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)

The concentrations of norepinephrine, dopamine-beta-hydroxylase, dopamine, tyrosine hydroxylase, phenylethanolamine-N-methyltransferase, serotonin, tryptophan hydroxylase, histamine, glutamic acid decarboxylase, and choline acetyltransferase were determined in selected hypothalamic nuclei and in the median eminence after deafferentation of the medial basal hypothalamus. Norepinephrine and dopamine-beta-hydroxylase fell markedly while dopamine and tyrosine hydroxylase did not. Serotonin also decreased in all regions studied; histamine decreased in none. Choline acetyltransferase, phenylethanolamine-N-methyltransferase, and glutamic acid decarboxylase declined in some areas, but not in others.
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PMID:Effect of surgical isolation of the hypothalamus on its neurotransmitter content. 1 Oct 35

Group-housed male C57BR/cdJ mice (victims) were exposed to attack for 10 min daily for up to 14 days by male Swiss-Webster mice, made aggressive by prolonged isolation. Their adrenal glands were analyzed for tyrosine hydroxylase (TH) and phenylethanolamine-N-methyltransferase (PNMT) activities and for norepinephrine (NE) and epinephrine (EPI) concentrations. TH was increased to 41 per cent above control after two exposures and remained elevated through 14 exposures to attack. PNMT was increased to 29 per cent above control after 2 days and increased further to 50 per cent above control after 14 days of attack. Both NE and EPI increased to 88 per cent and 51 per cent above control, respectively, after 7 days. In victim mice recuperating after 1 week of daily stress, EPI levels and PNMT activities were back to normal after 4 days whereas NE levels and TH activities returned to normal only after 1 week. Phenobarbital (40 mg/kg, i.m.) was effective in preventing the biochemical changes when given 2 h prior to each daily attack but was ineffective when given immediately after each daily stress.
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PMID:Alterations of mouse adrenal medullary catecholamines and enzymes in response to attack: effect of pre- and post-treatment with phenobarbital. 1 47

The rat olfactory bulb was studied at the light and electron microscopic level with the indirect immunofluorescence technique and the unlabelled antibody enzyme method (PAP-technique), respectively. Antibodies to all 4 enzymes in the catecholamine synthesis were used. In the principal bulb the first two enzymes, tyrosine hydroxylase (TH) and DOPA decarboxylase (DDC), but not dopamine-beta-hydroxylase (DBH), were present in a proportion of periglomerular cell bodies and dendrites indicating that these neurons synthesize dopamine (DA). This amine may therefore be released as a transmitter substance at some of the intraglomerular dendrodendritic synapses which periglomerular cells form with the mitral cells. There is evidence to suggest that some periglomerular cells use GABA as their transmitter. Thus, a morphologically and physiologically homogenous population of neurons can be subdivided on the basis of transmitter histochemical criteria. There was an impression of more DDC-positive than TH-positive fibers in the glomeruli. Such presumably DDC-positive, but TH-negative processes may represent 5-hydroxytryptamine (5-HT) nerve terminals. DBH-positive fibers were seen in the granular, external plexiform, and very rarely, in the glomerular layers, probably representing noradrenaline (NA) nerve terminals ascending from the lower brain stem. Weakly fluorescent DDC-positive fibers may represent nerve terminals of ascending 5-HT neurons. No phenylethanolamine-N-methyltransferase (PNMT)-positive neurons were observed.
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PMID:Transmitter histochemistry of the rat olfactory bulb. I. Immunohistochemical localization of monoamine synthesizing enzymes. Support for intrabulbar, periglomerular dopamine neurons. 1 85

The catecholamine-forming and metabolizing enzyme tyrosine hydroxylase, dopa decarboxylase, dopamine-beta-hydroxylase, phenylethanolamine N-methyltransferase, and catecholamine-O-methyltransferase, as well as the endogenous inhibitor of dopamine-beta-hydroxylase were compared in the brains of schizophrenics and controls. While there were no statistically significant differences in the enzyme or inhibitor activity between groups, tbre was a decided trend toward a decreased enzyme activity in the brains of the schizophrenics. From another set of control brains it was found that changes in human enzyme activity following death are variable and may be dependent on how the brains were handled. Thus, it is unclear whether the apparent differences between schizophrenics and controls were present when they were alive or occurred after death.
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PMID:Difficulties in comparing catecholamine-related enzymes from the brains of schizophrenics and controls. 2 53

