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)

The effect of Pb2+ was studied in embryonic mesencephalic primary cultures that contain neurons and glia. Pb2+ exposure in absence of serum, damaged more efficaciously the cultured cells than Pb2+ exposure in presence of serum. In serum-free medium, Pb2+ elicited mainly necrosis and apoptosis in maximally 13% of the cells in culture. The glial fibrillary acidic protein (GFAP) content was decreased by Pb2+ exposure in serum-containing medium. The abundance of GFAP was also decreased by serum deprivation that was augmented by the addition of 12.5 microM Pb2+ in serum-free medium. A 6h exposure to 6 microM Pb2+ in serum-free medium also lowered the low affinity 3H-D-aspartate uptake. A 6h exposure of mesencephalic cells to 3-25 microM Pb2+ in serum-free medium failed to alter the number of tyrosine hydroxylase- and calretinin-immunoreactive cells, whereas, 50 microM Pb2+ obliterated both cell types. A 6h exposure of cells to 3 microM Pb2+ in serum-free medium decreased 3H-dopamine uptake by 50 % and 12.5 microM Pb2+ obliterated it. Addition of albumin to serum-free medium failed to prevent the Pb2+ -elicited inhibition of [3H]-dopamine uptake suggesting that the serum-afforded delay of cell death may not be due to a removal of reactive Pb2+ by protein/chelate formation but rather to the Pb2+ -scavenging function of glial cells. Serum deprivation may exacerbate the Pb2+ -induced neurotoxicity presumably by impairing the metal scavenging function of astrocytes.
 ...
PMID:The effect of lead exposure and serum deprivation on mesencephalic primary cultures. 929 83

The importance of calcium in neuronal function has been amply demonstrated in recent years. The discovery of a class of proteins within neurons which bind calcium, therefore, has proven to be a catalyst for the generation of theories and hypotheses regarding mechanisms of neurotoxicity in the CNS. In addition, the distribution of certain calcium-binding proteins changes during neural development, suggesting that they may play a role in organization or pattern generation. We have examined the ontogeny of three related calcium-binding proteins, calbindin-D28, parvalbumin and calretinin, with respect to the ventral and dorsal compartments or tiers of the dopaminergic population in the ventral midbrain. Single and dual-label immunocytochemistry was employed to map the distributions of calcium-binding proteins and tyrosine hydroxylase from E18 through adulthood. The results show that each of the three proteins exhibits a unique developmental sequence and compartment preference, with calbindin D28 clearly related to the later-developing dorsal tier, and parvalbumin and calretinin to the ventral tier of the dopaminergic ventral mesencephalon.
 ...
PMID:Calcium-binding proteins in the substantia nigra and ventral tegmental area during development: correlation with dopaminergic compartmentalization. 937 56

The autonomic nervous system is involved in different functions such as transduction of afferent sensory inputs, trophic actions, modulation of immunologic events and thermoregulation. In the present investigation, we studied the pattern of human autonomic skin innervation with special reference to its relation to blood vessels, hair follicles, sweat glands and sensory receptors. For the first time, two clinically important areas have been compared: the skin of the forearm and of the face. Using indirect immunohistochemistry, we analyzed the distribution of calretinin (CR), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), substance P (SP), neurokinin A (NKA), vasoactive intestinal peptide (VIP), nitric oxide synthase (NOS), tyrosine hydroxylase (TH), histamine, serotonin, enkephalin, and, enzyme histochemically, NADPH-diaphorase (NADPH-d). In the epidermis, we found nerve fibers containing SP, NKA and CGRP. In the dermis, SP-, CR-, VIP-, CGRP- and NKA-positive nerve fibers were detected. Particularly the large nerve fibers contained CR. VIP-positive fibers occurred especially around hair follicles and sweat glands. CGRP-positive nerve fibers were located close to the epidermal basal membrane, in the wall of blood vessels, and to a lesser extent around hair follicles. Immunoreactivity for SP and NKA in the dermis was observed predominantly in the papillary layer near the epidermal basal membrane. All neuropeptides tested in this study were also detected in the nerve fibers of the subcutis. Most of them were CGRP- and VIP-positive. They occurred in association with sweat glands and large arteries. NPY-positive nerve fibers are predominant in the wall of arteries, arterioles and veins. Nerve fibers containing NKA and SP were less common and identified only in the walls of large arteries in deeper dermal layers. In double-staining experiments, the NADPH-d reaction and reactivity to tubulin revealed a partial co-localization in nerve fibers, blood vessel walls, around glands and ganglionic cells. VIP-positive fibers were more common in the face skin than in the forearm. However, in forearm we detected more NPY-, CGRP-, NKA- and SP-positive nerve fibers than in face skin. These findings are important for future studies on skin disorders, such as sensory neuropathies, inflammatory reactions or allergic responses of human skin.
 ...
PMID:Immunohistochemical detection of human skin nerve fibers. 938 13

