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)

Interactions between gamma-aminobutyric acid (GABA)- and catecholamine (CA)-containing cells in the rat retina was revealed by a double-labeling immunocytochemical technique using the antisera to GABA- and CA-synthesizing enzymes, such as tyrosine hydroxylase (TH) and phenylethanolamine-N-methyltransferase (PNMT). At the light microscopic level, GABA-, TH- and PMNT-immunoreactive (GABA-, TH- and PMNT-IR) amacrine cell bodies and their processes appeared in the inner nuclear layer and the inner plexiform layer, respectively. By electron microscopy observation, in the inner plexiform layer, GABA-, TH- or PMNT-IR amacrine cell processes were found making synaptic contacts with the axon terminals of immunonegative bipolar cells or with the processes of immunonegative amacrine cells. TH-IR amacrine cell processes formed synapse-like contacts with the GABA-IR amacrine cell perikarya and processes. In contrast, GABA-IR amacrine cell processes formed symmetric synaptic contacts onto the TH-IR as well as PNMT-IR amacrine cell processes. From these findings, it appears that the GABA- and CA-containing amacrine cells may interact with each other and play some important role in regulating the activities of bipolar cells and other unknown amacrine cells in the rat retina.
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PMID:Immunoelectron microscopic observation of cells in the rat retinal containing gamma-aminobutyric acid and catecholamine. 189 67

The presence of phosphate-activated glutaminase in monoaminergic neurons was shown in the rat brain by a double-staining method using a mouse monoclonal anti-glutaminase antibody combined with rabbit antisera against tyrosine hydroxylase, dopamine-beta-hydroxylase, phenylethanolamine-N-methyltransferase or serotonin. Glutaminase-like immunoreactivity was detected within perikarya of many monoaminergic neurons in the substantia nigra pars compacta, locus ceruleus, raphe nuclei, etc. Possible functional significance of glutaminase in monoamine neurons was discussed.
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PMID:Immunohistochemical demonstration of glutaminase in catecholaminergic and serotoninergic neurons of rat brain. 196 73

The localization of catecholamines (CA) in the brain of Apteronotus leptorhynchus was studied with immunohistochemical techniques using antibodies to the enzymes tyrosine hydroxylase (TH), dopamine B-hydroxylase (DBH), phenylethanolamine-N-methyltransferase (PNMT), and the neurotransmitter dopamine (DA). Telencephalic TH and DA immunoreactive (ir) neurons were located in the following structures: olfactory bulb, area ventralis telencephali partes ventralis, centralis, dorsalis, and intermediate. Diencephalic TH ir neurons were distributed in: nucleus preopticus periventricularis pars anterior, floor of preoptic recess, n. suprachiasmaticus, n. preopticus periventricularis pars posterior, n. anterior periventricularis, area ventralis lateralis, rostral region of posterior periventricular nucleus (paraventricular organ of other authors), periventricular nucleus of posterior tuberculum, n. recessus lateralis, n. tuberis lateralis pars anterior, and n. tuberis posterior. Although most diencephalic TH ir structures were also DAir, the posterior periventricular nucleus, n. recessus lateralis pars medialis, n. recessus posterioris, and ventral region of nucleus lateralis tuberis pars anterior showed differences in the distribution of TH and DA immunoreactivity. The rhombencephalic structures contained cell groups with different combinations of catecholamines as follows: TH and DBH ir neurons in the isthmic tegmentum (locus coeruleus); TH and DBH ir cells in the rostral medullary tegmentum ventral to VIIth nerve; TH and PNMT ir cells in the sensory nucleus of the vagus nerve; TH, DBH, and PNMT ir cells in the dorsal medullary tegmentum, TH and DBH ir cells in the dorsomedian postobecular region, ventral to the descending trigeminal tract and lateral to the central canal at medullospinal levels. This study shows that: (1) with few exceptions TH and DA ir coincides, (2) gymnotiforms possess similar DBH ir rhombencephalic groups, but additional telencephalic and rhombencephalic TH ir groups, and PNMT ir cells that were not reported previously in teleosts, and (3) the presence of CAergic fibers in the electrosensory system supports findings of their modulatory function in communication and aggression.
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PMID:Catecholaminergic systems in the brain of a gymnotiform teleost fish: an immunohistochemical study. 196 15

