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)

Immunoreactivity for the neurofilament protein triplet was investigated in neurons of the dorsal root ganglia of the guinea-pig by using a battery of antibodies. In unfixed tissue, nearly all neurons in these ganglia demonstrated some degree of neurofilament protein triplet immunoreactivity. Large neurons generally displayed intense immunoreactivity, whereas most small to medium-sized neurons showed faint to moderate immunoreactivity. Double-labelling immunofluorescence demonstrated that most antibodies to the individual subunits of the neurofilament protein triplet had the same distribution and intensity of labelling in sensory neurons. Increasing durations of tissue fixation in aldehyde solutions selectively diminished neurofilament protein triplet immunoreactivity in small to medium-sized neurons. Double-labelling with neurofilament protein triplet antibodies in combination with antibodies to other neuronal markers, such as neuron-specific enolase, substance P and tyrosine hydroxylase, showed that tissue processing conditions affect the degree of co-localization of immunoreactivity to the neurofilament protein triplet and to these other neuronal markers. These results indicate that, with a judicious manipulation of the duration of tissue fixation, neurofilament protein triplet immunoreactivity can be used in combination with other neuronal markers to distinguish groups of neurons according to their size and chemical coding.
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PMID:Neurofilament protein triplet immunoreactivity in the dorsal root ganglia of the guinea-pig. 171 54

Although a well-developed plexus of nerves and ganglia is known to be present in the wall of the gallbladder, little has previously been learned about the function or organization of this innervation. The current study was undertaken in order to evaluate the hypothesis that the ganglionated plexus of the gallbladder is analogous to elements of the enteric nervous system (ENS). The ganglionated plexus of the gallbladder was found to resemble closely the submucosal plexus of the small intestine in its organization into two irregular anastomosing and interwoven networks of ganglia, in the numbers of neurons per ganglion, and in the manifestation of histochemically demonstrable acetylcholinesterase activity in virtually all ganglion cells. In common with enteric ganglia, laminin immunoreactivity was observed to be excluded from the interiors of gallbladder ganglia, which were surrounded by a periganglionic laminin-immunoreactive sheath. As in the submucosal plexus, intrinsic substance P-, vasoactive intestinal polypeptide (VIP)-, and neuropeptide Y (NPY)-immunoreactive neurons were seen in the ganglionated plexus of the gallbladder. Extrinsic nerves in the gallbladder that degenerated following chemical sympathectomy with 6-hydroxydopamine (6-OHDA), and which contained NPY, tyrosine hydroxylase (TH), and dopamine-beta-hydroxylase (DBH) immunoreactivities, formed a perivascular plexus closely associated with blood vessels. Endogenous catecholamines could also be demonstrated in these perivascular nerves by aldehyde-induced histofluorescence. In addition to perivascular nerves, paravascular nerve bundles were observed that were loosely associated with vessels, did not degenerate following administration of 6-OHDA, and contained NPY immunoreactivity. Other paravascular nerves, probably visceral sensory axons, coexpressed substance P and calcitonin-gene-related peptide (CGRP) immunoreactivities. The ganglionated plexus of the gallbladder resembled enteric ganglia in having intrinsic 5-hydroxytryptamine (5-HT)-immunoreactive cells and highly varicose nerve fibers. The 5-HT-immunoreactive gallbladder axons were, like those of the gut, resistant to 6-OHDA, and separate from fibers that expressed TH immunoreactivity. Differences between the ganglionated plexus of the gallbladder and enteric ganglia of the small intestine included in the gallbladder are 1) the presence of TH-immunoreactive cells that contain an endogenous catecholamine, but not DBH; 2) DBH-immunoreactive neurons, some of which coexpress substance P immunoreactivity, but which contain neither a catecholamine nor TH immunoreactivity; 3) an apparent absence of CGRP-immunoreactive cell bodies.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Structure, afferent innervation, and transmitter content of ganglia of the guinea pig gallbladder: relationship to the enteric nervous system. 256 71

