Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.14.16.2 (tyrosine hydroxylase)
 14,760 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the rabbit retina, parvalbumin has been localized selectively to AII amacrine cells, while 28 kDa calbindin could be detected in horizontal cells, in one type of depolarizing cone bipolar cell and a population of wide-field amacrine cells. The distribution of the third neuronal calcium binding protein, calretinin, however, has not been studied to date in detail in the rabbit retina. Therefore in this study we aimed to describe the overall distribution of calretinin in the different retinal layers and the possible colocalization pattern with other neurochemical marker molecules. A few cone photoreceptor cells were found to be labeled, whereas the outer plexiform layer was free from immunoreactive elements. In the most proximal row of the inner nuclear layer amacrine cells were labeled, while more distally a few cells emitted beaded axon-like processes toward the outer retina. There were large (18-28 microm in diameter) cells labeled in the ganglion cell layer, of which many apparently had their axon stained. Some of the calretinin immunoreactive amacrine cells (the AII neurons) also contained parvalbumin. Colocalization of calretinin and 28 kDa calbindin could not be ascertained in the same amacrine cell populations, nor was tyrosine hydroxylase present in calretinin-containing cells. There was partial colocalization of calretinin in the gamma-aminobutyric acid-positive amacrine cell population. Parvalbumin containing ganglion cells were also positive for calretinin; however, the calretinin-positive ganglion cells were more numerous. gamma-Aminobutyric acid could be colocalized in some calretinin-positive neurons of the ganglion cell layer.
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PMID:Calretinin in neurochemically well-defined cell populations of rabbit retina. 927 31

The importance of calcium in neuronal function has been amply demonstrated in recent years. The discovery of a class of proteins within neurons which bind calcium, therefore, has proven to be a catalyst for the generation of theories and hypotheses regarding mechanisms of neurotoxicity in the CNS. In addition, the distribution of certain calcium-binding proteins changes during neural development, suggesting that they may play a role in organization or pattern generation. We have examined the ontogeny of three related calcium-binding proteins, calbindin-D28, parvalbumin and calretinin, with respect to the ventral and dorsal compartments or tiers of the dopaminergic population in the ventral midbrain. Single and dual-label immunocytochemistry was employed to map the distributions of calcium-binding proteins and tyrosine hydroxylase from E18 through adulthood. The results show that each of the three proteins exhibits a unique developmental sequence and compartment preference, with calbindin D28 clearly related to the later-developing dorsal tier, and parvalbumin and calretinin to the ventral tier of the dopaminergic ventral mesencephalon.
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PMID:Calcium-binding proteins in the substantia nigra and ventral tegmental area during development: correlation with dopaminergic compartmentalization. 937 56

Tachykinin (TK) peptides influence neuronal activity in the inner retina of mammals. The aim of this investigation was to determine the cellular localization of the neurokinin 1 receptor (NK1), whose preferred ligand is the TK peptide substance P (SP), in the rat retina. These studies used a polyclonal antiserum directed to the C-terminus of rat NK1. The majority of NK1-immunoreactive (IR) cells were located in the proximal inner nuclear layer (INL), and very rarely they were found in the distal INL. Some small and large NK1-IR somata were present in the ganglion cell layer. NK1-IR processes were densely distributed across the inner plexiform layer (IPL) with a maximum density over lamina 2 of the IPL. Immunoreactive processes also crossed the INL and ramified in the outer plexiform layer where they formed a sparse meshwork. NK1-IR processes were rarely observed in the optic nerve fiber layer. Double-label immunofluorescence studies with different histochemical markers for bipolar cells indicated that NK1 immunoreactivity was not present in bipolar cells. Together, these observations indicate that NK1 immunoreactivity is predominantly expressed by amacrine, displaced amacrine, interplexiform, and some ganglion cells. Double-label immunofluorescence experiments were also performed to characterize NK1-containing amacrine cells. Sixty-one percent of the gamma-aminobutyric acid (GABA)-IR cells, 71% of the large tyrosine hydroxylase (TH)-IR cells, and 100% of the small TH-IR cells contained NK1 immunoreactivity. In addition, most (91%) of the NK1-IR cells had GABA immunoreactivity. In contrast, vasoactive intestinal polypeptide-, TK-, choline acetyltransferase-, and parvalbumin-IR amacrine tells did not express NK1 immunoreactivity. Overall, the present findings suggest that SP acts directly upon several cell populations, including GABA-containing amacrine cells and ganglion cells, to influence visual information processing in the inner retina.
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PMID:Neurokinin 1 receptor expression in the rat retina. 941 9

