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)

To determine if oxytocin (OT) may have a modulatory role on corticotropin-releasing factor (CRF) and vasopressin (AVP) mediated ACTH-cortisol release in women, serial experiments were performed in which saline, OT, AVP and CRF were administered singly or in combinations. OT administration (2 IU intravenous bolus followed by 111 mIU/min infusion for 3 h) maintained a circulating concentration of 7.7 X 10(-8) M and did not significantly influence basal, AVP or CRF-induced ACTH-cortisol release. In contrast, OT inhibited significantly the potentiating effect of AVP on CRF-stimulated ACTH-cortisol release. These findings suggest that OT and AVP may modulate, in a reciprocal fashion, the CRF-mediated ACTH release and support the contention that OT may be involved in the neuroendocrine response to stress in women.
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PMID:Role of oxytocin in the modulation of ACTH release in women. 302 99

The hypothalamic paraventricular nucleus (PVN) has been implicated in a remarkable number of functions including control of pituitary-adrenocortical activity in response to stress, body fluid homeostasis, milk ejection reflex, prolactin secretion, thyroid hormone secretion, analgesia, food intake, gastrointestinal functions, cardiovascular functions, and control of pineal melatonin synthesis. Paraventricular neurons produce hormones of key importance in neuroendocrine regulation such as vasopressin (VP), oxytocin (OX), 41-residue corticotropin releasing factor (CRF), thyrotropin releasing hormone (TRH), somatostatin (SOM) and the putative prolactin releasing factor vasoactive intestinal polypeptide (VIP). Three recent advances pertinent to the organization of the PVN include: (1) the evidence that the structure of the PVN is compartmental in nature, topographically segregated cellular units seem to carry out different functions; (2) the discovery that paraventricular neurons are capable of expressing a multitude of neuromediators simultaneously, thus cellular units can be best specified by a certain combination of neuromediators; (3) evidence that the composition of the neuromediator "cocktail" in individual neurons is variable and depends on the physiological status of the animal. Hence, the PVN may be best considered as a dynamic mosaic of chemically specified subgroups of neurons. The flexibility of neurotransmitter status in paraventricular neurons may play a central role of a functional plasticity of fixed anatomical circuits.
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PMID:Dynamism of chemoarchitecture in the hypothalamic paraventricular nucleus. 304 19

In an electrophysiological study designed to examine the negative feedback effects of glucocorticoid hormones, we have recorded the electrical activity of 147 neurones in the paraventricular nucleus of the rat hypothalamus. 37 (25%) of the neurones were antidromically identified as projecting to the median eminence and were located at a mean depth of 2.35 +/- 0.08 mm from the base of the brain, corresponding with the corticotropin-releasing factor-rich region of the nucleus. The mean firing rate of the identified cells was 4.7 +/- 0.6 Hz which was not significantly different from that of adjacent, unidentified cells (5.6 +/- 0.6 Hz). Most (17/18, 94%) of these cells tested responded to painful somatosensory stimuli and 26 (74%) of the identified cells were inhibited by iontophoretic application of corticosterone and/or hydrocortisone, whereas only one cell was excited and 8 unaffected. Of the identified cells, only 18 (20%) were inhibited, 36 (41%) were excited and 34 (39%) were non-responsive. The proportion of inhibitory responses was thus greater for the identified cells (P less than 0.005; chi 2-test). For the identified cells, whose spontaneous activity was unaffected by glucocorticoid application, glutamate-evoked responses could usually be depressed by the application. The time course of all responses usually showed an immediate onset, increasing in magnitude and continuing for extended periods following cessation of iontophoresis. Electrophysiologically identified magnocellular neurones were also tested and the majority (7/12, 58%) of vasopressin-secreting neurons were also found to be inhibited, whilst all (8/8, 100%) of the oxytocin-secreting neurones were excited by the glucocorticoid application. These results may represent an electrophysiological correlate of the negative feedback control of adrenocortical secretion and are discussed within this context.
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PMID:Iontophoretic application of glucocorticoids inhibits identified neurones in the rat paraventricular nucleus. 340 57

