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)

The ultrastructural features of paraventricular (PVN) and supraoptic (SON) neurons and of their axons were studied in lactating and dehydrated rats. Under both conditions of stimulation, the PVN and SON neurons and their axons enlarge. The protein synthesizing apparatus of the neurons becomes activated, but the number of neurosecretory granules (NSG) is decreased. No differences are seen between the PVN and SON neurons during lactation or dehydration. The similarity and simultaneity of the response of the PVN and SON neurons to these two different stimuli is discussed in the light of the theory of nuclear and neuronal specialization for the production of only one hormone. After prolonged lactation of over 2 1/2 weeks' duration, neurons with extreme vacuolation of the rough endoplasmic reticulum (RER) appear in the PVN and SON; the vacuolated neurons appear earlier and predominantly in the PVN involving a maximum of 10-15% of all PVN neurons. Vacuolated neurons were never seen in either nucleus during dehydration of up to 6 days' duration. The vacuolation is suggested to represent an exhaustion phenomenon due to an intense, long-lasting stimulus for oxytocin synthesis. The predominant location of the vacuolated neurons in the PVN supports the theory that oxytocin is produced predominantly in the PVN. The decrease in the number of NSGs during these states of enhanced hormone secretion is considered to corroborate the proposed existence of an extragranular fast axoplasmic transport mechanism in PVN and SON neurons. The possible existence of a reuptake mechanism into NSGs, similar to that in the vesicles of monoaminergic nerve endings is discussed.
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PMID:Ultrastructural studies on the hypothalamic neurosecretory neurons of the rat. III. Paraventricular and supraoptic neurons during lactation and dehydration. 5 8

In the external layer of the median eminence of the fox, the somatostatin-containing fibers and neurophysin-containing fibers of the hypothalamo-infundibular tract are located in distinct areas. In the neural lobe, somatostatin-positive areas are simultaneously neurophysin-positive. Outside the SON and PVN, some somatostatin-positive and neurophysin-negative perikarya are scattered close to the third ventricle. These facts suggest the existence of two somatostatin systems: a hypothalamo-infundibular (neurophysin-negative) one and a hypothalamo-neurohypophyseal (neurophysin-positive) one.
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PMID:[Somatostatin-containing fibers and neurophysin-containing fibers in the median eminence of the fox, as seen with a double staining cytoimmunoenzyme technique]. 14 93

Synthetic oxytocin and [8-arginine]-vasopressin conjugated to bovine thyroglobulin were used to induce specific antibodies in rabbits. The specificity of the anti-oxytocin serum, and the suitability of the anti-[8-arginine]-vasopressin serum for the detection of [8-lysine]-vasopressin, was evaluated by immunofluorescent studies of the respective hormones bound to Sepharose 4B particles. Oxytocin and [8-lysine]-vasopressin were specifically localized in the paraventricular (PVN) and supraoptic (SON) nuclei of the pig hypothalamus using the immunoperoxidase staining technique. After an examination of serial transverse and sagittal sections stained for either of the hormones we observed that: 1. In the rostral SON, oxytocin and vasopressin containing neurons were uniformly distributed; 2. In the caudal SON, most of the neurons contained oxytocin, but there were still a few 'vasopressin' neurons; 3. In the rostral PVN, the two hormones were evenly spread in neurons close to the third ventricle; 4. In the caudal PVN, the oxytocin and vasopressin containing neurons were differentially distributed, with 'oxytocin' neurons adjacent to the third ventricle, and 'vasopressin' neurons lateral to these and concentrated in the dorso-caudal PVN. In the cells of the PVN, there was evidence that the distribution of oxytocin and vasopressin is similar to the distribution of porcine neurophysin-II and porcine neurophysin-I respectively. This similarity is consistent with the one hormone--one neurophysin concept in the pig.
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PMID:Immunocytochemical study of the hypothalamo-neurohypophysial system. III. Localization of oxytocin- and vasopressin-containing neurons in the pig hypothalamus. 32 54

