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

The mature functional architecture of the primate prefrontal cortex arises during a protracted period of postnatal development. Although catecholaminergic afferents arrive in the primate cortex quite early during fetal development, several lines of evidence suggest that substantial changes in the dopaminergic innervation of prefrontal cortex may occur during postnatal development. In this study, we used immunocytochemical techniques and antibodies against tyrosine hydroxylase, the rate-limiting enzyme in catecholamine biosynthesis, to examine the precise time course from birth to adulthood of the maturational changes of tyrosine hydroxylase-labeled axons in prefrontal cortical areas 9 and 46 and primary motor cortex (area 4) of rhesus monkeys. In area 9, the densities of tyrosine hydroxylase-labeled axons and varicosities in the superficial and deep cortical layers remained relatively constant during postnatal development. In contrast, marked developmental changes in innervation density occurred in the middle cortical layers. For example, in deep layer III, the density of tyrosine hydroxylase-positive varicosities was relatively low and uniform in animals under 1 month of age but then increased by a factor of three in animals 2-3 months of age. The density of labeled varicosities continued to increase, reaching a peak (sixfold greater than in the youngest animals) in animals 2-3 years of age before declining to stable adult levels. Similar laminar-specific patterns of change also occurred in areas 46 and 4, although regional differences were present in the magnitude and precise time course of these developmental changes. These findings demonstrate that the innervation of monkey frontal cortex by tyrosine hydroxylase-immunoreactive axons undergoes a protracted, laminar-specific pattern of change during postnatal development that continues through adolescence and into early adulthood. These developmental refinements may interact with other modifications of cortical circuitry that underlie the functional maturation of these regions.
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PMID:Postnatal maturation of the dopaminergic innervation of monkey prefrontal and motor cortices: a tyrosine hydroxylase immunohistochemical analysis. 756 Feb 93

We report our findings in the guinea pig involving dopamine in postsynaptic regulation of the activity of glutamatergic inner hair cells (IHCs) and in protection of primary auditory neurons during transient ischemia. Seven days after intracochlear perfusion of 6-hydroxydopamine, no immunoreactivity to tyrosine hydroxylase (TH) was demonstrable within the organ of Corti. TH and aromatic amino acid decarboxylase were immunolocalized at an ultrastructural level within lateral olivocochlear varicosities synapsing with radial auditory dendrites postsynaptic to the IHCs. The D2 agonist piribedil induced a dose-dependent decrease in the amplitude of the compound action potential of the auditory nerve. Piribedil also prevented appearance of ischemia-induced swelling of the radial dendrites.
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PMID:Synaptic connections and putative functions of the dopaminergic innervation of the guinea pig cochlea. 757 83

Parasympathetic preganglionic neurons in the superior salivatory nucleus (SSNNs) projecting to the pterygopalatine ganglion were labeled by retrograde transport of cholera toxin B subunit (CTB) in the rat. Morphological interactions between SSNNs and afferent fibers immunoreactive (IR) for neuropeptide and amine were examined with light and electron microscopes by double-immunostaining techniques. SSNNs were found in the ipsilateral ventrolateral part of the rostral medulla oblongata. Around SSNNs, substance P-, enkephalin-, neuropeptide Y-and somatostatin-IR nerve fibers were very rich and tyrosine hydroxylase (TH)-, serotonin (5-HT)-, vasoactive intestinal polypeptide- and calcitonin gene-related peptide (CGRP)-IR axons showed moderate density. Thyrotropin-releasing hormone-containing axons were scarce in this region. The electron microscopic examinations revealed that CTB-IR structures directly received synaptic input from axon varicosities IR for TH, 5-HT and all neuropeptides except for CGRP. These findings suggest that catecholamine, 5-HT and the neuropeptides directly influence the activity of SSNNs and are concerned with the autonomic regulation of nasal and palatal mucosa, lacrimal glands and cerebral blood vessels of the rat.
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PMID:Synaptic contact of neuropeptide-and amine-containing axons on parasympathetic preganglionic neurons in the superior salivatory nucleus of the rat. 758 52

Magnocellular perikarya within the retrochiasmatic division of the supraoptic nucleus of bovine and porcine hypothalami were immunoreactive (ir) with antiserum against tyrosine hydroxylase (TH), but not dopamine-beta-hydroxylase (DBH). Few cells in this region were also immunoreactive for vasopressin (VP) or oxytocin (OT). In contrast, the main division of the supraoptic nucleus contained numerous perikarya immunoreactive for VP and OT, but not TH nor DBH. Both the retrochiasmatic and principal divisions of the supraoptic nuclei contained TH- and DBH-ir fibers and varicosities. This region in bovine and porcine hypothalami corresponds to the ventral A15 catecholaminergic (dopamine-producing) cell group.
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PMID:Catecholaminergic region A15 in the bovine and porcine hypothalamus. 762 Sep 7

