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)

Tyrosine hydroxylase is synthesized de novo in rat superior cervical ganglia in organ culture. The differential rate of synthesis is not increased significantly by the addition of nerve growth factor to the culture. Prior administration of nerve growth factor in vivo, however, leads to an augmented synthesis of tyrosine hydroxylase in ganglia subsequently cultured in vitro. The differential rate of tyrosine hydroxylase synthesis was increased by a factor of between 3 and 4. Increases in the differential rate of synthesis were detected within 6 h; the rate reached a maximum 24 to 36 h after a single injection of nerve growth factor. Administration of actinomycin D or of nerve growth factor antibody in vivo prevented the nerve growth factor-induced increase in the differential rate of tyrosine hydroxylase synthesis in vitro. However, the increase in the synthetic rate of tyrosine hydroxylase was not prevented by the addition of actinomycin D to the culture.
 ...
PMID:Selective de novo synthesis of tyrosine hydroxylase in organ cultures of rat superior cervical ganglia after in vivo administration of nerve growth factor. 1 75

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 superior cervical ganglion (SCG) in the neonatal mouse and rat has been employed as a model system to study the regulation of ontogeny of presynaptic cholinergic nerves and postsynaptic adrenergic neurons. During postnatal development presynaptic choline acetyltransferase (ChAc) activity increases 30- to 40-fold, whereas postsynaptic tyrosine hydroxylase (T-OH) activity rises 6- to 8-fold. Transection of the presynaptic cholinergic nerves innervating the SCG prevents the normal development of T-OH activity and the normal accumulation of T-OH enzyme molecules in each postsynaptic neuron. The trans-synaptic regulation of T-OH development is apparently mediated by acetylcholine and postsynaptic depolarization, since pharmacologic ganglionic blockade also prevents normal maturation. Ganglion decentralization also prevents the normal maturation of adrenergic nerve terminals, and the development of end-organ innervation by SCG. Consequently, trans-synaptic factors regulate the ontogeny of adrenergic terminals as well as perikarya. Moreover, normal efferent as well as afferent connections are apparently required for sympathetic development, since removal of salivary glands and orbital contents, target organs of the SCG, in neonates also prevents T-OH development in the ganglia. The postsynaptic neuron contributes to the development of presynaptic cholinergic fibers in SCG. Selective destruction of adrenergic neurons in neonatal mice with either 6-hydroxydopamine or antiserum to nerve growth factor prevents the normal maturation of ChAc activity in presynaptic terminals of SCG. Thus, presynaptic and postsynaptic cells appear to exert reciprocal regulatory influences during ontogeny.
 ...
PMID:Regulation of the growth and development of sympathetic neurons in vivo. 2 85

We have established a clonal cell line, PC-G2, from an experimentally induced rat pheochromocytoma. Administration of nerve growth factor to PC-G2 causes a 4- to 8-fold induction in the specific activity of tyrosine hydroxylase [tyrosine 3-monooxygenase; L-tyrosine,tetrahydropteridine:oxygen oxidoreductase(3-hydroxylating); EC 1.14.16.2]. The response is elicited in a dose-dependent fashion, at concentrations above 0.1 microgram/ml. Antiserum to nerve growth factor inhibited the induction of tyrosine hydroxylase. Dexamethasone enhances the nerve growth factor-mediated elevation of tyrosine hydroxylase. After 3--4 days of exposure to nerve growth factor the maximal induction of tyrosine hydroxylase is seen, although a significant increase can be observed after 24 hr. In contrast to the PC-12 cell line (derived from the same tumor), in which neurite outgrowth occurs in response to nerve growth factor, there is no morphological change or alteration in growth rate of PC-G2 cells after exposure to nerve growth factor.
 ...
PMID:Nerve growth factor-mediated induction of tyrosine hydroxylase in a clonal pheochromocytoma cell line. 3 87

Exposure of rat sympathetic ganglia to 3 microgram/ml of 2.5 S nerve growth factor (NGF) resulted in a 100% increase in tyrosine hydroxylase activity within 48 h. Pulselabeling of proteins with [3H]leucine, followed by immunoprecipitation with antibodies to tyrosine hydorxylase and isolation of the precipitated enzyme by gel electrophoresis, demonstrated that the increase in tyrosine hydroxylase activity was due to enhanced de novo synthesis. The incorporation of [3H]leucine into tyrosine hydroxylase was increased by 150% compared to a 17% increase in total protein synthesis, which was not statistically significant. The fact that the half-life of pulse-labeled tyrosine hydroxylase was the same for NGF-treated and control organ cultures of superior cervical ganglia excludes the possibility that enhanced tyrosine hydroxylase labeling by NGF is due to decreased degradation. We conclude that, without modulatory factors which play a role in vivo, NGF can enhance the synthesis of tyrosine hydroxylase in sympathetic ganglia in vitro, provided organ culture conditions which permit optimal survival of adrenergic neurons are selected.
 ...
PMID:Nerve growth factor-mediated induction of tyrosine hydroxylase in rat superior cervical ganglia in vitro. 3 Jul 72