Recent studies dealing with the investigation of the afferent and efferent connections of the basal ganglia of amphibians have revealed many similarities with basal ganglia structures of amniotes. In a further step, the chemoarchitecture of basal ganglia of the frog Rana perezi has been investigated. For use as main markers of amphibian basal ganglia structures, antibodies against tyrosine hydroxylase, substance P, and enkephalin were selected. Moreover, the distributions of nitric oxide synthase (nicotinamide adenine dinucleotide phosphate-diaphorase histochemistry), calretinin, dopamine-beta-hydroxylase, choline acetyltransferase, mesotocin, vasotocin, somatostatin, neuropeptide Y, neuropeptide FF, and serotonin were studied to corroborate a comparison with both basal ganglia and amygdaloid structures of amniotes. On the basis of connections and chemoarchitecture, a striatum proper, nucleus accumbens, dorsal and ventral pallidum, bed nucleus of the stria terminalis, and amygdaloid complex have been identified. Accordingly, a new terminology is proposed that is in line with our current understanding of basal ganglia organization in amphibians.
 ...
PMID:Basal ganglia organization in amphibians: chemoarchitecture. 951 19

The anatomical relationships between immunocytochemically identified nerve fibers and MHC class II-expressing antigen presenting dendritic cells were investigated in the rat hepatobiliary system using immunocytochemistry, confocal laser scanning, and electron microscopy. Close proximity of nerve fiber varicosities immunostained for PGP 9.5 and MHC class II-expressing dendritic cells was frequently observed in the wall of extrahepatic bile ducts, in Glisson's area, around central and hepatic veins, and in the liver capsule. Contacts between nerve fibers staining for substance P, calcitonin gene-related peptide, calretinin, and vasoactive intestinal polypeptide and dendritic cells were more often observed around extrahepatic bile ducts than in Glisson's area. Nerve fibers immunostaining for tyrosine hydroxylase and neuropeptide Y were numerous both in the wall of extrahepatic bile ducts and in Glisson's area and frequently contacted dendritic cells there. At the ultrastructural level, close membrane contacts between bare axolemmal areas of unmyelinated nerve fibers and processes of MHC class II-expressing cells were observed. These results demonstrate close anatomical relationships of nerve fibers from various sources with antigen presenting dendritic cells in the visceral domain and suggest modulation of antigen presentation by the autonomic nervous system.
 ...
PMID:Close anatomical relationships between nerve fibers and MHC class II-expressing dendritic cells in the rat liver and extrahepatic bile duct. 956 91

The presence of a cholinergic innervation of arterioles within the gut wall is suggested by pharmacological studies of nerve mediated vasodilatation, but attempts to identify nerve cells that give rise to cholinergic vasodilator fibres have yielded discrepant results. In the present work, antibodies to the vesicular acetylcholine transporter protein (VAChT) were used to investigate the relationships of immunoreactive nerve fibres to submucosal arterioles. Comparison was made with cerebral arteries, which are known to be cholinergically innervated. Double labelling immunohistochemical techniques revealed separate VAChT and tyrosine hydroxylase (TH) immunoreactive (IR) fibres innervating all sizes of arteries of the submucosa of the stomach, ileum, proximal colon, distal colon and rectum as well as the cerebral arteries. Arterioles of all digestive tract regions had greater densities of TH-IR innervation than VAChT-IR innervation. In the ileum, double labelling for VAChT-IR and VIP-IR or calretinin-IR showed more VAChT-IR than either VIP-IR or calretinin-IR fibres. Calretinin-IR and VAChT-IR were colocalised in a majority of calretinin-IR axons, but VIP-IR and VAChT-IR were not colocalised. All calretinin-IR nerve cells in submucous ganglia were immunoreactive for choline acetyltransferase, but only 1-2% of VIP-IR nerve cells were immunoreactive. Extrinsic denervation of the ileum did not alter the distribution of VAChT-IR fibres, but it eliminated TH-IR fibres. Removal of myenteric ganglia (myectomy) did not alter the distribution of fibres with VAChT or TH-IR. This work thus provides evidence for cholinergic innervation of intrinsic arterioles throughout the digestive tract and indicates that the fibres in the small intestine originate from submucosal nerve cells.
 ...
PMID:Innervation of intestinal arteries by axons with immunoreactivity for the vesicular acetylcholine transporter (VAChT). 956 66

