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)

Catecholaminergic fibers in the suprachiasmatic nucleus of adult rats were investigated by use of light- and electron-microscopic immunocytochemistry. The suprachiasmatic nucleus receives a modest density of tyrosine hydroxylase-containing axons, homogeneously distributed in the nucleus and forming varicosities throughout its entire rostro-caudal extension. Immunolabeling with antibodies against dopamine showed that this catecholamine input comprises a dopaminergic component. Many tyrosine hydroxylase-positive cells were localized at the immediate periphery of the suprachiasmatic nucleus. With electron-microscopic examination, dendrites of these neurons were found within the limits of the nucleus as well as at a border zone between the suprachiasmatic nucleus proper and the optic tract where they received unlabeled synapses, providing a morphological support for a possible role of dopaminergic neurons in the integration and/or transfer of light-related signals. More than 91% of catecholaminergic axonal varicosities were found to establish morphologically defined synapses with dendrites. To investigate whether these synapses might be shared with neurons of one or both of the two main peptidergic populations of the nucleus, namely vasoactive intestinal peptide- and vasopressin-containing neurons, we carried out double-labelling experiments combining immunoperoxidase and immunogold-silver labeling. Results showed only a few cases of direct association of the catecholaminergic terminals with these peptidergic categories. In both types of dually stained sections, catecholaminergic synapses were preferentially made with unlabeled dendrites. The homogeneous distribution of tyrosine hydroxylase-immunoreactive fibers in the suprachiasmatic nucleus could therefore reflect a lack of significant catecholaminergic innervation of both vasoactive intestinal peptide- and vasopressin-synthesizing neurons.
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PMID:Catecholaminergic innervation of the suprachiasmatic nucleus in the adult rat: ultrastructural relationships with neurons containing vasoactive intestinal peptide or vasopressin. 775 Jan 39

We have used double-label immunohistochemistry to examine the presence and pattern of colocalization of vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), tyrosine hydroxylase (TH) and protein gene product (PGP) in nerve fibers supplying the human ureterovesical junction (UVJ). Several populations of nerve fibers within the UVJ region were identified according to their expression of potential transmitter substances. Presumptive noradrenergic axons containing TH- and NPY-like immunoreactivity (LIR) and non-noradrenergic fibers containing VIP- and NPY-LIR accounted for most of the total (PGP-LIR) innervation and supplied all regions of the UVJ. The distal ureter, Waldeyer's sheath and the trigone were supplied by predominantly noradrenergic TH/NPY-LIR nerve fibers, whereas the majority of fibers supplying the detrusor muscle were non-noradrenergic VIP/NPY-LIR axons. The similarity in innervation of Waldeyer's sheath, ureter and trigone is consistent with the notion that these structures are all derived from a common mesodermal origin. Regional differences in innervation were also noted within the musculature of the distal ureter: TH/NPY-LIR fibers were localized to the outer part of the ureter, while VIP/NPY-LIR fibers supplied the inner part. This finding suggests that the different layers of the ureter may be independently controlled by different populations of nerves. The findings of this study support the view that noradrenergic nerves are important in maintaining the tone of the UVJ, but indicate that other neurotransmitters or neuromodulators may also be involved in the control of this region.
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PMID:Regional differences in the innervation of the human ureterovesical junction by tyrosine hydroxylase-, vasoactive intestinal peptide- and neuropeptide Y-like immunoreactive nerves. 777 42

