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J B Penney

Publications and source records attributed to J B Penney.

At least 37 records · Page 2Linked to original sources
PubMed1998

Expression of N-methyl-D-aspartate receptor subunit mRNAs in the human brain: striatum and globus pallidus.

N-methyl-D-aspartate receptors (NRs) play an important role in basal ganglia function. By using in situ hybridization with ribonucleotide probes, we investigated the regional and cellular distribution of NR subunit mRNA expression in the human basal ganglia: caudate nucleus, putamen, lateral globus pallidus (LGP), and medial globus pallidus (MGP). Analysis of both film autoradiograms and emulsion-dipped slides revealed distinct distribution patterns for each subunit. On film autoradiograms, the signal for NR1, NR2B, and NR2C in the striatum (STR) was higher than in globus pallidus (GP). The NR2D probe gave a stronger signal in GP than in STR. For NR2A we found a signal in all regions. Analysis of emulsion-dipped sections demonstrated that in striatal neurons, the NR2B signal was higher than in GP neurons. In GP neurons, NR2D was more abundant than in striatal neurons. Despite the relatively low signal on film for NR2C in GP, we found a slightly higher signal in GP per neuron than in STR since in the pallidal areas neurons were sparse but intensely labeled. NR1 and NR2A were more evenly distributed over neurons of STR and GP Between the different parts of STR and GP, we observed only minor differences in the expression of NRs. In MGP a subpopulation of neurons exhibiting low NR2D signals could be separated from the majority of neurons showing an intense NR2D signal. Since the physiological properties of NRs are dependent on subunit composition, these data suggest a high degree of regional specialization of NR properties in the human basal ganglia.

Adult↗
PubMed1998

Expression of N-methyl-D-aspartate receptor subunit mRNA in the human brain: mesencephalic dopaminergic neurons.

Evidence is accumulating that glutamate-mediated excitotoxicity plays an important role in neuronal degeneration in Parkinson's disease (PD). In addition, alterations in excitatory amino acid neurotransmission in the basal ganglia contribute to the clinical manifestations of motor dysfunction. However, detailed knowledge of the anatomical distribution and subtype specificity of glutamate receptors in the dopamine neurons of human substantia nigra (SN) has been lacking. In order to test the hypothesis that selective expression of particular N-methyl-D-aspartate receptor (NR) subunit mRNA contributes to the differential vulnerability of specific neuronal populations to excitotoxic injury in PD, we have used a quantitative dual label, in situ hybridization technique with ribonucleotide probes to examine the cellular distribution of NR subunit mRNA in postmortem human mesencephalic dopaminergic neurons from subjects with no known neurological disorder. Analysis of both film autoradiograms and emulsion-dipped sections demonstrated significant labeling of nigral neurons for each NR subunit. Neuronal labeling was most intense for the NR1 and NR2D subunits, with low level labeling for the remaining subunits. In addition, we examined four subregions of the ventral mesencephalon for differential expression of NR subunit mRNA. For all NR subunits, the pars lateralis (PL) exhibited the most intense signal, while neurons of the ventral tier substantia nigra pars compacta (SNpc) failed to demonstrate a preponderance of a particular subunit. These results demonstrate that NRs are expressed to a significant degree in dopaminergic neurons of the SN and that their distribution does not correlate with the characteristic pattern of neuronal degeneration in PD.

Adult↗
PubMed1998

Expression of the early-onset torsion dystonia gene (DYT1) in human brain.

Early-onset torsion dystonia, an autosomal dominant disease associated with the DYT1 locus on 9q34, is the most frequent genetic form of dystonia. Recent work has revealed that the causative mutation in most cases is deletion of a glutamate residue from the carboxy terminal of torsinA, a 332 amino acid protein encoded by the DYT1 gene. To gain insight into how deletion of a single amino acid can produce such a profound movement disorder, we have mapped the expression of the DYT1 gene in normal human postmortem brain. DYT1 mRNA is highly enriched in the dopamine neurons of the substantia nigra pars compacta. Intense expression was also found in the cerebellum and hippocampal subfields. The prominent expression of the DYT1 gene within the substantia nigra pars compacta, which provides dopaminergic innervation to the basal ganglia, implicates a disturbance of dopaminergic function in the pathophysiology of early-onset torsion dystonia.

