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)

Clonal mouse neuroblastoma cells without tyrosine 3-monooxygenase [EC 1.14.16.2; tyrosine hydroxylase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating)] activity were fused with normal cells from embryonic mouse sympathetic ganglia. One of the 37 hybrid cell lines obtained possesses high tyrosine 3-monooxygenase activity and synthesizes dopamine. These cells also have excitable membranes and generate action potentials in response to electrical stimuli. Thus hybrid cells, generated by fusion of neuroblastoma cells with normal cells from the nervous system, can acquire neural properties not found with the parental neuroblastoma cells.
 ...
PMID:Neuronal properties of hybrid neuroblastoma X sympathetic ganglion cells. 0 45

Addition of dimethylsulfoxide at concentrations of 1% and 2% (vol/vol) to cells of mouse neuroblastoma clone NIE-115 in the confluent phase of growth resulted in the production of morphologically differentiated cultures with extensive process formation. Cell maintained in 2% dimethylsulfoxide remained in a stable nondividing condition for periods of up to 4 weeks. A high degree of electrical excitability was found in these cells, but there was no clear correlation of this property with the level of induction of either acetylcholinesterase (acetylcholine hydrolase; EC 3.1.1.7) or tyrosine hydroxylase [L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating); EC 1.14.16.2]. In addition, intracellular levels of cyclic 3':5'-AMP were not elevated in fully morphologically and electrically differentiated cells. While cell division was markedly inhibited by 2% or higher concentrations of dimethylsulfoxide, at 1% growth continued at a somewhat slowed rate and such cultures exhibited enhanced process formation and electrical activity for a relatively short period. High concentrations (3% or 4%) of dimethylsulfoxide totally suppressed process formation and did not result in increased excitability, but cells maintained high resting potentials. The results suggest that the development of the excitable membrane in neuroblastoma cells may be expressed independently of neurospecific enzyme induction, and does not require a sustained elevation of cyclic 3':5'-AMP levels.
 ...
PMID:Maturation of neuroblastoma cells in the presence of dimethylsulfoxide. 0 56

The tyrosine-3-monooxygenase activity [L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating); EC 1.14.16.2] of rat adrenal medulla is induced 20-24 hr after the injection of reserpine (16 mumol/kg intraperitoneally). This and other inducing stimuli increase the 3': 5'-cyclic AMP (cAMP) content in the medulla for longer than 60 min and activate the cAMP-dependent protein kinase (ATP: protein phosphotransferase; EC 2.7.1.37) for several hours. Corticotropin (ACTH), dopamine, and propranolol do not induce the monooxygenase, but elicit an increase in the cAMP content of the medulla which fails to activate protein kinase and lasts less than 1 hr. A high- and low-molecular-weight protein kinase are separated by gel filtration from the 20,000 X g pellet extract of adrenal medulla homogenate. The activity of the low-molecular-weight enzyme is expressed as its ability to phosphorylate histone. The protein kinase activity of the pellet is increased between 3 and 17 hr after reserpine injection. Our evidence indicates that this increase is due to a translocation from cytosol to subcellular structures of a kinase that utilizes lysine-rich histone as phosphate acceptor. The protein kinase activity that is extracted from a purified nuclear fraction prepared from the adrenal medulla of rats injected 7 hr previously with reserpine is greater than that extracted from medulla of saline-treated rats.
 ...
PMID:Activation and nuclear translocation of protein kinase during transsynaptic induction of tyrosine 3-monooxygenase. 0 93

The sixth lumbar (L-6) ganglion has been used to study the central regulation of peripheral sympathetic neuron development. During post-natal ontogeny, tyrosine hydroxylase [tyrosine 3-monooxygenase, L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] activity increased 60-fold, while total protein rose 10-fold in the ganglion. Transection of the spinal cord at the fifth thoracic (T-5) segment in neonatal rats prevented the normal developmental increase in tyrosine hydroxylase activity of the L-6 ganglion. However, spinal transection did not alter the ontogeny of tyrosine hydroxylase in the superior cervical ganglion, which derives its innervation from spinal segments rostral to the surgical lesion. Thus, spinal transection interfered with the maturation of sympathetic neurons distal to, but not proximal to, the lesion. The effect of transection on the L-6 ganglion persisted for at least one month, the longest time tested. Our observations suggest that trans-synaptic regulation of adrenergic maturation in the periphery is governed by suprasegmental mechanisms in the central nervous system.
 ...
PMID:Central regulation of sympathetic neuron development. 1 May 72

