The Same Magnocellular Neurons Send Axon Collaterals to the Posterior Pituitary and Retina or to the Posterior Pituitary and Autonomic Preganglionic Centers of the Eye in Rats

In rats, some parvocellular paraventricular neurons project to spinal autonomic centers. Using the virus tracing technique, we have demonstrated that some magnocellular paraventricular neurons, but not supraoptic neurons, also project to autonomic preganglionic centers of the mammary gland, gingiva, or lip. A part of these neurons has shown oxytocin immunoreactivity. In the present experiment, we have examined whether the same magnocellular neuron that sends fibers to the retina or autonomic preganglionic centers of the eye also projects to the posterior pituitary. Double neurotropic viral labeling and oxytocin immunohistochemistry were used. After inoculation of the posterior pituitary and the eye with viruses, spreading in a retrograde direction and expressing different fluorescence proteins, we looked for double-labeled neurons in paraventricular and supraoptic nuclei. Double-labeled neurons were observed in non-sympathectomized and cervical-sympathectomized animals. Some double-labeled neurons contained oxytocin. After the optic nerve was cut, the labeling did not appear in the supraoptic nucleus; however, it could still be observed in the paraventricular nucleus. In the paraventricular nucleus, the double-labeled cells may be the origin of centrifugal visual fibers or autonomic premotor neurons. In the supraoptic nucleus, all double-labeled neurons are cells of origin of centrifugal visual fibers.

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Nesfatin-1 Neurons in Paraventricular and Supraoptic Nuclei of the Rat Hypothalamus Coexpress Oxytocin and Vasopressin and Are Activated by Refeeding

Endocrinology ◽

10.1210/en.2007-1276 ◽

2007 ◽

Vol 149 (3) ◽

pp. 1295-1301 ◽

Cited By ~ 173

Author(s):

Daisuke Kohno ◽

Masanori Nakata ◽

Yuko Maejima ◽

Hiroyuki Shimizu ◽

Udval Sedbazar ◽

...

Keyword(s):

Feeding Behavior ◽

Mrna Expression ◽

Paraventricular Nucleus ◽

Supraoptic Nucleus ◽

Energy Homeostasis ◽

Rat Hypothalamus ◽

Hypothalamic Nuclei ◽

Vasopressin Neurons ◽

Fine Localization ◽

Supraoptic Nuclei

Nesfatin-1, a newly discovered satiety molecule, is located in the hypothalamic nuclei, including the paraventricular nucleus (PVN) and supraoptic nucleus (SON). In this study, fine localization and regulation of nesfatin-1 neurons in the PVN and SON were investigated by immunohistochemistry of neuropeptides and c-Fos. In the PVN, 24% of nesfatin-1 neurons overlapped with oxytocin, 18% with vasopressin, 13% with CRH, and 12% with TRH neurons. In the SON, 35% of nesfatin-1 neurons overlapped with oxytocin and 28% with vasopressin. After a 48-h fast, refeeding for 2 h dramatically increased the number of nesfatin-1 neurons expressing c-Fos immunoreactivity by approximately 10 times in the PVN and 30 times in the SON, compared with the fasting controls. In the SON, refeeding also significantly increased the number of nesfatin-1-immunoreactive neurons and NUCB2 mRNA expression, compared with fasting. These results indicate that nesfatin-1 neurons in the PVN and SON highly overlap with oxytocin and vasopressin neurons and that they are activated markedly by refeeding. Feeding-activated nesfatin-1 neurons in the PVN and SON could play a role in the postprandial regulation of feeding behavior and energy homeostasis.

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Release of oxytocin and vasopressin by magnocellular nuclei in vitro: specific facilitatory effect of oxytocin on its own release

Journal of Endocrinology ◽

10.1677/joe.0.1020063 ◽

1984 ◽

Vol 102 (1) ◽

pp. 63-NP ◽

Cited By ~ 186

Author(s):

F. Moos ◽

M. J. Freund-Mercier ◽

Y. Guerné ◽

J. M. Guerné ◽

M. E. Stoeckel ◽

...