We aimed to clarify the topology and immunohistochemistry of CO2/H+-sensitive neurons in the ventral medullary surface (VMS), the central chemoreceptor area in rats. Inhalation of 3 and 7% CO2 in air significantly decreased pH in arterial blood and increased paCO2, which caused hyperpneic and tachypneic responses. Following inhalation of 3 and 7% CO2 in air for 5 min, the density of c-Fos-immunoreactive (IR) neurons increased stepwise not only in the 3rd-5th divisions of the VMS (between the caudal end of the nucleus corporis trapezoidei and the caudal end of the area postrema), but also in the rostroventromedial medulla (RVMM). Following inhalation of 7% CO2 in air for 5 min, glutamate-, glutamic acid decarboxylase (GAD)-, calcineurin- and cAMP-IR neurons were found not only in the VMS, but also in the RVMM. The topology of these neurons was similar to that of the c-Fos-IR neurons. No immunoreactivity was found for serotonin, substance P, somatostatin, cholecystokinin-octapeptide, methionine-enkephalin, choline acetyltransferase, tyrosine hydroxylase, phenylethanolamine N-methyltransferase, NO-synthase, S-100, calbindin-D, calmodulin, or parvalbumin. The densities of c-Fos-, glutamate-, GAD-, calcineurin- and cAMP-IR neurons were almost zero in the 1st division of the VMS, but became higher along the 2nd-4th divisions of the VMS. Regression lines of the density against the 1st-4th divisions of the VMS were significantly linear. These results indicate that H+-sensitive neurons are common in the 4th-5th divisions of the VMS, and that they are glutamatergic, GABAergic, and containing calcineurin and cAMP.
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PMID:Topology and immunohistochemistry of proton-sensitive neurons in the ventral medullary surface of rats. 947 76

The present study characterizes expression of calbindin D28K (CB-D28K) and parvalbumin (PV) in ventral forebrain (VFB) grafts placed in the neocortex of adult rats bearing quisqualic acid lesions to the nucleus basalis magnocellularis. Three to nine months after transplantation surgery, rats were killed for in situ hybridization with probes to CB-D28K or PV and for immunohistochemistry with antibodies to CB-D28K or PV. In addition, an antibody to choline acetyltransferase (ChAT) was used to characterize the cholinergic component in the graft and an antibody to tyrosine hydroxylase (TH) to explore catecholaminergic innervation of the graft. Quantitative analysis of CB-D28K and PV messenger ribonucleic acid (mRNA) was based on counts of silver grains generated by emulsion autoradiography. Cells expressing CB-D28K mRNA were significantly larger than such cells in the adult VFB and the mean number of silver grains per cell was significantly greater than to such cells in the adult VFB. The level of CB-D28K mRNA expression as calculated by ratio of silver grains per unit area was also significantly increased. Quantification of PV mRNA showed no significant differences between the cells in the graft and in the adult VFB. In order to begin to interpret these findings, a comparison was made with such cells in the VFB of developing rats. Brain sections were sampled from embryonic day 17 and postnatal days 1, 5, 12, 19 and adult (6-12 months of age). Cells expressing CB-D28K mRNA were detected in ventral forebrain from postnatal day 5 and cells expressing PV mRNA were detected in ventral forebrain from postnatal day 19. In the course of normal development of the ventral forebrain, no CB-D28K cells were found that were as large or expressed such high levels of CB-D28K mRNA as observed in the grafts. We conclude that changes in grafted cells expressing CB-D28K do not reflect an arrest of developmental processes. TH immunohistochemistry revealed lack of catecholaminergic innervation of the graft, whereas adult mediolateral septal cells that express CB-D28K receive such innervation in addition to other neurotransmitter inputs. Imbalance in neurotransmitter inputs to grafted cells expressing CB-D28K is discussed as a possible factor in their increased size and gene expression.
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PMID:Calbindin D28K and parvalbumin gene expression in rat embryonic ventral forebrain grafts. 950 50