Age of Onset↗
PubMed1998

Expression of metabotropic glutamate receptor 1 isoforms in the substantia nigra pars compacta of the rat.

Metabotropic glutamate receptors, which are linked via G-proteins to second messenger systems, have been implicated in the physiological regulation of dopaminergic neurons of the substantia nigra pars compacta as well as in neurodegeneration. Of the eight known metabotropic glutamate receptors, metabotropic glutamate receptor 1 is the most abundant subtype in the substantia nigra pars compacta. Metabotropic glutamate receptor 1 is alternatively spliced at the carboxy terminal region to yield five variants: 1a, 1b, 1c, 1d and a form recently identified in human brain, 1g. We used an antibody recognizing metabotropic glutamate receptor 1, and another recognizing the splice form la only, to study the localization of these receptors in dopaminergic neurons identified by the presence of tyrosine hydroxylase. Metabotropic glutamate receptor immunoreactivity was present within the somata, axons, and dendrites of substantia nigra pars compacta neurons. The 1a splice form specific antibody, however, did not label these cells, suggesting that they express a metabotropic glutamate receptor 1 splice form different from 1a. In situ hybridization with splice form-specific oligonucleotide probes was used to determine which of the other known metabotropic glutamate receptor 1 splice forms might be present in the substantia nigra pars compacta. Each probe produced a very distinct labelling pattern in the rat brain with the exception of the 1g specific probe which produced only background signal. Substantia nigra pars compacta neurons were most intensely labelled by the metabotropic glutamate receptor 1d splice form specific probe. Metabotropic glutamate receptor 1a was expressed weakly whereas there was no detectable 1b, c, or g signal in the substantia nigra pars compacta. These data demonstrate that metabotropic glutamate receptor 1 protein is present within the perikarya and processes of dopaminergic neurons in the substantia nigra pars compacta. The majority of this protein is not the 1a splice form, which is abundant in other brain regions, and may be the 1d isoform. Since splicing alters the carboxy terminus of the receptor, it is likely to affect the interaction of the receptor with intracellular signalling systems.

Alternative Splicing↗
PubMed1998

Simultaneous isotopic and nonisotopic in situ hybridization histochemistry with cRNA probes.

In situ hybridization histochemistry is widely used to study gene expression at the mRNA level in tissues and cells. Double label in situ hybridization allows for coexpression studies. We describe a protocol for the simultaneous hybridization of two cRNA probes tagged with and digoxigenin-UTP, respectively, to frozen brain tissue sections. Hybridization signals of digoxigenin-tagged probes appear as purple cytoplasmic staining following detection of digoxigenin residues by an alkaline-phosphatase-(AP)-linked antibody. Signals resulting from hybridization of radiolabeled probes are detected as silver grains overlying cellular profiles in sections coated with autoradiographic emulsion. Grain counting allows for semiquantitatively estimates of the cellular expression levels of transcripts. Suitable cRNA-probes can be derived from linear templates generated by polymerase chain reaction (PCR) using nested primers which contain RNA-polymerase promotor sites. The cRNA-probes are sensitive and allow an application of this protocol to the detection of a wide range of mRNAs of medium or low abundance.

Corpus Striatum↗
PubMed1998

Regional dopamine transporter gene expression in the substantia nigra from control and Parkinson's disease brains.

OBJECTIVE: To test the hypothesis that differential regional dopamine transporter (DAT) gene expression may underlie the selective vulnerability of certain nigral dopaminergic neurons in Parkinson's disease, DAT mRNA expression was examined in neuronal subpopulations of human postmortem ventral mesencephalon from patients with Parkinson's disease and controls. METHODS: Radioactive in situ hybridisation histochemistry using a polymerase chain reaction derived ribonucleotide probe for DAT was performed on sections of ventral mesencephalon from the brains of five donors with no history of neurological illness and from five patients with pathologically established Parkinson's disease. The number of silver grains overlying melanised neurons from the paranigral nucleus, dorsal and ventral tier, and pars lateralis of the substantia nigra pars compacta were compared with each other and to background labelling by using a one way factorial analysis of variance (ANOVA) with a significance level of 5%. RESULTS: In control brains, there was intense DAT mRNA expression in the ventral midbrain with no significant difference in mRNA concentrations among the four regions studied. In the Parkinson's disease brains, there was an overall decrease in the intensity of DAT mRNA expression in the surviving dopaminergic neurons. There were no significant differences in signal between regions in either the control or parkinsonian brains. CONCLUSION: Taken together, these findings do not support the hypothesis that differential regional DAT gene expression underlies the selective vulnerability of certain nigral dopaminergic neurons in Parkinson's disease, as the vulnerable neurons of the substantia nigra pars compacta do not express more DAT mRNA than the resistant paranigral neurons.

