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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neuronal peptides exert neurohormonal and neurotransmitter (neuromodulator) functions in the central nervous system (CNS). Besides these functions, a group of neuropeptides may have a capacity to create cell proliferation, growth, and survival. Axotomy induces transient (1-21 d) upregulation of synthesis and gene expression of neuropeptides, such as galanin, corticotropin releasing factor, dynorphin, calcitonin gene-related peptide, vasoactive intestinal polypeptide, cholecystokinin, angiotensin II, and neuropeptide Y. These neuropeptides are colocalized with "classic" neurotransmitters (acetylcholine, aspartate, glutamate) or neurohormones (vasopressin, oxytocin) that are downregulated by axotomy in the same neuronal cells. It is more likely that neuronal cells, in response to axotomy, increase expression of neuropeptides that promote their survival and regeneration, and may downregulate substances related to their transmitter or secretory activities.
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PMID:Neuropeptide messenger plasticity in the CNS neurons following axotomy. 757 12

Galanin, oxytocin and cholecystokinin (CCK) are peptides that influence feeding behaviour. Galanin has been found to stimulate food intake and oxytocin and CCK have been suggested to be satiety agents. The present study was performed in order to investigate if galanin influences the secretion of oxytocin and CCK as a possible indication of a functional relationship between these peptides with respect to their influence on feeding behaviour. Galanin (0.1 and 1 micrograms) was administered intracerebroventricularly (i.c.v.) and intraperitoneally (i.p.) to anaesthetized rats and blood samples were collected 20 and 60 min after administration. Plasma levels of oxytocin and CCK were measured with radioimmunoassay. Galanin, 0.1 and 1 microgram, caused a significant decrease in oxytocin levels after 60 min, both when administered i.c.v. and i.p. In contrast, CCK levels increased following i.c.v. and also i.p. galanin. The possible mechanisms by which galanin causes a decrease in oxytocin and an increase in CCK levels are discussed.
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PMID:Effect of galanin on plasma levels of oxytocin and cholecystokinin. 768 Sep 10

In the present study we have investigated the effects of galanin and/or oxytocin on carrageenan-induced hyperalgesia, the relationship between oxytocin and galanin-containing nerve fibers in the spinal cord and the influence of galanin on oxytocin secretion. Galanin (1 microgram) given intrathecally (i.t.) decreased significantly the mechanical nociceptive threshold of the carrageenan-treated hindpaw, with no significant effect on thermal nociception. The decrease in the mechanonociceptive threshold exerted by galanin was modulated by oxytocin (1 microgram, i.t.) administered simultaneously. There was a close relationship between galanin- and oxytocin-immunoreactive fibers in the dorsal horn of the thoracic spinal cord, although there was no evidence for colocalization. Galanin 0.1 and 1 microgram given intracerebroventricularly or intraperitoneally significantly decreased the oxytocin level in plasma 60 min after injection. Taken together, these data indicate that galanin may contribute to mechanical hyperalgesia by inhibiting the release of oxytocin from nerve terminals in the spinal cord and that oxytocin may be a potential analgesic agent.
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PMID:Oxytocin modulates the effects of galanin in carrageenan-induced hyperalgesia in rats. 768 11

Galanin (GAL), a 29 amino acid peptide, is present in magnocellular neurones in the paraventricular and supraoptic nuclei with projections to the neurohypophysis. The effect of GAL on the release of vasopressin, oxytocin and cholecystokinin (CCK) from rat neural lobes was investigated using an in vitro method. GAL in a concentration of 10(-6) M did not affect basal or K(+)-induced release of vasopressin or oxytocin. In contrast, GAL (10(-6) M) significantly stimulated basal and K(+)-stimulated release of CCK. Double-labelling immunofluorescence histochemistry of the neurohypophysis showed that GAL-immunoreactive (-IR) fibres co-contained vasopressin-like immunoreactivity (-LI), whereas the majority of oxytocin-IR fibres were CCK-IR. There was no evidence for colocalization of GAL with CCK or oxytocin. The data suggest a stimulatory role of GAL on CCK release via a paracrine effect on neighbouring oxytocin-CCK-containing nerve fibres.
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PMID:Galanin stimulates the release of cholecystokinin from nerve fibres in the pituitary neurointermediate lobe. 768 86

In neurons, which are post-mitotic cells, a structural and biochemical plasticity occurs, namely for the mediators. The magnocellular hypothalamic neurons innervating the neural lobe are a favourable model for the study of the dynamic aspects of neuropeptides expression. In fact, they synthetize these peptides in large amounts, as a function of the physiological or experimental conditions. In addition to the major neuropeptides, oxytocin (OT) and vasopressin (VP) which are contained in control rats within different neuronal populations, immunocytochemistry and in situ hybridization used alone or in combination in the same preparations have revealed other neuropeptides and corresponding mRNAs respectively. These multiple labellings demonstrate that after osmotic stimulation or during lactation some neurons are able to synthetize OT and VP simultaneously, together with galanin and even tyrosine hydroxylase (but not catecholamines). Similarly, hypophysectomy or transection of the pituitary stalk differentially modify the contents in mRNA coding for VP, OT and galanin. These results have also been described in other neuronal types such as spinal ganglia sensory neurons, suggesting possible mechanisms at different levels of genetic expression: transcription, translation, post-translational events and possibly interneuronal exchanges of mRNA. The in vivo regulation of this neurochemical plasticity probably involves the innervation of these neurons and perhaps the colocalized peptides themselves. In fact, galanin selectively inhibits the expression of VP but not that of OT. Functional implications of the neuronal phenotypic plasticity in the adaptation of the nervous system to the changing physiological conditions are discussed, together with its possible implications in pathology and therapeutics.
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PMID:[A model of phenotypic plasticity: the hypothalamo-posthypophyseal neurons]. 783 3

