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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: The findings suggest that the neural network of the glucose monitoring system, which also analyzes and integrates information concerning other metabolites and peptides in the blood and cerebrospinal fluid, contributes to regulation of peripheral metabolism and endocrine activity as well as feeding behavior.
Abstract: Glucose-sensitive neural elements exist in the hypothalamus, the nucleus of the solitary tract (NTS) and autonomic afferents from visceral organs such as liver and gastrointestinal tract. Glucose affects neural activity through these central and peripheral chemosensors. Glucose is generally suppressive in the liver, the NTS and the lateral hypothalamic area (LHA), and generally excitatory in the small intestine and ventromedial hypothalamic nucleus (VMH). The hypothalamus is involved in the control of pancreatic hormone secretion through autonomic efferent nerves. Stimulation or lesion of the hypothalamus induces various changes in pancreatic autonomic nerve activity. The VMH, the dorsomedial hypothalamic nucleus and the paraventricular nucleus have inhibitory effects on vagal nerve activity and excitatory effects on splanchnic nerve activity. The LHA is excitatory to the vagal nerve, and both excitatory and inhibitory to the splanchnic nerve. These findings suggest that the neural network of the glucose monitoring system, which also analyzes and integrates information concerning other metabolites and peptides in the blood and cerebrospinal fluid, contributes to regulation of peripheral metabolism and endocrine activity as well as feeding behavior. The physiological function and input-output organization of this network are discussed.

232 citations

Journal ArticleDOI
TL;DR: The results suggest the existence of at least two distinct rhGRF‐containing systems: one responsible for delivery of the peptide to portal vessels in the median eminence, and one whose relationship, if any, to hypophysiotropic function is less direct.
Abstract: Immunohistochemical methods have been used to chart the distribution of rat hypothalamic growth-hormone-releasing factor (rhGRF) immunoreactivity in the brains of normal and colchicine-treated adult albino rats. The results suggest the existence of at least two distinct rhGRF-containing systems: one responsible for delivery of the peptide to portal vessels in the median eminence, and one whose relationship, if any, to hypophysiotropic function is less direct. A dense plexus of rhGRF-stained fibers was found throughout the external lamina of the median eminence that is the route by which the peptide is delivered to the anterior pituitary. This projection appears to arise primarily from a group of rhGRF-immunoreactive neurons centered in the arcuate nucleus. Some 1,000-1,500 rhGRF-positive neurons were counted on each side of the brain in rats pretreated with colchicine. Colocalization studies, using a sequential double staining technique, indicated that a subset of rhGRF-immunoreactive neurons in the arcuate region contain neurotensin immunoreactivity. No evidence was obtained for colocalization of rhGRF with either of two pro-opiomelanocortin-derived peptides (alpha-melanocyte-stimulating hormone, adrenocorticotropic hormone (1-24)) in individual neurons in the arcuate nucleus. Much smaller groups of neurons were localized in the parvicellular division of the paraventricular nucleus of the hypothalamus and in the dorsomedial nucleus, and it is unclear whether they contribute to the plexus of rhGRF-stained fibers in the median eminence. The only other region in the rat brain in which rhGRF-stained cells were found reliably was in the area that roughly encapsulates the caudal aspect of the ventromedial nucleus of the hypothalamus. Because cells in this region are not known to project to the median eminence, they may be assumed to contribute to the extrahypophysiotropic rhGRF-stained projections outlined below. From the level of the arcuate and ventromedial nuclei, rhGRF-immunoreactive fibers could be traced along the base of the brain and through the periventricular system to discrete terminal fields limited almost exclusively to the hypothalamus and adjoining parts of the basal telencephalon. All parts of the periventricular region of the hypothalamus receive an input, including the preoptic and anterior parts in which somatostatin-containing neurons that project to the median eminence are clustered. Other prominent terminal fields were localized in discrete parts of the dorsomedial, paraventricular, suprachiasmatic, and premammillary nuclei, and in the medial preoptic and lateral hypothalamic areas.(ABSTRACT TRUNCATED AT 400 WORDS)