Aged↗
PubMed1998

The importance of accurate lesion placement in posteroventral pallidotomy. Report of two cases.

Pallidotomy has become a widely used treatment for medically refractory Parkinson's disease. However, the optimal lesion size and location within the pallidum have not yet been determined, and the role of repeated pallidotomy remains undefined. The authors present two patients who had unsatisfactory results after their first unilateral pallidotomy but attained dramatic and long-lasting improvement with repeated surgery. The results obtained in these cases indicate that patients who have a good clinical outcome initially but relapse rapidly after surgery should be considered for repeated pallidotomy if the initial lesion was not placed in the optimal location.

Aged↗
PubMed1997

Selective metabotropic receptor agonists distinguish non-ionotropic glutamate binding sites.

Metabotropic glutamate receptors (mGluRs) are thought to mediate diverse processes in brain including synaptic plasticity and excitotoxicity. These receptors are often divided into three groups by their pharmacological profiles. [3H]Glutamate binding in the presence of compounds selective for ionotropic glutamate receptors can be used as a general assay for these receptors; subtypes of this non-ionotropic [3H]glutamate binding differ in both pharmacology and anatomical distribution, and are differentially sensitive to quisqualate. The characteristics of these binding sites are consistent with those of group 1 (high-affinity quisqualate) and group 2 (low-affinity quisqualate) mGluRs. Under our assay conditions, no [3H]glutamate binding to group 3-like (L-AP4 sensitive) sites could be demonstrated. We have attempted to characterize particular agents which may selectively measure [3H]glutamate binding to mGluR subtypes. We used two isomers of 2-(carboxycyclopropyl)glycine, L-CCG-I and L-CCG-II, and the (2S,1'R,2'R,3'R) isomer of 2-(2,3-dicarboxycyclopropyl)glycine (DCG-IV) as competitors of non-ionotropic [3H]glutamate binding sites. DCG-IV clearly distinguishes two binding sites. Quantitative levels of DCG-IV binding by anatomic region correlate with quisqualate-defined binding subtypes: high-affinity DCG-IV binding correlates with low-affinity quisqualate binding, whereas low-affinity DCG-IV binding correlates with high-affinity quisqualate binding. L-CCG-II displaces only one type of non-ionotropic [3H]glutamate binding, corresponding to high-affinity quisqualate binding. Therefore DCG-IV and L-CCG-II at appropriate concentrations appear to distinguish binding to putative group 2 vs. group 1 mGluRs. L-CCG-I displaces both high- and low-affinity quisqualate binding sites, but unlike the other two compounds, does not clearly distinguish between them.

Amino Acids, Dicarboxylic↗
PubMed1997

N-acetylaspartylglutamate (NAAG) protects against rat striatal quinolinic acid lesions in vivo.

We examined the effects of N-acetylaspartylglutamate (NAAG), an endogenous peptide thought to be involved in neurotransmission and neuromodulation, on striatal quinolinate lesions, a rodent model of Huntington's disease. We found that NAAG (500 and 1000 nmol) co-injected with quinolinic acid significantly reduced lesion volumes (by 50% and 65%, respectively). A 1000 nmol dose of the non-hydrolyzable analogue, beta-NAAG, also reduced quinolinic acid lesion volumes by 78.4%, indicating that the protection observed was not secondary to cleavage of NAAG into N-acetyl-aspartate (NAA) and glutamate. Likewise, co-injection of both NAA and glutamate (1000 nmol each) with quinolinic acid did not significantly alter the size of lesions. NAAG's protective effect may be mediated through actions on N-methyl-D-aspartate receptors or metabotropic glutamate receptors.

