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Sample records for gt1-7 hypothalamic neurons

  1. Chronic exposure to KATP channel openers results in attenuated glucose sensing in hypothalamic GT1-7 neurons.

    PubMed

    Haythorne, Elizabeth; Hamilton, D Lee; Findlay, John A; Beall, Craig; McCrimmon, Rory J; Ashford, Michael L J

    2016-12-01

    Individuals with Type 1 diabetes (T1D) are often exposed to recurrent episodes of hypoglycaemia. This reduces hormonal and behavioural responses that normally counteract low glucose in order to maintain glucose homeostasis, with altered responsiveness of glucose sensing hypothalamic neurons implicated. Although the molecular mechanisms are unknown, pharmacological studies implicate hypothalamic ATP-sensitive potassium channel (KATP) activity, with KATP openers (KCOs) amplifying, through cell hyperpolarization, the response to hypoglycaemia. Although initial findings, using acute hypothalamic KCO delivery, in rats were promising, chronic exposure to the KCO NN414 worsened the responses to subsequent hypoglycaemic challenge. To investigate this further we used GT1-7 cells to explore how NN414 affected glucose-sensing behaviour, the metabolic response of cells to hypoglycaemia and KATP activity. GT1-7 cells exposed to 3 or 24 h NN414 exhibited an attenuated hyperpolarization to subsequent hypoglycaemic challenge or NN414, which correlated with diminished KATP activity. The reduced sensitivity to hypoglycaemia was apparent 24 h after NN414 removal, even though intrinsic KATP activity recovered. The NN414-modified glucose responsiveness was not associated with adaptations in glucose uptake, metabolism or oxidation. KATP inactivation by NN414 was prevented by the concurrent presence of tolbutamide, which maintains KATP closure. Single channel recordings indicate that NN414 alters KATP intrinsic gating inducing a stable closed or inactivated state. These data indicate that exposure of hypothalamic glucose sensing cells to chronic NN414 drives a sustained conformational change to KATP, probably by binding to SUR1, that results in loss of channel sensitivity to intrinsic metabolic factors such as MgADP and small molecule agonists.

  2. Cholesterol secoaldehyde, an ozonation product of cholesterol, induces amyloid aggregation and apoptosis in murine GT1-7 hypothalamic neurons.

    PubMed

    Sathishkumar, K; Xi, Xiaochun; Martin, Roy; Uppu, Rao M

    2007-06-01

    Aldehydic products from ozonation of cholesterol and peroxidation of phospholipids have been shown to accelerate aggregation of amyloid-beta (Abeta) in vitro. Here, we show that 3beta-hydroxy-5-oxo-5,6-secocholestan-6-al (ChSeco), an ozonation product of cholesterol, induces Abeta aggregation, generation of reactive oxygen species (ROS), and cytotoxicity in murine GT1-7 hypothalamic neurons. The formation of Abeta aggregates in situ was dose-dependent at ChSeco concentrations ranging from 1 to 20 microM. The increase in insoluble Abeta aggregates at increasing concentrations of ChSeco was accompanied by a decrease in soluble Abeta as evidenced by Western blot analysis. The formation of ROS in neuronal cells was found to be dose- and time-dependent with the magnitude being higher at 20 microM compared to 10 microM ChSeco or untreated controls. The increase in ROS was associated with depletion of GSH. The cytotoxicity induced by ChSeco involved changes in phosphatidylserine translocation, DNA fragmentation, and caspase 3/7 activity that are characteristic of apoptosis. Pretreatment of neuronal cells with Trolox, a water-soluble analog of alpha-tocopherol offered partial, but significant protection against ChSeco-induced cell death, whereas, N-acetyl-L-cysteine (NAC) completely prevented the cytotoxic effects of ChSeco. NAC and Trolox were without any effects on ChSeco-induced Abeta aggregation. Fibrillogenesis inhibitors, which inhibited Abeta aggregation, did not inhibit cell death induced by ChSeco, implying that ROS generation, and not Abeta aggregation, plays a major role in the observed cytotoxicity. However, since Alzheimer's and other neurodegenerative diseases are slow and progressive, the formation of Abeta aggregates in vivo by ChSeco may have long-term pathological consequences.

  3. Effect of glutamate and extracellular calcium on uptake of inorganic lead (Pb2+) in immortalized mouse hypothalamic GT1-7 neuronal cells.

