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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: In vitro, apelin-13 stimulated the release of CRH and AVP from hypothalamic explants, but had no effect on NPY release, suggesting that apelin may play an important role in the hypothalamic regulation of water intake and endocrine axes.

290 citations

Journal ArticleDOI
TL;DR: The median eminence, pituitary stalk and anterior pituitsary as well as the adjacent diencephalon were exposed through a parapharyngeal approach to enable us to visualize these structures directly and to inject isotonic salt solutions containing dopamine, epinephrine, norepinephrine, serotonin or melatonin into the third ventricle, a stalk portal vessel or the basilar artery of anesthetized male rats.
Abstract: The median eminence, pituitary stalk and anterior pituitary as well as the adjacent diencephalon were exposed through a parapharyngeal approach to enable us to visualize these structures directly and to inject isotonic salt solutions containing dopamine, epinephrine, norepinephrine, serotonin or melatonin into the third ventricle, a stalk portal vessel or the basilar artery of anesthetized male rats. The rate of LH release in these animals was evaluated from the changes in the concentration of serum LH as determined by radioimmunoassay. Within 10 min after 1.25 μg of dopamine hydrochloride was injected into the third ventricle, the serum LH concentration had increased 4-fold. After 20 min, the serum LH level had increased 9-fold. At 30 and 60 min after the injection, there was a moderate decline followed by a steady rise for at least 1 hr. At the end of the 120-min observation period, the serum LH level was 20 times greater than that of the control animals which received an isotonic salt solution only. Fo...

290 citations

Journal ArticleDOI
TL;DR: It is shown here that Sim1 heterozygous mice are viable but develop early-onset obesity, with increased linear growth, hyperinsulinemia and hyperleptinemia, and proposed that abnormalities of PVN development cause the obesity of Sim1(+/-) mice.
Abstract: The bHLH-PAS transcription factor SIM1 is required for the development of the paraventricular nucleus (PVN) of the hypothalamus. Mice homozygous for a null allele of Sim1 (Sim1 -/- ) lack a PVN and die perinatally. In contrast, we show here that Sim1 heterozygous mice are viable but develop early-onset obesity, with increased linear growth, hyperinsulinemia and hyperleptinemia. Sim1 +/- mice are hyperphagic but their energy expenditure is not decreased, distinguishing them from other mouse models of early-onset obesity such as deficiencies in leptin and melanocortin receptor 4. Quantitative histological comparison with normal littermates showed that the PVN of Sim1 +/- mice contains on average 24% fewer cells without a selective loss of any identifiable major cell type. Since acquired lesions in the PVN also induce increased appetite without a decrease in energy expenditure, we propose that abnormalities of PVN development cause the obesity of Sim1 +/- mice. Severe obesity was described recently in a patient with a balanced translocation disrupting SIM1. Pathways controlling the development of the PVN thus have the potential to cause obesity in both mice and humans.

289 citations

Journal ArticleDOI
TL;DR: Direct projections from the SCN to the posterior hypothalamus mediate the arousal function of the circadian timing system, and it is demonstrated that both HCT and MCH-producing neurons are immunoreactive for glutamate (GLU).
Abstract: The suprachiasmatic nucleus (SCN) temporally organizes behavior in part by sustaining arousal during the wake period of the sleep/wake cycle to consolidate adaptive waking behavior. In this study, we demonstrate direct projections from the SCN, in both the rat and the human brains, to perikarya and proximal dendrites of two groups of posterior hypothalamic neurons with axonal projections that suggest they are important in the regulation of arousal, one producing hypocretins (HCT) and the other melanin-concentrating hormone (MCH). In addition, we demonstrate that both HCT and MCH-producing neurons are immunoreactive for glutamate (GLU). These observations support the hypothesis that direct projections from the SCN to the posterior hypothalamus mediate the arousal function of the circadian timing system.

289 citations

Journal ArticleDOI
TL;DR: Together these findings provide an anatomical basis for the exploration of Gpr54 actions outside the reproductive axis and reveal a complex temporal and spatial pattern of GPR54 gene expression in developing GnRH neurons.
Abstract: Kisspeptin and G protein-coupled receptor 54 (GPR54) are now acknowledged to play essential roles in the neural regulation of fertility. Using a transgenic Gpr54 LacZ knock-in mouse model, this study aimed to provide 1) a detailed map of cells expressing Gpr54 in the mouse brain and 2) an analysis of Gpr54 expression in GnRH neurons across postnatal development. The highest density of Gpr54-expressing cells in the mouse central nervous system was found in the dentate gyrus of the hippocampus beginning on postnatal d 6 (P6). Abundant Gpr54 expression was also noted in the septum, rostral preoptic area (rPOA), anteroventral nucleus of the thalamus, posterior hypothalamus, periaqueductal grey, supramammillary and pontine nuclei, and dorsal cochlear nucleus. No Gpr54 expression was detected in the arcuate and rostral periventricular nuclei of the hypothalamus. Dual-labeling experiments showed that essentially all Gpr54-expressing cells in the rPOA were GnRH neurons. Analyses of mice at birth, P1, P5, P20, and P30 and as adults revealed a gradual increase in the percentage of GnRH neurons expressing Gpr54 from approximately 40% at birth through to approximately 70% from P20 onward. Whereas GnRH neurons located in the septum displayed a consistent increase across this time, GnRH neurons in the rPOA showed a sharp reduction in Gpr54 expression after birth (to approximately 10% at P5) before increasing to the 70% expression levels by P20. Together these findings provide an anatomical basis for the exploration of Gpr54 actions outside the reproductive axis and reveal a complex temporal and spatial pattern of Gpr54 gene expression in developing GnRH neurons.

289 citations


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