The chronic administration of high doses of guanethidine to rats produces complete destruction of the peripheral sympathetic nervous system. In a study of the effect of guanethidine-induced sympathectomy on the development of hypertension is spontaneous hypertensive rats (SHR, Okomoto strain), only a partial sympathectomy could be produced as assessed by biochemical parameters (tyrosine hydroxylase activity in ganglia and tissue norepinephrine concentrations) and by evaluation of response to stimulation of vasomotor outflow in pithed rat preparations. Other strains of rats (Sprague-Dawley, American Wistar, Kyoto Wistar) were uniformly sensitive to guanethidine sympathectomy. The resistance to guanethidine was not due to a lower accumulation of guanethidine in the neurons of SHR. Addition to the guanethidine treatment of low doses of antibody to nerve growth factor (NGF), which itself produced only a modest sympathectomy, resulted in an almost complete sympathectomy. SHR did not become hypertensive when sympathectomized by combined guanethidine-anti NGF. These results show that the sympathetic neurons of SHR differ from those of other strains with respect to sensitivity to guanethidine cytotoxicity and suggest the possibility of a role for NGF in that altered responsiveness.
 ...
PMID:Unique resistance to guanethidine-induced chemical sympathectomy of spontaneously hypertensive rats: a resistance overcome by treatment with antibody to nerve growth factor. 3 37

Previous studies have shown that nerve growth factor (NGF) produces a selective induction of tyrosine hydroxylase (TH) in peripheral adrenergic neurons and that NGF is transported retrogradely with a high selectivity from the adrenergic nerve terminals to the perikaryon. In order to investigate the biological importance of retrograde NGF transport, the following experiments have been performed; (a) effect of NGF on TH activity in superior cervical ganglia (SCG) after unilateral injection into the anterior eye chamber and the submaxillary gland; and (b) effect of systemic injection of NGF on TH activity in SCG after blockage of retrograde axonal transport by axotomy. After unilateral injection of NGF into the anterior eye chamber and submaxillary gland of both 8-10-day-old rats and adult mice, the increase in TH activity in the SCG was considerably larger on the injected than on the non-injected side although the adrenergic neurons supplying the two organs do not account for more than 25% of the total number of adrenergic neurons in the SCG. A direct diffusion mechanism could be excluded by the fact that unilateral local injection of [125 I] produced no significant side difference in the accumulation of radioactivity in the SCG 2 after injection whereas after 14 h there was a several-fold difference between the injected and non-injected side. Moreover, the nodose ganglia which are located very close to the SCG exhibited no statistically significant difference in the accumulation of radioactivity at any time. Forty-eight hours after subcutaneous injections of 10 mg/kg of NGF the increase in TH activity of the SCG amounted to 154% on the intact side and to 92% on the axotomized side. However, these experiments do not permit decisions about the extent the axotomy, as such, impaired the response to NGF. It is concluded that the biological effect of NGF results to a considerable extent, from the moiety which reaches the cell body by retrograde transport from the nerve terminals.
 ...
PMID:Biological importance of retrograde axonal transport of nerve growth factor in adrenergic neurons. 4 56

An injection of nerve growth factor (NGF) into one eye of neonatal rats results in an increase in the tyrosine hydroxylase activity of the ipsilateral superior cervical ganglion. This effect was seen maximally after the intraocular injection of a depot preparation of NGF linked to cellulose. The sympathetic neurones that innervate the eye can be identified by autoradiography after the retrograde axonal transport of either NGF or tetanus toxin labelled with [125I]iodine. It was only those cells having their terminals in the vicinity of the depot preparation. This demonstrates that NGF transported from the periphery to the cell bodies is effectively retained within the transporting cell and is not released to act on extracellular receptors within the ganglion. It is suggested that this specificity of action for NGF reaching the ganglion in this fashion is important during normal development in determining the survival of adrenergic neurones.
 ...
PMID:The effect of the retrograde axonal transport of nerve growth factor on the morphology of adrenergic neurones. 7 Feb 61

An experimental autoimmune model of nerve growth factor (NGF) deprivation has been used to assess the role of NGF in the development of various cell types in the nervous system. Adult rats immunized with 2.5S mouse NGF in complete Freund's adjuvant produced antibodies that crossreacted with their own NGF and that were transferred in utero to the fetus and in milk to the neonate. Cross-fostering experiments were carried out to separate the effects of exposure to anti-NGF in utero from those due to exposure through the milk. Anti-NGF transferred in utero and in milk resulted in the destruction of peripheral sympathetic neurons assessed by morphological methods (light microscopy) and biochemical methods (tyrosine hydroxylase activity, choline acetyltransferase activity, and protein content). No effects were observed on the adrenal medulla. Offspring of NGF-immunized females exposed to anti-NGF in utero had a decreased protein content in the dorsal root ganglia and were unable to transport (125)I-labeled NGF injected in the forepaw to the dorsal root ganglia. These results suggest that a subpopulation of sensory neurons is dependent on NGF for survival during some period of fetal development. This model offers the potential for determining the degree and time of dependence of various cell types on NGF.
 ...
PMID:Experimental autoimmune model of nerve growth factor deprivation: effects on developing peripheral sympathetic and sensory neurons. 9 24

Concomitant daily treatment of newborn rats for a 2-week to 1-month period with 10 mug/g of body weight of nerve growth factor and 100 mug/g of body weight of 6-hydroxydopamine produces in the cell bodies of adrenergic neurons the characteristic effects of the growth factor but in the nerve terminals the characteristic effects of 6-hydroxydopamine. The dual opposite effects result in a striking volume increase of sympathetic ganglia which far exceeds that produced by nerve growth factor alone. The selective induction of tyrosine hydroxylase [L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] in these chemically axotomized adrenergic neurons is even more pronounced than that produced by nerve growth factor alone in intact neurons.
 ...
PMID:Nerve growth factor induces volume increase and enhances tyrosine hydroxylase synthesis in chemically axotomized sympathetic ganglia of newborn rats. 23 59


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