Parvalbumin (PV) is a calcium-binding protein localized to selected neurons in the nervous system, including the retina. This investigation evaluated the distribution of PV immunoreactivity in the rabbit retina using immunohistochemistry with a monoclonal antibody directed to carp PV. In the inner nuclear layer (INL), PV immunoreactivity was present in horizontal and amacrine cells. In the ganglion cell layer, PV immunostaining was confined to somata that are likely to be both displaced amacrine cells and ganglion cells. PV-immunoreactive (IR) amacrine cells were positioned in the proximal INL adjacent to the inner plexiform layer (IPL). These cells usually gave rise to a single primary process, which arborized into two distinct bands in the IPL. In sublamina a, the processes were thin and had large, irregular endings. In sublamina b, multiple processes branched from the primary process and were characterized by varicosities and spines. PV-IR amacrine cell bodies measured from 8 to 10 microns in diameter. Their density was highest in the visual streak and lowest in the periphery of the superior retina. The average number of PV-IR amacrine cells was 464,045 cells per retina (N = 3), and the average regularity index of the PV-IR cell mosaic was 3.23. PV-IR amacrine cells were further characterized by double-label immunofluorescence experiments using antibodies to PV and tyrosine hydroxylase (TH). Varicose TH-IR processes were in close apposition to many PV-IR amacrine cells and often formed "ring structures" around them. Together, these morphological, quantitative, and histochemical observations indicate that PV immunoreactivity in the INL is localized predominantly to AII amacrine cells, and therefore it is a valuable marker for the identification of this cell type.
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PMID:AII amacrine cell population in the rabbit retina: identification by parvalbumin immunoreactivity. 762 7

A recently developed technique of immunoautoradiography on nitrocellulose transfers of serial frozen sections was used to determine tryptophan hydroxylase concentration in selected areas of the adult rat brain following neonatal 6-hydroxydopamine destruction of nigrostriatal dopamine neurons. Particular attention was paid to the neostriatum, known to be serotonin-hyperinnervated under these conditions, and to the nucleus raphe dorsalis, containing the cell bodies of origin for these nerve terminals. The hippocampus was also investigated as a territory of structurally intact serotonin innervation arising primarily from the nucleus raphe medianus. Tryptophan hydroxylase protein was measured at successive transverse levels across the entire caudorostral extent of all these regions. Similar measurements of tyrosine hydroxylase protein across the substantia nigra and the neostriatum verified the disappearance of the nigrostriatal dopamine neurons. The average tryptophan hydroxylase tissue concentration in the dorsal third of the serotonin-hyperinnervated neostriatum was up by 36% above control, i.e. significantly less than the number of its serotonin axon terminals or varicosities. This was therefore indicative of a lowering of the tryptophan hydroxylase protein content per serotonin ending. Interestingly, a tight correlation between the respective level-by-level concentrations of tryptophan hydroxylase and tyrosine hydroxylase protein in the control neostriatum allowed the prediction the tryptophan hydroxylase concentration after dopamine denervation with a serotonin hyperinnervation. Tryptophan hydroxylase concentration was also significantly reduced in both the nucleus raphe dorsalis and nucleus raphe medianus, notably at those raphe dorsalis levels known to give rise to the serotonin hyperinnervation of neostriatum. It is hypothesized that the lower steady-state level of tryptophan hydroxylase inside the terminals and cell bodies of hyperinnervating serotonin neurons was the result of a feedback inhibition of the synthesis of the enzyme by its end-product, presumably because of the increased amount of serotonin in these terminals.
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PMID:Changes in steady-state levels of tryptophan hydroxylase protein in adult rat brain after neonatal 6-hydroxydopamine lesion. 767 79

The colocalization of immunoreactivities to substance P and calcitonin gene-related peptide (CGRP) in nervous structures and their correlation with other peptidergic structures were studied in the stellate ganglion of the guinea pig by the application of double-labelling immunofluorescence. Three types of fibre were distinguished. (1) Substance P+/CGRP+ fibres, which sometimes displayed additional immunoreactivity for enkephalin, constituted a small fibre population of sensory origin, as deduced from retrograde labelling of substance P+/CGRP+ dorsal root ganglion cells. (2) Substance P+/CGRP- fibres were more frequent; some formed baskets around non-catecholaminergic perikarya that were immunoreactive to vasoactive intestinal polypeptide (VIP). (3) CGRP+/substance P- fibres were most frequent and were mainly distributed among tyrosine hydroxylase (TH)-immunoreactive cell bodies. The peptide content of fibre populations (2) and (3) did not correspond to that of sensory ganglion cells retrogradely labelled by tracer injection into the stellate ganglion. Therefore, these fibres are thought to arise from retrogradely labelled preganglionic sympathetic neurons of the spinal cord, in which transmitter levels may have been too low for immunohistochemical detection of substance P or CGRP. CGRP-immunoreactivity but no substance P-immunolabelling was observed in VIP-immunoreactive postganglionic neurons. Such cell bodies were TH-negative and were spared by substance P-immunolabelled fibre baskets. Retrograde tracing with Fast Blue indicated that the sweat glands in the glabrous skin of the forepaw were the targets of these neurons. The streptavidin-biotin-peroxidase method at the electron-microscope level demonstrated that immunoreactivity to substance P and CGRP was present in dense-cored vesicles of 50-130 nm diameter in varicosities of non-myelinated nerve fibres in the stellate ganglion. No statistically significant difference in size was observed between vesicles immunolabelled for substance P and CGRP. Immunoreactive varicosities formed axodendritic and axosomatic synaptic contacts, and unspecialized appositions to non-reactive neuronal dendrites, somata, and axon terminals. Many varicosities were partly exposed to the interstitial space. The findings provide evidence for different pathways utilizing substance P and/or CGRP in the guinea-pig stellate ganglion.
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PMID:Immunohistochemical evidence for different pathways immunoreactive to substance P and calcitonin gene-related peptide (CGRP) in the guinea-pig stellate ganglion. 768 30

