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PubMed2006

ppGalNAc-T13: a new molecular marker of bone marrow involvement in neuroblastoma.

BACKGROUND: To identify new molecular markers of bone marrow dissemination in human neuroblastoma (NB), we studied the transcriptome profiles of malignant neuroblasts established from the human MYCN-amplified IGR-N-91 model. METHODS: This experimental model includes human neuroblastoma cells derived from a subcutaneous stage 4 disease, myocardium (Myoc) and bone marrow (BM) metastatic cells. RESULTS: Gene expression profiles obtained with Agilent oligo microarrays revealed a set of 107 differentially expressed genes in the metastatic neuroblasts. This set included up-regulated genes involved in chemoresistance, cell motility, neuronal structure/signaling, and the recently characterized GALNT13 gene encoding a glycosyltransferase that initiates mucin-type O-glycosylation. Because the glycosylation process is involved in the progression of primary tumor to metastatic disease, we investigated whether the most strongly up-regulated gene, GALNT13, might be a marker of bone marrow involvement in stage 4 NB patients. Importantly, in the BM of healthy adults no GALNT13 transcript was detected with analysis by quantitative (n = 3) and nested reverse transcription-PCR (n = 4) assays. In contrast, GALNT13 transcripts were detected in 23/23 cytologically involved BM samples obtained at diagnosis of stage 4 NB patients and in 5/27 cytologically noninvolved BM samples obtained from patients with stage 1-4 and 4S and treated stage 4 NB. The quantitative measurements of tyrosine hydroxylase (TH), ganglioside D2 synthase, dopa decarboxylase, and GALNT13 transcript values were compared in the same NB patients, and the results showed that GALNT13 expression was most highly correlated to poor clinical outcome at diagnosis. CONCLUSION: We propose ppGalNAc-T13 as a new informative marker for the molecular diagnosis of BM involvement and the follow-up of minimal residual disease in NB patients.

Adolescent↗
PubMed2000

Beta-cell activity and destruction in type 1 diabetes.

Type 1 diabetes is the result of a chronic inflammatory process that causes elimination of insulin-producing beta-cells, resulting in insulin deficiency and hyperglycemia. The destruction is thought to be mediated by an autoimmune process involving cytotoxic T cells recognizing beta-cell autoantigens in the context of MHC class I-peptide complexes. Autoantibodies against insulin, glutamic acid decarboxylase (GAD) and and ICA 512 protein tyrosine phosphatase are frequently found. At the clinical onset of diabetes, some beta-cells remain and after initiation of insulin treatment, most patients enter a period of remission, a phenomenon that may reflect diminished autoimmune activity in the islets. There is evidence to suggest that a further loss of beta-cells can be curtailed, and that patients, who maintain endogenous insulin production, have better glycemic control and less risk of complications. This is the basis for our current research. We are characterizing the remission phenomenon in epidemiological studies in order to identify determinants of beta-cell survival. In randomized, prospective multicenter trials, we are evaluating the benefit of beta-cell secretory rest for rescue of insulin production in patients at onset of clinical disease. In experimental studies, we are investigating expression and regulation of the key molecules of an autoimmune process in the islets. Further, selective beta-cell damage is induced in rat islets and measures to enhance beta-cell resistance and repair are being examined. We have recently identified a remarkable, beta-cell protective effect of K(ATP)-channel opening.

Animals↗
PubMed2002

The molecular mechanisms for the antitumorigenic effect of curcumin.

Curcumin, an active yellow pigment of turmeric and curry, possesses anti-inflammatory, antioxidative and anticarcinogenic properties. Analysis of its structure revealed the presence of beta-diketone moiety and phenolic hydroxy groups that were believed to contribute to antioxidation. And vanillin, ferulic acid and a dimer of curcumin were identified as the curcumin-derived radical reaction products. In addition to antioxidation, curcumin could also induce apoptosis by targeting mitochondria, affecting p53-related signaling and blocking NF-kappaB activation. To further dissect its anticarcinogenic mechanisms, a number of curcumin targets were identified. These included the aryl hydrocarbon receptor, cytochrome P450, glutathione S-transferase, serine/threonine kinases, transcription factors, cyclooxygenase, ornithine decarboxylase, nitric oxide synthase, matrix metalloproteinases and tyrosine kinases. This review will summarize our current knowledge on how these important proteins are affected by curcumin, and hopefully, may provide a whole picture illustrating how the chemopreventive and antitumorigenic effect of curcumin is achieved.