The catecholaminergic systems in the lizard Gekko gecko and the turtle Pseudemys scripta elegans have been studied with specific and sensitive antibodies against the neurotransmitters dopamine (DA) and noradrenaline (NA) and the biosynthetic enzymes tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine-N-methyltransferase. Our results demonstrate that: (1) the hypothalamic periventricular organ contains both DA and NA cerebrospinal fluid-contacting cells. These cells are immunonegative for TH and DBH which suggests that they accumulate rather than synthesize these amines; (2) at several places, particularly in the olfactory bulb, the hypothalamus, the nucleus of the solitary tract and the area postrema, cells are present that stain with TH-antibodies but not with any of the other antisera, suggesting that these neurons contain L-dihydroxyphenylalanine as their endproduct; (3) antibodies against TH demonstrate primarily DA fibres and varicosities, whereas the distribution of DBH-immunoreactive fibres generally corresponds to that shown by antibodies against NA. The present study underscores the importance of utilizing different approaches for a complete understanding of catecholaminergic systems.
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PMID:New insights into the reptilian catecholaminergic systems as revealed by antibodies against the neurotransmitters and their synthetic enzymes. 196 76

1. The mechanism of action of trimipramine, a clinically efficacious tricyclic antidepressant, is not well understood. In order to investigate whether it might affect the activities of different enzymes involved in biogenic amine metabolism we have undertaken a comparative study of it along with amitriptyline. 2. Neither trimipramine nor amitriptyline, at concentrations up to 1 mM, exhibited any significant effect on phenylalanine hydroxylase, tyrosine hydroxylase, L-aromatic amino acid decarboxylase, dopamine-beta-hydroxylase, phenylethanolamine-N-methyltransferase, catechol-O-methyltransferase, phenylsulfotransferase or tyrosine aminotransferase. 3. Monoamine oxidase, however, was inhibited by both drugs with the greatest effect being on MAO-B. The inhibition was reversible, non-competitive and relatively weak.
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PMID:Effect of trimipramine, an atypical tricyclic antidepressant, on the activities of various enzymes involved in the metabolism of biogenic amines. 197 1

Alpha 2-adrenergic binding sites in the medulla oblongata of tree shrews and rats were detected and quantified by in vitro-autoradiography with the alpha 2-antagonist 3H-rauwolscine (3H-RAUW). The autoradiographic pattern of the radioligand binding in the tree shrew medulla oblongata resembles that which has been described by others for the human myelencephalon. This pattern coincides well with the occurrence of catecholaminergic structures detected by immunocytochemistry with antibodies against phenylethanolamine-N-methyltransferase and tyrosine hydroxylase. In contrast to the rat, where only the nucleus tractus solitarii and the nucleus dorsalis nervi vagi were labeled, five discrete nuclei specifically bound 3H-RAUW in tree shrews. The highest number of binding sites was detected in the nucleus dorsalis nervi vagi (nX; Bmax: 333 fmoles/mg) and the nucleus tractus solitarii (NTS; 311 fmoles/mg), followed by the nucleus nervi hypoglossi (nXII; 297 fmoles/mg), the nucleus reticularis parvocellularis (FRS; 230 fmoles/mg), and the area of the catecholamine cell groups A1 and C1 (area C1; 202 fmoles/mg). Maximal binding in the two labeled nuclei of the rat was 158 fmoles/mg. The discrete nuclei of the two species also showed different affinities for 3H-RAUW with Kd ranging from 0.17 to 0.83 nM in tree shrews and 1.80 to 1.95 nM in rats. Competition experiments revealed that the radioligand bound specifically to alpha 2-binding sites. In the tree shrew, nX, nXII and the area C1, also have a relatively high affinity for the alpha 1-antagonist prazosin which is a quality of the adrenoceptor subtype alpha 2B. Furthermore, in the area C1, 3H-RAUW binding was inhibited by the dopamine antagonist haloperidol. There are thus species related as well as regional differences with respect to the number, the affinity, and the pharmacological properties of alpha 2-binding sites in the medulla oblongata. In tree shrews, alpha 2-adrenoceptors can be autoradiographically quantified in regions which are not labeled in the rat, although former data predicted the existence of such receptors, e.g., in the area of the adrenaline cell group C1.
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PMID:Alpha 2-adrenergic binding sites in the medulla oblongata of tree shrews demonstrated by in vitro autoradiography: species related differences in comparison to the rat. 197 22