A single, large dose of N-methyl-D-aspartate (NMDA) or quisqualic acid (QA) injected into the chick eye has been shown previously to destroy many retinal amacrine cells and to induce excessive ocular growth accompanied by myopia. The purpose of this study was to identify distinct populations of retinal cells, particularly those believed to be involved in regulating ocular growth, that are sensitive to NMDA or QA. Two pmol of NMDA or 0.2 micromol of QA were injected unilaterally into eyes of 7-day-old chicks, and retinas were prepared for observation 1, 3, or 7 days later. Retinal neurons were identified by using immunocytochemistry, and cells containing fragmented DNA were identified by 3'-nick-end labelling in frozen sections. NMDA and QA destroyed many amacrine cells, including those immunoreactive for vasoactive intestinal polypeptide, Met-enkephalin, and choline acetyltransferase, but they had little effect upon tyrosine hydroxylase-immunoreactive cells. Other cells affected by both QA and NMDA included those immunoreactive for glutamic acid decarboxylase, gamma-aminobutyric acid, parvalbumin, serotonin, and aminohydroxy methylisoxazole propionic acid (AMPA) receptor subunits GluR1 and GluR2/3. Cells largely unaffected by QA or NMDA included bipolar cells immunoreactive for protein kinase C (alpha and beta isoforms) and amacrine cells immunoreactive for glucagon. DNA fragmentation was detected maximally in many amacrine cells and in some bipolar cells 1 day after exposure to QA or NMDA. We propose that excitotoxicity caused by QA and NMDA induces apoptosis in specific populations of amacrine cells and that these actions are responsible for the ocular growth-specific effects of QA and NMDA reported elsewhere.
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PMID:Immunocytochemical characterization of quisqualic acid- and N-methyl-D-aspartate-induced excitotoxicity in the retina of chicks. 952 96

Our previous studies have demonstrated that septohippocampal neurons in the rat septal complex have substantial glial coverage and have a number of synaptic associations with catecholaminergic terminals. While similar ultrastructural characteristics are observed for septal cholinergic neurons, the morphology and synaptic relations of catecholaminergic terminals with septal GABAergic neurons is largely unknown. Since the GABAergic septohippocampal neurons colocalize the calcium-binding protein, parvalbumin (PVA), the present study examined the ultrastructural relations of PVA neurons with catecholaminergic terminals in the septal complex. Single sections were dually labeled with antibodies to PVA and either tyrosine hydroxylase (TH) or dopamine-beta-hydroxylase (DBH). By light microscopy, processes with TH- and DBH- (TH/DBH) immunoreactivity were near PVA-labeled neurons. By electron microscopy, PVA-labeled perikarya had an average diameter of 14.9+/-6 microm and were ovoid or elongated. PVA-labeled perikarya (n = 124) had a large amount of astrocytic coverage (75+/-14%) and a low amount of terminal coverage (15+/-12%). PVA-labeled perikarya and dendrites mostly were contacted by terminals lacking immunoreactivity for either PVA or TH/DBH (82% of 1,663). Of the TH/DBH terminals or axons near PVA somata and dendrites, few (3% of 1,663) directly contacted them while the majority abutted adjacent glial or neuronal profiles. Some TH/DBH- and PVA-labeled terminals contacted the same dendrites; a few of these contained immunoreactivity for PVA. The results demonstrate that PVA-containing GABAergic septal neurons, like cholinergic neurons, are mostly surrounded by astrocytes and have very little terminal coverage. However, in contrast to cholinergic neurons, PVA-containing neurons are contacted primarily by non-catecholaminergic terminals suggesting that any functional interactions would be indirect. These findings further support the functional diversity of subpopulations of septohippocampal neurons.
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PMID:Parvalbumin immunoreactive neurons in the rat septal complex have substantial glial coverage and receive few direct contacts from catecholaminergic terminals. 966 21

