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)

With the indirect immunofluorescence technique using antisera to three catecholamine synthesizing enzymes, labeled periglomerular cells as well as their intraglomerular processes were observed in the turtle olfactory bulb. These cells could also be recognized in the EPL and the glomerular layer. Unlabeled periglomerular cells were also seen. Thick labeled processes (presumably dendrites) entered the glomerular neuropil, and there formed a dense network, with numerous terminal varicosities. These results support the existence of a unique, homologous dopaminergic subdivision of the periglomerular interneurons throughout classes of vertebrates. In addition, a second type of weakly tyrosine hydroxylase immunoreactive neurons was observed in the outer part of the granule layer. Dopamine beta-hydroxylase positive fibers were seen in the granule, mitral and external plexiform layers.
 ...
PMID:Dopaminergic periglomerular cells in the turtle olfactory bulb. 612 42

The immunocytochemical localization of tyrosine hydroxylase (TH) and methionine-enkephalin (met-enkephalin) was determined at two representative caudal and rostral levels of the human mesencephalon. Four main groups of catecholaminergic neurons were delineated, situated in the substantia nigra and the lateral, ventromedial and dorsomedial tegmentum, extending over several cytoarchitectonic divisions. They matched fairly well the dopaminergic cell groups described in monkey midbrain. TH-like immunoreactivity and neuromelanin were closely related in neurons of substantia nigra, but less so in the other groups. A widespread met-enkephalinergic innervation was observed in most areas containing catecholaminergic neurons. It followed a characteristic pattern: homogeneous and very dense in the lateral and posterior portions of substantia nigra; patchy and less dense in the other areas, the medio-ventral and periaqueductal gray being only sparsely innervated, in contrast to observations in rodents. Dopaminergic cell bodies surrounded by met-enkephalinergic varicosities were seen in most groups, particularly in the lateral substantia nigra and medioventral tegmentum. The topography of met-enkephali-like immunoreactive terminals in the substantia nigra was reminiscent of the distribution of neostriatal and pallidal afferents.
 ...
PMID:Tyrosine hydroxylase and methionine-enkephalin in the human mesencephalon. Immunocytochemical localization and relationships. 613 45

The ultrastructural morphology of serotoninergic terminals and their synaptic relation with catecholaminergic neurons were examined in the medial nuclei of the solitary tracts (m-NTS) using combined autoradiographic and immunocytochemical methods. Adult rats were pretreated with a monoamine oxidase inhibitor and subjected to a 2-hour intraventricular infusion of 50 nM tritiated 5-hydroxytryptamine (3H-5HT). At the termination of the infusion, the brains were fixed by aortic arch perfusion with a mixture of 4% paraformaldehyde and 0.5% glutaraldehyde. Coronal Vibratome sections through the NTS and more rostral raphe nuclei were immunocytochemically labeled with specific antiserum to serotonin or tyrosine hydroxylase and then processed for autoradiography. By light microscopy, concentrations of reduced silver grains indicating uptake of 3H-5HT usually paralleled the localization of peroxidase immunoreactivity for serotonin in neuronal perikarya of the rostral raphe nuclei and in varicosities in the brainstem. The 3H-5HT-containing varicosities were found throughout the medial and commissural portions of the NTS, where they were frequently associated with processes showing immunoreactivity for the catecholamine-synthesizing enzyme tyrosine hydroxylase. Ultrastructural examination of the m-NTS revealed that the silver grains for 3H-5HT were accumulated over axon terminals. The 5HT-labeled terminals contained a heterogeneous population of vesicles and formed both symmetric and asymmetric synapses with dendrites. The recipient dendrites were either, unlabeled or showed immunoreactivity for tyrosine hydroxylase. These findings support a direct serotoninergic modulation of catecholaminergic neurons within the rat m-NTS.
 ...
PMID:Serotoninergic terminals: ultrastructure and synaptic interaction with catecholamine-containing neurons in the medial nuclei of the solitary tracts. 614 1