Animals↗
PubMed1997

Differential expression of kainate receptors in the basal ganglia of the developing and adult rat brain.

Glutamate is the principal excitatory transmitter of the mammalian brain and plays a particularly important role in the physiology of the basal ganglia structures responsible for movement regulation. Using in situ hybridization with oligonucleotide probes, we examined the expression patterns of the five known kainate type glutamate receptor subunit genes, KA1, KA2 and GluR5-7, in the basal ganglia of adult and developing rat brain. In the adult rat, a highly organized and selective pattern of expression of the kainate subunits was observed in the basal ganglia and associated structures as well as in other regions of the brain. KA2 mRNA was abundant in the striatum, nucleus accumbens, subthalamic nucleus and substantia nigra pars compacta, and was present at lower levels in the globus pallidus and substantia nigra pars reticulata. Neither KA1 nor GluR5 expression was observed in the basal ganglia of adult rats, although these messages were present in other regions. GluR6 was highly expressed in the striatum and subthalamic nucleus and to a lesser extent in the substantia nigra pars reticulata, while no hybridization signal was detectable in the large, presumably dopaminergic neurons of the substantia nigra pars compacta. In contrast, GluR7 was strongly expressed in the substantia nigra pars compacta, was present at lower levels in the striatum, globus pallidus and substantia nigra pars reticulata, and was not detectable in the subthalamic nucleus. During postnatal development, expression of the kainate receptor subunits was characteristically highest on postnatal day 1 and declined to adult levels by day 20; however, in the globus pallidus we did observe the transient expression of KA1 and GluR5 between day 1 and day 10. These results demonstrate that the neuronal structures comprising the basal ganglia express a distinct combination of kainate receptor subunit genes, suggesting that the pharmacological properties of the resultant glutamate receptors are likely to be regionally specific. The organization of expression of these genes is established early in life, which is consistent with the important role they may play in establishing the functions of the motor system.

Animals↗
PubMed1997

CAG repeat number governs the development rate of pathology in Huntington's disease.

We compared the number of CAG repeats, the age at death, and the severity of neuropathology in 89 Huntington's disease brains. We found a linear correlation between the CAG repeat number and the quotient of the degree of atrophy in the striatum (the brain region most severely affected in Huntington's disease) divided by age at death, with an intercept at 35.5 repeats. The largest CAG repeat length, therefore, at which no pathology is expected to develop is 35.5. These results imply that striatal damage in Huntington's disease is almost entirely a linear function of the length of the polyglutamine stretch beyond 35.5 glutamines multiplied by the age of the patient. Thus, it is predicted that the pathological process develops linearly from birth. Analysis of other measures of striatal function could test this hypothesis and might determine when treatment for CAG repeat diseases should start.

Adult↗
PubMed1997

Huntingtin immunoreactivity in the rat neostriatum: differential accumulation in projection and interneurons.

Huntington's disease is caused by a mutation of the gene encoding the protein huntingtin. Features of the human disease, characterized by selective loss of neurons from the neostriatum, can be replicated in rodents by administration of excitotoxins. In both affected individuals and the rodent model, there is massive loss of striatal projection neurons with selective sparing of interneurons. Furthermore, in the human disease the earliest evidence of striatal injury is found in striosomal regions of the striatum. The mRNA encoding huntingtin is known to be expressed by neurons throughout the brain, a distribution which does not account for the selective patterns of neuronal death which are observed. Using fluorescence immunocytochemistry and confocal microscopy with an antibody to huntingtin, we have observed that in rats a subset of striatal projection neurons contains dense accumulations of huntingtin immunoreactivity (HT-ir), while most neurons in the striatum contain much smaller amounts. The intensely stained neurons are concentrated within the striatal striosomes, as defined by calbindin-D28K staining. In the matrix regions, relatively few neurons contain dense accumulations of HT-ir, and these cells always lack perikaryal staining for calbindin-D28K. Striatal interneurons, identified by the presence of immunoreactivity for choline acetyltransferase, parvalbumin, calretinin, or neuronal nitric oxide synthase, exhibit little or no HT-ir. The paucity of HT-ir in striatal interneurons, as well as the prominence of staining in a subset of striosomal neurons, mirrors the selective vulnerability of these different types of cells in early stages of human Huntington's disease and in rodent excitotoxic models of the disorder. Our observations suggest that mechanisms which modulate the accumulation of huntingtin may play a central role in the neuronal degeneration of Huntington's disease.

