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)

Three morphofunctional techniques for the detection of biogenic monoamines have been used in order to find evidence for the presence of dopaminergic neurons in the preoptic region of the goldfish. The formaldehyde-induced fluorescence technique and the immunohistochemical demonstration of tyrosine hydroxylase allowed the detection of cell bodies containing catecholamines in the ventral and lateral walls of the preoptic recess of the goldfish. Specific antibodies indicated that at least part of these perikarya contain dopamine. Evidence for the projection of these neurons to the pituitary are given. These results support the assumption that dopamine, originating from the preoptic region, may act as a gonadotrophin release-inhibiting factor in goldfish.
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PMID:Existence of dopaminergic neurons in the preoptic region of the goldfish. 614 27

The catecholamine-synthesizing enzymes, tyrosine hydroxylase, dopamine-beta-hydroxylase and phenylethanolamine-N-methyltransferase were examined by immunohistochemistry in hypertrophied paraganglia of aged male Fischer-344 rats. All paraganglionic cells reacted with antibodies against tyrosine hydroxylase. Dopamine beta-hydroxylase was identified in most paraganglionic cells, indicating that they synthesized norepinephrine. A variable number of paraganglia were positive for phenylethanolamine-N-methyltransferase, which suggested that they synthesized epinephrine. The formaldehyde-induced fluorescence method demonstrated greenish-yellow fluorescence or yellowish-brown fluorescence. The intensity of the fluorescence was in the same range as in adrenal medullary cells. The observations indicate that paraganglia are capable of synthesizing epinephrine.
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PMID:Catecholamine-synthesizing enzymes in paraganglia of aged Fischer-344 rats. Immunohistochemistry and fluorescence microscopy. 615 Jul 62

Adequate fixative in immunohistochemistry requires not only a rapid and total immobilization of the antigen, but also a sufficient preservation of its immunoreactivity and maintenance of its accessibility to the immunochemical reagents for localization. Thus, the optimal fixation condition for a specific antigen necessitates a compromise between these opposing variables and can be determined by the preparation of a series of tissues with a progressively increasing degree of fixation. Unless the results of localization using such a series is available, one must be satisfied with adequate but less than optimal results. In the present study, this principle is demonstrated using the localization of tyrosine hydroxylase in the dopaminergic system with formaldehyde as the fixative. The rate and degree of fixation with formaldehyde was shown to be highly pH dependent. By perfusing the tissue with formaldehyde at pH 6.5 (where the rate of fixation is extremely slow) it is possible to rapidly distribute the fixative homogeneously into the tissue. By suddenly changing to a formaldehyde perfusate of higher pH, the cross-linking reaction is rapidly increased. This two-step fixation procedure provides a means of obtaining a rapid and uniform immobilization of the antigen, so that its translocation can be avoided. The final degree of fixation is controlled by the duration and pH of the second fixative solution. The results obtained by increasing the pH of the second solution demonstrated that complete fixation of tyrosine hydroxylase in the dopaminergic system with formaldehyde maybe obtained using a very basic formaldehyde solution (pH 11) while still retaining immunoreactivity of the enzyme. The localization that was achieved at lower pH appeared adequate until it was compared to the results obtained by perfusion at pH 11 in the second step.
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PMID:Importance of fixation in immunohistochemistry: use of formaldehyde solutions at variable pH for the localization of tyrosine hydroxylase. 616 11

Acrolein was examined as an alternative fixative to formaldehyde for immunocytochemical localization of neuropeptides in the rat brain. A brief (5 min) vascular perfusion with a 5% acrolein solution allowed the identification of thyrotropin-releasing hormone (TRH), vasoactive intestinal peptide (VIP), somatostatin (SRIF), neurotensin (NT), methionine enkephalin (Menk), adrenocorticotropic hormone (ACTH), tyrosine hydroxylase (TH), and luteinizing hormone-releasing hormone (LHRH) in fibers and perikarya within the central nervous system of the rat using the peroxidase-antiperoxidase (PAP) technique. Acrolein appears to be particularly valuable for immunocytochemistry, as it 1) stabilizes heterogeneous peptides and proteins rapidly and effectively, 2) retains antigenicity, and 3) preserves morphological detail.
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PMID:Acrolein: a fixative for immunocytochemical localization of peptides in the central nervous system. 618 5