Combined radioautographic and immunocytochemical detection of [3H]serotonin-labeled axon terminals and tyrosine hydroxylase-immunoreactive processes in the same thin sections allowed for electron microscopic demonstration of direct appositions between serotoninergic axonal varicosities and dopaminergic nerve cell bodies and/or dendrites in the anterior part of the arcuate nucleus and in the medial zona incerta. Although no junctional specializations were apparent at the sites of contacts, it is proposed that the observed appositions may represent a serotonin input onto tubero-infundibular and incerto-hypothalamic dopaminergic neurons. This innervation could account for some of the central neuroendocrine effects of serotonin, particularly its regulatory role on prolactin and gonadotropin secretion.
 ...
PMID:Ultrastructural relationships between serotonin and dopamine neurons in the rat arcuate nucleus and medial zona incerta: a combined radioautographic and immunocytochemical study. 614 25

The catecholaminergic and peptidergic neurons in the area postrema and adjacent portion of the medial nucleus tractus solitarii (mNTS) were characterized by the immunocytochemical localization of the catecholamine synthesizing enzymes tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine-N-methyltransferase (PNMT) and two neuropeptides, substance P and (Leu5)-enkephalin. The catecholamine synthesizing enzymes TH and DBH, found jointly only in noradrenergic and adrenergic neurons, were localized in cells having a similar morphology and topographical distribution. These cells were located throughout the rostrocaudal and dorsoventral extent of the area postrema, as well as in neurons within the mNTS. The processes showing TH and DBH immunoreactivity appear to form reciprocal connections between the area postrema and mNTS. Phenylethanolamine-N-methyltransferase, the enzymatic marker found only in adrenergic neurons, was detected immunocytochemically in terminals distributed throughout the area postrema and in neuronal perikarya and varicosities within the adjacent mNTS. Like the catecholamine synthesizing enzymes TH and DBH, enkephalin-like immunoreactivity was localized to perikarya, proximal processes and varicose axon terminals within the area postrema and the adjacent mNTS. However, in contrast to the widespread distribution of the enzymes, the enkephalin-like immunoreactivity was localized predominantly along the dorsal and ventrolateral margins of the area postrema. The distribution of substance P immunoreactivity, which was detected only in varicose processes, paralleled the distribution of enkephalin-like immunoreactivity, being predominantly located along the dorsal and ventrolateral margins of the area postrema. Within the mNTS adjacent to the area postrema, substance P immunoreactivity was localized to neuronal perikarya, proximal processes and varicose axon terminals. Based upon the presence of appropriate biosynthetic enzyme markers and neuropeptide localization, these findings suggest that neurons within the area postrema contain noradrenalin and enkephalin and that the afferent axons contain substance P, adrenalin and, probably, noradrenalin.
 ...
PMID:Immunocytochemical localization of catecholamine synthesizing enzymes and neuropeptides in area postrema and medial nucleus tractus solitarius of rat brain. 616 96

The distribution of neuropeptide- (neuropeptide Y, substance P, vasoactive intestinal peptide) and catecholamine-synthesizing enzyme-immunoreactive axons in guinea-pig trigeminal, nodose, and cervical dorsal root ganglia was studied by double-labelling immunofluorescence in controls and after extirpation of either the cervical sympathetic trunk or the stellate ganglion; tyrosine hydroxylase- and dopamine-beta-hydroxylase-immunoreactive terminals in dorsal root ganglia were ultrastructurally investigated. Six neurochemically identifiable axons innervated the trigeminal ganglion, five kinds were found in the nodose and dorsal root ganglia. Two of them (catecholaminergic with and without neuropeptide Y) were of sympathetic origin and, besides their termination at arteries, provided a direct innervation of capsule cells of the trigeminal and cervical dorsal root ganglia facing the subarachnoid space. Varicosities which were interpreted as being of sensory origin were equally numerous in all ganglia, whereas those being likely of parasympathetic origin decreased in numbers from the trigeminal to the dorsal root and nodose ganglia. It is concluded that the sensory ganglia are the target of postganglionic sympathetic, parasympathetic and primary afferent neurons, each of which are specifically organized with respect to the neurochemical phenotype and inter- and intraganglionic distribution. Among other targets, these "nervi gangliorum" appear to be intimately linked to the ganglionic capsular cells and meningeal sheaths facing the liquor spaces.
 ...
PMID:Sensory ganglia as a target of autonomic and sensory nerve fibres in the guinea-pig. 751 9