    PubMed

    Loikkanen, J; Naarala, J; Vähäkangas, K H; Savolainen, K M

    2006-01-25

    We have previously shown that although glutamate alone has no effects on viability of mouse hypothalamic GT1-7 cells, it clearly enhances Pb2+-induced cytotoxicity. It is likely that Pb2+ must enter cells to exert most of its toxic effects. Pb2+ is known to substitute for Ca2+ in many cellular processes. Therefore, we studied the uptake mechanisms of Pb2+ into GT1-7 neuronal cells with a special focus on the role of extracellular calcium (Ca2+), voltage-sensitive calcium channels (VSCCs) and glutamate. Basal uptake of Pb2+ (1 microM or 10 microM), i.e. without any external stimulus, clearly increased in nominally Ca2+-free buffer and was partially abolished by 13 mM Ca2+ when compared to uptake in the presence of a physiological concentration of extracellular Ca2+ (1.3 mM). Depolarization by 25 mM K+, or antagonists of VSCCs, verapamil (10 microM) or flunarizine (10 microM) had no clear effect on basal Pb2+ uptake. Glutamate (1 mM) increased Pb2+ uptake, but only when cells were treated with 1 microM Pb2+ in the presence of 1.3 mM Ca2+. Our data suggest that Pb2+ competes for the same cellular uptake pathways with Ca2+, although not via VSCCs. In addition, enhancement of Pb2+-induced neurotoxicity by glutamate may be due to increased neuronal uptake of Pb2+.

  4. Regulation of GNRH production by estrogen and bone morphogenetic proteins in GT1-7 hypothalamic cells.

    PubMed

    Otani, Hiroyuki; Otsuka, Fumio; Takeda, Masaya; Mukai, Tomoyuki; Terasaka, Tomohiro; Miyoshi, Tomoko; Inagaki, Kenichi; Suzuki, Jiro; Ogura, Toshio; Lawson, Mark A; Makino, Hirofumi

    2009-10-01

    Recent studies have shown that bone morphogenetic proteins (BMPs) are important regulators in the pituitary-gonadal endocrine axis. We here investigated the effects of BMPs on GNRH production controlled by estrogen using murine GT1-7 hypothalamic neuron cells. GT1-7 cells expressed estrogen receptor alpha (ERalpha; ESR1 as listed in MGI Database), ERbeta (ESR2 as listed in MGI Database), BMP receptors, SMADs, and a binding protein follistatin. Treatment with BMP2 and BMP4 had no effect on Gnrh mRNA expression; however, BMP6 and BMP7 significantly increased Gnrh mRNA expression as well as GnRH production by GT1-7 cells. Notably, the reduction of Gnrh expression caused by estradiol (E(2)) was restored by cotreatment with BMP2 and BMP4, whereas it was not affected by BMP6 or BMP7. E(2) activated extracellular signal-regulated kinase (ERK) 1/2 and stress-activated protein kinase/c-Jun NH(2)-terminal kinase (SAPK/JNK) signaling but did not activate p38-mitogen-activated protein kinase (MAPK) signaling in GT1-7 cells. Inhibition of ERK1/ERK2 reversed the inhibitory effect of estrogen on Gnrh expression, whereas SAPK/JNK inhibition did not affect the E(2) actions. Expression levels of Eralpha and Erbeta were reduced by BMP2 and BMP4, but were increased by BMP6 and BMP7. Treatment with an ER antagonist inhibited the E(2) effects on Gnrh suppression including reduction of E(2)-induced ERK phosphorylation, suggesting the involvement of genomic ER actions in Gnrh suppression. BMP2 and BMP4 also suppressed estrogen-induced phosphorylation of ERK1/ERK2 and SAPK/JNK signaling, suggesting that BMP2 and BMP4 downregulate estrogen effects by attenuating ER-MAPK signaling. Considering that BMP6 and BMP7 increased the expression of alpha1E-subunit of R-type calcium channel (Cacna1e), which is critical for GNRH secretion, it is possible that BMP6 and BMP7 directly stimulate GNRH release by GT1-7 cells. Collectively, a newly uncovered interaction of BMPs and ER may be involved in

  5. Differential protein expression profile in the hypothalamic GT1-7 cell line after exposure to anabolic androgenic steroids

    PubMed Central

    Martínez-Rivera, Freddyson J.; Pérez-Laspiur, Juliana; Santiago-Gascot, María E.; Alemán-Reyes, Abner G.; García-Santiago, Emanuel; Rodríguez-Pérez, Yolanda; Calo-Guadalupe, Cristhian; Otero-Pagán, Inelia; Ayala-Pagán, Roxsana N.; Martínez, Magdiel; Cantres-Rosario, Yisel M.; Meléndez, Loyda M.; Barreto-Estrada, Jennifer L.