The present study examines the distribution and morphological characteristics of neurons containing immunoreactivity of tyrosine hydroxylase in the cat hypothalamus. We used the indirect immunoperoxidase technique on vibratome sections. Tyrosine hydroxylase-immunoreactive cell bodies were widely distributed in discrete regions of the cat hypothalamus. Several principal cell groups were identified. They were seen in the posterior and dorsal hypothalamic areas, zona incerta, dorsomedial and lateral hypothalamic areas, arcuate nucleus, periventricular nucleus, paraventricular nucleus, and an area of the tuber cinereum and preoptic area. These cells presented two different morphological characteristics; small with two to three short processes and medium to large, multipolar with three to five long dendritic trees. The atlas is presented in twelve cross-sectional drawings of the cat hypothalamus from the level A8.5 to A15 of the Horsley-Clarke stereotaxic planes. We also examined the distribution of hypothalamic catecholamine fluorescent neurons by using the aqueous aldehyde method in combination with glyoxylic acid applied to vibratome sectioned tissues, which improves sensitivity. Comments are made on the relative localizations of the tyrosine hydroxylase-immunoreactive and aldehyde-induced histofluorescent cells, as well as on species differences between the cat, rat, and mouse.
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PMID:Localization of tyrosine hydroxylase-immunoreactive neurons in the cat hypothalamus, with special reference to fluorescence histochemistry. 288 55

The morphology, number and distribution of catecholaminergic neurons, as visualized either with the aluminum-catalysed formaldehyde method for catecholamines or with the immunohistochemical method for the catecholamine-synthesizing enzymes tyrosine hydroxylase and aromatic L-amino acid decarboxylase, respectively, were analysed within the rat dorsal hypothalamus, ventral thalamus and adjoining regions (A11 and A13 cell groups). Both polyclonal rabbit and monoclonal mouse tyrosine hydroxylase antibodies were used in elution-restaining and double-staining experiments, respectively. Some of the animals also received spinal injections of the fluorescent tracer True Blue in order to retrogradely label cells projecting to the spinal cord. With respect to the number and distribution of catecholaminergic neurons in the A11 and medial A13 cell groups, including the spinal-projecting subpopulation, the results obtained with the two methods were very similar, indicating that within these regions of the CNS the two methods in principle visualize identical cell populations. However, the catecholaminergic cells were distinctly larger and their processes appeared more extensive with the immunohistochemical method. Animals processed for immunohistochemistry exhibited a lower total number of retrogradely labelled cells in the A11 area than those analysed with aldehyde-induced fluorescence despite the fact that both methods revealed similar numbers of retrogradely labelled tyrosine hydroxylase-positive and catecholamine-containing cells, respectively. The reason for these discrepancies, which are probably of methodological nature, are discussed. While this study shows that the results obtained with the two methods within the A11 and medial A13 cell group are very similar and thus strengthens the earlier proposed concept of the organization of the diencephalospinal dopaminergic system, it also documents that in intermingling and nearby CNS regions there are cell bodies which cannot be demonstrated with the aldehyde fluorescence method, but which still contain tyrosine hydroxylase and/or aromatic L-amino acid decarboxylase-like immunoreactivity. One explanation is low levels of enzyme and/or dopamine combined with a comparatively low sensitivity of the histochemical method. Thus, neurons containing both enzymes are probably dopaminergic, even if catecholamine fluorescence cannot be demonstrated. Neurons containing tyrosine hydroxylase, but lacking both aldehyde induced fluorescence and aromatic L-amino acid decarboxylase, may also still be dopaminergic.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Studies on dopamine-, tyrosine hydroxylase- and aromatic L-amino acid decarboxylase-containing cells in the rat diencephalon: comparison between formaldehyde-induced histofluorescence and immunofluorescence. 289 14

The autofluorescent serotonin analogue 5,7-dihydroxytryptamine (5,7-DHT) was used to identify living catecholaminergic neurons in monolayer cultures derived from the embryonic rat mesencephalon. A high correlation between 5,7-DHT accumulation and aldehyde-induced catecholamine fluorescence as well as tyrosine hydroxylase but not dopamine-beta-hydroxylase or phenylethanolamine-N-methyltransferase immunoreactivity was found. This indicates that these cells were dopamine-containing neurons. Whole-cell patch recordings showed that all mesencephalic neurons had resting membrane potentials of -50 mV or greater and input resistances ranging between 200 and 700 M omega and exhibited spontaneous action potentials and postsynaptic potentials. The duration of the action potential of the dopamine-containing neurons was characteristically longer than that of the non-dopamine-containing mesencephalic cells. In some dopamine-containing neurons, repolarization of the action potential was clearly biphasic, and the slow phase of repolarization was reversibly blocked by local application of Cd2+ or Co2+. This "shoulder" in the action potential was never observed in non-dopamine-containing neurons, where Cd2+ or Co2+ application was always without effect. It is concluded that 5,7-DHT can be used to identify living dopamine-containing neurons in dissociated mesencephalic cultures and these neurons express distinct electrical properties.
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PMID:5,7-Dihydroxytryptamine identifies living dopaminergic neurons in mesencephalic cultures. 305 Sep 94