The monoaminergic innervation of the amygdala of the squirrel monkey (Saimiri sciureus) was studied by using immunohistochemical methods with primary antisera raised against serotonin, and the catecholamine synthesizing enzymes tyrosine hydroxylase, dopamine-beta-hydroxylase and phenylethanolamine-N-methyltransferase. Serotonin was widely distributed within the amygdala including profuse terminal labeling in central, basolateral and cortical nuclear groups. The accessory basal and medial nuclei were the only two areas receiving relatively poor serotoninergic innervation. Tyrosine hydroxylase was more discretely distributed, with very dense to moderate terminal labeling in central, basal and lateral nuclei, but only scant labeling within accessory basal and corticomedial nuclei, except at the cortical transitional area where dense terminal labeling was noted. Dopamine-beta-hydroxylase immunoreactivity was moderate in central and corticomedial nuclei, but comparatively light in other nuclear groups. Phenylethanolamine-N-methyltransferase was only sparsely distributed in the amygdala. The findings of the present study reveal that the monoaminergic innervation of the primate amygdala is similar to that reported in rodents, although some conspicuous exceptions do exist. Whereas the noradrenergic and serotoninergic neuronal systems ramify profusely within the amygdala, the dopaminergic system appears to be more discretely and topographically organized.
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PMID:The monoaminergic innervation of the amygdala in the squirrel monkey: an immunohistochemical study. 197 1

An immunohistological analysis of the chromaffin cell system of the American eel revealed the presence of tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DBH) in all cells. However, phenylethanolamine-N-methyltransferase (PNMT) was seen only in a fraction of the chromaffin cells. This suggests the presence of both norepinephrine and epinephrine cells and the absence of specific dopamine cells. The chromaffin cells are most numerous in the anterior region of the posterior cardinal vein, where they occupy a subendothelial position. Their number decreases caudally, and a relatively small number are present in the larger veins of the opisthonephric kidney. No PNMT-positive cells were identified in this region, although a radioenzymatic assay had previously shown the presence of epinephrine. Methionine-enkephalin immunoreactivity seems to be restricted to the chromaffin cells. However, particularly large amounts of leucine immunoreactivity occur in the interrenal cells, with smaller quantities in the chromaffin cells. The chromaffin cells of the eel also contain morphine immunoreactivity.
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PMID:Catecholamines, opioid peptides, and true opiates in the chromaffin cells of the eel: immunohistochemical evidence. 198 Feb 50