Colocalization of vasoactive intestinal peptide, neuropeptide Y, calcitonin gene-related peptide, substance P, and tyrosine hydroxylase, respectively, with NADPH-diaphorase staining in rat adrenal gland was investigated using the double labelling technique. All vasoactive intestinal peptide- and some neuropeptide Y-immunoreactive intrinsic neuronal cell bodies seen in the gland were double stained with NADPH-diaphorase. Double labelling also occurred in some nerve fibres immunoreactive to vasoactive intestinal peptide and neuropeptide Y in the medulla and cortex. No colocalization of calcitonin gene-related peptide, substance P or tyrosine hydroxylase immunoreactivity with NADPH-diaphorase staining was observed. However, nerve fibres with varicosities immunoreactive for all the neuropeptides examined were closely associated with some of the NADPH-diaphorase-stained neuronal cell bodies. Thus, in rat adrenal gland, nitric oxide is synthesized in all ganglion cells containing vasoactive intestinal peptide and in some containing neuropeptide Y, but not in those containing calcitonin gene-related peptide, substance P or tyrosine hydroxylase.
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PMID:Colocalization of neuropeptides and NADPH-diaphorase in the intra-adrenal neuronal cell bodies and fibres of the rat. 778 Oct 27

The goal of the present study was to identify cytochemical markers characteristic of muscle afferents in hatchling chicks. To this end, we stained neurons in the trigeminal mesencephalic nucleus with a variety of markers that label subsets of neurons in avian dorsal root ganglia. We found that trigeminal mesencephalic neurons are surprisingly heterogeneous in their cytochemical make-up, expressing, to varying degrees, substance P, cholecystokinin, carbonic anhydrase, calbindin D-28k, parvalbumin, and S-100 beta. Calbindin D28k and S-100 beta appeared to be expressed equally in medial and lateral divisions of the trigeminal mesencephalic nucleus. In contrast, substance P- and cholecystokinin-immunoreactive neurons were more abundant in the medial division, whereas carbonic anhydrase activity and parvalbumin immunoreactivity were stronger in the lateral division. We were unable to detect met-enkephalin, neuropeptide Y, calcitonin gene-related peptide, vasoactive intestinal peptide, somatostatin, gamma-aminobutyric acid, or tyrosine hydroxylase in the trigeminal mesencephalic nucleus. Moreover, these neurons did not appear to bind the lectin Dolichos biflorus agglutinin. The heterogeneity of expression of markers among trigeminal mesencephalic nucleus neurons, especially between neurons in the medial and lateral divisions, suggests that these neurons are functionally diverse.
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PMID:Cytochemical characteristics of neurons in the trigeminal mesencephalic nucleus of hatchling chicks. 788 44

The nodose ganglion contains placode-derived visceral sensory neurons of the vagus nerve. Previous study showed that axotomy-induced deafferentation reduced the number of tyrosine hydroxylase-immunoreactive and increased the number of vasoactive intestinal peptide-immunoreactive neurons in the ganglion. The present study was conducted to determine whether the changes in neuropeptide/neurotransmitter enzyme content are associated with changes in the expression of tyrosine hydroxylase and vasoactive intestinal peptide messenger RNAs in the nodose ganglion. We used in situ hybridization histochemistry with 35S-labeled oligonucleotide probes for tyrosine hydroxylase and vasoactive intestinal peptide precursor messenger RNAs. Peripheral axotomy of visceral afferent inputs reduced tyrosine hydroxylase messenger RNA and increased vasoactive intestinal peptide messenger RNA expression in neurons of the nodose ganglion of the rat. The number of tyrosine hydroxylase messenger RNA-containing neurons was significantly reduced at three, seven and 14 days after axotomy-induced deafferentation compared with intact and sham-operated controls. Labeling density of tyrosine hydroxylase messenger RNA-containing neurons was significantly reduced at three and seven days. Conversely, the number of vasoactive intestinal peptide messenger RNA-containing neurons increased significantly at three, seven and 14 days, while the labeling density of vasoactive intestinal peptide messenger RNA-containing neurons also increased at one, three, seven and 14 days. The results of the present study indicate that the axotomy-induced down-regulation of tyrosine hydroxylase and up-regulation of vasoactive intestinal peptide in the neurons of the nodose ganglion are associated with changes in their messenger RNAs in response to axotomy-induced deafferentation.
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PMID:Plasticity of tyrosine hydroxylase and vasoactive intestinal peptide messenger RNAs in visceral afferent neurons of the nodose ganglion upon axotomy-induced deafferentation. 789 70