    2017-01-01

    The abuse of anabolic androgenic steroids (AAS) has been considered a major public health problem during decades. Supraphysiological doses of AAS may lead to a variety of neuroendocrine problems. Precisely, the hypothalamic-pituitary-gonadal (HPG) axis is one of the body systems that is mainly influenced by steroidal hormones. Fluctuations of the hormonal milieu result in alterations of reproductive function, which are made through changes in hypothalamic neurons expressing gonadotropin-releasing hormone (GnRH). In fact, previous studies have shown that AAS modulate the activity of these neurons through steroid-sensitive afferents. To increase knowledge about the cellular mechanisms induced by AAS in GnRH neurons, we performed proteomic analyses of the murine hypothalamic GT1-7 cell line after exposure to 17α-methyltestosterone (17α-meT; 1 μM). These cells represent a good model for studying regulatory processes because they exhibit the typical characteristics of GnRH neurons, and respond to compounds that modulate GnRH in vivo. Two-dimensional difference in gel electrophoresis (2D-DIGE) and mass spectrometry analyses identified a total of 17 different proteins that were significantly affected by supraphysiological levels of AAS. Furthermore, pathway analyses showed that modulated proteins were mainly associated to glucose metabolism, drug detoxification, stress response and cell cycle. Validation of many of these proteins, such as GSTM1, ERH, GAPDH, PEBP1 and PDIA6, were confirmed by western blotting. We further demonstrated that AAS exposure decreased expression of estrogen receptors and GnRH, while two important signaling pathway proteins p-ERK, and p-p38, were modulated. Our results suggest that steroids have the capacity to directly affect the neuroendocrine system by modulating key cellular processes for the control of reproductive function. PMID:28719635

  6. Glutamate increases toxicity of inorganic lead in GT1-7 neurons: partial protection induced by flunarizine.

    PubMed

    Loikkanen, Jarkko; Naarala, Jonne; Vähäkangas, Kirsi H; Savolainen, Kai M

    2003-12-01

    Recent studies point to an interaction between the glutamatergic neurotransmitter system and inorganic lead (Pb) neurotoxicity. Pb (1-100 microM) evoked cytotoxicity over the period of 72 h in mouse hypothalamic GT1-7 neurons. Glutamate (0.1 or 1 mM) on its own did not have any effect on cell viability. However, 1 mM glutamate clearly increased Pb-induced cell death at 48 and 72 h. Although flunarizine (0.1-10 microM), an antagonist of L- and T-type voltage-sensitive calcium channels (VSCCs), partially protected from the cytotoxicity induced by co-exposure to Pb (10 or 100 micro M) and glutamate (1 mM), it had no protective effect on cytotoxicity induced by Pb alone. The flunarizine-induced protection was dependent on time and observed only at 48 h. Neither verapamil, an antagonist of L-type VSCCs, nor DIDS, an inhibitor of anion exchange, at non-toxic concentrations (0.1-10 microM) had any effect on cytotoxicity induced by Pb alone or together with glutamate at any studied time point. Co-exposure to Pb and glutamate also resulted in more prominent production of reactive oxygen species (ROS) than either of the compounds alone. Interestingly, we observed an increase in intracellular glutathione (GSH) levels in cells exposed to micromolar concentrations of Pb. Glutamate decreased the levels of intracellular GSH and also partially reduced the Pb-induced increase in GSH levels. These results suggest that the interaction of glutamate and Pb results in increased neuronal cell death via mechanisms that involve an increase in ROS production, a decrease in intracellular GSH defense against oxidative stress and probably T-type VSCCs.

  7. Expression of gonadotropin-inhibitory hormone receptors in mouse pituitary gonadotroph LβT2 cells and hypothalamic gonadotropin-releasing hormone-producing GT1-7 cells.

    PubMed

    Sukhbaatar, Unurjargal; Kanasaki, Haruhiko; Mijiddorj, Tselmeg; Oride, Aki; Miyazaki, Kohji

    2014-01-01

    Gonadotropin-inhibitory hormone (GnIH) was first identified in quail as a novel neurohormone that acts directly on the anterior pituitary to inhibit gonadotropin release. GnIH inhibits not only gonadotropin release from the pituitary gland but also inhibits the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus. In this study, we examined how GnIH receptors were regulated in pituitary gonadotroph cells and GnRH-producing neurons in the hypothalamus. In the mouse pituitary gonadotroph cell line LβT2, GnRH increased expression of the GnIH receptor, G-protein coupled receptor 74 (GPR74). GnRH also stimulated the expression of GPR74 and GPR147 in primary cultures of rat anterior pituitary cells. In addition, when GnRH was administered to LβT2 cells in a pulsatile manner, low frequency GnRH pulse stimulation stimulated GPR74 and GPR147 expression more than did high frequency GnRH pulses. In the mouse hypothalamic GnRH-producing cell line GT1-7, hypothalamic kisspeptin did not significantly increase the expression of GnIH receptors. However, the intermittent administration of kisspeptin to GT1-7 cells significantly increased GPR74 and GPR147 mRNA expression. The overexpression of either constitutively active MEK kinase (MEKK) or protein kinase A (PKA) in LβT2 cells increased the expression of GPR74 mRNA. Conversely, in GT1-7 cells, although the overexpression of either MEKK or PKA failed to stimulate GnIH receptor expression, the combined overexpression of both kinases together increased GPR74 and GPR147 mRNA levels. Our current observations suggest that two central controllers of reproductive function, GnRH and kisspeptin, stimulate the expression of GnIH receptors in pituitary gonadotroph cells and hypothalamic GnRH neurons.