Animals↗
PubMed1997

Cellular distribution of NMDA glutamate receptor subunit mRNAs in the human cerebellum.

We have used a quantitative in situ hybridization method with human ribonucleotide probes to examine the regional and cellular distribution of N-methyl-D-aspartate receptor (NMDAR) subunit mRNAs in the human cerebellum. Purkinje cells showed very dense labeling for NMDAR1 mRNA, dense labeling for NMDAR2A mRNA, and moderate labeling for NMDAR2D mRNA, whereas labeling for NMDAR2C mRNA was low. Granule cells showed high hybridization signals for the NMDAR1 and NMDAR2C mRNAs and moderate signals for the NMDAR2A and NMDAR2D mRNAs. In addition intense labeling with the NMDAR2B probe was observed in medium-sized neurons with chromophilic cell bodies in the upper part of the granule cell layer, most likely representing Golgi cells. Neurons in the molecular layer, i.e., basket cells and stellate cells, showed moderate hybridization signals for NMDAR1 and NMDAR2D and low signal for NMDAR2C. Each type of cerebellar neuron analyzed displayed a distinct NMDAR2 subunit profile, suggesting that they are likely to have NMDA receptors with distinct properties.

Cerebellar Cortex↗
PubMed1997

Expression of group one metabotropic glutamate receptor subunit mRNAs in neurochemically identified neurons in the rat neostriatum, neocortex, and hippocampus.

Metabotropic glutamate receptors (mGluRs) can be divided into three groups based on sequence homology and pharmacology. We studied expression of group I mGluRs (mGluR1 and mGluR5) in identified neurons of the rat neostriatum, neocortex, and hippocampus using in situ hybridization. Tissue sections were hybridized with radiolabeled RNA probes for mGluR1 or mGluR5 and digoxygenin labeled RNA probes detecting somatostatin (SOM), preproenkephalin (ENK), preprotachykinin (SP), glutamic acid decarboxylase 67 (GAD67), parvalbumin (PARV), or choline acetyltransferase (ChAT) mRNA. In the striatum, mGluR1 hybridization signal was observed in all six neuronal populations. The strongest signal was found in SP-positive neurons, with a lower signal in ENK-positive neurons. All striatal interneurons were labeled less intensely than ENK- and SP-positive projection neurons. For striatal mGluR5 mRNA, both SP- and ENK-positive projection neurons were intensely labeled, but only GAD67-positive interneurons exhibited a significant signal. In the neocortex and hippocampus, mGluR1 and mGluR5 hybridization signals were studied in SOM-, GAD67-, and PARV-positive neurons. Hybridization signal for mGluR1 mRNA was intense in SOM-positive neurons of the cortex, CA1, CA3, and dentate gyrus, and weaker in GAD67-positive neurons of CA3 and dentate gyrus. MGluR5 signals were intensely labeled in SOM-, GAD67- and PARV-positive neuronal populations of the cortex and hippocampus. SOM-positive neurons were more intensely labeled in the hippocampus than cortex.

Animals↗
PubMed1996

Expression of N-methyl-D-aspartate glutamate receptor subunits in the prefrontal cortex of the rat.