By repeated inbreeding, 2 strains of spontaneously hypertensive and normotensive rats have been simultaneously selected. The activities of tyrosine hydroxylase and phenylethanolamine-N-methyltransferase were determined in various central catecholaminergic nuclei (C1, C2, A6 and A9) and in two peripheral tissues (adrenal glands and superior cervical ganglion). These assays were performed on rats belonging to the normotensive or the hypertensive strain at 3 ages which characterize the development of hypertension (5, 9 and 21 weeks). Except for a decrease in the C1 region of 9-week-old rats, no significant change in tyrosine hydroxylase activity occurred in central or peripheral structures of the spontaneously hypertensive rats when compared to the normotensive rats. In contrast, the activity of the phenylethanolamine-N-methyltransferase (PNMT), was increased in the C2 adrenergic group of the medulla oblongata in young spontaneously hypertensive rats: +43% (P less than 0.001) at 5 weeks of age and +32% (P less than 0.001) in 9-week-old rats. However, there was no significant difference between the 21-week-old rats. No modification of the PNMT activity was found in the C1 adrenergic group of the medulla oblongata. PNMT activity was increased significantly in the adrenal glands of 5-week-old hypertensive rats (+22%, P less than 0.001). By 9 weeks, the difference in PNMT activity in the adrenals was no longer significant. Thus, in young rats of the hypertensive strain, there was an increase in the capacity to synthetize adrenaline in the C2 area of the medulla oblongata and in the adrenal glands. While the enzymatic change present in the adrenals seems to be specific to this new strain of hypertensive rats, the elevation of PNMT activity in a specific region of the medulla oblongata (C2 group) is a characteristic common to at least two independently derived strains of genetically hypertensive rats.
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PMID:Early increase in phenylethanolamine-N-methyltransferase activity in a new strain of spontaneously hypertensive rats. 3 64

1. Sinoaortic deafferentation in the rat leads to increased blood pressure and heart rate. 2. Early increases in tyrosine hydroxylase activity both in brain stem and hypothalamus suggest that increased noradrenaline synthesis may contribute to the development of neurogenic hypertension. 3. After 4 weeks, phenylethanolamine-N-methyltransferase activity was reduced in the hypothalamus. 4. Noradrenaline- and adrenaline, but not dopamine-containing neurones may participate in regulation of sympathetic efferent activity.
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PMID:Effect of baroreceptor deafferentation on central catecholamines in the rat. 4 31

Dihydralazine treatment which lowered blood pressure in young rats from the Lyon Hypertensive Strain (LHS), did not change phenylethanolamine-N-methyltransferase (PNMT) activity, but decreased tyrosine hydroxylase and dopamine-beta-hydroxylase activities in the C2 medullary region. These data suggest that the increase in PNMT activity, previously described for this strain, is not a consequence of the developing hypertension and that hypotensive treatment could inactivate some catecholaminergic neurons of the medulla oblongata.
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PMID:Dihydralazine and catecholamine-synthesizing enzymes in spontaneous hypertension. 49 52