  8. Pb2+-induced toxicity is associated with p53-independent apoptosis and enhanced by glutamate in GT1-7 neurons.

    PubMed

    Loikkanen, Jarkko; Chvalova, Katerina; Naarala, Jonne; Vähäkangas, Kirsi H; Savolainen, Kai M

    2003-09-30

    Recent studies indicate that the glutamatergic neurotransmitter system is involved in neurotoxicity caused by inorganic lead (Pb2+). We studied the role of apoptosis in the effects induced by Pb2+ (0.01-100 microM) and glutamate (0.1 and 1 mM) in mouse hypothalamic GT1-7 neurons. Although glutamate alone had no effect on cell viability, it enhanced neuronal cell death induced by Pb2+ (1-100 microM) within 72 h. Glutamate alone neither induced caspase-3-like protease activity nor promoted internucleosomal DNA fragmentation, both biochemical hallmarks of apoptosis. However, concurrent exposure to Pb2+ (10 or 100 microM) and glutamate (1 mM) resulted in more prominent cleavage of the fluorogenic caspase-3 substrate (Ac-DEVD-AMC) than caused by the same Pb2+ concentrations alone at 24-72 h. The highest caspase-3-like protease activities were measured at 48 h. Internucleosomal DNA fragmentation caused by Pb2+ (10 or 100 microM) alone or together with glutamate (1 mM) was evident at 96 h, less clear at 72 h and absent at 48 h. Immunoblotting did not reveal any changes in p53 protein levels in cells exposed to Pb2+, glutamate or their combination at any studied time point (3-72 h). Our results suggest that Pb2+-induced neurotoxicity may partially be mediated through p53-independent apoptosis and enhanced by glutamate.

  9. Serotonin stimulates GnRH secretion through the c-Src-PLC gamma1 pathway in GT1-7 hypothalamic cells.

    PubMed

    Kim, Hyeon Soo; Yumkham, Sanatombi; Choi, Jang Hyun; Son, Gi Hoon; Kim, Kyungjin; Ryu, Sung Ho; Suh, Pann-Ghill

    2006-09-01

    Serotonin is a neurotransmitter that alters the hypothalamic-pituitary-adrenal axis. To date, however, the molecular mechanisms underlying the role of serotonin in hormone secretion have remained largely unclear. In this study, we report that serotonin activates phospholipase C (PLC) gamma1 in an Src-dependent manner in hypothalamic GT1-7 cells, and that pretreatment with either 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazole [3, 4-d] pyrimidine, an Src-kinase inhibitor, or U73122, a PLC inhibitor, attenuates the serotonin-induced increase in calcium levels. Also, PLC gamma1 binds to c-Src through the Src-homology (SH) 223 domain upon serotonin treatment. Moreover, calcium increase is alleviated in the cells transientlyexpressing SH223 domain-deleted PLC gamma1 or lipase inactive mutant PLC gamma1, as compared with cells transfected with wild-type PLC gamma1. Furthermore, the inhibition of the activities of either PLC or Src results in a significant diminution of the serotonin-induced release of gonadotropin-releasing hormone (GnRH). In addition, the results of our small-interfering RNA experiment confirm that endogenous PLC gamma1 is a prerequisite for serotonin-mediated signaling pathways. Taken together, our findings demonstrate that serotonin stimulates the release of GnRH through the Src-PLC gamma1 pathway, via the modulation of intracellular calcium levels.

  10. Amylin and leptin activate overlapping signalling pathways in an additive manner in mouse GT1-7 hypothalamic, C₂C₁₂ muscle and AML12 liver cell lines.

    PubMed

    Moon, H-S; Chamberland, J P; Mantzoros, C S

    2012-01-01

    It has been suggested that amylin amplifies leptin's effects and affects energy homeostasis synergistically with leptin in animals and humans. However, no previous study has reported on amylin and leptin signalling in hypothalamic, muscle and liver cells. Leptin and amylin signalling studies were performed in vitro in mouse GT1-7 hypothalamic, C₂C₁₂ muscle and AML12 liver cell lines. Treatment of mouse GT1-7 and C₂C₁₂ cells with leptin or amylin increased signal transducer and activator of transcription 3 (STAT3) phosphorylation in a dose- and time-dependent manner. In mouse AML12 cells, leptin and amylin produced a biphasic response of STAT3 activity. Importantly, all leptin and amylin signalling pathways were saturable at leptin and amylin concentrations of ∼100 and ∼50 to 100 ng/ml, respectively. Leptin and amylin in combination activated STAT3, AMP-activated protein kinase (AMPK), extracellular signal-regulated kinase (ERK) 1/2 and Akt signalling pathways in an additive manner, effects that were abolished under endoplasmic reticulum (ER) stress. Leptin, but not amylin, increased IRS-1 phosphorylation in GT1-7 hypothalamic, but not in C₂C₁₂ muscle and AML12 liver cell lines. Our data suggest that leptin and amylin have overlapping and additive, but not synergistic, effects in the activation of intracellular signalling pathways. ER stress may induce leptin and amylin resistance in hypothalamic, muscle and liver cell lines. These novel insights into the mode of action of leptin and amylin suggest that these hormones may play an additive role in regulating energy homeostasis in humans.