This study tested for the presence of androgen receptor-immunoreactivity in somatostatin, galanin, vasopressin, corticotropin-releasing hormone, and oxytocin neurons in the rat forebrain. The brains of adult male Sprague-Dawley rats were fixed with 4% paraformaldehyde. Androgen receptor was visualized in coronal sections using nickel intensification of diaminobenzidine, and the neuropeptides were identified using a brown diaminobenzidine reaction product. Androgen receptor was localized to the nuclei of neurons in the septum, amygdala, cortex, hippocampus, and hypothalamus. The majority of somatostatin-containing neurons in the periventricular hypothalamic nucleus also contained androgen receptor. Androgen receptor was also found within galanin-expressing cells in the bed nucleus of the stria terminalis and in the amygdala. Androgen receptor was not observed in corticotropin-releasing hormone, vasopressin, or oxytocin neurons in all areas examined. The data suggest that androgens may be capable of directly regulating somatostatin-expressing neurons of the periventricular nucleus of the hypothalamus and galanin-containing neurons of the bed nucleus of the stria terminalis and amygdala.
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PMID:Localization of androgen receptor within peptidergic neurons of the rat forebrain. 785 Apr 90

Because of the enormous growth over the last three decades of research on the role of peptides in the brain, the need became apparent to determine the status of these compounds in terms of their current research interest. Since 1965, over a quarter of a million research papers have been published on peptides that have since been classified as neuroactive. The present study was undertaken to analyze systematically the yearly trends of research emphasis in neuroactive peptides as reflected by their individual frequency of publication by year, beginning in 1966. A computer analysis of the publication characteristics was carried out using the Medline data base in which the citation search was limited to the topic brain crossed with the topic mammal. One criterion for the inclusion of a given peptide in the analysis was a frequency of 25 or more citations following its discovery, as related to the mammalian brain. The 42 peptides that met this criterion were: adrenocorticotropic hormone, angiotensin II, atrial natriuretic factor, bombesin, bradykinin, calcitonin, calcitonin gene-related peptide, carnosine, beta-casomorphin, cholecystokinin, corticotropin-releasing factor, delta sleep-inducing peptide, dynorphin, beta-endorphin, Leu-enkephalin, Met-enkephalin, galanin, gastrin, glucagon, growth hormone, growth hormone-releasing factor, insulin, kyotorphin, beta-lipotropin, luteinizing hormone-releasing factor, melanocyte-stimulating hormone release inhibitory factor-1, alpha-melanocyte-stimulating hormone, motilin, neurokinin A, neurokinin B, neuropeptide Y, neurotensin, oxytocin, pituitary adenylate cyclase activating polypeptide, peptide HI, prolactin, secretin, somatostatin, substance P, thyroid-releasing hormone, vasopressin, and vasoactive intestinal peptide. An overall analysis of the 298,105 papers published on these 42 peptides since 1965 revealed that the research activity of 24,742, or 8.30%, of the studies, focused on their neuroactive properties. Taken as a whole, the research on neuroactive peptides reached a peak in 1986, as reflected by the total of 1793 papers published during that year. Although the level of publication has fluctuated between 1548 and 1774 research papers over the last 6 years, it is now clear that the trend in research on neuroactive peptides has reached an asymptote today that shows no sign of deviation. A temporal analysis year by year of individual publication profiles revealed three distinct trends: 1) peptides showed a slow development in research interest and did not exceed more than 15-30 publications per year; 2) peptides exhibited a steady increase in research activity over the years that continues today; and 3) peptides displayed an initial, often intense, research emphasis that inexplicably declined, in some cases precipitously, in the mid 1980s.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Neuroactive peptides: unique phases in research on mammalian brain over three decades. 800 41