Since neuroimmunomodulation is brought about in part, at least, by secretion of pituitary hormones involved in stress and immune responses, we review briefly the hypothalamic control of the release of ACTH, growth hormone, and prolactin. The release of ACTH is controlled particularly by corticotropin-releasing factor (CRF), but vasopressin has intrinsic releasing activity and potentiates the action of CRF at both hypothalamic and pituitary levels. Oxytocin may even potentiate the action of CRF, but has little, if any, ACTH-releasing activity by itself. In addition, epinephrine may augment responses to the CRFs. In contrast, growth hormone is under dual control by growth-hormone-releasing factor (GRF) and somatostatin, and prolactin is under multifactorial control by a series of inhibitors and stimulators. Dopamine is accepted as a physiological prolactin-inhibiting factor (PIF), but probably GABA and possibly acetylcholine as well are PIFs. There is good evidence for a peptide PIF as well. There are a number of prolactin-releasing factors (PRFs) which include oxytocin, vasoactive intestinal polypeptide, PHI and TRH. Several other peptides can also release prolactin, including angiotensin II. In response to stress there is a complex interaction of peptides intrahypothalamically. CRF augments its own release by an ultra short-loop positive feedback, and there is negative ultra short-loop feedback of GRF and somatostatin. Vasopressin appears to augment CRF release as well as to act directly on the pituitary, and there are complex interactions of various peptides to influence prolactin and GH release.
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PMID:The role of brain peptides in neuroimmunomodulation. 347 67

These studies determined the differential autoradiographic distribution of [125I]alpha-bungarotoxin versus [3H]nicotine relative to the histochemically defined perikarya for neurophysin and corticotropin releasing factor (CRF). Specific [3H]nicotine binding sites occurred in relatively greater density within the neuropil surrounding PVN and SON compared to within the nuclei. In contrast, the highest density of [125I]alpha-BTX sites codistributed with neurophysin immunoreactive perikarya within these nuclei.
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PMID:Distribution of nicotinic binding sites with respect to CRF and neurophysin immunoreactive perikarya within the rat hypothalamus. 349 57

By use of the indirect immunofluorescence method in conjunction with an elution-restaining technique, cells in the caudal neurosecretory system of the big skate (Raja binoculata) and the plainfin midshipman (Porichthys notatus) were shown to contain both urotensin I (UI)/corticotropin-releasing factor (CRF) and urotensin II (UII) immunoreactivities. In the skate coexistence was complete, while in the midshipman some cells demonstrated immunoreactivity for only one or the other neuropeptide. The present results do not support previous suggestions that, like vasopressin and oxytocin in the hypothalamic magnocellular system, UI and UII exist in separate cellular populations in the caudal neurosecretory system. Results of these and other experiments indicate that there exists a wide range of species variation in the degree of coexistence of UI/CRF and UII immunoreactivities within caudal neurosecretory cells.
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PMID:Coexistence of urotensin I/corticotropin-releasing factor and urotensin II immunoreactivities in cells of the caudal neurosecretory system of a teleost and an elasmobranch fish. 353 60