Using an in vitro incubation system, the role of the cyclic AMP-dependent protein kinase A (PKA) pathway in the regulation of the in situ activity of tyrosine hydroxylase (TH) was studied in the hypothalamuses of young and aged ovariectomized rats. Hypothalamic tissue was incubated for 60 min in medium containing 3-hydroxybenzylhydrazine dihydrochloride, a dihydroxyphenylalanine (DOPA) decarboxylase inhibitor, and various agents that modify the activity of the PKA pathway. At the end of the incubation, the tissue was homogenized and analyzed for DOPA and TH mass. The in situ molar activity of TH was expressed as the moles of DOPA accumulating in the tissue per mole of TH per hour. Forskolin, an activator of adenylyl cyclase and the cyclic AMP agonist, (Sp)-cyclic adenosine 3',5'-monophosphothioate, significantly (P < .01) increased the in situ molar activity of TH in the hypothalamic dopaminergic (DAergic) neurons of both young and aged rats. Theophylline, a phosphodiesterase inhibitor, did not affect the TH molar activity in the hypothalamuses of aged animals but did significantly (P < .001) increase its activity in those of young rats. When vasoactive intestinal peptide was evaluated, the TH molar activity was significantly (P < .005) increased in the hypothalamuses of young rats but not in those of aged rats. It was suggested that the deficiency of DA secretion by hypothalamic DAergic neurons of aged rats may be the result of insufficient activation of PKA caused by failure of transduction of an extracellular signal to activate adenylyl cyclase and produce cyclic AMP.
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PMID:Localization of a defect in hypothalamic dopaminergic neurons of the aged brain that results in impaired PKA-dependent activation of tyrosine hydroxylase. 790 91

Retrograde transport studies using Fast Blue dye demonstrated that the ductus deferens, seminal vesicle, prostate and rectum, but not the urinary bladder of the male guinea pig are at least in part innervated by the anterior major pelvic ganglion. In the ductus deferens, seminal vesicle and prostate innervation is derived from ipsilateral and contralateral ganglia. In addition to retrograde studies, dye-filled neurons were analysed immunohistochemically for neuronal markers and associations with specifically identified neuronal projections. Neurons of the ganglion projecting to the ductus deferens either contained tyrosine hydroxylase alone, tyrosine hydroxylase and neuropeptide Y, neuropeptide Y alone, neuropeptide Y and vasoactive intestinal peptide, or vasoactive intestinal peptide alone. These neurons were associated with three classes of neuronal projections, substance P-, leucine-enkephalin-, and methionine-enkephalin-immunoreactive. Neurons projecting to the seminal vesicles were similar to the neurons supplying the ductus deferens, except none of the seminal vesicle-specific neurons exhibited vasoactive intestinal peptide immunoreactivity. Neurons supplying the prostate were immunoreactive for either tyrosine hydroxylase or neuropeptide Y; these neurons were infrequently associated with the three classes of varicose neuronal projections. Neurons projecting to the rectum contained neuropeptide Y and were only associated with methionine-enkephalin immunoreactive neuronal projections in one animal.
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PMID:Chemical coding of neurons projecting to pelvic viscera in the male guinea pig: a study by retrograde transport and immunohistochemistry. 791 61