Animals↗
PubMed1986

Characterization of human neuroblastoma cell lines established before and after therapy.

Six new cell lines have been established from human neuroblastomas. Cell line SMS-KAN, from primary tumor before therapy, and line SMS-KANR, from bone marrow after chemotherapy and radiotherapy, were established from the same patient. Cell lines SMS-KCN (from primary tumor before any therapy) and SMS-KCNR (from bone marrow after chemotherapy) were established from another patient. Two other lines (SMS-MSN and SMS-SAN) were established from different patients before any therapy was given. Cell lines established from recurrent disease after chemotherapy (SMS-KANR and SMS-KCNR) had significantly shorter doubling times and increased plating efficiencies compared to those of cell lines derived from the same patient before chemotherapy (SMS-KAN and SMS-KCN). All cell lines contained tyrosine hydroxylase, aromatic L-amino acid decarboxylase, and dopamine-beta-hydroxylase. Measurable amounts of choline acetyltransferase were also detected in SMS-KAN and SMS-KANR. Karyotype analysis showed all cell lines except SMS-MSN to be pseudodiploid with modal numbers of 46 and deletions of the short arm of chromosome 1; SMS-MSN had a modal number of 57-58 chromosomes. All cell lines had double-minute chromosomes, except SMS-KANR, which had abnormally banding regions. These new cell lines provide in vitro models of neuroblastoma suitable for the study of differences in neuroblastoma cell populations before chemotherapy as compared to the cell populations that proliferate after therapy.

Catecholamines↗
PubMed1986

Hypothalamic catecholamine metabolism in diabetic rats: the effect of insulin deficiency and meal ingestion.

The effect of moderate insulin deficiency of 2 weeks in duration on hypothalamic catecholamine metabolism in food-deprived and meal-fed rats was evaluated. Hypothalamic tyrosine content in food-deprived (from 0700 to 1600 h), diabetic rats was normal. Also normal were the rates of 3,4-dihydroxyphenylalanine accumulation following aromatic amino acid decarboxylase inhibition, norepinephrine and 3,4-dihydroxyphenylethylamine (dopamine) clearance after tyrosine hydroxylase inhibition, and intraneuronal amine accumulation following monoamine oxidase inhibition. Differences in hypothalamic amine metabolism were apparent, however, when diabetic and normal rats were fed 2-g meals. The 3-methoxy-4-hydroxyphenylethyleneglycol sulfate accumulation rate was depressed in diabetic rats by the carbohydrate meal but was stimulated by the tyrosine-supplemented protein meal. In contrast, the tyrosine-supplemented diet had no effect on 3,4-dihydroxyphenylacetic acid accumulation in diabetic animals, whereas the production rate in normal rats was increased. We conclude that normal responses occurring in hypothalamic catecholamine metabolism after the consumption of a meal are modified by the presence of diabetes.

Animals↗
PubMed1979

Dissociation between the presynaptic dopamine-sensitive adenylate cyclase and [3H]spiperone binding sites in rat substantia nigra.

[3H]Spiperone binding sites and the dopamine-sensitive adenylate cyclase were measured in rat substantia nigra (s. nigra) 7 or 14 days after various lesions. Hemisections, which resulted in a 66% decline in tyrosine hydroxylase and cyclic nucleotide phosphodiesterase and a 73% decrease in glutamate decarboxylase, led to a 50% decrease in [3H]spiperone binding and to the almost complete disappearance of the dopamine-sensitive adenylate cyclase from the s. nigra on the lesioned side. 6-Hydroxydopamine injection into the s. nigra, which depleted tyrosine hydroxylase activity within the s. nigra by 85%, while leaving phosphodiesterase unaffected, resulted in a 40% decrease in [3H]spiperone binding but no change in the dopamine-sensitive adenylate cyclase. Intrastriatal injections of kainic acid did not alter tyrosine hydroxylase activity in the s. nigra, but decreased both glutamate decarboxylase (54%) and phosphodiesterase (68%); [3H]spiperone binding was unaffected by this lesion while the dopamine-sensitive adenylate cyclase was greatly reduced (50-75%). These results suggest that within the s. nigra the dopamine receptor binding sites as defined using [3H]spiperone are located on dopamine neurones while the dopamine-sensitive adenylate cyclase is located presynaptically on striatonigral nerve terminals.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed2006

Dopaminergic development of prenatal ventral mesencephalon and striatum in organotypic co-cultures.