Localization studies of the hypothalamohypophysial and tuberoinfundibular neurosecretory systems were performed in the adult male mallard duck with an immunoperoxidase techinque for the demonstration of neurophysin (NP) and gonado-tropin-releasing hormone (Gn-RH) and with aldehyde fuchsin for the staining of neuosecretory material (NSM). A comparison was made between the distribution of NSM stained with aldehyde fuchsin and NP seen by immunocytochemistry. The magnocellular perikarya of the supraoptic (SON) and paraventricular (PVN) nuclei, the zona externa of the anterior median eminence (ME), the fiber layer of both the anterior and posterior ME, and small neurons in the tractus quintofrontalis were stained by both the immunoperoxidase method for NP and by the aldehyde fuchsin stain. In contrast, the parvocellular neurons of the PVN, extra-hypothalamic neurosecretory fibers dorsal to the anterior commissure in the septal region and tanycytes lining the ventral 1/3 of the third ventricle at the level of the anterior ME, were stained only by the immunocytochemical procedure for NP. These observations indicate that immunocytochemistry is more sensitive than aldehyde fuchsin staining for detecting low concentrations of NP in cells and tissues, but the two techniques produce comparable results where the concentration of the NP is relatively high. Two populations of beaded axons containing Gn-RH were distributed throughout the zone externa of both the anterior and posterior ME. One group of fibers paralleled the hypothalamo-hypophysial neurosecretory tract whereas the other was distributed in the contact zone of the ME. Immunoreactive Gn-RH was found in the cytoplasm of a sparse population of cell bodies in the dorsolateral portion of the arcuate nucleus as well as in the axons that project from this nucleus ventrally towards the ME.
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PMID:Neurosecretory pathways in the mallard duck (Anas platyrhynchos) brain: localization by aldehyde fuchsin and immunoperoxidase techniques for neurophysin (NP) and gonadotrophin releasing hormone (Gn-RH). 79 39

The present paper deals with the development of an immunofluorescence procedure that allows specific localization of vasopressin and oxytocin in the hypothalamo-neurohypophyseal system(hnx) of the rat. Antibodies against arginine vasopressin (AVP), lysine-vasopressin (LVP) and oxytocin were raised by injecting these hormones that were covalently bound to thyroglobulin into rabbits. The vasopressin-immunized rabbits showed periods of diabetes insipidus, while histoloty of the "hns revealed an intact neurosecretory system with signs of increased endogenous hormone synthesis in the supraoptic nucleus and increased release in the neuro-hypophysis of some rabbits. The daily water intake of the oxytocin-immunized rabbits was similar to that of control rabbits. The development of antibodies against vasopressin as measured in the immunofluorescence procedure showed a course that was quite different from the curve of the titer as determined by radioimmunoassay (RIA). Also the specificity of the antibodies used in the immunofluorescence procedure was found to be quite different from their specificity in a RIA system. Potency and specificity of the antibodies have to be studied therefore within the immunofluorescence procedure itself. Using freshly frozen acetone-postfixed hypotalami or pituitaries, no sharp localization of immunofluorescence could be obtained in the HNS. Therefore prefixation was performed. Both, the type and the duration of prefixation revealed quite different results regarding the immunofluorescence in the neurosecretory cell boides in the hypotalamus and of their endings in the neurohypophysis. The best immunofluorescence results were obtained using 6 hours glyoxal-prefixation for the hypothalamus and 24 hours formalin-prefixation for the pituitary. The cross-reaction of the antibodies for oxytocin or vasopressin was tested on synthetic hormones that were bound to CNBR-activated agarose beads and mounted on glass sides. All anti-plasmas showed cross-reaction on beads containing the heterologou- antigen. The plasmas were purified by incubation with beads containing the heterologous hormone until the cross-reacting component had been removed. Using purified antibodies, the distribution of oxytocin and vasopressin cells within the HNS was investigated. More oxytocin containing cells were localized in the rostral part and more vasopressin in the caudal part of both, the supraoptic (SON) and paraventricular nucleus (PVN). Comparable percentages of oxytocin and vasopressin containing cells were found in the SON and PVN. The absolute amount of oxytocin containing cells was 2.5 times more in the SON than in the PVN, which seems to contradict the "classical" view that the PVN predominantly or entirely synthetizes oxytocin. In addition, fluorescence was found using antobodies against vasopressin in the suprachiasmatic nucleus in Wistar rats and heterozygous Brattleboro rats, but not in this nucleus of homozygous Brattleboros.
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PMID:Immunofluorescence of vasopressin and oxytocin in the rat hypothalamo-neurohypophypopseal system. 110 Jul 84