Previous studies have focused on the role of the central nucleus of the amygdala (CeA) in cardiovascular and other amygdaloid functions. The combined retrograde tracing/immunohistochemical method was used to test for the presence of enkephalin, neurotensin, neuropeptide Y, and catecholamine neurons within the nucleus of the solitary tract that send efferents to the CeA. After injections of retrograde tracer into the CeA, retrogradely labeled neurons were observed within the caudal, medial nucleus of the solitary tract. Most CeA-projecting neurons were located ipsilaterally within the medial nucleus of the solitary tract at the level of the area postrema. Retrogradely labeled enkephalin- and neurotensin-immunoreactive neurons were found within the medial nucleus of the solitary tract at this level, while retrogradely labeled neuropeptide Y-immunoreactive neurons were found within the medial nucleus of the solitary tract rostral to the area postrema. About 60-74% of CeA-projecting cells were also immunoreactive for tyrosine hydroxylase. Approximately 9% of retrogradely neurons were phenylethanolamine-N-methyltransferase immunoreactive. The results provide evidence that within the nucleus of the solitary tract, peptidergic CeA-projecting neurons have a topographic distribution. In addition, noradrenergic neurons within the A2 group, rather than adrenergic neurons of the C2 group, provide the bulk of catecholaminergic input to the CeA from the nucleus of the solitary tract. Cell counts indicate that each of these peptides may be colocalized (to varying extents) within catecholamine-producing neurons. Also the catecholaminergic and enkephalinergic contribution to the ascending pathway from the nucleus of the solitary tract to the CeA distinguishes it neurochemically from the descending pathway. Thus, although there are afferent and efferent connections between the nucleus of the solitary tract and CeA, their peptidergic/neurotransmitter connections are not necessarily reciprocal. Input from nucleus of the solitary tract peptidergic and catecholaminergic neurons to the CeA may be important in the etiology of a number of pathophysiological conditions including hypertension, gastric ulcers, and schizophrenia.
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PMID:Organization of peptidergic and catecholaminergic efferents from the nucleus of the solitary tract to the rat amygdala. 198 Nov 74

I studied the neuropsychiatric disorders occurring after overdose with manganese (Mn), which have been shown to be neurologically similar to Parkinson's disease. MnCl2 doses of 10 mg Mn/kg, administered a total of 15 times, were injected intraperitoneally into rats. Then I determined the concentration of monoamines, their metabolites and the activity of catecholamine-related enzymes of the rat brain using high-performance liquid chromatography (HPLC). 1) In the Mn-loaded rats, the concentration of dopamine (DA) was significantly decreased in the nucleus caudatus-putamen (C/P)(p less than 0.05), the thalamus (p less than 0.05) and in the mesencephalon (ME) (p less than 0.001), while that of homovanillic acid decreased in the C/P (p less than 0.05). The concentration of norepinephrine (NE) was decreased in the hypothalamus (p less than 0.01) and that of 3-methoxy-4-hydroxyphenyl-glycol was decreased in the C/P (p less than 0.001) and in the thalamus (less than 0.05); however serotonin and 5-hydroxyindoleacetic acid concentrations showed no variation from those of the controls. 2) As for the enzymes of catecholamine biosynthesis, tyrosine hydroxylase (TyrOHase) activity was increased in the hypothalamus (p less than 0.05) and was reduced in the ME (p less than 0.01). Dopa decarboxylase activity showed no change. Dopamine-beta-hydroxylase (DBH) activity was reduced in the C/P and the thalamus (p less than 0.05 respectively). Phenylethanolamine-N-methyltransferase activity was detected in the hypothalamus, the ME, and at low levels in the thalamus (p less than 0.01). Among the enzymes of catecholamine metabolism, catechol-O-methyltransferase activity showed no variation, but monoamine oxidase (MAO) type-a and type-a + b activities were significantly increased in the cerebral cortex (p less than 0.01), and MAO type-a + b as significantly reduced in the C/P and the hypothalamus (p less than 0.01). The decrease on DA and NE contents found could be due to the reduction of such biosynthesizing enzymes as TyrOHase and DBH. Especially, the DA content was markedly decreased in the ME, found mostly in regions where DA neurons originate. Thus the variation of this region would be the first disorder. And it was interesting to note that MAO type-a + b was reduced by Mn administration.
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PMID:[Studies on monoamine metabolism in the rat brain with overdosage of manganese]. 240 98


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