The laminar distribution and cellular levels of expression of mRNAs encoding N-methyl-D-aspartate receptor subunits (NMDAR1, NMDAR2A-D and the alternatively spliced isoforms of NMDAR1) were examined in prefrontal cortex of rat by in situ hybridization using film and emulsion autoradiography. Film autoradiograms demonstrated a distinctive laminar distribution of hybridization signals for each of the probes recognizing NMDAR1, NMDAR2A, and NMDAR2B messenger RNA; hybridization with probes for NMDAR2C and NMDAR2D resulted in scattered signals without laminar organization. Grain counting disclosed that neurons in layer V displayed the highest and neurons in layer IV the lowest absolute number of grains for all probes examined. Correction for cell size demonstrated statistically significant differences in cellular labelling density of up to 50% across neurons in different cortical layers. The cellular density profiles across cortical laminae differed between probes. Hybridization with a probe recognizing all isoforms of NMDAR1 resulted in significantly lower densities of cellular labelling in neurons of layer IV than of layers II/III, V and VI. Cellular labelling densities following hybridization with probes recognizing alternatively spliced segments of NMDAR1 were examined. Densities were low in neurons of the upper cortical layers II/III and IV using probes for the messenger RNA encoding the amino terminal insert, NMDAR11XX and the second carboxy terminal deletion, NMDAR1XX1; hybridization with a probe for the messenger RNA encoding the first carboxy terminal deletion, NMDAR1X1X, resulted in low cellular signal densities in neurons of layers IV and VIb. NMDAR2A messenger RNA expression was of relatively uniform intensity in neurons of layers II-V but significantly lower in neurons of the inner part of layer VI. NMDAR2B expression was most dense in layer II neurons. These data indicate that neurons in different cortical laminae express distinct N-methyl-D-aspartate receptor subunit messenger RNA phenotypes. In addition, the observed differences in density of N-methyl-D-aspartate receptor subunit messenger RNA expression suggest that cortical laminae differ in the relative contribution of N-methyl-D-aspartate receptors to their excitatory responses.

Alternative Splicing↗
PubMed1996

Expression of NMDAR2D glutamate receptor subunit mRNA in neurochemically identified interneurons in the rat neostriatum, neocortex and hippocampus.

NMDA receptors are composed of proteins from two families: NMDAR1, which are required for channel activity, and NMDAR2, which modulate properties of the channels. The mRNA encoding the NMDAR2D subunit has a highly restricted pattern of expression: in the forebrain, it is found in only a small subset of cortical, neostriatal and hippocampal neurons. We have used a quantitative double-label in situ hybridization method to examine the expression of NMDAR2D mRNA in neurochemically defined populations of neurons. In the neostriatum, NMDAR2D was expressed by the interneuron populations marked by preprosomatostatin (SOM), the 67-kDa form of glutamic acid decarboxylase (GAD67), parvalbumin (PARV), and choline acetyltransferase (ChAT) mRNAs but not by the projection neurons expressing beta-preprotachykinin (SP) or preproenkephalin (ENK) mRNAs. In the neocortex, NMDAR2D expression was observed in only a small number of neurons, but these included almost all of the SOM-, GAD67-, and PARV-expressing interneurons. In the hippocampus, NMDAR2D was not present in pyramidal or granule cells, but was abundant in SOM-, GAD67-, and PARV-positive interneurons. NMDAR2D expression appears to be a property shared by interneurons in several regions of the brain. The unique electrophysiological characteristics conveyed by this subunit, which include resistance to blockade by magnesium ion and long channel offset latencies, may be important for the integrative functions of these neurons. NMDAR2D-containing receptor complexes may prove to be important therapeutic targets in human disorders of movement. In addition, the presence of NMDAR2D subunits may contribute to the differential vulnerability of interneurons to excitotoxic injury.

Animals↗
PubMed1995

Metabotropic receptors in excitotoxicity: (S)-4-carboxy-3-hydroxyphenylglycine ((S)-4C3HPG) protects against rat striatal quinolinic acid lesions.

Striatal quinolinate lesions mimic many of the neuropathological characteristics of Huntington's disease. This excitotoxicity is mediated by combined activity of N-methyl-D-aspartate and metabotropic glutamate receptors (mGluRs). Using recently developed phenylglycine derivatives, (S)-4-carboxy-3-hydroxyphenylglycine ((S)-4C3HPG) and (+)-alpha-methyl-4-carboxyphenylglycine ((+)-MCPG), we investigated the role of the different sub-classes of mGluRs in the in vivo excitotoxic process. (S)-4C3HPG (500 and 1000 nmol), co-injected with quinolinic acid, significantly reduced lesion volumes by 52 and 89%, respectively, whereas the same doses of (+)-MCPG had no effect on lesion size. The differential actions of these two drugs at Group 1 and Group 2 metabotropic receptors may explain their differential effects. These observations confirm the important role of mGluRs in excitotoxicity and identify them as promising targets for intervention.

Animals↗