Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pre- and postembedding immunocytochemical procedures were used, together with antisera raised against oxytocin or its neurophysin, to characterize oxytocinergic pathways in the rat spinal cord, at the electron microscopic level. Pre-embedding immunoperoxidase staining performed on vibratome sections revealed oxytocin- and neurophysin-positive axonal profiles and terminals scattered predominantly in laminae I and II of the dorsal horn and in the central gray (lamina X). They were also visible, but to a lesser extent, in the intermediolateral columns, at thoracic and lumbar levels. Postembedding immunogold staining performed directly on ultrathin sections of the same areas, fixed in osmium and embedded in resin, permitted to show clearly that the oxytocinergic axons made symmetrical and asymmetrical synaptic contacts onto dendritic profiles. It also allowed subcellular localization of the neuropeptide immunoreactivities which were restricted to relatively large, electron-dense vesicles in the immunopositive terminals. Oxytocinergic terminals were never seen to participate in glomerular configurations in the superficial layers of the dorsal horn nor were immunoreactive cell bodies visible in any spinal area. Our results provide direct morphological evidence that oxytocinergic pathways make synapses in several regions of the spinal cord, thus supporting the contention that oxytocin may exert neurotransmitter/neuromodulator actions in this area of the CNS.
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PMID:Oxytocinergic innervation of the rat spinal cord. An electron microscopic study. 228 92

The biosynthesis of oxytocin, vasopressin and their associated neurophysins were studied in the projection from the paraventricular nucleus of the hypothalamus to the spinal cord in individual freely-moving adult male rats. Neuropeptide biosynthesis was studied in vivo by the delivery of [35S]cysteine through stereotaxically implanted indwelling cannulae using an osmotic minipump delivery system. Following the appropriate chase times, the neural lobe and spinal cord segments T1-T4 and T12-L2 were removed from fresh tissue; in addition, the nucleus of the solitary tract was punched from frozen coronal sections. The radiolabeled peptides were purified from the tissue homogenates by sequential linear and exponential gradient elution from reverse-phase high performance liquid chromatography columns. This approach has allowed us to purify radiolabeled oxytocin and vasopressin from both the upper and lower spinal cord. However, the kinetics of oxytocin and vasopressin biosynthesis appeared to be remarkably different, as judged by their differential labeling with different pulse and chase times. Additionally, the use of different chase periods following the pulse of radiolabel has allowed us to determine that oxytocin reaches the spinal cord via the fast component of axonal transport (greater than 8 mm h-1). Using immunoprecipitation and purification by high performance liquid chromatography, we were also able to purify radiolabeled neurophysins from spinal cord tissue homogenates. These results lend further support to a role for oxytocin and vasopressin in the modulation of autonomic nervous system function and to the role of the paraventricular nucleus as an integration center for endocrine and autonomic function.
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PMID:In vivo biosynthesis and transport of oxytocin, vasopressin and neurophysin from the hypothalamus to the spinal cord. 242 Nov 98

Age-related changes in the regeneration of vasopressin (AVP) and oxytocin (OXT) axons after hypophysectomy in rats was immunohistochemically examined. Rats were hypophysectomized at 9, 16, 23, 30 and 90 days of age, and sacrificed 10 days after the operation. AVP or OXT immunoreactivity in the external layer of the median eminence (ME) was generally stronger in hypophysectomized immature rats than in hypophysectomized adult rats, and the age-related difference in immunoreactivity was more conspicuous for AVP axons than OXT ones. The cell body size of AVP or OXT neurons in hypophysectomized adult rats was not significantly different from the value of unoperated or initial control rats. However, the neurons in immature rats became significantly larger after hypophysectomy, compared with those of initial controls. These results indicate that AVP- and OXT-producing neurons in immature rats, as early as at 9 days of age, are endowed with the capacity of axonal rearrangement to the external layer of the ME after hypophysectomy, and that the stronger immunoreactivity in the external layer of the ME in immature rats than in the adult may be due to the differences in the rate of synthesis of neurohypophyseal hormones and the regenerative potency of neurons.
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PMID:Regeneration of neurohypophyseal hormone-producing neurons in hypophysectomized immature rats. 244 36

