Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.14.16.2 (tyrosine hydroxylase)
 14,760 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the distribution of tyrosine hydroxylase (TH) immunoreactive (IR) neurons in the adult human hypothalamus using a modification of the peroxidase-antiperoxidase immunohistochemical method which can be applied on autopsy brain material following prolonged formalin fixation. We observed that most of the TH-IR perikarya localized within the paraventricular (PVN) and supraoptic (SON) nuclei were large and showed homogeneous staining over the entire cytoplasm and processes. These results show that in the human brain a large population of neurons within the neurosecretory nuclei are able to synthesize a catecholamine.
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PMID:Tyrosine hydroxylase-immunoreactive neurons in paraventricular and supraoptic nuclei of the human brain demonstrated by a method adapted to prolonged formalin fixation. 168 32

In situ hybridization histochemistry and indirect immunofluorescence histochemistry were used to study changes in the expression of vasopressin (VP), oxytocin (OXY), tyrosine hydroxylase (TH), galanin (GAL), dynorphin (DYN) and cholecystokinin (CCK) in hypothalamic magnocellular neurons of the paraventricular (PVN) and supraoptic (SON) nuclei of rats. After prolonged administration of 2% sodium chloride as drinking water (salt-loading), the treatment increased the levels of VP, OXY, TH, GAL, DYN and CCK mRNA in the PVN and SON. The increase in CCK mRNA was, however, proportionally higher in the PVN than in the SON. Within cell bodies of the PVN and SON of salt-loaded rats, a depletion of VP- and OXY-like immunoreactivity (LI) and an increase in TH-LI were seen. In salt-loaded/colchicine-treated rats, a marked decrease in GAL- and DYN-LI, but no specific changes in CCK-LI were observed. Within nerve fibers of the posterior pituitary of salt-loaded rats, a marked depletion of VP-, GAL- and DYN-LI was found. Less pronounced depletion was observed in OXY- and CCK-LI, and no specific changes in TH-LI were seen. The results show that high plasma osmolality induces increased mRNA levels for VP, OXY, TH, GAL, DYN and CCK, presumably indicating increased synthesis, an increased export from cell somata of VP, OXY, GAL and DYN, and a decrease in levels of these peptides in the posterior pituitary, suggesting increased release. The catecholamine-synthesizing enzyme TH, however, which has a cytoplasmic localization and is not released from nerve endings, remains high in the cell bodies and nerve endings during this state of increased activity.
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PMID:Peptides and transmitter enzymes in hypothalamic magnocellular neurons after administration of hyperosmotic stimuli: comparison between messenger RNA and peptide/protein levels. 169 5

The objective of this study was to determine whether chronic arterial baroreceptor deficit induces time-related changes in central vasopressin (AVP) and catecholamine systems. Groups of sinoaortic-denervated (SAD) and sham-operated (SO) rats were studied 1, 3, 4, 7, and 14 days after surgery. Supraoptic (SON), paraventricular (PVN) and arcuate (ARC) nuclei, median eminence (ME) region, and A1 region of medulla were obtained by micropunch from frozen brain sections and assayed for AVP, tyrosine hydroxylase (TH) activity, catecholamines, and their metabolites, dihydroxyphenylethyleneglycol (DOPEG) and 2,5-dihydroxyphenylacetic acid (DOPAC). AVP concentration in SON and PVN was increased in 1-day-SAD rats, reduced in 3- and 4-day-SAD rats, equal and above control values in 7- and 14-day-SAD rats, respectively. TH activity was increased in SON and reduced in ME and ARC of 1- and 7-day-SAD rats. In SON, DOPEG was increased, whereas in ME all catecholamines and DOPEG and DOPAC were reduced in 1-day-SAD rats. ME catecholamines returned toward control levels in 3- to 4-day-SAD rats. These studies show that the chronic absence of arterial baroreceptor input produces time-related, regionally specific central changes of vasopressin and regionally associated catecholamines.
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PMID:Effects of chronic sinoaortic denervation on central vasopressin and catecholamine systems. 290 84