Besides the dopaminergic afferent projection system, calbindin (CALB)- and calretinin (CR)-immunoreactive fibres of intrinsic and extrinsic origin represent the most abundant axonal categories in the rat striatal and lateral septal areas. The question arises whether or not they may represent separate populations, or whether they form subgroups which co-express more than one of these antigens. Therefore, the present study is focused on the distribution patterns of the axons single-immunolabelled by the catecholaminergic marker tyrosine hydroxylase (TH), and on TH-immunoreactive axons displaying also CR- and/or CALB-immunoreactivity in double-immunostained sections. Striking differences were found between the patch and matrix compartments of the caudate-putamen (CP). Whereas the vast majority of TH-immunoreactive fibres in the patches and a patch-associated subcallosal layer co-expressed CR but not CALB, fibres mono-labelled by the TH-immunoreactivity were predominant in the matrix. The matrix-like regions of the core of nucleus accumbens (CACC), fundus striati (FS), the striatal cell bridges (CB) and the striatal part of olfactory tubercle (OTU) coincided in this respect with the matrix in CP. The absence of CR-immunoreactivity was also characteristic of the TH-immunoreactive fibres in the patch-like areas of the accumbal core, although a high number of separate CR-immunoreactive axons were present. In the shell of nucleus accumbens (SACC) which receives a rich catecholaminergic innervation, fibres co-expressing either one of the calcium-binding proteins were absent. The islands of Calleja (CJI) displaying a strongly TH-immunoreactive centre and a periphery of lower staining intensity, showed only a low number of TH-immunoreactive fibres co-expressing CR or CALB. The broad shell-like band of TH-immunoreactive axons between medial and lateral part of the septum was single-stained with the TH-immunoreactivity. In contrast, the TH-positive fibres forming basket-like arrangements around some neurons in the dorsal lateral septal nucleus co-expressed also CR, but not CALB. The results are discussed in view of the recent concepts of basal forebrain organization and the cytochemical characteristics of mesencephalic dopaminergic nuclei giving rise to the vast majority of the striatal and septal TH-immunoreactive fibre supply, in order to correlate the known projection patterns with the content of calcium-binding proteins in TH-immunolabelled fibres and presumed cells of origin. The TH-immunoreactive fibres in the striatal patches displaying CR- but not CALB-immunoreactivity may originate mainly from neurons in the ventral tier of pars compacta (SNC) and from the pars reticulata of substantia nigra (SNR) which show identical cytochemical properties. Axons in the matrix of CP and the accumbal core as well as in the islands of Calleja single-labelled by the TH-immunoreactivity or additionally containing CALB and CR may originate from neurons in the dorsal tier of mesencephalic nuclei like SN, pars compacta and ventral tegmental area. CR-containing TH-immunoreactive basket-like axon terminations in the dorsal lateral septal nucleus are likely to originate either from mesencephalic nuclei or from the supramammillary region.
 ...
PMID:Axonal expression sites of tyrosine hydroxylase, calretinin- and calbindin-immunoreactivity in striato-pallidal and septal nuclei of the rat brain: a double-immunolabelling study. 962 41