Corticotropin-releasing factor (CRF), a 41 amino acid polypeptide, has been isolated from ovine hypothalamic extracts, sequenced, and synthesized. It has a high potency for stimulating the secretion of corticotropin-like and beta-endorphin-like immunoactive substances in vitro and in vivo in laboratory animals and humans. The high concentration of CRF-like immunoactivity in hypophyseal portal plasma supports the hypothesis that CRF is the physiological hypothalamic factor. Human and rat CRF (rCRF) also have been purified and synthesized. They have an 83% sequence homology with ovine CRF (oCRF). oCRF-like activity has been found in human hypothalamus, pituitary stalk, posterior pituitary, thalamus, cerebral cortex, cerebellum, pons, medulla oblongata, spinal cord and in the adrenal, lung, liver, stomach, duodenum and pancreas. oCRF-like activity also has been found in the human placenta and in tissues producing ectopic ACTH. The action of CRF can be potentiated by vasopressin, oxytocin, epinephrine, norepinephrine, VIP, and angiotensin II. Intracerebroventricular administration of CRF in the rat produces prolonged elevations of plasma epinephrine, norepinephrine, glucose and glucagon; elevates mean arterial pressure and heart rate; increases motor activity and exploration in familiar surroundings and oxygen consumption; and decreases feeding and sexual behavior. Testing with CRF has enabled the separation of patients with hypothalamic and pituitary adrenal insufficiency. The CRF stimulation test has been useful in distinguishing pituitary from ectopic causes of Cushing's disease. The distribution of CRF within and beyond the hypothalamus provides an anatomical context for the observation that CRF can simultaneously activate and coordinate metabolic, circulatory and behavioral responses that are adaptative in 'stressful' situations. CRF not only stimulates the pituitary-adrenal axis in man, but it also influences several aspects of CNS function which may be of relevance to psychiatric illnesses.
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PMID:Corticotropin-releasing factor (CRF)--a review. 353 10

Recent evidence suggests that oxytocin (OXT) potentiates corticotropin releasing factor-induced secretion of ACTH. The present study was therefore designed to investigate the possible role of oxytocin in the response to predictable and unpredictable novelty stress. The results clearly demonstrate that oxytocin produced a significant increase in corticosterone in all OXT treated animals. Repeated unpredictable exposure also produced a more substantial increase in corticosterone than predictable exposure to the same stressor. However, a significant interaction between stress and oxytocin was not obtained. It was concluded that whereas corticosterone is released in response to most types of stress, administration of oxytocin does not potentiate the corticosterone response to psychological stress.
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PMID:A possible role for oxytocin in the response to a psychological stressor. 374 16

The intracerebroventricular (i.c.v.) injection of oxytocin, in doses ranging from 5 to 90 ng (5-90 pmol) induced penile erection and yawning in male rats. Such response was not induced by doses of the peptide higher than 100 ng, nor by equimolar doses of i.c.v. [Arg8]vasopressin, ACTH-(1-24), alpha-MSH, rat corticotropin-releasing factor (rCRF), delta sleep-inducing peptide, neurotensin or substance P. Oxytocin-induced penile erection and yawning were prevented by atropine and morphine, but not by methylatropine or the opiate antagonist naloxone. Haloperidol, a dopamine receptor antagonist, was ineffective at low doses; it partially prevented penile erection but not yawning at high doses. Since oxytocin is present not only in the neurohypophysis but also in other brain areas, our results suggest that oxytocin is implicated in the regulation of penile erection and yawning, and provide further evidence that oxytocin acts as a neuropeptide in the central nervous system.
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PMID:Oxytocin: an extremely potent inducer of penile erection and yawning in male rats. 379 49

Corticotropin-releasing factor (CRF), a potent ACTH secretagogue, has been found to exhibit many characteristics of central neurotransmitter/neuromodulatory substances. In this capacity, hypothalamic CRF might participate in postulated autoregulatory processes which regulate net secretion of adenohypophysical ACTH. We have examined the actions of centrally injected ovine CRF on the secretion of immunoreactive CRF, arginine vasopressin (AVP) and oxytocin (OT) into the hypophysial-portal circulation of urethane-anesthetized rats. Our observations do not support a short-term autoregulatory role for CRF. However, central administration of CRF was associated with a dose-dependent inhibition of hypophysial-portal concentrations of immunoreactive AVP and OT, suggesting potentially important central interactions among putative ACTH-regulatory factors.
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PMID:Central modulation of immunoreactive arginine vasopressin and oxytocin secretion into the hypophysial-portal circulation by corticotropin-releasing factor. 387 93


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