Single- and double-immunohistochemical staining methods were used to assay the effect of estrogen on the expression of co-existing peptides in the magnocellular neurosecretory system of the female rat. It was confirmed in colchicine-treated, ovariectomized animals that immunoreactive corticotropin-releasing factor and cholecystokinin co-exist in subsets of oxytocinergic neurons; in addition, dynorphin immunoreactivity was detected in a substantial majority of oxytocin containing magnocellular neurons. Consistent with previous studies, magnocellular vasopressinergic cells were found to display angiotensin II-, dynorphin- and galanin-immunoreactivities. Comparable results occurred in colchicine-treated ovariectomized rats independent of whether or not the animals received replacement injections of estradiol benzoate or vehicle. Ovariectomized rats that were not pretreated with colchicine showed enhanced staining (increased cell number and staining intensity of both cell bodies and terminals in the posterior pituitary) for each of the peptides that was found to co-exist in vasopressinergic neurons after treatment with estradiol; staining for vasopressin was similar in steroid- and oil-treated animals. Perikaryal staining for peptides co-localized with oxytocin was not discernibly different in estradiol- vs vehicle-treated animals, while in the posterior lobe, differential effects of hormone replacement on oxytocin, cholecystokinin, and corticotropin-releasing factor immunostaining of terminals were apparent. Perikaryal staining for co-existing peptides in gonadally intact animals killed at the estrus or the diestrus II phases of the estrous cycle provided a pattern of results compatible with those seen in ovariectomized animals treated with estradiol or oil, respectively. These observations suggest that circulating gonadal steroids affect co-existing peptide expression differentially in oxytocinergic vs vasopressinergic neurons. All peptides examined that could be co-localized in vasopressinergic cells showed evidence of enhanced expression in the presence of estrogen, while at least two of these co-localized with oxytocin appeared driven in the opposite direction. The results in normally cycling rats indicate that this kind of influence may be manifest under normal physiological conditions.
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PMID:Neuropeptide co-expression in the magnocellular neurosecretory system of the female rat: evidence for differential modulation by estrogen. 834 19

The nucleus tractus solitarii (NTS), which receives visceral afferent information from the cardiovascular, respiratory, gastrointestinal and taste systems, contains multiple neurotransmitters and neuropeptides throughout its rostral to caudal extent. The neurotransmitters and neuropeptides immunoreactivity is located predominately in varicose fibers and small puncta throughout the neuropil. In addition, immunoreactive NTS neurons for a variety of neurotransmitters and neuropeptides are present in subnuclear regions. The neuroactive substances localized immunohistochemically in the NTS include acetylcholine, the neuropeptides, substance P, methionine- and leucine-enkephalin, beta-endorphin, cholecystokinin, neurotensin, galanin, calcitonin gene-related peptide, somatostatin, FMRMamide, neuropeptide Y, angiotensin II, vasoactive intestinal polypeptide, vasopressin, oxytocin, thyrotropin-releasing hormone, luteinizing hormone-releasing hormone, atrial natriuretic peptide, the catecholamines, dopamine, norepinephrine, epinephrine, serotonin, histamine and the amino acids, GABA and glutamate. The pattern of innervation for each neurotransmitter and neuropeptide is not homogeneously distributed throughout the NTS. Each substance has a unique pattern within the NTS as each subnuclear region contains different immunohistochemical staining patterns and densities of fibers. At the ultrastructural level both neurotransmitters and neuropeptides are present in synaptic terminals that are in contact with different parts of the neuronal membranes. Typically, the labeled terminals contain both small, clear vesicles and large, dense core vesicles with the exception of synaptic terminals containing acetylcholine, GABA and glutamate which do not typically have the large, dense core vesicles. The most frequent post-synaptic target are dendrites and spinous processes. Less frequently, synaptic contacts are present on the cell soma.
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PMID:Immunohistochemical localization of neuropeptides and neurotransmitters in the nucleus solitarius. 867 Jul 16

The magnocellular oxytocin neurons within the paraventricular and supraoptic nuclei (PVN and SON) of the hypothalamus are important relays in the milk ejection reflex in lactating animals, and are activated by suckling. It has been suggested that proto-oncogene transcription factors such as Fos/Jun act as early nuclear transducers of sensory stimuli in neurons. Therefore, we have studied with immunohistochemistry Fos-related antigens (FRAs) as a marker for neuronal activity in the PVN and SON during suckling in lactating rats. In nonlactating rats, only few cells exhibiting FRAs were observed in these nuclei. Also in lactating rats subjected to continuous suckling Fos-like activity was low. In contrast, lactating rats separated from their pups for 4 h and then exposed to suckling for 1 h expressed strong Fos-like immunoreactivity, both in vasopressin and oxytocin neurons. Using in situ hybridization and immunohistochemistry we have also investigated the expression of the mRNAs for oxytocin, dynorphin, galanin and galanin message-associated peptide and of oxytocin and dynorphin in the PVN of lactating and nonlactating rats. In lactating rats, an increase in oxytocin and dynorphin and their mRNAs was observed, whereas mRNAs for galanin and galanin message-associated peptide were downregulated. With the help of immunohistochemistry and double-staining methods, a substantial coexistence between oxytocin- and dynorphin-like immunoreactivities was shown in magnocellular neurons. These results indicate that FRAs are activated in the PVN in the beginning of a suckling period, while this response cannot be seen after continuous stimulation. Furthermore, in the PVN of lactating rats, an upregulation of oxytocin and dynorphin occurs while galanin expression decreases. Finally, the coexistence between oxytocin and dynorphin is more pronounced in lactating rats and nonlactating female rats than has previously been described in male rats.
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PMID:Expression of Fos-related antigens, oxytocin, dynorphin and galanin in the paraventricular and supraoptic nuclei of lactating rats. 873 91


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