Rats were decapitated and the complete head stored at 4 degrees C. At various time intervals, up to a maximum of 14 days, the brains and pituitary glands were removed and fixed in formalin-picric acid. Neurosecretory material (NSM), as revealed with crotonaldehyde fuchsin, and neurophysin as demonstrated by means of immunoperoxidase histochemistry were localized in the hypothalamic magnocellular nuclei, median eminence and posterior pituitary gland. NSM and neurophysin were present in the paraventricular (PVN) and supra-optic (SON) nuceli up to periods of 14 days although the cellular morphology was disrupted after about 4 days. After 4 days there was an abundance of positive staining "droplets" in both the SON, PVN and along the nerve fibers of the supraoptico-neurohypophysial tract. Pituitary gland NSM and neurophysin were still present 14 days post mortem. The slab gradient polyacrylamide gel electrophoresis pattern of soluble proteins extracted from the posterior pituitary gland from the experimental and normal animals showed almost complete identity confirming the minimal action of proteolytic enzymes at 4 degrees C up to a period of 6 days. It is concluded that as long as the tissue is cooled, rapid fixation of hypothalamic tissue is not essential for the localization of NSM and neurophysin.
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PMID:Time of fixation and the localization of Gomori-positive and neurophysin-containing structures in the rat hypothalamus. 110 5

The cellular distribution of neurophysin was examined in hypothalami and neural lobes of normal Long-Evans rats and Brattleboro rats deficient in vasopressin and a major neurophysin. Tissue sections were treated with antisera to bovine, human, and rat neurophysins, using immunoperoxidase bridge techniques. Antisera to oxytocin (OT) and vasopressin (VP) were applied to adjacent sections. Two distinct cell populations were discernible in both magnocellular nuclei on the basis of the intensity of cytoplasmic staining. About half of the magnocellular neurons in the supraoptic (SON) and paraventricular (PVN) nuclei of homozygous Brattleboro rats with diabetes insipidus (DI) were devoid of immunoreactive neurophysin, OT, and VP. These cells were presumably the defective counterparts of those neurons that produce VP and its associated neurophysin in normal and heterozygous Brattleboro rats. The cells in homozygous DI rats which were stained with immunoreaction products to NP and OT were more concentrated in the dorsal part of the SON and in the periphery of the PVN. Spatial segregation of different neurons was also seen in the neural lobe, where clusters of stained axons were surrounded by bundles of nerve fibers lacking immunoreactive material. In normal rats and heterozygotes nearly all magnocellular neurons reacted immunologically with antiserum to neurophysin but with different intensities, so that "dark" and "light" cells could be distinguished. The darker cells in heterozygous Brattleboro rats had the same pattern of distribution as cells which contained OT. In homozygous DI rats, only some of those cells which contained neurophysin and OT exhibited a positive reaction with antiserum to VP due to slight reactivity with OT. The results obtained in the homozygous Brattleboro rat would suggest that OT and VP and their associated neurophysins are produced in different neurons in both the SON and PVN. However, in normal rats and in heterozygous Brattleboro rats, VP appeared to be present in both OT-positive and OT-negative neurons suggesting that some cells may have the capacity to synthesize two hormones.
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PMID:The hypothalamic-neurohypophysial system of the rat: localization and quantitation of neurophysin by light microscopic immunocytochemistry in normal rats and in Brattleboro rats deficient in vasopressin and a neurophysin. 126 12