The synthesis of neurotransmitters in mammalian brain responds rapidly to changes in precursor availability. Serotonin synthesis depends largely on the brain concentrations of L-tryptophan, its precursor amino aicd. This relationship appears to be physiologic: when brain tryptophan levels vary because of insulin secretion or meal ingestion, corresponding alterations occur in the rate of serotonin formation. The ability of any food to modify brain tryptophan (and serotonin) depends on how its ingestion changes the serum concentration of not only tryptophan, but also several other large neutral amino acids that compete with tryptophan for uptake into the brain. Such precursor-induced changes in brain serotonin appear to be functionally important: animals having a reduced level of brain serotonin (caused by the chronic ingestion of a naturally tryptophan-poor diet, such as corn) demonstrate a heightened sensitivity to painful stimuli; this pain sensitivity can be acutely restored to normal values by a single injection of L-tryptophan, which rapidly elevates brain serotonin. The synthesis of catecholamines (e.g., dopamine, norepinephrine) in the brain also varies with the availability of the precursor amino acid L-tyrosine. Single injections of this amino acid increase brain tyrosine levels and accelerate brain catechol synthesis, while injections of a competing neutral amino acid (e.g., leucine, tryptophan) reduce brain tyrosine and its rate of conversion to dopa. The rate of catecholamine synthesis, however, appears to be influenced less by precursor levels than is serotonin formation: tyrosine hydroxylase, whcih catalyzes the rate-limiting step in catecholamine synthesis, responds strongly to end-product inhibition and to other controls that reflect variations in neuronal activity. The synthesis of acetylcholine in brain responds to substrate (choline) availability much like serotonin synthesis. Short-term alterations in brain choline levels are mirrored by similar changes in brain acetylcholine concentration. Variations in the daily dietary intake of choline also modify brain choline and acetylcholine. The relationship between choline availability and acetylchyoline synthesis has already foudn a cletween choline availability and acetylchyoline synthesis has already found a clinical application: choline has been used successfully in the treatment of tardive dyskinesia, a disorder of the central nervous system thought to reflect a deficiency in cholinergic transmission. These relationships between precursor availability from the periphery and brain neurotransmitter synthesis may ultimately provide the brain with information about peripheral metabolic state.
 ...
PMID:Effects on the diet on brain neurotransmitters. 1 61

Twenty-four hours after rats receive choline chloride (20 mmol/kg, by stomach tube) the activity of tyrosine hydroxylase [tyrosine 3-monooxygenase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] increases by 31% within adrenomedullary chromaffin cells. This treatment also causes major elevations in the levels of choline and acetylcholine within the adrenal gland; however, acetylcholine levels return to normal by 16 hr after the choline is given. The daily administration of 10 or 20 mmol/kg of choline for 4 days elevates adrenal tyrosine hydroxylase activity by 29% or 51%, respectively. Such increases in tyrosine hydroxylase activity are not observed in animals given ammonium chloride, another basic chloride-containing compound, by stomach tube or in animals treated with cycloheximide, an inhibitor of adrenal protein synthesis. They are also absent in denervated adrenals. These observations demonstrate that the increase in presynaptic acetylcholine levels produced by giving animals the neurotransmitter's precursor (choline) can be associated with parallel changes in the transmission of signals across cholinergic synapses, probably because more of the transmitter is released per nerve impulse.
 ...
PMID:Trans-synaptic induction of adrenomedullary tyrosine hydroxylase activity by choline: evidence that choline administration can increase cholinergic transmission. 1 50