VGF is the designation for a new 712 amino acid protein, regulated by nerve growth factor (NGF) in PC12 cells, that has not been previously described in the CNS. Northern blot analysis with a nick-translated VGF cDNA probe revealed a single band of mRNA in the brain with a molecular weight identical to that found in PC12 cells. The current paper presents a series of immunocytochemical studies of VGF expression with a focus on the hypothalamus. Two different antisera were raised against nonoverlapping amino acid sequences of a bacterial-expressed protein from the VGF gene cloned from PC12 cells. VGF immunoreactivity is strongly expressed in the rat suprachiasmatic nucleus (SCN), particularly in the dorsomedial part of the nucleus. The administration of colchicine to block axonal transport facilitates detection of the VGF immunoreactivity also in the ventrolateral suprachiasmatic nucleus. This protein appears to be the first one of limited neuronal distribution which is found in both dorsomedial SCN and ventrolateral SCN. Immunostaining of serial 1 micron SCN sections reveals co-localization of VGF in cells which also contain vasopressin or vasoactive intestinal polypeptide. Weaker immunoreactivity is also found in the magnocellular paraventricular and supraoptic nuclei, where the VGF immunoreactivity co-localizes with oxytocin or vasopressin. Mutant Brattleboro rats which do not express vasopressin showed strong VGF immunoreactivity both in the dorsomedial SCN and in cells of the magnocellular neuronal systems, including cells which normally express vasopressin. When axonal transport of the protein is blocked by colchicine, VGF-immunoreactive cells in the hypothalamic arcuate, parvocellular paraventricular, and tuberomammillary nuclei can also be detected, in addition to weakly immunoreactive scattered cells in the hippocampus, amygdala, thalamus, and cortex. VGF immunoreactivity is strong in the axonal projections of SCN and weak in the axons of the paraventricular and supraoptic nuclei. With ultrastructural studies, VGF immunoreactivity is found in presynaptic boutons in the SCN and in axons in the neurohypophysis. Weak axonal staining is present in some regions of the hypothalamus and in the external and internal zones of the median eminence. Immunoreactivity is absent from the intermediate lobe of the hypophysis. In neonatal rats strong VGF immunoreactivity is found throughout the SCN at postnatal day 4 but not in the adjacent hypothalamus. VGF immunoreactivity is also seen in other areas of the brain in neonatal rats, including the lateral geniculate nucleus; while the staining in the dorsal lateral geniculate disappears in the adult, that in the intergeniculate leaflet, a visual center which projects to the SCN, remains.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Hypothalamic expression of a novel gene product, VGF: immunocytochemical analysis. 255 5

Using quantitative ultrastructural analysis on cells identified by immunogold postembedding immunocytochemistry, we show that magnocellular oxytocinergic neurons in the adult rat paraventricular nucleus (PVN) undergo significant neuronal-glial and synaptic changes upon stimulation. Thus, during lactation, the surface membranes of most PVN oxytocinergic somata and dendrites were directly juxtaposed; many were also contacted synaptically by the same axonal terminal ('shared' synapses). Non-oxytocinergic profiles showed few plasmalemma juxtapositions and 'shared' synapses. These ultrastructural changes are similar to those that modify oxytocin neurons in the supraoptic nucleus under the same conditions, and indicate that the whole oxytocinergic system in the hypothalamus is capable of neuronal-glial and synaptic plasticity when stimulated to release its neurohormone.
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PMID:Neuronal-glial and synaptic plasticity in the adult rat paraventricular nucleus. 271 93

Acetylcholinesterase activity was demonstrated histochemically at light- and electron-microscopic levels, in Vibratome sections of the supraoptic nucleus of fixed hypothalami derived from osmotically stimulated and unstimulated Long Evans rats, from homozygous Brattleboro rats with hypothalamic diabetes insipidus, from lactating rats, from normal adult male house mice (Mus musculus) and from mice with hereditary nephrogenic diabetes insipidus (di/di). Reaction product was located in supraoptic magnocellular neurons; in dorsal and rostral aspects of the supraoptic nuclei lightly stained cells predominate, whereas in ventral and caudal regions densely staining perikarya predominate. Pre- and post-embedding immunocytochemical detection of oxytocin-neurophysin or vasopressin-neurophysin, combined with acetylcholinesterase histochemistry, showed that the lightly staining cells are oxytocinergic, and the densely staining cells vasopressinergic. Osmotic stimulation of the animals, either by substitution of drinking water for 3 days with 2.5% saline or reason of genetic defects which result in diabetes insipidus, enhanced the acetylcholinesterase activity of the vasopressin neurons but had little effect on the weekly acetylcholinesterase-reactive oxytocin cells. Acetylcholinesterase activity was particularly marked in the hypertrophied abnormal magnocellular neurons of homozygous Brattleboro rats which do not release significant amounts of vasopressin. The increased acetylcholinesterase activity in osmotically stimulated animals cannot, therefore, be a function of vasopressin. Acetylcholinesterase activity was also detected in large multipolar neurons lying dorsolateral to the supraoptic nucleus, and in their fine axonal processes which project towards the supraoptic nucleus. A very few synaptic boutons surrounded by acetylcholinesterase reaction product were found in contact with magnocellular neuron basal dendrites. However, much of the punctate acetylcholinesterase reactivity observed at the light microscopic level and previously interpreted as representing the loci of cholinergic synaptic boutons was shown to be intracellular, and probably caused by acetylcholinesterase activity in some large, secondary lysosomes.
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PMID:Differential distribution of acetylcholinesterase activity among vasopressin- and oxytocin-containing supraoptic magnocellular neurons. 276 86