The neuropeptide- and catecholamine-synthesizing enzyme content and ultrastructure of the peri-ureteric ganglia of guinea-pigs were investigated. Small numbers of neuronal perikarya were present at frequent intervals forming ganglia close to, and along the entire length of, the ureter. Each of these ganglia was surrounded by a connective tissue capsule, and was located in the peri-ureteric connective tissues. Within each ganglion were typical nerve terminals and varicosities containing small, clear synaptic vesicles or synaptic vesicles with an electron-dense core, or a mixture of the two. In the ganglia, immunoreactivity to tyrosine hydroxylase, dopamine beta hydroxylase, neuropeptide tyrosine, or vasoactive intestinal peptide was present in neuronal perikarya; immunoreactivity to substance P or leucine enkephalin was present in nerve terminals and varicosities. Electron-microscopic immunogold studies indicated that there was no coexistence of substance P and enkephalin in the nerve terminals, unlike related ganglia in the pelvis of guinea-pigs.
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PMID:An immunohistochemical and electron microscopic study of the peri-ureteric ganglia of the guinea-pig. 769 80

Tuberoinfundibular dopaminergic (TIDA) neurons, which represent the final common pathway in the inhibitory neuronal control of prolactin (PRL) secretion, are regulated by synaptic input from various transmitter systems. Because adrenergic receptors at hypothalamic sites were implicated in the central regulation of lactotrophs, we hypothesized that a synaptic communication might exist between adrenergic pathways ascending from the brain stem and the TIDA system. Polyclonal antisera directed towards phenylethanolamine N-methyltransferase (PNMT) and tyrosine hydroxylase (TH), biosynthetic enzymes of catecholamines, were used for the simultaneous immunocytochemical detection of adrenergic fibers and TIDA neurons, respectively, in Vibratome sections of the rat hypothalamus. By the light microscopic evaluation of double-immunostained sections, PNMT-immunoreactive (IR) axon varicosities were localized in juxtaposition to TH-IR cell bodies and dendrites in the arcuate nucleus (AN) which contains perikarya and dendrites of TIDA neurons. The ultrastructural analysis of contacts provided firm evidence for the occurrence of synaptic interactions between the adrenergic and TIDA neuronal systems. These morphological findings show that adrenergic neurons are involved in the afferent regulation of the TIDA system and indicate a putative pathway of central adrenergic effects upon PRL secretion.
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PMID:Adrenergic innervation of dopamine neurons in the hypothalamic arcuate nucleus of the rat. 771 98

Secretoneurin is a novel 33-amino-acid neuropeptide produced by endoproteolytic processing from secretogranin II, which is a member of the chromogranin/secretogranin family. In this immunocytochemical study, we compared the distribution pattern of secretoneurin immunoreactivity with that of tyrosine hydroxylase, calbindin, substance P, and Leu-enkephalin in adjacent sections of rat forebrain. Secretoneurin appeared mainly in varicosities and fibers. Only a few cell bodies were stained. In the nucleus accumbens, a partial overlap of secretoneurin-immunoreactive patches with enkephalin-immunopositive areas was found. Secretoneurin displayed low to moderate levels of immunoreaction in calbindin-rich as well as in calbindin-immunonegative areas of the caudate-putamen. In the globus pallidus, entopeduncular nucleus, and substantia nigra, secretoneurin immunoreactivity was oriented ventromedially preferentially in woolly fibers. The dense immunostaining in the medial nucleus accumbens was directly continuous with dense secretoneurin immunoreactivity in the bed nucleus of the stria terminalis. Two strongly secretoneurin-immunopositive bands, one in the sublenticular portion and a smaller one along the posterior limb of the anterior commissure, interconnected the highly secretoneurin-immunopositive centromedial amygdala with the bed nucleus of the stria terminalis. Thus, the distribution pattern of secretoneurin immunoreactivity provides a marker of the extended amygdala that forms a continuum between the centromedial amygdala and the bed nucleus of the stria terminalis.
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PMID:Evidence for a high density of secretoneurin-like immunoreactivity in the extended amygdala of the rat. 774 36


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