Keyword(s):

Paraventricular Nucleus ◽

Supraoptic Nucleus ◽

Male Rats ◽

Facilitatory Effect ◽

Vasopressin Release ◽

Paraventricular Nuclei ◽

Magnocellular Nuclei ◽

Oxytocin Release ◽

Supraoptic Nuclei

ABSTRACT The release of endogenous oxytocin and vasopressin by rat paraventricular and supraoptic nuclei in vitro during a 10-min period, 30 min after beginning the incubation, was measured radioimmunologically. Mean basal hormone release per 10 min and per pair of nuclei was: 128·4 ± 12·4 (s.e.m.) pg vasopressin (n = 15) and 39·0 ± 3·0 pg oxytocin (n = 66) for supraoptic nuclei from male rats; 273·9 ± 42·6 pg vasopressin (n = 11) and 34·2 ± 3·5 pg oxytocin (n = 15) for supraoptic nuclei from lactating rats; 70·0 ± 8·6 pg vasopressin (n = 52) and 21·8 ± 1·3 pg oxytocin (n = 68) for paraventricular nuclei from male rats; 59·1 ± 8·6 pg vasopressin (n = 10) and 27·0 ± 4·6 pg oxytocin (n = 16) for paraventricular nuclei from lactating rats. In male and lactating rats, both nuclei contained and released more vasopressin than oxytocin. For oxytocin alone, the paraventricular nucleus of male rats contained and released significantly less hormone than the supraoptic nucleus. This difference was not apparent in lactating rats. For vasopressin alone, the paraventricular nucleus contained and released significantly less hormone than the supraoptic nucleus in both male and lactating rats. When the hormone released was calculated as a percentage of the total tissue content the release was about 0·9% for oxytocin from both nuclei in male and lactating rats and also for vasopressin in lactating rats, but was only about 0·5% for vasopressin from both nuclei in male rats. The influence of oxytocin and analogues of oxytocin (including one antagonist) upon the release of oxytocin and vasopressin was studied. Adding oxytocin to the incubation medium (0·4–4 nmol/l solution) induced a dose-dependent rise in oxytocin release from both nuclei of male or lactating rats. A 4 nmol/l solution of isotocin had a similar effect to a 0·4 nmol/l solution of oxytocin, but arginine-vasopressin never affected basal release of oxytocin. In no case was vasopressin release modified. An oxytocin antagonist (1 μmol/l solution) significantly reduced basal oxytocin release and blocked the stimulatory effect normally induced by exogenous oxytocin, as did gallopamil hydrochloride (D600, 10 μmol/l solution), a Ca2+ channel blocker, or incubation in a Ca2+-free medium. These findings are discussed in relation to the literature on the central effects of neurohypophysial peptides. It may be concluded that the regulatory role of endogenous oxytocin in the hypothalamus on the milk-ejection reflex could result from its local release in the extracellular spaces of magnocellular nuclei. J. Endocr. (1984) 102, 63–72

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THE RELATION BETWEEN THE HYPOTHALAMIC NEUROSECRETION AND THE CORTICOTROPHIN RELEASE IN EXPERIMENTAL CONDITIONS

Acta Endocrinologica ◽

10.1530/acta.0.xxxiv0008 ◽

1960 ◽

Vol XXXIV (I) ◽

pp. 8-18 ◽

Cited By ~ 6

Author(s):

E. Kivalo ◽

U. K. Rinne

Keyword(s):