The hypothalamus has been claimed to be involved in a great number of physiological functions in development, such as sexual differentiation (gender, sexual orientation) and birth, as well as in various developmental disorders including mental retardation, sudden infant death syndrome (SIDS), Kallman's syndrome and Prader-Willi syndrome. In this review a number of hypothalamic nuclei have therefore been discussed with respect to their development in health and disease. The suprachiasmatic nucleus (SCN) is the clock of the brain and shows circadian and seasonal fluctuations in vasopressin-expressing cell numbers. The SCN also seems to be involved in reproduction, adding interest to the sex differences in shape of the vasopressin-containing SCN subnucleus and in its VIP cell number. In addition, differences in relation to sexual orientation can be seen in this perspective. The vasopressin and VIP neurons of the SCN develop mainly postnatally, but as premature children may have circadian temperature rhythms, a different SCN cell type is probably more mature at birth. The sexually dimorphic nucleus (SDN, intermediate nucleus, INAH-1) is twice as large in young male adults as in young females. At the moment of birth only 20% of the SDN cell number is present. From birth until two to four years of age cell numbers increase equally rapidly in both sexes. After this age cell numbers start to decrease in girls, creating the sex difference. The size of the SDN does not show any relationship to sexual orientation in men. The large neurosecretory cells of the supraoptic (SON) and paraventricular nucleus (PVN) project to the neurohypophysis, where they release vasopressin and oxytocin into the blood circulation. In the fetus these hormones play an active role in the birth process. Fetal oxytocin may initiate or accelerate the course of labor. Fetal vasopressin plays a role in the adaptation to stress--caused by the birth process--by redistribution of the fetal blood flow. Corticotropin-releasing hormone (CRH) neurons of the PVN play a central role in stress response. Thus fetal CRH neurons may play a role in the timing of the moment of birth. Recently, alterations have been described in peptidergic, aminergic and cholinergic transmitters in the hypothalamus in SIDS. Future research will have to establish whether these changes are part of the course of SIDS. A large proportion of the SON and PVN neurons also produce tyrosine hydroxylase (TH). In neonates the majority of TH-immunoreactive neurons colocalizes vasopressin, while in the adult the majority of TH-positive neurons colocalizes oxytocin.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Development of the human hypothalamus. 764 57

In the developing and adult human paraventricular (PVN) and supraoptic (SON) nucleus, a large proportion of neurons contains the catecholamine-synthesizing enzyme tyrosine hydroxylase (TH). In the present study we investigated the possible colocalization of TH with oxytocin (OXT) or vasopressin (VP) in the adult and neonatal PVN and SON. Adjacent paraffin sections were incubated simultaneously with two antibodies: a polyclonal against TH and a monoclonal against OXT or VP and stained with a double peroxidase-antiperoxidase/alkaline phosphatase method. We observed that TH-immunoreactive(IR) perikarya in the human PVN and SON were also positive for OXT or VP. A clear difference between the neonates and adult cases of our sample was observed in the proportion of TH-IR neurons that colocalize OXT or VP. In the neonates the majority of the TH-IR perikarya was also stained for VP, while only few TH-IR neurons were also positive for OXT. The opposite was observed in the adults, where the majority of the double-stained TH-IR neurons colocalizes OXT while only few TH-IR perikarya appear to contain VP. Our study establishes the colocalization of TH with OXT or VP in the adult and neonatal PVN and SON and indicates that antemortem factors such as perinatal hypoxia might increase TH-immunoreactivity of the VP neurons in man.
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PMID:Colocalization of tyrosine hydroxylase with oxytocin or vasopressin in neurons of the human paraventricular and supraoptic nucleus. 769 71