A new technique for studying axonal transport has been developed. The technique, which is based on histofluorescence techniques, enables the measurement of several different accumulated substances and parameters within a single nerve in relation to a nerve crush or local cooling. Any substance that can be made to fluoresce can be measured. The tissue is treated according to the formaldehyde-induced fluorescence method of Hillarp and Falck for visualization of monoamines, or according to the indirect immunofluorescence method. For immunofluorescence the nerve is cryostat-sectioned and various sections can be incubated with primary antisera against different antigens. After incubation and mounting the sections are placed in a cytofluorimeter (Leitz MPV II). They are passed under a measuring slit at a steady speed by a motor driven cross-table. The fluorescence intensity passing through the measuring slit is continuously registered by a recording unit with an integrator. This recorder produces a graphical nerve accumulation profile, and the area under the profile, relating to the fluorescence, is expressed in arbitrary units. This article presents data on the accumulation of noradrenaline, dopamine beta-hydroxylase, and tyrosine hydroxylase in crush-operated rat sciatic nerve. The time-course accumulations for noradrenaline (visualized by the Falck and Hillarp method) and dopamine beta-hydroxylase (visualized by immunofluorescence) demonstrated a striking similarity, which is to be expected since the two substances are stored in the same organelle. Tyrosine hydroxylase (visualized by immunofluorescence) showed a slower accumulation with time, but faster than would be expected had the enzyme been 100% soluble. Colchicine but not lumi-colchicine blocked the transport of noradrenaline organelles. With the new scanning technique we have the potential to study accumulation profiles of several different substances within a single nerve. Morphometric data, morphological observations, and photograph documentation of the same nerve section are also available.
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PMID:A new methodological approach for studying axonal transport: cytofluorometric scanning of nerves. 619 39

The aim of the present investigation was to study the developing peptidergic innervation of the human fetal heart of 7-24 wk gestational age. An immunohistochemical approach was adopted and the total innervation visualised with antisera to general neuronal and Schwann cell markers, while the onset and development of specific neuropeptide-containing subpopulations were investigated using antisera to neuropeptide Y (NPY), somatostatin, vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP) and substance P (SP). Cardiac ganglia and nerves were demonstrated from 7 wk of gestation whereas peptide-immunoreactive nerves were not observed until the 10th week of gestation. NPY-immunoreactive nerve fibres constituted the major subpopulation of peptide-containing nerves identified in the fetal heart, exhibiting a descending atrial to ventricular density gradient, and were first identified during the 10th wk of gestation. Somatostatin- and VIP-immunoreactive nerves appeared at 10-12 wk of gestation and were mainly distributed in the atria. Somatostatin immunoreactivity was localised to cell bodies in cardiac ganglia, as well as to nerve fibres, indicating an intrinsic origin for this nerve subpopulation. Conversely, the other peptide-containing nerves appear to be of extrinsic origin, including those immunoreactive for VIP. Intracardiac neurons exhibit a transient expression of tyrosine hydroxylase immunoreactivity. Putative sympathetic nerve fibres, displaying tyrosine hydroxylase and NPY immunoreactivity, were demonstrated before the adrenergic innervation has previously been shown to be present by formaldehyde-induced fluorescence staining of catecholamines. The onset of the CGRP- and SP-immunoreactive innervation, at 18-24 wk of gestation, followed the appearance of other peptide-containing nerves, suggesting that the sensory, afferent innervation occurs later than the autonomic. The differential appearance and distribution of peptide-containing nerve subpopulations indicate that there is a chronological order to the development of the autonomic and sensory components of human cardiac innervation.
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PMID:Development of the peptidergic innervation of human heart. 750 78