Double immunostaining for c-fos and oxytocin (OXY) was used to study the topography and time course of the metabolic activation of the hypothalamic oxytocinergic system upon osmotic stress in the male rat. Animals injected i.p. with hypertonic saline expressed c-fos-like immunoreactivity (FLI) in the paraventricular (PVN), periventricular (PEV) and supraoptic (SON) hypothalamic nuclei, and in the preoptic and retrochiasmatic regions, as early as 30 min after stimulation and up to 6 h, while these areas were mostly devoid of staining in isotonic saline-injected animals. The activation of the oxytocinergic system peaked at 30 min and declined at different rates in the PVN and in the SON after 90 min. The maximal percentage of OXY neurons expressing FLI upon osmotic stress was about 80% in the SON, PEV and LSN, 60% in the PVN and 50% in the medial preoptic area. Activated OXY neurons were found in both the magnocellular and parvocellular divisions of the system. These data show that OXY nuclei in the rat hypothalamus are differentially activated by osmotic stress. They also suggest a role of OXY in the central as well as in the humoral response to changes in plasma osmolarity.
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PMID:Expression of c-fos protein by immunohistochemically identified oxytocin neurons in the rat hypothalamus upon osmotic stimulation. 139 70

The oxytocin positive elements of the hypothalamic supraoptic (SON) and paraventricular (PVN) nuclei, were instigated in 160 male rats through immunohistochemical, morphometric and statistical methods. The rats subdivided into five groups: 20 control rats; 20 rats treated with physiological saline intraperitoneal via (ip); 20 rats treated with physiological saline intracerebroventricular via (icv); 20 histamine (HA) treated rats, ip; and 20 HA treated rats, icv. Some labeled nerve cells appear, mainly, in the lateral part of the SON and the PVN of the control animals. These neurons have central nucleus and oxytocin positive cytoplasmic granulations. After the treatment with physiological saline, ip or icv, no alterations were observed. In HA treated rats, icv, numerous neurons and pathways were observed strongly labeled. Large droplets appear in the SON and in the PVN of these animals. In HA treated rats, ip, the oxytocin positive material is similar to that observed in the control rats. The morphometric and statistical studies confirm these findings. The results are discussed in this paper.
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PMID:The oxytocin positive elements in the hypothalamic magnocellular nuclei of rats treated with histamine. 142 May 94

Recent evidence has implicated hypothalamic peptides, such as arginine vasopressin (AVP) and oxytocin (OT) in the control of feeding behavior. In this study, we investigated the impact of food deprivation (48 h) and subsequent refeeding (6 h) on the concentration of AVP and OT in discrete hypothalamic areas, as well as in the neurohypophysis. We also estimated in these rats certain peripheral measures, including hydroelectrolytic parameters, plasma and urine AVP, and plasma corticosterone. The results of this study revealed that food deprivation for 48 h produced little change in OT concentration in the various hypothalamic nuclei studied, including the paraventricular and supraoptic nuclei, with the exception of the median eminence (ME), where a significant decline (-36%; p < 0.05) was detected. This effect was not significantly reversed by 6 h of refeeding. With respect to AVP concentration, food deprivation caused a reliable decline exclusively in the parvocellular subdivision of the paraventricular nucleus (pPVN; -45%; p < 0.01) and in the supraoptic nucleus (SON; -45%; p < 0.01). No change in AVP was detected in the ME or in most other hypothalamic nuclei examined. Refeeding for 6 h actually potentiated the effect of food deprivation, decreasing further from baseline the content of AVP in the pPVN and SON. The only other hypothalamic area to exhibit a change in AVP content was the ventromedial nucleus, where AVP level increased (p < 0.001) after deprivation and declined to normal after 6 h of refeeding. The content of AVP and OT in the neurohypophysis was unaffected by food deprivation and subsequent refeeding.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of food deprivation and refeeding on the concentration of vasopressin and oxytocin in discrete hypothalamic sites. 144 84


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