232 citations

Journal ArticleDOI
TL;DR: LH is secreted as discrete pulses throughout all stages of the reproductive cycle of the ewe, including pre‐pubertal, seasonal and lactational anoestrus, and the luteal and follicular phases of the oestrous cycle.
Abstract: Summary (1) Luteinizing hormone (LH) is secreted as discrete pulses throughout all stages of the reproductive cycle of the ewe, including pre-pubertal, seasonal and lactational anoestrus, and the luteal and follicular phases of the oestrous cycle. Secretion is probably also pulsatile during the preovulatory surge of LH. (2) The secretion of LH is affected by the ovarian steroids, oestradiol and progesterone, both of which act principally to reduce the frequency of the pulses. During the luteal phase the two steroids act synergistically to exert this effect, and during anoestrus oestradiol acts independently of progesterone. Androstenedione secreted by the ovary apparently has no role in the control of LH secretion. (3) The amplitude of the pulses may also be affected by the steroids but there are conflicting reports on these effects, some showing that amplitude is lowered by the presence of oestrogen and others showing increases in amplitude in the presence of oestrogen and progesterone. (4) The secretion of LH pulses is affected by photoperiod, social environment and nutrition. Under the influence of decreasing day-length, oestradiol alone cannot reduce the frequency of pulses and the ewe experiences oestrous cycles. When day-length is increasing, the hypothalamus becomes more responsive to oestradiol which reduces the frequency of the pulses. (5) A hypothetical pheromone secreted by rams can increase the frequency of the LH pulses in anoestrous ewes and thereby induce ovulation, possibly by inhibiting the negative feedback exerted by oestradiol. (6) The relationships between nutrition and reproduction are poorly understood, but it seems likely that the effects of nutrition are mediated partly through the hypothalamus and its control of the secretion of LH pulses. (7) The pulses of LH secreted by the anterior pituitary gland are evoked by pulses of GnRH secreted by the hypothalamus. The location of the centre controlling the GnRH pulses and the neurotransmitter involved are not known.

231 citations

Journal ArticleDOI
TL;DR: A hypothalamus-pituitary-gonads pathway, in which d-Asp is involved, has been formulated and a summary of previous and current research done on the role of d- aspartic acid in the nervous and endocrine systems of invertebrates and vertebrates, including mammals is summary.

230 citations

Journal ArticleDOI
08 Jul 1982-Nature
TL;DR: It is reported here that the dopamine antagonist spiperone does not affect the release of either oxytocin or vasopressin from the isolated rat neurohypophysis, and the opiate antagonist naloxone markedly enhances the electrical stimulation of oxytocIn release, but has no effect on vasoppressin release.
Abstract: The neurohypophysis not only contains the nerve endings of the oxytocin- and vasopressin-secreting neurones of the hypothalamus, but also receives both dopamine1- and opiate peptide2,3-containing nerve fibres. This secondary innervation may regulate hormone secretion at the level of the nerve terminals by an action analogous to presynaptic inhibition4. Electrical stimulation of the isolated neurohypophysis releases oxytocin and vasopressin in amounts readily detectable by radio-immunoassay, and presumably also releases dopamine5 and endogenous opiates. If these neurosecretory products are indeed regulators of hormone release, then specific antagonists to dopamine and opiates should modify the electrically stimulated release of hormone. We report here that the dopamine antagonist spiperone does not affect the release of either oxytocin or vasopressin from the isolated rat neurohypophysis. In contrast, the opiate antagonist naloxone markedly enhances the electrical stimulation of oxytocin release, but has no effect on vasopressin release. Thus an endogenous opiate, released by electrical stimulation of the isolated neurohypophysis, inhibits the release of oxytocin, but this opiate control does not appear to be exerted on the vasopressin-secreting terminals. We have not found similar evidence that endogenous neuro-hypophysial dopamine regulates hormone release.

230 citations


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