The dorsal raphe nucleus (DR) harbours the largest single collection of serotonin (5-HT)-containing neurons in the brain but also comprises other types of chemospecific neurons. The aim of the present study was to characterise morphologically and immunohistochemically the DR in the squirrel monkey (Saimiri sciureus). The morphology of the DR 5-HT-immunoreactive (ir) neurons was analysed and their distribution compared to that of neurons displaying immunoreactivity for either tyrosine hydroxylase (TH), gamma-aminobutyric acid (GABA), substance P (SP), calbindin-D28k (CB), calretinin (CR) or parvalbumin (PV). The 5-HT-ir neurons were distributed in a highly heterogeneous manner throughout the rostrocaudal extent of the DR. The morphology and density of the 5-HT neurons were found to vary significantly in the major subdivisions of the primate DR, that is, the median, ventral, dorsal, ventrolateral, lateral and caudal subnuclei. Numerous SP-, GABA- and PV-ir neurons occurred in all six subnuclei of the DR. The distribution of SP-ir neurons was largely in register with that of 5-HT-ir neurons. Neurons expressing the other neuronal markers (TH, CB, CR) were not present in all six DR subnuclei and their distribution was either complementary to, or in register with, that of 5-HT-ir neurons. The median subnucleus was unique because it contained all the different types of chemospecific neurons. This study has revealed that the primate DR is chemically highly heterogeneous, a finding that may explain the multifarious influence that this nucleus exerts upon various forebrain structures.
 ...
PMID:Chemoarchitecture of the primate dorsal raphe nucleus. 971 63

The ability of dopamine to regulate the cognitive functions of the prefrontal cortex (PFC) involves complex modulatory actions on GABA-containing local circuit neurons in addition to pyramidal cells. However, the subclasses of cortical neurons that receive direct dopamine input are not known. We sought to determine whether dopamine terminals innervate the subclasses of local circuit neurons that contain the calcium-binding protein parvalbumin (PV), namely the wide arbor and chandelier neurons that target pyramidal cell soma and axon initial segments respectively. Sections through area 9 of five monkeys were labeled with immunoperoxidase for tyrosine hydroxylase (TH), to identify dopamine terminals, and with immunogold-silver for PV. Electron microscopic examination of the middle cortical layers (IIIb-IV) revealed that TH-positive terminals were sometimes directly apposed to PV-labeled dendrites, and approximately one-third of these contacts exhibited morphological features that are typically associated with symmetric synapses. In contrast, TH-immunolabeled terminals in the superficial layers (I-IIIa) were less frequently apposed to PV-positive dendrites, and none of these contacts exhibited synapse-like morphology. These findings, in concert with previous studies of GABA- or calretinin-containing local circuit neurons, suggest that dopamine's modulatory action in the PFC involves selective effects on only certain interneuron populations, including those that mediate potent inhibitory actions on pyramidal cells.
 ...
PMID:Dopamine innervation of a subclass of local circuit neurons in monkey prefrontal cortex: ultrastructural analysis of tyrosine hydroxylase and parvalbumin immunoreactive structures. 982 82

Small-eye (Sey) is a spontaneous, semidominant murine mutation that results from a point mutation in the Pax-6 gene. Both the eyes and the olfactory system fail to develop in homozygotes and these animals die neonatally. Heterozygotes (Sey/+) have different degrees of eye abnormalities including decreased lens size and cataracts. In the present study, we examined whether one mutated allele of Pax-6 also affects olfactory system development. By 42 days of age, main olfactory bulb volume was significantly decreased in Sey/+ animals compared with wild-type littermates, and this effect was even more dramatic in 70-day-old animals. In contrast, there was no effect on accessory olfactory bulb, olfactory epithelial, or vomeronasal organ development at any age in Sey/+ animals, demonstrating the specificity of the effect. In the main olfactory bulb, the largest differences in laminar volume were found in the glomerular and granule cell layers. These layers contain the olfactory bulb interneurons, and a subpopulation of these cells were found to be Pax-6 immunoreactive. Examination of the neurochemical consequences of this mutation showed that the number of both tyrosine hydroxylase (TH)- and gamma-aminobutyric acid (GABA)-immunoreactive profiles were dramatically decreased in Sey/+ animals as compared with controls. In contrast, neither calretinin nor calbindin immunoreactivity was affected by this mutation. Dual-labeling immunohistochemistry showed that nearly all TH-immunoreactive cells and a subpopulation of GABA-immunoreactive cells coexpressed Pax-6. However, calretinin- and calbindin-immunoreactive cells were not Pax-6 immunopositive. These data indicate that two normal alleles of Pax-6 are required for normal olfactory bulb development and, as part of this effect, this gene may be involved in the development of specific neurotransmitter systems.
 ...
PMID:Olfactory bulb development is altered in small-eye (Sey) mice. 985 7


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