Neural regulation of islets of Langerhans mediates responses to stress and food ingestion. Transplantation of isolated islets offers hope to patients with insulin dependent diabetes mellitus but denervation of isolated islets may affect the capacity for appropriate metabolic control. Previous examination of the endocrine response to stress in islet autografted dogs revealed differences consistent with loss of neural regulation. Therefore, in the present study, islets grafted in rats were examined for extent and nature of reinnervation. Islets isolated from syngeneic donors were grafted under the kidney capsule of Wistar-Furth rats (n = 7) after 3 wk of streptozotocin induced diabetes. After 4 mo, graft-bearing kidneys were recovered and processed for double immunofluorescence. Antibodies were directed against (a) neuron associated proteins: synapsin (SYN) and L1; (b) neurotransmitters; tyrosine hydroxylase (TH), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and calcitonin gene-related peptide (CGRP); and (c) islet hormones: insulin and somatostatin. SYN and L1 immunoreactivities in nerve fibres suggested reinnervation of the grafted islets although fibres were not associated with structures within the transplanted islets as in intact islets. CGRP immunoreactivity was observed in fibres and in a subpopulation of cells within intact islets but only in cells of the grafted islets. VIP, TH, and NPY immunoreactivities were found in nerve fibres of intact islets but only VIP was observed in fibres of grafted islets suggesting an absence of sympathetic reinnervation. In conclusion, transplanted islets of Langerhans become reinnervated but with a distribution and complement of neurotransmitters distinct from intact islets.
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PMID:Reinnervation of isolated islets of Langerhans transplanted beneath the kidney capsule in the rat. 791 58

The innervation and vasomotor responses to several vasoactive agents of guinea pig epicardial coronary veins were investigated by means of immunohistochemical, histochemical, ultrastructural and in vitro pharmacological techniques. The use of an antiserum to the general neuronal marker protein gene product 9.5 revealed that coronary veins are supplied by a network of fine varicose nerve fibres in the adventitia. The majority of the nerve fibres possessed neuropeptide Y (NPY) and tyrosine hydroxylase immunoreactivity. Only a few nerve fibres displayed substance P, neuropeptide K (NK) and calcitonin gene-related peptide (CGRP) immunoreactivity. In double stained preparations substance P immunoreactivity was co-localized with NK and CGRP in the same nerve fibres. Nerve fibres containing vasoactive intestinal peptide (VIP) immunoreactivity or acetylcholinesterase activity were not detected. Endothelin immunoreactivity was also found in the vein endothelial cells. Ultrastructural studies revealed the presence of axon varicosities at the adventitial-medial border. In vitro pharmacological studies showed that endothelin-1 and -2 elicited a significant contractile response of epicardial vein segments. Noradrenaline, NPY, serotonin and uridine 5'-triphosphate induced only a relatively weak contractile response in the vein segments. Although vasodilatory responses were difficult to examine in these preparations, it was found that substance P, CGRP and VIP elicited a relaxation of the vein segments. These results indicate that guinea pig epicardial coronary veins are innervated by several nerve populations, however, the control of vasomotor tone of coronary veins appears to be predominantly regulated by 'non-neuronal' vasoactive agents such as endothelin and 5-HT.
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PMID:The innervation of guinea pig epicardial coronary veins: immunohistochemistry, ultrastructure and vasomotility. 791 47

The distribution of catecholamines in the small and large intestine of flying foxes (Pteropus spp.) was investigated using glyoxylic-acid-induced fluorescence and immunohistochemical staining of tyrosine hydroxylase and dopamine-beta-hydroxylase. Dense networks of varicose axons stained by each of these methods supplied blood vessels, the mucosa and both submucous and myenteric ganglia, but were scarce in the circular and longitudinal muscle. The majority (> 90%) of submucous neuronal perikarya contained both enzymes and most of these also exhibited catecholamine fluorescence. Somata of similar staining characteristics were less common in the myenteric plexus, where single cells were found in only the minority of ganglia. All of the stained submucosal somata and mucosal axons contained vasoactive intestinal peptide, whereas catecholamine-containing axons that supplied the ganglia, external muscle and blood vessels did not. It is concluded that (1) there is dense catecholamine innervation of most tissues in the flying-fox intestine, similar to many other mammals, (2) mucosal axons originate from enteric catecholamine neurons, not found in other mammals, and (3) axons supplying the blood vessels and enteric ganglia are probably of sympathetic origin and can be distinguished from the intrinsic catecholamine-containing axons by their lack of vasoactive intestinal peptide. The roles and interactions of these two types of catecholamine innervation in the control of secretion and motility remain to be identified.
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PMID:Catecholamine innervation of the intestine of flying foxes (Pteropus spp.): a substantial supply from enteric neurons. 791 56


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