Using organotypic co-cultures of rat embryonic day 14 (E14) ventral mesencephalon (VM) and E21 striatum, we have described the developmental changes in (i) dopamine (DA) neurochemistry; (ii) numbers of DA neurons; and (iii) protein expression of tyrosine hydroxylase (TH), DA transporter (DAT), and glutamic acid decarboxylase (GAD 65/67), over 17 days in vitro (DIV). Co-cultures demonstrated changes in DA development similar to those observed in vivo. The numbers of VM DA neurons remained relatively constant, while levels of VM DA progressively increased through 10 DIV. After 3 DIV, the levels of striatal DA increased substantially, through 10 DIV. Tissue levels of DA metabolites homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) reflected changes in tissue DA concentrations, indicating that release and metabolism of DA are similar to these characteristics observed in vivo. Western blot analysis of TH protein expression revealed large increases in VM TH after only 3 DIV, followed by a decline in levels through 17 DIV; levels of striatal TH, in contrast, increased through this period. Additionally, DAT and GAD 65/67 expression increased, in both the VM and striatum, over 17 DIV. By 17 DIV, many measures of DA function had decreased from those assessed at 10 DIV, thus providing an approximate limit to the effective duration of use of this co-culture model. Our results provide a much-needed description of the neurochemical changes that occur during the maturation of VM and striatum in organotypic co-cultures. Additionally, these results provide a foundation for future studies to assess toxic challenges of the developing nigrostriatal DA system, in vitro.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2003

Distribution of gamma-aminobutyric acid receptors in cultured adrenergic and noradrenergic bovine chromaffin cells.

Fluorescence imaging techniques for recording cytosolic [Ca(2+)](i) from single chromaffin cells were used to characterize and discriminate between cell subpopulations containing gamma-aminobutyric acid (GABA)(A) and GABA(B) receptor subtypes. By combining this methodology with the immunoidentification of individual chromaffin cells using specific antibodies against tyrosine hydroxylase (TH), phenyl-etanolamine-N-methyl transferase (PNMT), and glutamic acid decarboxylase (GAD) linked to different fluorescent probes, we have been able to ascribe single-cell calcium responses to identified adrenergic and noradrenergic chromaffin cells. GAD enzyme is present in 30% of the chromaffin cell population, located primarily in adrenergic cells; 86% of GAD(+) cells were also PNMT(+). GAD expression was not correlated with the presence of GABA receptors. GABA-responsive cells were found with equal frequency in the GAD(+) and GAD(-) groups. However, the expression of GABA receptors was correlated with the adrenergic phenotype. [Ca(2+)](i) responses to GABA were found more frequently in adrenergic than in noradrenergic cells. GABA(A) receptors are more evenly distributed; about 90% of GABA-responsive cells have them. GABA(B) receptors have a more restricted distribution (present in 45% of responding cells). The coexpression of both GABA(A) and GABA(B) subtypes is the rule; only a minor subpopulation (about 12%) displays exclusively GABA(B) receptors. GABA receptor subtypes are distributed in a similar way when chromaffin cells are separated according to GAD(+)/GAD(-) or PNMT(+)/PNMT(-) classifications, with only minor differences. These data indicate that the intrinsic GABAergic system in the adrenal medulla is not designed as a paracrine model in which a group of cells specializes in transmitter synthesis and a different group serves as a specific target.

Animals↗
PubMed1975

Reversible changes in the accumulation and activities of tyrosine hydroxylase and dopamine-beta-hydroxylase in neurons of nucleus locus coeruleus during the retrograde reaction.

To examine the biochemical events associated with the retrograde reaction in central noradrenergic neurons, changes in the activities of several enzymes subserving the metabolism of catecholamines, including tyrosine hydroxylase (TH),dopamine-beta-hydroxylase (DBH), DOPA decarboxylase (DDC), and monoamine oxidase (MAO), were measured in the nucleus locus coeruleus of rat brain following transection of the ascending axons from neurons in this nucleus by electrolytic lesions of the posterolateral hypothalamus. Such lesions produced a triphasic response in the activities of TH and DBH consisting of: (a) an increase to approximately 150 percent of control during the first 48 h followed by (b) a reduction reaching 60 percent of control by day 14, and (c) a full recovery of activity by day 21-28. In contrast, the activities of DDC and MAO, enzymes non-specific for catecholamine neurons, were unchanged. Immunochemical titration with specific antibodies to TH and DBH demonstrated that the fall in enzyme activity was entirely attributable to reduced accumulation of specific enzyme protein and not inhibition of pre-existing enzyme molecules. There was no reduction in the number of neurons in the nucleus locus coeruleus as a consequence of the lesion. We conclude that a reduction in the accumulation of specific enzymes subserving transmitter biosynthesis characterizes a reversible retrograde reaction of central noradrenergic neurons. The coincidence of the time course of reduced enzyme accumulation with regenerative sprouting from damaged noradrenergic axons and also the absence of classical signs of chromatolysis in locus coeruleus neurons following comparable lesions suggest that, first, during the retrograde reaction there may be a reordering of priorities governing accumulation of specific proteins favoring accumulation of those required for reconstitution of cellular processes by sprouting at the expense of proteins utilized in the synthesis of neurotransmitters, and second, some intrinsic neurons of the CNS may undergo reversible biochemical changes of a retrograde reaction in the absence of the classical morphological appearance of chromatolysis.