Daily treatment of neonatal rats with 1-triiodothyronine for 30 days increased locomotor activity as well as the synthesis and presumably, release of brain norepinephrine, dopamine and 5-hydroxytryptamine. Whereas administration of lithium carbonate (60 mg/kg) to normal rats for 10 days, beginning from the 20th day of age, produced no significant effect, this antimanic drug significantly decreased the observed increase in spontaneous locomotor activity in l-triiodothyronine-treated rats. Lithium treatment in normal rats increased the activity of striatal tyrosine hydroxylase, but produced no significant effect on the endogenous levels of norepinephrine and dopamine in several discrete brain regions examined. Lithium, enhanced deamination of catecholamines as evidenced by increased level of 3,4-dihydroxyphenylacetic acid and monoamine oxidase activity in normal rats. The activity of catechol o-methyltransferase was decreased to 82 and 59% in midbrain and crebral cortex of normal rats, respectively. Furthermore, chronic treatment with lithium increased endogenous levels of tryptophan, tryptophan hydroxylase, 5-hydroxytryptamine and its metabolite, 5-hydroxyindoleacetic acid, in normal animals. In contrast to the effects seen in normal rats, admininstration of lithium in l-triiodothyronine-treated animals significantly decreased tyrosine hydroxylase as well as dopamine and its metabolite, 3,4-dihydroxyphenylacetic acid, suggesting that this antimanic drug reduced the synthesis and turnover of dopamine. However, the steady-state levels of norepinephrine were raised in hypothalamus, pons-medulla, midbrain and striatum of lithium-treated hyperthyroid rats. As seen in normal animals, lithium in l-triidothyronine-treated rats increased trytophan, tryptophan hydroxylase and 5-hydroxytryptamine levels, but decreased the concentration of 5-hydroxyindoleacetic acid. The results show that the suppressed behavioral activity seen in lithium-treated hyperthyroid rats may be associated with decreased synthesis of norepinephrine and dopamine in the brain. Finally, the effects exerted by lithium on the brain catecholamine metabolizing system of young hyperthyroid rats were not similar to those seen in normal rats of the corresponding age group.
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PMID:Lithium: modification of behavioral activity and brain biogenic amines in developing hyperthyroid rats. 85 Jan 49

We previously showed that long-term hypoxia increases the dopamine content in rat laryngeal nerve paraganglia. In the present study paraganglia of rats exposed to hypoxia (10 +/- 0.5% O2) for 14 days were examined immunohistochemically to detect changes in the expression of neuropeptides and catecholamine-synthesizing enzymes. Hypoxia induced an intense cellular substance P (SP)-like immunoreactivity (LI) in some paraganglia and an increase in the number of stromal nerve fibers showing SP-LI in others. The patterns of tyrosine hydroxylase-, dopamine-beta-hydroxylase-, phenylethanolamine-N-methyltransferase-, vasoactive intestinal polypeptide-, neuropeptide-Y and calcitonin gene-related peptide-LI were not changed in response to hypoxia. The results show that hypoxia induces changes in the pattern of SP immunoreactivity in laryngeal nerve paraganglia and may indicate that SP plays a role in the regulation of catecholamine metabolism in this tissue.
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PMID:Long-term hypoxia induces changes in the substance P immunoreactivity pattern in laryngeal nerve paraganglia. 127 34

The rat recurrent and superior laryngeal nerves with adjacent connective tissue were examined by immunohistochemical techniques for localization of the catecholamine-synthesizing enzymes tyrosine hydroxylase, dopamine-beta-hydroxylase and phenylethanolamine-N-methyltransferase. Most of the cells in the paraganglia of the recurrent and superior laryngeal nerves showed an intense tyrosine hydroxylase-like immunoreactivity. A few paraganglionic cells exhibited dopamine-beta-hydroxylase-like immunoreactivity while none of the cells displayed phenylethanolamine-N-methyltransferase-like immunoreactivity. Some of the ganglionic cells in the recurrent and superior laryngeal nerves showed dopamine-beta-hydroxylase-like immunoreactivity whilst these cells never showed tyrosine hydroxylase- or phenylethanolamine-N-methyltransferase-like immunoreactivity. The arterioles were supplied with plexuses of nerve fibres showing tyrosine hydroxylase- and dopamine-beta-hydroxylase-like immunoreactivity. The results indicate that dopamine is the major catecholamine located in the laryngeal nerve paraganglia and show that ganglionic cells in the recurrent and superior laryngeal nerves show immunolabelling for one of the enzymes in the catecholamine synthetic pathway, dopamine-beta-hydroxylase.
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PMID:Expression of catecholamine-synthesizing enzymes in paraganglionic and ganglionic cells in the laryngeal nerves of the rat. 134 29


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