Microinfusion of serotonin (5-hydroxytryptamine; 5-HT) into the ventral tegmental area enhances the release of dopamine in the nucleus accumbens, a major target of midbrain dopamine neurons. We examined the synaptic basis for 5-HT modulation of neurons in the ventral tegmental area which either (i) project to the nucleus accumbens or (ii) contain the catecholamine synthesizing enzyme tyrosine hydroxylase, a marker of dopamine neurons in this brain region. In the first study, immunoperoxidase labeling of 5-HT in the ventral tegmental area was combined with retrograde transport of gold particles following unilateral injections of the tracer into the nucleus accumbens of adult rats. The gold particles had been previously coupled to wheat germ agglutinin conjugated to inactive horseradish peroxidase. Gold particles were enlarged for visualization using a silver enhancement procedure. By brightfield microscopy, retrogradely labeled neurons contained black punctate granules within their perikarya and proximal processes. The labeled cells were scattered ipsilateral to the injection within the paranigral and parabrachial subdivisions of the ventral tegmental area. Both regions also contained 5-HT immunoreactive varicosities. By electron microscopy, irrespective of the ventral tegmental subdivision, 5-HT labeling was seen primarily in unmyelinated axons and axon terminals. The terminals contained small, clear and large dense core vesicles and ranged from 0.3 micron to 1.4 microns in cross-sectional diameter. 22% (n = 250) of the axon terminals containing 5-HT immunoreactivity formed synaptic contacts with neurons containing the retrograde label. Of these 5-HT terminals, 16% formed asymmetric type contacts and 6% formed symmetric junctions on the retrogradely labeled neurons. The remaining 5-HT terminals were either apposed to (but lacked recognized synapses on) perikarya and large dendrites containing the retrogradely transported protein-gold tracer or contacted unlabeled neurons. In the second set of experiments combining immunoperoxidase of 5-HT and immunogold silver for tyrosine hydroxylase, 32% (n = 250) of the 5-HT-labeled terminals formed synaptic junctions with perikarya or dendrites containing tyrosine hydroxylase immunoreactivity. Of these 5-HT terminals, 23% formed asymmetric type junctions. The remainder were either symmetric or lacked recognized membrane densities. The prominence of asymmetric junctions formed by 5-HT-labeled terminals on neurons projecting to the nucleus accumbens and those containing tyrosine hydroxylase in the ventral tegmental area suggests a cellular basis for serotonergic excitation of mesoaccumbens dopamine neurons. Additionally, the multiplicity of junctions formed by 5-HT terminals on targets with or without retrograde labeling or tyrosine hydroxylase immunoreactivity is consistent with known diverse physiological actions of 5-HT in the tegmental area.
 ...
PMID:Synaptic structure and connectivity of serotonin terminals in the ventral tegmental area: potential sites for modulation of mesolimbic dopamine neurons. 752 22