Animals↗
PubMed1977

Regulation of ornithine decarboxylase and S-adenosyl-L-methionine decarboxylase in regenerating rat liver by various amines: Evidence for translational control.

The activity of ornithine decarboxylase in regenerating rat liver could be completely or partially inhibited in vivo by a single intraperitoneal injection of various amines. Un physiological, 1,3-diaminopropane depressed most effectively the activity of ornithine decarboxylase. It depressed also the activity of adenosylmethionine decarboxylase, which was not inhibited by other amines. The activity of tyrosine aminotransferase was invariably stimulated by injection of the amines. Cycloheximide caused a rapid decay of the activity of liver ornithine decarboxylase (half-life 15 min) and also a decay of the activity of adenosylmethionine decarboxylase (half-life 36 min). 1,3-Diaminopropane inhibited the activity of ornithine decarboxylase (half-life 13 min) and to lesser extent also the activity of adenosylmethionine decarboxylase (half-life 120 min). On the contrary, alpha-amanitin did not have any effect on the activity of the decarboxylases. These experiments are consistent with the view that diamines and spermidine might conceivably control the activity of ornithine decarboxylase in regenerating rat liver in vivo at steps beyond transcription. It is also possible that 1,3-diaminopropane similarly controls the activity of adenosylmethionine decarboxylase thus suggesting that the synthesis of ornithine and adenosylmethionine decarboxylases may be coordinatively regulated in liver.

Adenosylmethionine Decarboxylase↗
PubMed2003

Marked disparity between age-related changes in dopamine and other presynaptic dopaminergic markers in human striatum.

Because age-related changes in brain dopaminergic innervation are assumed to influence human disorders involving dopamine (DA), we measured the levels of several presynpatic DAergic markers [DA, homovanillic acid, tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC), vesicular monoamine transporter 2 (VMAT2), and dopamine transporter (DAT)] in post-mortem human striatum (caudate and putamen) from 56 neurologically normal subjects aged 1 day to 103 years. Striatal DA levels exhibited pronounced (2- to 3-fold) post-natal increases through adolescence and then decreases during aging. Similarly, TH and AADC increased almost 100% during the first 2 post-natal years; however, the levels of TH and, to a lesser extent, AADC then declined to adult levels by approximately 30 years of age. Although VMAT2 and DAT levels closely paralleled those of TH, resulting in relatively constant TH to transporter ratios during development and aging, a modest but significant decline (13%) in DAT levels was observed in only caudate during aging. This biphasic post-natal pattern of the presynaptic markers suggests that striatal DAergic innervation/neuropil appears to continue to develop well past birth but appears to become overelaborated and undergo regressive remodeling during adolescence. However, during adulthood, a striking discrepancy was observed between the loss of DA and the relative preservation of proteins involved in its biosynthesis and compartmentation. This suggests that declines in DA-related function during adulthood and senescence may be explained by losses in DA per se as opposed to DAergic neuropil.

Adolescent↗
PubMedDate not supplied

Endocrine autoimmunity in young patients with juvenile chronic arthritis.