The dorsal raphe nucleus (DR) harbours the largest single collection of serotonin (5-HT)-containing neurons in the brain but also comprises other types of chemospecific neurons. The aim of the present study was to characterise morphologically and immunohistochemically the DR in the squirrel monkey (Saimiri sciureus). The morphology of the DR 5-HT-immunoreactive (ir) neurons was analysed and their distribution compared to that of neurons displaying immunoreactivity for either tyrosine hydroxylase (TH), gamma-aminobutyric acid (GABA), substance P (SP), calbindin-D28k (CB), calretinin (CR) or parvalbumin (PV). The 5-HT-ir neurons were distributed in a highly heterogeneous manner throughout the rostrocaudal extent of the DR. The morphology and density of the 5-HT neurons were found to vary significantly in the major subdivisions of the primate DR, that is, the median, ventral, dorsal, ventrolateral, lateral and caudal subnuclei. Numerous SP-, GABA- and PV-ir neurons occurred in all six subnuclei of the DR. The distribution of SP-ir neurons was largely in register with that of 5-HT-ir neurons. Neurons expressing the other neuronal markers (TH, CB, CR) were not present in all six DR subnuclei and their distribution was either complementary to, or in register with, that of 5-HT-ir neurons. The median subnucleus was unique because it contained all the different types of chemospecific neurons. This study has revealed that the primate DR is chemically highly heterogeneous, a finding that may explain the multifarious influence that this nucleus exerts upon various forebrain structures.
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PMID:Chemoarchitecture of the primate dorsal raphe nucleus. 971 63

Leukemia inhibitory factor (LIF) can regulate the survival and differentiation of certain neurons and glial cells in culture. To determine the role of this cytokine in the central nervous system in vivo, we examined the brains of young and adult mice in which the LIF gene was disrupted. Immunohistochemical staining of neurons for choline acetyltransferase, tyrosine hydroxylase, serotonin, parvalbumin, calbindin, neuropeptide Y, vasoactive intestinal polypeptide, and calcitonin gene-related peptide revealed no significant differences between null mutant and wild-type (WT) brains. In contrast, analysis of glial phenotypes demonstrated striking deficits in the LIF-knockout brain. Staining with several anti-glial fibrillary acidic protein (GFAP) antibodies showed that the number of GFAP-positive cells in various regions of the hippocampus in the female mutant is much lower than in the WT. The null male hippocampus also displays a significant, though less marked deficit. The number of astrocytes in the mutant hippocampus, as determined by S-100 staining, is not, however, significantly different from WT. In addition, quantification of immunohistochemical staining of female, but not male, mutants reveals a significant deficit in myelin basic protein content in three brain regions, suggesting alterations in oligodendrocytes as well. Thus, while overall brain histology appears normal, the absence of LIF in vivo leads to specific, sexually dimorphic alterations in glial phenotype.
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PMID:Analysis of neuronal and glial phenotypes in brains of mice deficient in leukemia inhibitory factor. 974 23

The ability of dopamine to regulate the cognitive functions of the prefrontal cortex (PFC) involves complex modulatory actions on GABA-containing local circuit neurons in addition to pyramidal cells. However, the subclasses of cortical neurons that receive direct dopamine input are not known. We sought to determine whether dopamine terminals innervate the subclasses of local circuit neurons that contain the calcium-binding protein parvalbumin (PV), namely the wide arbor and chandelier neurons that target pyramidal cell soma and axon initial segments respectively. Sections through area 9 of five monkeys were labeled with immunoperoxidase for tyrosine hydroxylase (TH), to identify dopamine terminals, and with immunogold-silver for PV. Electron microscopic examination of the middle cortical layers (IIIb-IV) revealed that TH-positive terminals were sometimes directly apposed to PV-labeled dendrites, and approximately one-third of these contacts exhibited morphological features that are typically associated with symmetric synapses. In contrast, TH-immunolabeled terminals in the superficial layers (I-IIIa) were less frequently apposed to PV-positive dendrites, and none of these contacts exhibited synapse-like morphology. These findings, in concert with previous studies of GABA- or calretinin-containing local circuit neurons, suggest that dopamine's modulatory action in the PFC involves selective effects on only certain interneuron populations, including those that mediate potent inhibitory actions on pyramidal cells.
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PMID:Dopamine innervation of a subclass of local circuit neurons in monkey prefrontal cortex: ultrastructural analysis of tyrosine hydroxylase and parvalbumin immunoreactive structures. 982 82


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