Paraventricular Nucleus ◽

Median Eminence ◽

Supraoptic Nucleus ◽

Acute Stress ◽

Neurosecretory Material ◽

Experimental Conditions ◽

Hypothalamic Cells ◽

The One ◽

Hypophysial Portal ◽

Acth Release

ABSTRACT Acute stress, chronic stress plus hydration, cortisone treatment, cortisone treatment plus dehydration were used as methods of investigation and the relation between the neurosecretory activity of the hypothalamic supraoptic nucleus and paraventricular nucleus and the neurosecretory material around the hypophysial portal vessels of the median eminence on the one hand and the corticotrophin release on the other hand, has been studied in the rat. Whereas stress stimulates both the activity of the above mentioned cells of the hypothalamus and the ACTH release, stress plus hydration causes a depression of these hypothalamic cells but nevertheless causes a marked ACTH release. Cortisone inhibits the activity of the cells in the supraoptic nucleus and the paraventricular nucleus as well as the ACTH release whereas cortisone plus dehydration causes stimulation but inhibits the ACTH release. In some stress and cortisone treatment groups the variations of the neurosecretory material around the hypophysial portal vessels and of the ACTH release were found to show a correlation. It is concluded that the activity of the cells of the supraoptic nucleus and the paraventricular nucleus and the ACTH release do not seem to have any definite connection, whereas some observations indicate that the neurosecretory material in the region of the median eminence around the hypophysial portal vessels may have some significance in ACTH release.

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THE IN VITRO METABOLISM OF MAMMARY GLAND SLICES IN THE PRESENCE OF POSTERIOR PITUITARY LOBE EXTRACTS RICH IN MELANOPHORE-DISPERSING ACTIVITY

Journal of Endocrinology ◽

10.1677/joe.0.0150366 ◽

1957 ◽

Vol 15 (4) ◽

pp. 366-373 ◽

Cited By ~ 1

Author(s):

T. R. BRADLEY ◽

G. M. MITCHELL

Keyword(s):

Mammary Gland ◽

Guinea Pigs ◽

Incubation Medium ◽

Mammary Glands ◽

Gas Evolution ◽

Early Lactation ◽

Posterior Pituitary ◽

Rats And Mice ◽

Posterior Pituitary Lobe

SUMMARY Slices cut from mammary glands of rats and mice during gestation and lactation were incubated in vitro in the presence of pig posterior pituitary lobe extracts rich in melanophore-dispersing ('B') activity. Slices taken in early lactation but not during gestation or late lactation showed increased net gas evolution compared with control slices. Similar tissue from rabbits and guinea-pigs did not give rise to this effect, nor did slices of other tissues taken from lactating rats. The increased net gas evolution was not observed in the absence of glucose from the incubation medium. Treatment of the 'B' extract with NaOH or hypophysectomy of the rats prior to use decreased the response.

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SULPHUR METABOLISM IN THE PITUITARY AND HYPOTHALAMUS OF THE RAT: A STUDY OF RADIOISOTOPE-UPTAKE AFTER THE INJECTION OF 35S dl-CYSTEINE, METHIONINE, AND SODIUM SULPHATE

Journal of Endocrinology ◽

10.1677/joe.0.0200009 ◽

1960 ◽

Vol 20 (1) ◽

pp. 9-23 ◽

Cited By ~ 74

Author(s):

J. C. SLOPER ◽

D. J. ARNOTT ◽

BARBARA C. KING

Keyword(s):

Sodium Sulphate ◽

Pars Intermedia ◽

Posterior Pituitary ◽

Pars Distalis ◽

Active Protein ◽

Lateral Border ◽

Nuclear Regions ◽

Radioisotope Uptake ◽

Different Parts ◽

Supraoptic Nuclei

SUMMARY 1. The relative radioactivity of different parts of the pituitary and hypothalamus has been assessed with a flow counter, and, more satisfactorily, both visually and by granule-counts in autoradiographs. These experiments have involved 103 rats killed between 15 sec and 97 hr after the administration of 35S dl-cysteine, dl-methionine and sodium sulphate. 2. Subarachnoid injections proved more satisfactory than intraperitoneal or intracarotid ones. They were followed by the rapid localization of radioisotope in the adenohypophysis as well as in nervous tissue. 3. The early and marked uptake of radioisotope shown by the cell bodies of neurones in various nuclear regions, and in particular in the supraoptic nuclei, has been interpreted as evidence of active protein synthesis; this pattern of uptake was observed after the injection of labelled cysteine and methionine, but not sodium sulphate. 4. A similar, early, but less marked uptake of radioisotope was noted in the pars distalis after the injection of both cysteine and methionine. Only after the injection of methionine was there a marked uptake in the pars intermedia, and this was confined to its lateral border. 5. Uptake by the infundibular process of the neurohypophysis became greater than that in pars distalis or in the superjacent hypothalamus 9½ hr and longer after injection of labelled cysteine, but not methionine. This pattern of uptake was confirmed by granule counts in twenty-five animals. 6. It is suggested that the late neurohypophysial uptake of radioisotope reflects the storage in the nerve-terminals of the gland of slowly metabolizing proteins or polypeptides synthesized in the supraoptic and paraventricular nuclear regions. These substances probably include the posterior pituitary principles, since the latter are rich in cystine, but lack methionine.