  11. 17beta-estradiol at physiological concentrations augments Ca(2+) -activated K+ currents via estrogen receptor beta in the gonadotropin-releasing hormone neuronal cell line GT1-7.

    PubMed

    Nishimura, Ichiro; Ui-Tei, Kumiko; Saigo, Kaoru; Ishii, Hirotaka; Sakuma, Yasuo; Kato, Masakatsu

    2008-02-01

    Estrogens play essential roles in the neuroendocrine control of reproduction. In the present study, we focused on the effects of 17beta-estradiol (E2) on the K(+) currents that regulate neuronal cell excitability and carried out perforated patch-clamp experiments with the GnRH-secreting neuronal cell line GT1-7. We revealed that a 3-d incubation with E2 at physiological concentrations (100 pm to 1 nm) augmented Ca(2+)-activated K(+) [K(Ca)] currents without influencing Ca(2+)-insensitive voltage-gated K(+) currents in GT1-7 cells. Acute application of E2 (1 nm) had no effect on the either type of K(+) current. The augmentation was completely blocked by an estrogen receptor (ER) antagonist, ICI-182,780. An ERbeta-selective agonist, 2,3-bis(4-hydroxyphenyl)-propionitrile, augmented the K(Ca) currents, although an ERalpha-selective agonist, 4,4',4''-[4-propyl-(1H)-pyrazole-1,3,5-triyl]tris-phenol, had no effect. Knockdown of ERbeta by means of RNA interference blocked the effect of E2 on the K(Ca) currents. Furthermore, semiquantitative RT-PCR analysis revealed that the levels of BK channel subunit mRNAs for alpha and beta4 were significantly increased by incubating cells with 300 pm E2 for 3 d. In conclusion, E2 at physiological concentrations augments K(Ca) currents through ERbeta in the GT1-7 GnRH neuronal cell line and increases the expression of the BK channel subunit mRNAs, alpha and beta4.

  12. Effect of Chlorotriazine Pesticides on Gonadotrophin Releasing Hormone in the Neuronal GT1-7 Cell Line and Hypothalamic Explants

    EPA Science Inventory

    Gonadotrophin releasing hormone (GnRH) stimulates the release of pituitary luteinizing hormone (LH) and follicle stimulating hormone. These pituitary hormones are necessary for normal reproductive function in both males and females. It is well recognized that disruption of nor...

  13. Effect of Chlorotriazine Pesticides on Gonadotrophin Releasing Hormone in the Neuronal GT1-7 Cell Line and Hypothalamic Explants

    EPA Science Inventory

    Gonadotrophin releasing hormone (GnRH) stimulates the release of pituitary luteinizing hormone (LH) and follicle stimulating hormone. These pituitary hormones are necessary for normal reproductive function in both males and females. It is well recognized that disruption of nor...

  14. Algae Undaria pinnatifida Protects Hypothalamic Neurons against Endoplasmic Reticulum Stress through Akt/mTOR Signaling.

    PubMed

    Kim, Jongwan; Moon, Il Soo; Goo, Tae-Won; Moon, Seong-Su; Seo, Minchul

    2015-11-25

    Increased endoplasmic reticulum (ER) stress is known to be one of the causes of hypothalamic neuronal damage, as well as a cause of metabolic disorders such as obesity and diabetes. Recent evidence has suggested that Undaria pinnatifida (UP), an edible brown algae, has antioxidant activity. However, the neuroprotective effect of UP has yet to be examined. In this study, to investigate the neuroprotective effect of UP on ER stress-induced neuronal damage in mouse hypothalamic neurons, mice immortal hypothalamic neurons (GT1-7) were incubated with extract of UP. ER stress was induced by treating with tunicamycin. Tunicamycin induced apoptotic cell death was compared with the vehicle treatment through excessive ER stress. However UP protected GT1-7 cells from cell death, occurring after treatment with tunicamycin by reducing ER stress. Treatment with UP resulted in reduced increment of ATF6 and CHOP, and recovered the decrease of phosphorylation of Akt/mTOR by tunicamycin and the increment of autophagy. These results show that UP protects GT1-7 cells from ER stress induced cell death through the Akt/mTOR pathway. The current study suggests that UP may have a beneficial effect on cerebral neuronal degeneration in metabolic diseases with elevated ER stress.