Immunocytochemical evidence is presented for the existence of choline acetyltransferase (ChoAcTase), cysteine sulfinic acid decarboxylase (CSADCase), tyrosine hydroxylase (TyrOHase), and glutamic acid decarboxylase (GluDCase) in large motor neurons of the hypoglossal nucleus and the spinal cord and in nerve terminals of motor end plates in tongue and skeletal muscle of five mammalian species, including man. These enzymes, which are responsible for the synthesis of acetylcholine (AcCho), taurine, dopamine, and gamma-aminobutyrate (GABA), respectively, were detected by immunocytochemical studies with monoclonal or polyclonal antibodies raised against the enzymes. Electron microscopy of the neuromuscular junctions showed that the immunoreactivity in each case was confined to the cytoplasmic matrix of presynaptic nerve terminals. Immunoreactivity obtained for each enzyme antibody varied with the species. It was highest in fresh, unfixed muscle and lowest in aldehyde-fixed specimens. Negative controls were obtained with preimmune sera and antisera preabsorbed with pure ChoAcTase, CSADCase, or GluDCase antigen. Double-labeling studies with ChoAcTase antibodies and acetylcholinesterase (AcChoEase) antibodies, AcChoEase enzyme activity, or alpha-bungarotoxin binding indicated that ChoAcTase, AcChoEase, and AcCho receptors were colocalized at the same end plates.
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PMID:Synthesizing enzymes for four neuroactive substances in motor neurons and neuromuscular junctions: light and electron microscopic immunocytochemistry. 612 35

This study provides evidence of catecholaminergic neurons in the cranial division of the parasympathetic nervous system. Presumptive catecholaminergic preganglionic neurons in the dorsal motor nucleus of the vagus (DMX) were revealed by a clearcut depletion of intracellular catecholamine-synthesizing enzyme immunoreactivity induced by unilateral cervical vagotomy and identified on tissues immunocytochemically processed for tyrosine hydroxylase (TH), dopamine beta-hydroxylase (D beta H) or phenylethanolamine N-methyltransferase (PNMT). This experimental design was essential because of the recent failure in two species to reproduce data previously obtained in double-label (combined immunocytochemical-retrograde transport) studies. Vagotomy data confirmed three spatially-segregated populations of catecholaminergic visceromotor neurons in the DMX. These cell bodies were morphologically identical to preganglionic neurons observed on alternate tissues stained for Nissl substance or immunostained for choline acetyltransferase (ChAT), the enzyme biosynthesizing acetylcholine. Neurons in the central and medial DMX demonstrated fall-off of TH-like immunoreactivity (LI) ipsilateral to the vagotomy at levels caudal to the obex. This cell group is assumed to be predominantly dopaminergic since relatively few neurons at this level of the DMX expressed D beta H-LI and none were immunostained for PNMT. A second population of immunoreactive neurons, concentrated in the rostral-lateral region of the DMX, was depleted of D beta H-LI on the ipsilateral side but did not express PNMT. These visceromotor neurons may, therefore, biosynthesize noradrenaline and belong to the rostral pole of the A2 area. A third population of presumptive adrenergic vagal dorsomotor neurons in the rostral-medial DMX was depleted of TH-, D beta H- and PNMT-LI at levels of the ipsilateral nucleus anterior to obex. Patterns of depletion of cytoplasmic enzyme-immunoreaction product were identical in all cases irrespective of the site of the transection or the postoperative survival period. Quantitative analysis demonstrated statistically significant loss of immunolabeled neurons in rostral and caudal subgroups of the DMX on the side ipsilateral to the vagotomy. It is concluded that catecholaminergic processes in the vagus nerve, as previously identified by the aldehyde-induced histofluorescence method, may partly arise from the lower brainstem.
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PMID:Effect of cervical vagotomy on catecholaminergic neurons in the cranial division of the parasympathetic nervous system. 837 39