A single-base deletion in the single-copy vasopressin gene is the cause of diabetes insipidus in the homozygous Brattleboro rat (di/di). It results in the synthesis of an altered vasopressin precursor of which the axonal transport is blocked. Paradoxically, a small number of solitary hypothalamic neurons displays all the immunoreactivities of the wild-type vasopressin precursor (i.e., vasopressin, neurophysin, and a glycopeptide). In the present paper we provide evidence that these neurons have undergone a switch to a genuine heterozygous (di/+) phenotype; i.e., they contain the immunoreactivities of both the wild-type and the mutated vasopressin precursors. In the neural lobe, glycopeptide fibers are also present, showing that axonal transport of the wild-type precursor is restored. Moreover, the number of neurons displaying this di/+ phenotype increases markedly and in a linear way (from 0.1% up to 3% of the vasopressin cells) with age. These findings indicate that after mitotic division has ceased, genomic alterations occur in somatic neurons in vivo. The molecular event generating the di/+ phenotype in the di/di animal could involve a somatic intrachromosomal gene conversion between the homologous exons of the vasopressin and the related oxytocin genes.
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PMID:Age-related development of a heterozygous phenotype in solitary neurons of the homozygous Brattleboro rat. 276 32

The application of freeze-substitution (FS) and freeze-drying (FD) techniques and the protein A-gold-antibody complex immunocytochemical methods are described. The two tissue-preparation techniques produced excellent ultrastructure and topographical fixation of antigens when compared with conventional tissue-preparation techniques. In the FS preparation, however, occasional extragranular immunolabeling was recognized. This may suggest the leakage of antigens from the secretory granules. The FD procedure was considered the best, since such labeling was almost negligible. The protein A-gold-antibody complexes are easily prepared and label the antigens clearly. If the protein A-coated gold particles are saturated with antibodies, there is no interaction between gold particles. Thus, multiple antigens can be determined even in single secretory granules. In fact, we demonstrated intragranular colocalization of immunoreactive oxytocin, labeled with 50-nm gold particles, and immunoreactive methionine-enkephalin, labeled with 15-nm gold particles, in the axonal terminals of the FD-prepared rat neurohypophysis. This study demonstrates the value of the use of gold-antibody complexes for immunocytochemical labeling on FS- or FD-treated tissues.
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PMID:Some improvement in tissue preparation and colloidal-gold immunolabeling for electron microscopy. 287 47

Immunohistochemical and axonal transport methods were used to chart the distribution of somatostatin-immunoreactive (SS-IR) fibres in the paraventricular (PVH) and supraoptic (SO) nuclei of the rat hypothalamus and to identify the cell group(s) from which they originate. Fibres and varicosities immunoreactive for SS-28 and/or SS-281-12 are found primarily in the parvocellular division of the PVH, though aspects of the magnocellular division, and of the SO, in which oxytocinergic neurons are clustered also receive moderate inputs. Combined retrograde transport-immunohistochemical studies indicated that these arise principally from non-catecholaminergic neurons in the lateral aspect of the commissural part of the nucleus of the solitary tract (NTS). SS-28 has been shown to act within the central nervous system to elicit both oxytocin and vasopressin secretory responses, and may be involved in mediating vasopressin secretory responses to haemorrhage. Direct SS-28-IR inputs to the magnocellular cell groups from the NTS, which receives primary visceral sensory inputs, are in a position to play a role in mediating oxytocin secretory responses to interoceptive stimuli; the pathway(s) and mechanism(s) which allow SS-28 to interact with vasopressinergic neurons are not clear.
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PMID:Somatostatin 28-immunoreactive inputs to the paraventricular and supraoptic nuclei: principal origin from non-aminergic neurons in the nucleus of the solitary tract. 290 91

Neurohypophysial hormones and neurophysins are former domains of common precursors processed during the axonal transport from hypothalamus to neurohypophysis. Two neurohormones, an oxytocin-like and a vasopressin-like, and two neurophysins, termed VLDV- and MSEL-neurophysins according to residues in positions 2, 3, 6 and 7, are usually found in vertebrate species. In mammals, a non-covalent stoichiometric and reversible complex including the two neurohormones and the two neurophysins has been isolated. In contrast to other mammals investigated, the three-domain precursor of vasopressin (vasopressin, MSEL-neurophysin and copeptin) is not completely processed in guinea pig and an intermediate precursor including MSEL-neurophysin and copeptin linked by an arginine residue has been isolated and sequenced. "In vitro" processing of this intermediate through trypsin-Sepharose has revealed cleavages only in the inter-domain region, showing the role of precursor conformation in the processing. In neurosecretory granules from guinea pig, only free vasopressin and MSEL-neurophysin have been detected. In bovine foetus at the age of 3 and 7 months, only vasopressin and oxytocin in molar ratios 4 and 3, respectively, have been identified as well as adult MSEL- and VLDV-neurophysins. No vasotocin and no additional neurophysin when compared to the adult have been found. Diabetes insipidus rats from the Brattleboro strain have been examined in order to identify an abnormal vasopressin precursor. No free vasopressin and no free MSEL-neurophysin have been detected through high pressure liquid chromatography whereas oxytocin and VLDV-neurophysin have been identified.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Common precursors of neurohypophysial hormones and neurophysins]. 305 82


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