  15. Mutual interaction of kisspeptin, estrogen and bone morphogenetic protein-4 activity in GnRH regulation by GT1-7 cells.

    PubMed

    Terasaka, Tomohiro; Otsuka, Fumio; Tsukamoto, Naoko; Nakamura, Eri; Inagaki, Kenichi; Toma, Kishio; Ogura-Ochi, Kanako; Glidewell-Kenney, Christine; Lawson, Mark A; Makino, Hirofumi

    2013-12-05

    Reproduction is integrated by interaction of neural and hormonal signals converging on hypothalamic neurons for controlling gonadotropin-releasing hormone (GnRH). Kisspeptin, the peptide product of the kiss1 gene and the endogenous agonist for the GRP54 receptor, plays a key role in the regulation of GnRH secretion. In the present study, we investigated the interaction between kisspeptin, estrogen and BMPs in the regulation of GnRH production by using mouse hypothalamic GT1-7 cells. Treatment with kisspeptin increased GnRH mRNA expression and GnRH protein production in a concentration-dependent manner. The expression levels of kiss1 and GPR54 were not changed by kisspeptin stimulation. Kisspeptin induction of GnRH was suppressed by co-treatment with BMPs, with BMP-4 action being the most potent for suppressing the kisspeptin effect. The expression of kisspeptin receptor, GPR54, was suppressed by BMPs, and this effect was reversed in the presence of kisspeptin. It was also revealed that BMP-induced Smad1/5/8 phosphorylation and Id-1 expression were suppressed and inhibitory Smad6/7 was induced by kisspeptin. In addition, estrogen induced GPR54 expression, while kisspeptin increased the expression levels of ERα and ERβ, suggesting that the actions of estrogen and kisspeptin are mutually enhanced in GT1-7 cells. Moreover, kisspeptin stimulated MAPKs and AKT signaling, and ERK signaling was functionally involved in the kisspeptin-induced GnRH expression. BMP-4 was found to suppress kisspeptin-induced GnRH expression by reducing ERK signaling activity. Collectively, the results indicate that the axis of kisspeptin-induced GnRH production is bi-directionally controlled, being augmented by an interaction between ERα/β and GPR54 signaling and suppressed by BMP-4 action in GT1-7 neuron cells.

  16. Estrogen inhibition of norepinephrine responsiveness is initiated at the plasma membrane of GnRH-producing GT1-7 cells.

    PubMed

    Morales, Araceli; Gonzalez, Miriam; Marin, Raquel; Diaz, Mario; Alonso, Rafael

    2007-07-01

    The modulatory action of estradiol (E2) on the GnRH network can be exerted indirectly on presynaptic neurons or directly on estrogen receptors (ERs) located within GnRH hypothalamic neurons. Using the GnRH-producing GT1-7 cell line, we have investigated whether E2 is able to modify the response of these cells to norepinephrine (NE) stimulation. A 48-h exposure of GT1-7 cells to 10 nM E2 reduced NE-induced cAMP accumulation. However, 15-min exposure was enough to induce this inhibitory action, provided that a hormone-free period of 48 h after steroid treatment was allowed. Furthermore, this effect was mimicked by E2 coupled to (E-BSA), indicating that it may be exerted through a membrane-mediated mechanism. In addition, competition experiments using E-BSA coupled to fluorescein isothiocyanate (FITC) revealed the presence of cell membrane-binding sites for E2. Binding of E-BSA coupled to FITC was blocked by preincubation of cells with either E2, antiestrogen ICI 182 780, or tamoxifen. Moreover, fluorescence staining of non-permeabilized cells with antibodies against receptors alpha and beta confirmed the presence of both receptor subtypes at the cell membrane. To determine the nature of the ER involved in this response, specific agonists for ERalpha 4,4',4''-(4-propyl-[1H]pyrazole-1,3,5-triyl)tris-phenol (PPT) and ERbeta 2,3-bis(4-hydroxyphenyl)-propionitrile (DPN) were used. Since PPT, but not DPN, reproduced the effect of E2, it is suggested that estrogen-induced modulatory action on NE responsiveness was mediated by the ERalpha isoform. Taken together, these results indicate that E2 modulates the adrenergic sensitivity of GT1-7 cells by a mechanism compatible with the activation of membrane-associated ERs.