OBJECTIVE: The aim of our study was to investigate the coexistence of autoimmune diseases (autoimmune thyroid disease and type 1 diabetes mellitus, T1DM) in patients affected by Juvenile Chronic Arthritis (JCA). METHODS: We studied 66 patients affected by JCA, 42 females and 24 males: 42/66 patients had a pauciarticular form of JCA, 13/66 had a polyarticular form and 11/66 had a systemic form. All the patients underwent autoimmune thyroid screening through determination of anti-thyroglobulin (TgA) and anti-peroxidase (TPOA) autoantibodies. Patients with TgA and/ or TPOA, underwent thyroid sonography. T1DM screening included determination of anti-glutamic acid decarboxylase (GADA), anti-insulin (IAA), anti-tyrosine phosphatase-like protein (IA-2A) and anti-islet cell (ICA) autoantibodies. Oral glucose tolerance test (OGTT) was performed only in patients with autoantibody positive values. HLA typing for risk of T1DM was performed in 43 patients. RESULTS: Nine female patients (14%) showed anti-thyroid autoantibodies, in particular: TgA in 3 cases, TPOA in 5, TgA and TPOA in only 1. In 3 of these patients, ultrasound examinations showed thyroid abnormal pattern, suggesting Hashimoto's thyroiditis. As regards T1DM, only 2 patients showed positive levels of GADA. As regards HLA typing, one or more T1DM susceptibility heterodimers were detected in 20 patients (46%) (13 with 1 heterodimer, 7 with 2 heterodimers). CONCLUSION: Our study showed that anti-thyroid autoantibody frequency (9/66, 14%) was higher in JCA than in the general population, while T1DM markers (islet autoantibodies and genetic markers) were not frequent. These results suggest to investigate specific markers of thyroid autoimmunity in patients with JCA, in particular in females with JCA pauciarticular form.

Adolescent↗
PubMed2004

Distribution and development of glutamic acid decarboxylase immunoreactivity in the spinal cord of the dogfish Scyliorhinus canicula (elasmobranchs).

The adult distribution and development of gamma-aminobutyric acid (GABA)-synthesizing cells and fibers in the spinal cord of the lesser spotted dogfish (Scyliorhinus canicula L.) was studied by means of immunohistochemistry using antibodies against glutamic acid decarboxylase (GAD). Complementary immunostaining with antibodies against GABA, tyrosine hydroxylase (TH), and HuC/HuD (members of the Hu/Elav family of RNA-associated proteins) and staining with a reduced silver procedure ("en bloc" Bielschowski method), Nissl, and hematoxylin were also used. In adults, GAD-immunoreactive (GAD-ir) cells were observed in the ventral horns, in the spinal nucleus of the dorsal horn, at the base of the dorsal horns, and around the central canal, where some GAD-ir cells were cerebrospinal fluid-contacting (CSF-c). In addition, a few GAD-ir cells were observed in the lateral funiculus between the ventral horn and the marginal nucleus. The adult spinal cord was richly innervated by GAD-ir fibers. Large numbers of GAD-ir fibers and boutons were observed in the dorsal and ventral horns and also interstitially in the dorsal, lateral, and ventral funiculi. In addition, a rich GAD-ir innervation was observed in the marginal nucleus of the spinal cord. In the embryonic spinal cord, GAD-ir cells develop very early: The earliest cells were observed in the very thin mantle/marginal layer of stage 22 embryos in a short length of the spinal cord. At stages 25 and 26, several types of GAD-ir cells (commissural and noncommissural) were distinguished, and two of these cells were of CSF-c type. At stages 28, 30, and 31, the GAD-ir populations exhibited a marked longitudinal columnar organization. Double-immunolabeling experiments in embryos showed the presence of two different GAD-ir CSF-c cell populations, one ventral that is simultaneously TH-ir and other more dorsal that is TH-negative. By stage 33 (prehatching), GAD-expressing cells are present in virtually all loci, as in adults, especially in the ventral horn and base of the dorsal horn. The present results for the lesser spotted dogfish suggest an important role for gamma-aminobutyric acid in sensory and motor circuits of the spinal cord.

Animals↗
PubMed1995

Identification and evaluation of the role of endogenous tyrosine kinases in azoxymethane induction of proliferative processes in the colonic mucosa of rats.

