with digital imaging analysis also demonstrated a significant reduction in GluR1 immunoreactivity in the lesioned neostriatum. Interestingly, the reduction in GluR1 immunoreactivity was primarily observed in presumed striatal medium spiny neurons but not in parvalbumin-labeled striatal GABAergic interneurons. Immunoreactivity for GluR2, GluR2/3, GluR4, NR1 and NR2B was unchanged in neurons of the neostriatum of the lesioned side. The present results indicate that there is an opposite trend in modulation in the gene expressions of GluR1 and NR1 in the neostriatum of 6-OHDA-lesioned rats after dopamine denervation. Modulation of GluR1 mRNA and immunoreactivity is likely to be limited in the striatal projection neurons. These findings have implications for the use of NMDA and AMPA receptor antagonists in the treatment of Parkinson's disease.
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PMID:Gene expression of glutamate receptors GluR1 and NR1 is differentially modulated in striatal neurons in rats after 6-hydroxydopamine lesion. 1289 51

The post-synaptic AMPA receptors play an important role in mediating fast excitatory transmission in the mammalian brain. Over-activated AMPA receptors induce excitotoxicity, implicated in a number of Chronic neurodegenerative disorders such as Parkinson's disease, Huntington's disease, and AIDS encephalitis. AMPA receptor antagonists offer protection against neurodegeneration in the experimental models even if they are given 24 h after the injury. Because AMPA receptors seem to be involved in the neurodegenerative diseases, modulating the activity of the AMPA receptors could be an attractive approach to reduce or prevent excitotoxicity. Studies conducted recently have exhibited a number of new mechanisms for AMPA receptor regulation. Modulations of these were found to have protective implications. AMPA receptor depolarization and desensitization are protective to the neurons. Receptor desensitization depends on the receptor subunit composition. The R/G editing site and the flip/flop cassettes in AMPA receptor subunits contribute to a great extent in receptor desensitization and recovery rates. Molecules that could quicken receptor desensitization or delay recovery could be of use. AMPA receptors limit neuronal entry of Ca2+ ions by regulating Ca2+-permeability. Ca2+-permeable receptor channels are made up of GluR1, GluR3, or GluR4 subunits, whereas presence of the GluR2 subunit restricts Ca2+ entry and renders the receptor Ca2+-impermeable. GluR2 levels, however, experience a fall after neuronal insult rendering the AMPA receptors Ca2+-permeable, thus factors that could interfere with this event might prove to be very beneficial against excitotoxicity. AMPA receptor clusters are stabilized by PSD-95, which requires palmitoylation at two sites. Targeting palmitoylation of the PSD-95 can also be a useful approach to disperse AMPA clusters at the synapse. In the perisynaptic region, mGluRs are present a little away from the synapse and are among the glutamate transporters, which require high-frequency firing for activation. On activation they might enhance the activity of NMDA receptors at the synapse to increase the levels of AMPA receptors. AMPA receptors surfaced at this juncture can contribute to heavy Ca2+ influx. Thus, blocking this pathway could be of considerable importance in preventing the excitotoxicity. A number of proteins such as the GRIP, PICK, and NSF also modulate the functions of AMPA receptors. Polyamines also block Ca2+ permeable AMPA receptors and thus are protective. NO and cGMP also play an important role in negatively regulating AMPA receptors and thus could offer protection. Modulation of AMPA receptor by different mechanisms has been discussed in the present review to implicate importance of these targets/pathways for safer and future neuroprotective drugs.
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PMID:AMPA receptor regulation mechanisms: future target for safer neuroprotective drugs. 1520 61