  17. Subunit profiling and functional characteristics of acetylcholine receptors in GT1-7 cells.

    PubMed

    Arai, Yuki; Ishii, Hirotaka; Kobayashi, Makito; Ozawa, Hitoshi

    2017-03-01

    GnRH neurons form a final common pathway for the central regulation of reproduction. Although the involvement of acetylcholine in GnRH secretion has been reported, direct effects of acetylcholine and expression profiles of acetylcholine receptors (AChRs) still remain to be studied. Using immortalized GnRH neurons (GT1-7 cells), we analyzed molecular expression and functionality of AChRs. Expression of the mRNAs were identified in the order α7 > β2 = β1 ≧ α4 ≧ α5 = β4 = δ > α3 for nicotinic acetylcholine receptor (nAChR) subunits and m4 > m2 for muscarinic acetylcholine receptor (mAChR) subtypes. Furthermore, this study revealed that α7 nAChRs contributed to Ca(2+) influx and GnRH release and that m2 and m4 mAChRs inhibited forskolin-induced cAMP production and isobutylmethylxanthine-induced GnRH secretion. These findings demonstrate the molecular profiles of AChRs, which directly contribute to GnRH secretion in GT1-7 cells, and provide one possible regulatory action of acetylcholine in GnRH neurons.

  18. Cultured hypothalamic neurons are resistant to inflammation and insulin resistance induced by saturated fatty acids.

    PubMed

    Choi, Sun Ju; Kim, Francis; Schwartz, Michael W; Wisse, Brent E

    2010-06-01

    Hypothalamic inflammation induced by high-fat feeding causes insulin and leptin resistance and contributes to the pathogenesis of obesity. Since in vitro exposure to saturated fatty acids causes inflammation and insulin resistance in many cultured cell types, we determined how cultured hypothalamic neurons respond to this stimulus. Two murine hypothalamic neuronal cell cultures, N43/5 and GT1-7, were exposed to escalating concentrations of saturated fatty acids for up to 24 h. Harvested cells were evaluated for activation of inflammation by gene expression and protein content. Insulin-treated cells were evaluated for induction of markers of insulin receptor signaling (p-IRS, p-Akt). In both hypothalamic cell lines, inflammation was induced by prototypical inflammatory mediators LPS and TNFalpha, as judged by induction of IkappaBalpha (3- to 5-fold) and IL-6 (3- to 7-fold) mRNA and p-IkappaBalpha protein, and TNFalpha pretreatment reduced insulin-mediated p-Akt activation by 30% (P < 0.05). By comparison, neither mixed saturated fatty acid (100, 250, or 500 microM for hypothalamic neurons, whereas they did in control muscle and endothelial cell lines. Despite the lack of evidence of inflammatory signaling, saturated fatty acid exposure in cultured hypothalamic neurons causes endoplasmic reticulum stress, induces mitogen-activated protein kinase, and causes apoptotic cell death with prolonged exposure. We conclude that saturated fatty acid exposure does not induce inflammatory signaling or insulin resistance in cultured hypothalamic neurons. Therefore, hypothalamic neuronal inflammation in the setting of DIO may involve an indirect mechanism mediated by saturated fatty acids on nonneuronal cells.

  19. Neuropeptide Y stimulates autophagy in hypothalamic neurons

    PubMed Central

    Aveleira, Célia A.; Botelho, Mariana; Carmo-Silva, Sara; Ferreira-Marques, Marisa; Nóbrega, Clévio; Cortes, Luísa; Valero, Jorge; Sousa-Ferreira, Lígia; Álvaro, Ana R.; Santana, Magda; Kügler, Sebastian; Pereira de Almeida, Luís

    2015-01-01

    Aging is characterized by autophagy impairment that contributes to age-related disease aggravation. Moreover, it was described that the hypothalamus is a critical brain area for whole-body aging development and has impact on lifespan. Neuropeptide Y (NPY) is one of the major neuropeptides present in the hypothalamus, and it has been shown that, in aged animals, the hypothalamic NPY levels decrease. Because caloric restriction (CR) delays aging, at least in part, by stimulating autophagy, and also increases hypothalamic NPY levels, we hypothesized that NPY could have a relevant role on autophagy modulation in the hypothalamus. Therefore, the aim of this study was to investigate the role of NPY on autophagy in the hypothalamus. Using both hypothalamic neuronal in vitro models and mice overexpressing NPY in the hypothalamus, we observed that NPY stimulates autophagy in the hypothalamus. Mechanistically, in rodent hypothalamic neurons, NPY increases autophagy through the activation of NPY Y1 and Y5 receptors, and this effect is tightly associated with the concerted activation of PI3K, MEK/ERK, and PKA signaling pathways. Modulation of hypothalamic NPY levels may be considered a potential strategy to produce protective effects against hypothalamic impairments associated with age and to delay aging. PMID:25775546