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Stimuli and consequences of dendritic release of oxytocin within the brain

Biochemical Society Transactions ◽

10.1042/bst0351252 ◽

2007 ◽

Vol 35 (5) ◽

pp. 1252-1257 ◽

Cited By ~ 102

Author(s):

I.D. Neumann

Keyword(s):

Paraventricular Nucleus ◽

Stress Responses ◽

Supraoptic Nucleus ◽

Brain Regions ◽

Model System ◽

Intracerebral Microdialysis ◽

Psychotherapeutic Intervention ◽

Psychiatric Illnesses ◽

Oxytocin Release ◽

The Brain

The brain oxytocin system has served as a distinguished model system in neuroendocrinology to study detailed mechanisms of intracerebral release, in particular of somatodendritic release, and its behavioural and neuroendocrine consequences. It has been shown that oxytocin is released within various brain regions, but evidence for dendritic release is limited to the main sites of oxytocin synthesis, i.e. the hypothalamic SON (supraoptic nucleus) and PVN (paraventricular nucleus). In the present paper, stimuli of dendritic release of oxytocin and the related neuropeptide vasopressin are discussed, including parturition and suckling, i.e. the period of a highly activated brain oxytocin system. Also, exposure to various pharmacological, psychological or physical stressors triggers dendritic oxytocin release, as monitored by intracerebral microdialysis within the SON and PVN during ongoing behavioural testing. So far, dendritic release of the neuropeptide has only been demonstrated within the hypothalamus, but intracerebral oxytocin release has also been found within the central amygdala and the septum in response to various stimuli including stressor exposure. Such a locally released oxytocin modulates physiological and behavioural reproductive functions, emotionality and hormonal stress responses, as it exerts, for example, pro-social, anxiolytic and antistress actions within restricted brain regions. These discoveries make oxytocin a promising neuromodulator of the brain for psychotherapeutic intervention and treatment of numerous psychiatric illnesses, for example, anxiety-related diseases, social phobia, autism and postpartum depression.

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Rapid morphological changes in supraoptic nucleus and posterior pituitary induced by a single hypertonie saline injection

Brain Research Bulletin ◽

10.1016/0361-9230(92)90111-a ◽

1992 ◽

Vol 28 (4) ◽

pp. 613-618 ◽

Cited By ~ 43

Author(s):

Gwyneth H. Beagley ◽

Glenn I. Hatton

Keyword(s):

Supraoptic Nucleus ◽

Morphological Changes ◽

Posterior Pituitary ◽

Saline Injection

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Central noradrenergic activity in intact and sinoaortic denervated Dahl rats

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y89-072 ◽

1989 ◽

Vol 67 (5) ◽

pp. 450-455 ◽

Cited By ~ 2

Author(s):

K. P. Patel ◽

J. D. Peuler ◽

D. A. Morgan ◽

B. J. Pardini ◽

D. D. Lund ◽

...

Keyword(s):

