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Hypothalamus

About: Hypothalamus is a research topic. Over the lifetime, 22301 publications have been published within this topic receiving 1085925 citations.


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Journal ArticleDOI
TL;DR: Dispersed anterior pituitary cells harvested from lactating female rats and OVX estrogen-primed rats released PRL in a specific, significant, and dose-related fashion when perifused in vitro with incubation medium containing 10(-7)-10(-9) M OT, doses similar to levels found previously in hypophysial portal plasma.
Abstract: The presence of oxytocin (OT) in neuronal elements of the external layer of the median eminence and in hypophysial portal plasma suggests a role for the peptide in the control of anterior pituitary function. We have reported previously that OT stimulates PRL release in vitro; therefore, we attempted to establish evidence for a physiological PRL-releasing role for OT. Plasma OT levels rose significantly just before the PRL surges occurring during a suckling stimulus in lactating rats (10 min after pup reinstatement vs. 15 min for PRL) and 48 h after estrogen injection in ovariectomized (OVX) rats (at 1200 h vs. 1300 h). Dispersed anterior pituitary cells harvested from lactating female rats and OVX estrogen-primed rats released PRL in a specific, significant, and dose-related fashion when perifused in vitro with incubation medium containing 10−7–10−9 m OT, doses similar to levels found previously in hypophysial portal plasma. Infusion of antiserum specific for OT into lactating females before pup reinstate...

215 citations

Journal ArticleDOI
TL;DR: In situ hybridization histochemistry studies have provided novel information about the distribution of ER beta mRNA in the ER alphaKO mouse forebrain and morphological data provides evidence that estrogen may exert its actions in the EMT mouse brain via ER beta and thereby maintain organizational and activational effects.
Abstract: Neurons in the hypothalamus of estrogen receptor alpha-knockout (ER alphaKO) mice have been shown to concentrate radiolabeled estrogen and estrogen treatment regulates the expression of progesterone receptor mRNA The purpose of the present study was to utilize in situ hybridization histochemistry to determine the anatomical distribution of ER beta mRNA in ER alphaKO mouse forebrain The results of these studies revealed an extensive distribution of ER beta mRNA in the hypothalamic regions including medial preoptic area, suprachiasmatic nucleus, paraventricular nucleus, dorsomedial nucleus, medial tuberal nucleus, and the premammillary nuclei Additional labeled perikarya were also detected in the glomerular layer of the olfactory bulb; tenia tecta; anterior septum; bed nucleus of the stria terminalis; medial, basolateral and cortical nuclei of the amygdala; cerebral and entorhinal cortex; the septohippocampal nucleus; Ammon's horn of the hippocampus and the dorsal raphe The results of these in situ hybridization histochemical studies have provided novel information about the distribution of ER beta mRNA in the ER alphaKO mouse forebrain In addition, these morphological data provides evidence that estrogen may exert its actions in the ER alphaKO mouse brain via ER beta and thereby maintain organizational and activational effects

215 citations

Journal ArticleDOI
TL;DR: Findings indicate that neuronal cell loss in the mediobasal preoptic area induced a long lasting insomnia in cats, and it may be hypothesized that the integrity of this structure is necessary for sleep appearance.

215 citations

Journal ArticleDOI
TL;DR: Under normal conditions, endogenous oxytocin seemed to be involved in the control of neurosecretory activation, and no effect was observed after injection into the venous blood or into the 4th ventricle, which suggested that Oxytocin acts in the hypothalamus.
Abstract: Antidromically identified paraventricular neurones were recorded simultaneously with intramammary pressure in urethane (12 g/kg) anaesthetized rats during suckling The correlation of the firing pattern of these neurones with milk ejection enabled distinction between oxytocin and vasopressin neurones Oxytocin neurones displayed a short (2-6 s) characteristic high-frequency burst of spikes This activation probably occurred simultaneously in all oxytocin neurones 12-18 s before milk ejection and was regular in both frequency and amplitude (total number of spikes) The role of neurohypophysial peptides and analogues in the control of these characteristics was studied Injecting 10 pg, 100 pg and 1 ng of oxytocin into the 3rd ventricle increased background activity of slow-firing oxytocin neurones (less than 3 spikes/s) and had a strong dose-dependent facilitatory effect on the milk ejection reflex, increasing both the amplitude and frequency of neurosecretory bursts No effect was observed on non-neurosecretory neurones Such injection also triggered the milk ejection reflex when it had not appeared an hour after suckling began Oxytocin did not itself induce neurosecretory activation, which only appeared if the young rats were sucking Injecting oxytocin into the lateral ventricle was less effective than into the 3rd ventricle No effect was observed after injection into the venous blood or into the 4th ventricle, which suggested that oxytocin acts in the hypothalamus Injecting mesotocin or isotocin into the 3rd ventricle had a facilitatory effect similar to that of oxytocin but vasopressin, vasotocin, MIF I (pro-leu-gly-NH2, terminal triplet oxytocin) or bovine neurophysins I and II did not modify neurosecretory activation or the milk ejection pattern Injecting an oxytocin antagonist, ([1(beta-mercapto-beta, beta cyclopentamethylene propionic acid), 8-ornithine] vasotocin, d(CH2)5OVT) into the 3rd ventricle decreased milk ejection frequency and considerably delayed the reappearance of the first milk ejection This resulted from a decrease in both frequency and amplitude of neurosecretory bursts, which were too small to induce detectable oxytocin release Moreover, d(CH2)5OVT suppressed the facilitatory effect of exogenous oxytocin Under normal conditions, endogenous oxytocin seemed to be involved in the control of neurosecretory activation Injecting 1 ng oxytocin or 1 or 10 ng vasopressin into the 3rd ventricle did not modify the firing pattern of vasopressin neurones whether activated by hyperosmotic stimulation (1 ml NaCl, 9% solution (w/v) IP) or not(ABSTRACT TRUNCATED AT 400 WORDS)

215 citations

Journal ArticleDOI
TL;DR: Leptin regulates the TRH neurons through both direct and indirect pathways, consistent with a direct ability of leptin to promote TRH biosynthesis through actions on TRH cells.

215 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023425
2022950
2021295
2020316
2019326
2018289