An immunohistochemical and immunoelectron microscopic study was used to demonstrate tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH) immunoreactivities in the rat pancreas. Small TH immunoreactive cells were found in close contact with large TH immunonegative ganglion cells among the exocrine glands and were occasionally found in some islets. Some of these TH immunoreactive cells were also DBH immunopositive. The immunoreaction product was seen diffusely in the cytoplasm and in the granule cores of TH immunoreactive cells. All intra-pancreatic ganglion cells were immunoreactive for DBH, but not for TH. The TH immunoreactive cells were identified as small intensely fluorescent (SIF) cells due to their localization and morphological characteristics and showed no insulin, glucagon, somatostatin or pancreatic polypeptide immunoreactivities. These results indicate that SIF cells may release dopamine or noradrenaline to adequate stimuli while the intra-pancreatic ganglion cells with only DBH may not synthesize catecholamines in a normal biosynthetic pathway. TH immunoreactive nerve bundles without varicosities and fibers with varicosities, associated or unassociated with blood vessels, were found in both the exocrine and endocrine pancreas. Close apposition of TH immunoreactive nerve fibers to the smooth muscle and endothelial cells of the blood vessels was observed. A close apposition between TH immunoreactive nerve fibers and exocrine acinar cells and islet endocrine cells was sometimes found in the pancreas. The immunoreaction product was seen diffusely in the axoplasm and in the granular vesicles of the immunoreactive nerve fibers. Since no TH immunoreactive ganglion cells were present in the rat pancreas, the present study suggests that noradrenergic nerve fibers in the pancreas may be extrinsic in origin, and may exert an effect on the regulation of blood flow and on the secretory activity of the acinar cells, duct cells and endocrine cells.
 ...
PMID:Immunocytochemical study of tyrosine hydroxylase and dopamine beta-hydroxylase immunoreactivities in the rat pancreas. 752 36

Recently, we observed that atrial natriuretic peptide (ANP) immunoreactivity (IR) was present not only in the Purkinje fibres, but also in nerve fibre varicosities in the conduction system of the bovine heart. These findings and previous observations that ANP is able to influence autonomic neurotransmission in the heart, lead us to elucidate the possible occurrence of ANP in the sympathetic and/or parasympathetic nervous systems and/or in various types of peptidergic innervation in the conduction system. The different parts of the conduction system of bovine hearts were dissected out and processed for immunohistochemistry including double-staining, using antisera against ANP, tyrosine hydroxylase and different neuropeptides. We observed that some of the nerve fibre varicosities exhibiting ANP-IR showed substance P-IR and that ANP was present as scattered immunoreactive granules in intracardial, presumably parasympathetic, ganglionic cells. The study shows that ANP is likely to be present in parasympathetic innervation and in afferent nerve endings in the bovine heart conduction system.
 ...
PMID:Atrial natriuretic peptide in the innervation of the bovine heart conduction system: relationship with substance P and autonomic innervation--immunohistochemical studies. 753 9

Nitric oxide (NO) is synthesized in neurons and is a potent relaxor of vascular and nonvascular smooth muscle. The uterus contains abundant NO-synthesizing nerves which could be autonomic and/or sensory. This study was undertaken to determine: 1) the source(s) of NO-synthesizing nerves in the rat uterus and 2) what other neuropeptides or transmitter markers might coexist with NO in these nerves. Retrograde axonal tracing, utilizing Fluorogold injected into the uterine cervix, was employed for identifying sources of uterine-projecting neurons. NO-synthesizing nerves were visualized by staining for nicotinamide adenine dinucleotide phosphate (reduced)-diaphorase (NADPH-d) and immunostaining with an antibody against neuronal/type I NO synthase (NOS). NADPH-d-positive perikarya and terminal fibers were NOS-immunoreactive (-I). Some NOS-I/NADPH-d-positive nerves in the uterus are parasympathetic and originate from neurons in the pelvic paracervical ganglia (PG) and some are sensory and originate from neurons in thoracic, lumbar, and sacral dorsal root ganglia. No evidence for NOS-I/NADPH-d-positive sympathetic nerves in the uterus was obtained. Furthermore, double immunostaining revealed that in parasympathetic neurons, NOS-I/NADPH-d-reactivity coexists with vasoactive intestinal polypeptide, neuropeptide Y, and acetylcholinesterase and in sensory nerves, NOS-I/NADPH-d-reactivity coexists with calcitonin gene-related peptide and substance P. In addition, tyrosine hydroxylase(TH)-I neurons of the PG do not contain NOS-I/NADPH-d-reactivity, but some TH-I neurons are apposed by NOS-I varicosities. These results suggest NO-synthesizing nerves in the uterus are autonomic and sensory, and could play significant roles, possibly in conjunction with other putative transmitter agents, in the control of uterine myometrium and vasculature.
 ...
PMID:Nitric oxide nerves in the uterus are parasympathetic, sensory, and contain neuropeptides. 753 54


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