Oxytocin is synthesized by magnocellular neurons in the supraoptic and paraventricular nuclei (SON and PVN) and during pregnancy progesterone prevents premature activation of oxytocin neurons. Progesterone receptors (PR) are not detectable in SON oxytocin neurons of non-pregnant rats, so we sought to determine whether they are expressed during pregnancy and parturition. In addition, we examined PR expression in brainstem and hypothalamic regions that have known direct projections to the SON. Neuronal immunoreactive PR (irPR)-labeled nuclei were counted in sections from proestrous virgin, late pregnant (day 21) and parturient rats (90 min from birth onset). IrPR nuclei were not evident in the SON at any stage but irPR expression in the medial preoptic nucleus (MPA) significantly increased in pregnancy and parturition (159% and 189% of proestrous controls, respectively). Other hypothalamic areas did not exhibit a significant change in irPR expression. In the nucleus tractus solitarius (NTS) in the brainstem, there was no significant change in irPR in late pregnancy, but there was a significant reduction in irPR expression at parturition (22% of proestrous controls). Very few NTS neurons immunoreactive for tyrosine hydroxylase (irTH), and thus putatively noradrenergic, contained irPR. These findings taken with evidence that brainstem irTH neurons projecting to the SON are stimulated at parturition, whereas MPA cells projecting to the SON are not, suggest that any direct actions of progesterone or progesterone withdrawal on NTS or SON neurons are not mediated through the classical PR. Upregulation of PR expression in the MPA during pregnancy and parturition may relate to the onset of maternal behavior and/or regulation of GnRH neuronal activity.
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PMID:Progesterone receptor expression in the pregnant and parturient rat hypothalamus and brainstem. 1181 28

Our previous studies indicated that in the human paraventricular (PVN) and supraoptic (SON) nuclei, tyrosine hydroxylase (TH)--the first and rate-limiting enzyme in catecholamine synthesis--is localized mainly in magnocellular neurons and that antemortem factors regulate its expression. The purpose of the present study was to investigate the distribution of TH-immunoreactive (TH-IR) perikarya of the hypothalami of a large sample of well-documented adult subjects without neurological, psychiatric or endocrinological disease in order to identify factors that could regulate the expression of TH in the human neurosecretory neurons. Our material consisted of the hypothalami of 38 subjects studied immunohistochemically for TH using the peroxidase-antiperoxidase method. Striking individual differences were observed among the subjects studied concerning the number and distribution of TH-IR perikarya within the PVN and SON. These differences were evident throughout the entire rostrocaudal length of the hypothalamus and appeared to be related neither to the age or sex of the subjects nor to the postmortem interval or staining procedures. In the sample studied, a large number of TH-IR perikarya were observed specifically in all subjects that had suffered from right-sided heart failure due to pulmonary hypertension, liver cirrhosis or dehydration. In all the above illnesses, increased production and secretion of vasopressin (VP) are reported to occur due to a decrease in 'effective' blood volume or to osmotic stimulation. We conclude that somatic illnesses leading to prolonged osmotic or nonosmotic stimulation of VP release may induce increased expression of TH immunoreactivity in the human neurosecretory neurons related to neuronal activation.
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PMID:Increased expression of tyrosine hydroxylase immunoreactivity in paraventricular and supraoptic neurons in illnesses with prolonged osmotic or nonosmotic stimulation of vasopressin release. 1241 42

The quantity and topography of activated vasopressin (AVP), oxytocin (OXY), and tyrosine hydroxylase (TH) neurons were studied immunohistochemically in the anterior, middle, and posterior portions of the PVN and SON in mice 60 min after a single injection of hypertonic saline (HS, 400 microl 1.5M, i.p.). Fos-neuropeptide double-stainings revealed: (1) Fos expression in each portion of the PVN and SON; (2) maximal number of Fos-AVP (79 cells) and Fos-OXY (50 cells) double-labelings in the middle portion of the PVN; (3) low number of Fos-TH perikarya in the PVN and their lack in the SON; (4) similar incidence (around 50%) of Fos-AVP and Fos-OXY perikarya in the SON; and (5) presence of activated AVP, OXY, and TH neurons in the periventricular, subependymal, and sub-PVN zones of the PVN. Topographic analysis revealed that the majority of AVP neurons expressing Fos occupied the dorsolateral and central part of the middle portion of the PVN. In the same PVN portion, Fos-OXY neurons occurred in similar frequency, however, they were primarily distributed along the lateral and medial margins of the PVN. In the SON, Fos-OXY cells occupied mainly its dorsal, while Fos-AVP cells predominated in its ventral part. The data clearly indicate that HS is not a selective stimulus neither for PVN nor SON itself and provide evidence that both PVN and SON AVP and OXY cells play important role in the mediation of signals induced by HS. In addition, the limited number of AVP, OXY, and TH neurons activated by HS may account for their differential functional specializations selective for stress/osmotic circuits activated by HS.
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PMID:Fos protein expression in mouse hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei upon osmotic stimulus: colocalization with vasopressin, oxytocin, and tyrosine hydroxylase. 1523 1