Norepinephrine turnover rates and tyrosine hydroxylase activities were determined in the interscapular brown fat pad of the rat during cold acclimation, hyperthyroxinism, and after thyroidectomy. Rats were cold acclimated by placement in a cold room, one rat to a cage, for a period of 6 wk. Hyperthyroxinism was induced by daily subcutaneous injections of L-thyroxine (1 mg/kg) for 6 days. Norepinephrine turnover rate and enzyme activity were determined at the end of each experimental period and at 8 wk after thyroidectomy. The rate of norepinephrine turnover increased during cold acclimation and hyperthyroxinism and decreased after thyroidectomy. Cold acclimation resulted in a significant increase in tyrosine hydroxylase activity, whereas no significant effect on enzyme activity was observed in hyperthyroxinism or after thyroidectomy. None of the conditions produced a change compared to controls in the apparent Km of tyrosine hydroxylase for L-tyrosine. Cold acclimation resulted in a significant decrease in the apparent Km of tyrosine hydroxylase for pterin cofactor, whereas thyroxine treatment and thyroidectomy had no effect.
 ...
PMID:Thyroid cold acclimation influences on norepinephrine metabolism in brown fat. 1 13

The effect of synaptic stimulation on tyrosine hydroxylase [tyrosine 3-monooxygenase: L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] activity in the rat superior cervical ganglion was studied. The preganglionic cervical sympathetic trunk was stimulated unilaterally at 10 Hz for 30 min. Forty-eight hours later tyrosine hydroxylase activity was 33% higher on the stimulated than on the control side. The enzyme activity restimulated than on the control side. The enzyme activity remained elevated in the stimulated ganglia for 2 days. No change was observed in total ganglion protein. Comparable increases in tyrosine hydroxylase activity were observed in anesthetized and conscious animals.
 ...
PMID:Electrical stimulation of preganglionic nerve increases tyrosine hydroxylase activity in sympathetic ganglia. 1 42

The morphologic and biochemical development of the embryonic mouse superior cervical ganglion was characterized in vivo and in tissue culture. From 13 days of gestation, when the superior cervical ganglion was first visible, to birth at 19 days, tyrosine hydroxylase [tyrosine 3-monooxygenase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating); EC 1.14.16.2] activity increased 100-fold in vivo. Explants of ganglia from 14-day embryos exhibited abundant neurite outgrowth in basal medium without added nerve growth factor (NGF), and increases in tyrosine hydroxylase activity paralleled that observed in vivo. Ganglia from 14-day embryos elaborated neurites and exhibited 3-fold increases in enzyme activity in vitro in the presence of antiserum to NGF (anti-NGF) or NGF + anti-NGF. In direct contrast, ganglia from 18-day fetuses failed to grow without added NGF or in medium containing anti-NGF or NGF + anti-NGF: virtually no axon outgrowth occurred and tyrosine hydroxylase activity decreased by half. These observations suggest that developmental regulatory mechanisms change radically during embryologic and fetal life of mammalian superior cervical ganglion.
 ...
PMID:Embryologic development of a mouse sympathetic ganglion in vivo and in vitro. 2 Jun 28

The ontogenetic pattern of noradrenergic differentiation in rat embryonic autonomic neuroblasts was defined in vivo. Noradrenergic specialization was examined by documenting the immunohistochemical appearance of tyrosine hydroxylase [Tyr-OH; tyrosine 3-monooxygenase; L-tyrosine,-tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] and the development of histofluorescence due to catecholamine (CA). Tyr-OH and CA were undetectable in the dorsal neural crest or the ventrally migrating crest cells and first appeared at 12.5 days of gestation (36--37 somite stage) in sympathoblasts that had formed sympathetic ganglion primordia. Fluorescence intensity and the number of fluorescent cells increased progressively thereafter. In addition, Tyr-OH and CA transiently appeared in scattered presumptive neuroblasts in the gut. The enzyme and transmitter were first detectable at 11.5 days of gestation and thereafter decreased progressively so that, by 14.5 days, only rare cells were encountered. There was remarkable synchrony in the appearance and disappearance of Tyr-OH and CA. These observations suggest that a number of noradrenergic transmitter mechanisms develop simultaneously in the differentiating neuroblast. The relevance of these results to the elucidation of developmental regulatory mechanisms is discussed.
 ...
PMID:Ontogenetic appearance and disappearance of tyrosine hydroxylase and catecholamines in the rat embryo. 2 19


1 2 3 4 5 6 7 8 9 10 Next >>