Although tyrosine kinases (Tyr-k) are known to play a role in regulating proliferation of normal, preneoplastic and neoplastic cells, little is known about the identity of different species of Tyr-k involved in this process. Utilizing a non-denaturing polyacrylamide gel electrophoresis system, in which the separated proteins from tissue extracts are assayed directly for Tyr-k, we attempted to identify the species of Tyr-k that may be involved in azoxymethane (AOM) induction of colonic mucosal ornithine decarboxylase (ODC) activity, an enzyme whose activity is known to rise in rapidly proliferating cells. We have observed that 5 days after a single injection of the colonic carcinogen AOM (20 mg/kg body wt) to 3-4-month old rats, a significant 230% rise in colonic mucosal proliferative activity (as evidenced by 5-bromo-2'-deoxyuridine (BrdU) immunoreactivity) was also accompanied by a 550% increase in ODC activity. This was also associated with a marked rise (140-240%) in the relative activity of Tyr-k of three mucosal proteins with MI of 165, 145 and 125 kDa. Since the molecular mass of one of the Tyr-k (165 kDa) corresponded to that of EGF-receptor (EGF-R), this led us to examine the role of EGF-R Tyr-k in AOM induction of colonic mucosal ODC. We observed that a 320% increase in mucosal ODC activity, 5 days after AOM injection, was accompanied by over 200% rise in Tyr-k activity of EGF-R. Daily injection of tyrphostin (300 micrograms/kg body wt.), a Tyr-k inhibitor with a higher specificity for EGF-R Tyr-k, significantly attenuated AOM-induced stimulation of both ODC and Tyr-k activity of EGF-R. Administration of AOM also stimulated the rate of synthesis and secretion of TGF-alpha in isolated colonocytes. In addition, the levels of TGF-alpha and its mRNA in the colonic mucosa were also found to be 100% and 250% higher, respectively, in AOM-treated rats when compared with the controls. We suggest that (a) activation of intrinsic Tyr-k of EGF-R is an important event in AOM induction of colonic mucosal proliferative processes, and (b) this activation is thought to be mediated by TGF-alpha through an autocrine mechanism.

Animals↗
PubMed1978

Hypokinesia produced by anterolateral hypothalamic 6-hydroxydopamine lesions and its reversal by some antiparkinson drugs.

Hypokinesia produced by stereotaxic microinjection of solutions of 6-hydroxydopamine into the anterolateral hypothalamus of male rats is accompanied by a generalized reduction in brain noradrenaline levels and a reduction of dopamine in the striatum and cerebral cortex. The hypokinesia is reversed by the putative dopamine-receptor agonists apomorphine, ET-495 and CB-154 as well as by the amino acids L-Dopa and m-tyrosine when administered in combination with the peripheral decarboxylase inhibitor Ro 4-4602. The relative importance of noradrenergic and dopaminergic systems in the mediation of the action of anti-akinesia drugs is discussed.

Animals↗
PubMed1977

Development of nicotinic responses in the rat adrenal medulla and long-term effects of neonatal nicotine administration.

1. The development of nicotinic responses in the rat adrenal medulla was examined at various ages from 1 to 50 days of age by testing the ability of nicotine (10 mg/kg, s.c.) to deplete catecholamines and induce tyrosine hydroxylase. 2. Catecholamines were depleted 25% 3 h after injection of nicotine at all ages tested, but the degree of tyrosine hydroxylase induction 24 h after nicotine increased with age. 3. These data indicate that functional nicotinic receptors are present in the neonatal adrenal medulla before the development of functional splanchnic innervation, but that the development of the ability to induce tyrosine hydroxylase is not coupled directly to the development of secretory mechanisms. 4. The long-term effects of a single dose of nicotine (10 mg/kg, s.c.) administered to one day old rats were also examined. 5. After the short-term catecholamine depletion caused by nicotine, there were persistent elevations of catecholamines and tyrosine hydroxylase until 23 days of age; however, dopamine beta-hydroxylase remained elevated into young adulthood. 6. These data indicate that neonatal nicotine administration can produce long-term changes in adrenal catecholamine biosynthetic enzymes.

Adrenal Medulla↗
PubMed1975

Effects of reserpine on activities and amounts of tyrosine hydroxylase and dopamine-beta-hydroxylase in catecholamine neuronal systems in rat brain.

Reserpine (10 mg/kp i.p.) increased the activities of the enzymes tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase, but not dopa decarboxylase, 2- to 3-fold in the nucleus locus ceruleus of rat brain. The TH response was dose-dependent, reached a maximum by 48 hours and recovered by 3 weeks. The increased activities of TH and dopamine-beta-hydroylase were shown by immunotitration with specific antibodies to each enzyme to be due entirely to increased accumulation of specific enzyme protein. At a time when the reserpine-elicited accumulation of TH was increased 300% in the locus ceruleus, activity of the enzyme only increased 20% in hypothalamus and not at all in substantia nigra or caudate nucleus. Reserpine increased the accumulation of TH, primarily in the cell bodies and to a far less degree in the terminals of neurons of locus ceruleus but not in dopaminergic neurons of the nigrostriatal system. The time course of enzyme accumulation parallels that of depletion of monoamines in brain.

Animals↗