Paraventricular Nucleus ◽

Genetic Predisposition ◽

Supraoptic Nucleus ◽

Locus Ceruleus ◽

Preoptic Nucleus ◽

Brain Areas ◽

Brain Nuclei ◽

Salt Diet ◽

Median Preoptic Nucleus ◽

Norepinephrine Turnover

Lesions in forebrain areas richly innervated by noradrenergic terminals and involved in cardiovascular function reduce or prevent hypertension in the Dahl salt-sensitive (S) rats fed a high (H) salt diet. This led us to examine two questions. (1) Is the noradrenergic activity altered in discrete forebrain and brainstem areas of SH rats? (2) Are these changes in noradrenergic activity eliminated by sinoaortic denervation (SAD)? Studies were done in 10-week-old female SH and Dahl salt-resistant (RH) rats. Half of the rats in each group had SAD surgery 1 week prior to study. An index of norepinephrine (NE) turnover was determined by measuring the decline in tissue NE concentration 8 h after administering α-methyl-p-tyrosine, a NE synthesis blocker, to animals from each of four groups: sham-RH, SAD-RH, sham-SH, and SAD-SH (n = 18–20 per group). Various discrete brain areas were obtained using the "punch technique." In SH rats the index of NE turnover was increased in the median preoptic nucleus and decreased in the paraventricular nucleus compared with RH rats regardless of SAD. In contrast, in SH rats the index of NE turnover was increased in the supraoptic nucleus and locus ceruleus compared with RH rats; however, SAD-RH had greater turnover of NE at these sites than SAD-SH. In summary, changes in noradrenergic activity in the median preoptic nucleus and the paraventricular nucleus may be related to genetic predisposition to hypertension in SH rats. In contrast, changes in the locus ceruleus and the supraoptic nucleus of SH rats may be related to impaired baroreflexes and thereby contribute to hypertension.Key words: hypertension, brain nuclei, norepinephrine, turnover.

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ATP increases intracellular calcium in supraoptic neurons by activation of both P2X and P2Y purinergic receptors

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00495.2006 ◽

2007 ◽

Vol 292 (1) ◽

pp. R423-R431 ◽

Cited By ~ 29

Author(s):

Zhilin Song ◽

Sukumar Vijayaraghavan ◽

Celia D. Sladek

Keyword(s):

Intracellular Calcium ◽

Supraoptic Nucleus ◽

Purinergic Receptors ◽

Calcium Concentration ◽

Pyridoxal Phosphate ◽

Combined Treatment ◽

Vasopressin Release ◽

Intracellular Ca ◽

Disulphonic Acid ◽

Supraoptic Neurons

ATP increases intracellular calcium concentration ([Ca2+]i) in supraoptic nucleus (SON) neurons in hypothalamo-neurohypophyseal system explants loaded with the Ca2+-sensitive dye, fura 2-AM. Involvement of P2X purinergic receptors (P2XR) in this response was anticipated, because ATP stimulation of vasopressin release from hypothalamo-neurohypophyseal system explants required activation of P2XRs, and activation of P2XRs induced an increase in [Ca2+]i in dissociated SON neurons. However, the ATP-induced increase in [Ca2+]i persisted after removal of Ca2+ from the perifusate ([Ca2+]o). This suggested involvement of P2Y purinergic receptors (P2YR), because P2YRs induce Ca2+ release from intracellular stores, whereas P2XRs are Ca2+-permeable ion channels. Depletion of [Ca2+]i stores with thapsigargin (TG) prevented the ATP-induced increase in [Ca2+]i in zero, but not in 2 mM [Ca2+]o, indicating that both Ca2+ influx and release of intracellular Ca2+ contribute to the ATP response. Ca2+ influx was partially blocked by cadmium, indicating a contribution of voltage-gated Ca2+ channels. PPADS (pyridoxal-phosphate-6-azophenyl-2′,4′-disulphonic acid), and iso-PPADS, P2XR antagonists, attenuated, but did not abolish, the ATP-induced increase in [Ca2+]i. Combined treatment with PPADS or iso-PPADS and TG prevented the response. A cocktail of P2YR agonists consisting of UTP, UDP, and 2-methylthio-ADP increased [Ca2+]i (with or without tetrodotoxin) that was markedly attenuated by TG. 2-Methylthio-ADP alone induced consistent and larger increases in [Ca2+]i than UTP or UDP. MRS2179, a specific P2Y1R antagonist, eliminated the response to ATP in zero [Ca2+]o. Thus, both P2XR and P2YR participate in the ATP-induced increase in [Ca2+]i, and the P2Y1R subtype is more prominent than P2Y2R, P2Y4R, or P2Y6R in SON.

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