In rats which were injected with horseradish peroxidase (HRP) into the midbrain periaqueductal gray (PAG) and then administered with formaldehyde into the stomach, Fos-like immunoreactivity was found in tyrosine hydroxylase-like immunoreactive neurons in the nucleus tractus solitarii (NTS) which were retrogradely labeled with HRP. The results indicate that catecholaminergic NTS neurons may mediate nociceptive visceral information to the PAG.
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PMID:Catecholaminergic neurons in the nucleus tractus solitarii which send their axons to the midbrain periaqueductal gray express Fos protein after noxious stimulation of the stomach: a triple labeling study in the rat. 762 39

The medulla oblongata was examined with Fos and tyrosine hydroxylase (TH) immunohistochemistry after 2 h of intermittent nasopharyngeal stimulation with formaldehyde vapour in the conscious rabbit. The stimulation caused apnoea, bradycardia and a rise in blood pressure known to be associated with vigorous vasoconstriction. Fos-positive neurons occurred in the spinal trigeminal nucleus, the nucleus tractus solitarius, the raphe nuclei and the ventrolateral medulla. In the rostral ventrolateral medulla, 68% of the Fos-positive neurons were TH-positive C1 cells. Our data indicate that nasopharyngeally-evoked peripheral vasoconstriction is associated with activation of C1 neurons.
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PMID:Vasoconstriction induced by inhalation of irritant vapour is associated with appearance of Fos protein in C1 catecholamine neurons in rabbit medulla oblongata. 790 52

To get more insight into developmental aspects of catecholamine systems in vertebrates, in particular anuran amphibians, these systems were studied immunohistochemically in embryos and larvae of Xenopus laevis and Rana ridibunda. Antisera against tyrosine hydroxylase (TH) and dopamine (DA) revealed that catecholamine systems are already present at early embryonic stages. The first dopamine group to be detected was found ventral to the central canal of the spinal cord of Xenopus, soon followed by DA cell groups in the posterior tubercle, the hypothalamic periventricular organ, the accompanying cell group of the periventricular organ, and the suprachiasmatic nucleus. Although weakly TH-immunoreactive cells were found in the olfactory bulb at about the same embryonic stages, DA immunoreactivity was not detected until premetamorphic stage 49. Dopamine cell groups in the caudal brainstem, midbrain, and pretectum appeared at late premetamorphic and prometamorphic stages, whereas the preoptic group was first observed at the metamorphic climax stage. Rana showed an almost similar timetable of development of catecholamine cell groups, except for the caudal brainstem group which was already present at the end of the embryonic period. When compared with previous studies by means of formaldehyde-induced fluorescence technique, it becomes clear that TH/DA immunohistochemistry enables an earlier detection of catecholamine cell groups and fiber systems in anuran amphibians. The present study also revealed that the DA-immunoreactive cells of the hypothalamic periventricular organ never stained with the TH antiserum during development, thus supporting their putatively DA accumulating nature. Another notable result is the site of origin and rather late appearance of the midbrain dopaminergic cell group. It is suggested that the latter cell group only partly corresponds to the ventral tegmental area and substantia nigra of amniotes.
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PMID:Ontogeny of catecholamine systems in the central nervous system of anuran amphibians: an immunohistochemical study with antibodies against tyrosine hydroxylase and dopamine. 796 12

Pacinian corpuscles in the cat urinary bladder were studied using the hematoxylin and eosin staining, formaldehyde-induced fluorescence histochemistry, immunohistochemistry for tyrosine hydroxylase (TH) and immunoelectron microscopy. The existence of catecholaminergic nerve fibers penetrating into the corpuscles was clarified. (1) About 10 Pacinian corpuscles which were mainly located in the subserosa were found in the lower one-third portion of each urinary bladder. (2) One or two corpuscles containing blue-green fluorescent fibers were detected in each bladder. These fibers were equivalent to TH-immunopositive varicose fibers using the avidin-biotin-peroxidase complex method. (3) Thin nerve fibers containing dense-cored vesicles were found in the corpuscle by immunoelectron microscopy. These fibers spirally encompassed a swollen sensory terminal at a distance in the inner core. According to the above findings, we discuss a modulatory function of the catecholaminergic fibers in this mechanoreceptor.
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PMID:Noradrenergic fibers in the Pacinian corpuscles of the cat urinary bladder. 809 85


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