HPNS (high pressure neurological syndrome) is considered to be reversible condition of the nervous system caused by elevated (atmospheric) pressure. Clinical observations and experimental findings gave rise to the belief that this syndrome at least partly functions as a model of a dopamin dependent psychosis. Morphological alterations during or after HPNS in man and animals have not been reported so far. We treated rats for three hours with an increasing pressure of helium-oxygen mixture up to 61 ATA in a pressure chamber. This pressure was subsequently maintained for one hour and then released to zero within twenty seconds. The rats died within the first three seconds of pressure release due to complete deoxygenation. Brains were immediately removed and either cooled in liquid nitrogen or fixed in formalin. In both instances the central nervous tissue was excellently preserved. In paraffin embedded formalin fixed specimens, dark neurons in different brain regions were found, especially within parts of the dentate gyrus, the CA 4 subfield of the ammons horn, in dopaminergic brainstem nuclei and in some cortical pyramidal cells. In dopaminergic cells, tyrosine hydroxylase was found to be absent in cells transformed into dark neurons. These dark neurons which have long been recognized in neuropathology, probably represent reversibly damaged neurons transformed into the dark configuration by aldehyde fixation. They may correspond to early apoptosis or they may be the consequence of cytoskeletal disruption.
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PMID:Early morphological findings in experimental high pressure neurological syndrome. 949 42

Catecholamines have long been thought to play important roles in different mollusc neural functions. The present study used glyoxylate- and aldehyde-induced histofluorescence to identify central and peripheral catecholaminergic neurons in the snail Lymnaea stagnalis. The majority of these cells were also found to react to antibodies raised against tyrosine hydroxylase. A minority of the catecholaminergic neurons, however, exhibited no such immunoreactivity. The number of central catecholaminergic neurons nearly doubled (from about 45 to about 80 cells) during the first 2-3 days of postembryonic development. Thereafter, catecholaminergic neurons again doubled in number and generally grew by about 100-200% in soma diameter as the snails grew by 1,000% in overall linear measurements. In contrast to the relatively meager addition of central catecholaminergic neurons, several thousand catecholaminergic somata were added to different peripheral tissues during postembryonic development. These small, centrally projecting neurons were particularly concentrated in the lips, esophagus, anterior margin of the foot, and different regions of the male and female reproductive tracts. Chromatographic analyses indicated that dopamine was the major catecholamine present in the central ganglia, foot, and esophagus, although detectable levels of norepinephrine (approximately 20% of dopamine levels) were also found in the ganglia. The total content but not the concentration of dopamine increased within the tissue samples during postembryonic development. The companion study (Voronezhskaya et al. [1999] J. Comp. Neurol. 404:285-296) and the present study furnish a complete description of central and peripheral catecholaminergic neurons from their first appearance in early embryonic development to adulthood.
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PMID:Development of catecholaminergic neurons in the pond snail, Lymnaea stagnalis: II. Postembryonic development of central and peripheral cells. 995 49

Mammalian intrinsic cardiac neurons subserve different functions in different cardiac regions, but the regional anatomical organisation of the intracardiac nervous system is not well understood. We investigated the quantitative and qualitative distribution of cholinergic and adrenergic elements, and the intracardiac pathways of extrinsic cardiac nerves, in whole-mount preparations of guinea pig atria. Protein gene product 9.5 immunoreactivity (PGP 9.5-IR) marked intracardiac neuronal elements; immunoreactions for choline acetyltransferase (ChAT-IR) and tyrosine hydroxylase (TH-IR) distinguished cholinergic and adrenergic components, respectively. Catecholamine-containing components were identified by aldehyde-induced fluorescence histochemistry. Mean total number of atrial neurons was 1510+/-251 (SE); 85% of these occurred in ganglia of < or = 20 neurons. All neuronal somata expressing PGP 9.5-IR also expressed ChAT-IR, suggesting that these neurons were cholinergic. Right (RA) and left (LA) atria had statistically similar neuronal densities (6.4+/-1.2 and 2.4+/-0.7 neurons/mm2, respectively; analysis of variance, P< or =0.05). Neurons in RA were concentrated intercavally; LA neurons were concentrated near pulmonary vein ostia. Greatest density occurred in the interatrial septum (16.3+/-4.0 neurons/mm2). No neuronal somata expressed TH-IR or contained detectable amines but these elements were expressed by somata of small cells (mean total 124+/-33) throughout the atria, primarily associated with ganglia. Amine- and TH- containing varicosities were also present in ganglia, representing potential sites for adrenergic modulation of ganglionic neurotransmission. Branches of extrinsic cardiopulmonary and vagus nerves were distributed to all parts of both atria. The organisation of the intracardiac nervous system revealed in this study will facilitate further investigations of regional autonomic control of the heart.
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PMID:Regional distribution and extrinsic innervation of intrinsic cardiac neurons in the guinea pig. 1032 Feb 13


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