Fos expression in the hypothalamus and its quantification in vasopressinergic (AVP), oxytocinergic (OXY) and tyrosine hydroxylase (TH) immunoreactive cells in the hypothalamic paraventricular (PVN), supraoptic (SON), suprachiasmatic (SCh), and arcuate (Arc) nuclei was performed in response to physiologically two different, i.e. osmotic (i.p. hypertonic saline, HS) and immobilization (IMO), stimuli in mouse using a dual Fos-neuropeptide immunohistochemistry. Both 60 min of HS and 120 min of IMO evoked Fos induction in many hypothalamic structures, whereas, HS evoked more extensive Fos labeling than IMO in the SON, ventromedial (VMN) and dorsomedial (NDM) hypothalamic nuclei and the retrochiasmatic area (RCh). Other hypothalamic structures including the anterior hypothalamic area (AHA), the latero-anterior hypothalamic nucleus (LA), the Arc, the perifornical nucleus (PeF), and the lateral hypothalamic area (LH) showed similar Fos incidence after both HS and IMO. However, after both stimuli explicitly most extensive Fos expression was observed in the PVN. In addition, in the PVN substantially more Fos-AVP (62-67% versus 10-15%) and Fos-OXY (38-45% versus 4-8%) perikarya were observed after HS than IMO, respectively. Incidence of TH-immunoreactive Fos labeled cells in the PVN was also more frequent after HS. In the SON, HS activated more than 50% of AVP and OXY neurons while IMO less than 4%. The number of TH activated neurons in Arc was also higher after HS (11%) than IMO (4%). Lowest number of colocalizations was revealed in the SCh where both HS and IMO activated around 2% of AVP neurons. The present data demonstrate that both HS and IMO are powerful stimuli for the majority of hypothalamic structures displaying considerable topographic similarity in Fos expression suggesting their multifunctional involvement. The quantity and phenotypic differences of activated hypothalamic neurons may speak out for functional dissimilarities in response to HS and IMO.
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PMID:Fos expression variances in mouse hypothalamus upon physical and osmotic stimuli: co-staining with vasopressin, oxytocin, and tyrosine hydroxylase. 1583 97

The intention of this review is to emphasize the current knowledge about the extent and importance of the substances co-localized with magnocellular arginine vasopressin (AVP) and oxytocin (OXY) as potential candidates for the gradual clarification of their actual role in the regulation of hydromineral homeostasis. Maintenance of the body hydromineral balance depends on the coordinated action of principal biologically active compounds, AVP and OXY, synthesized in the hypothalamic supraoptic and paraventricular nuclei. However, on the regulation of water-salt balance, other substances, co-localized with the principal neuropetides, participate. These can be classified as (1) peptides co-localized with AVP or OXY with unambiguous osmotic function, including angiotensin II, apelin, corticotropin releasing hormone, and galanin and (2) peptides co-localized with AVP or OXY with an unknown role in osmotic regulation, including cholecystokinin, chromogranin/secretogranin, dynorphin, endothelin-1, enkephalin, ferritin protein, interleukin 6, kininogen, neurokinin B, neuropeptide Y, vasoactive intestinal peptide, pituitary adenylate cyclase-activating polypeptide, TAFA5 protein, thyrotropin releasing hormone, tyrosine hydroxylase, and urocortin. In this brief review, also the responses of these substances to different hyperosmotic and hypoosmotic challenges are pointed out. Based on the literature data published recently, the functional implication of the majority of co-localized substances is still better understood in non-osmotic than osmotic functional circuits. Brattleboro strain of rats that does not express functional vasopressin was also included in this review. These animals suffer from chronic hypernatremia and hyperosmolality, accompanied by sustained increase in OXY mRNA in PVN and SON and OXY levels in plasma. They represent an important model of animals with constantly sustained osmolality, which in the future, will be utilizable for revealing the physiological importance of biologically active substances co-expressed with AVP and OXY, involved in the regulation of plasma osmolality.
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PMID:Response of substances co-expressed in hypothalamic magnocellular neurons to osmotic challenges in normal and Brattleboro rats. 1877 90


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