  20. Transcriptional profiling of fetal hypothalamic TRH neurons

    PubMed Central

    2011-01-01

    Background During murine hypothalamic development, different neuroendocrine cell phenotypes are generated in overlapping periods; this suggests that cell-type specific developmental programs operate to achieve complete maturation. A balance between programs that include cell proliferation, cell cycle withdrawal as well as epigenetic regulation of gene expression characterizes neurogenesis. Thyrotropin releasing hormone (TRH) is a peptide that regulates energy homeostasis and autonomic responses. To better understand the molecular mechanisms underlying TRH neuron development, we performed a genome wide study of its transcriptome during fetal hypothalamic development. Results In primary cultures, TRH cells constitute 2% of the total fetal hypothalamic cell population. To purify these cells, we took advantage of the fact that the segment spanning -774 to +84 bp of the Trh gene regulatory region confers specific expression of the green fluorescent protein (GFP) in the TRH cells. Transfected TRH cells were purified by fluorescence activated cell sorting, various cell preparations pooled, and their transcriptome compared to that of GFP- hypothalamic cells. TRH cells undergoing the terminal phase of differentiation, expressed genes implicated in protein biosynthesis, intracellular signaling and transcriptional control. Among the transcription-associated transcripts, we identified the transcription factors Klf4, Klf10 and Atf3, which were previously uncharacterized within the hypothalamus. Conclusion To our knowledge, this is one of the first reports identifying transcripts with a potentially important role during the development of a specific hypothalamic neuronal phenotype. This genome-scale study forms a rational foundation for identifying genes that might participate in the development and function of hypothalamic TRH neurons. PMID:21569245

  1. Leptin signalling pathways in hypothalamic neurons.

    PubMed

    Kwon, Obin; Kim, Ki Woo; Kim, Min-Seon

    2016-04-01

    Leptin is the most critical hormone in the homeostatic regulation of energy balance among those so far discovered. Leptin primarily acts on the neurons of the mediobasal part of hypothalamus to regulate food intake, thermogenesis, and the blood glucose level. In the hypothalamic neurons, leptin binding to the long form leptin receptors on the plasma membrane initiates multiple signaling cascades. The signaling pathways known to mediate the actions of leptin include JAK-STAT signaling, PI3K-Akt-FoxO1 signaling, SHP2-ERK signaling, AMPK signaling, and mTOR-S6K signaling. Recent evidence suggests that leptin signaling in hypothalamic neurons is also linked to primary cilia function. On the other hand, signaling molecules/pathways mitigating leptin actions in hypothalamic neurons have been extensively investigated in an effort to treat leptin resistance observed in obesity. These include SOCS3, tyrosine phosphatase PTP1B, and inflammatory signaling pathways such as IKK-NFκB and JNK signaling, and ER stress-mitochondrial signaling. In this review, we discuss leptin signaling pathways in the hypothalamus, with a particular focus on the most recently discovered pathways.

  2. GnRH agonist reduces estrogen receptor dimerization in GT1-7 cells: evidence for cross-talk between membrane-initiated estrogen and GnRH signaling.

    PubMed

    Chason, Rebecca J; Kang, Jung-Hoon; Gerkowicz, Sabrina A; Dufau, Maria L; Catt, Kevin J; Segars, James H

    2015-03-15

    17β-estradiol (E2), a key participant on the initiation of the LH surge, exerts both positive and negative feedback on GnRH neurons. We sought to investigate potential interactions between estrogen receptors alpha (ERα) and beta (ERβ) and gonadotropin releasing hormone receptor (GnRH-R) in GT1-7 cells. Radioligand binding studies demonstrated a significant decrease in saturation E2 binding in cells treated with GnRH agonist. Conversely, there was a significant reduction in GnRH binding in GT1-7 cells treated with E2. In BRET(1) experiments, ERα-ERα dimerization was suppressed in GT1-7 cells treated with GnRH agonist (p < 0.05). There was no evidence of direct interaction between ERs and GnRH-R. This study provides the first evidence of reduced ERα homodimerization by GnRH agonist. Collectively, these findings demonstrate significant cross-talk between membrane-initiated GnRH and E2 signaling in GT1-7 cells.

  3. Susceptibility of GT1-7 cells to mouse-passaged field scrapie isolates with a long incubation.

    PubMed

    Miyazawa, Kohtaro; Okada, Hiroyuki; Iwamaru, Yoshifumi; Masujin, Kentaro; Yokoyama, Takashi

    2014-01-01

    A typical feature of scrapie in sheep and goats is the accumulation of disease-associated prion protein. Scrapie consists of many strains with different biological properties. Nine natural sheep scrapie cases were transmitted to wild-type mice and mouse-passaged isolates were classified into 2 types based on incubation time: short and long. These 2 types displayed a distinct difference in their pathology. We attempted to transmit these mouse-passaged isolates to 2 murine cell lines (GT1-7 and L929) to compare their properties. All of the isolates were transmitted to L929 cells. However, only mouse-passaged field isolates with a long incubation time were transmitted to GT1-7 cells. This specific susceptibility of GT1-7 cells was also confirmed with a primary-passaged isolate that was not completely adapted to the new host species. Characterization of the mechanisms of the specific susceptibility of GT1-7 cells to isolates with a long incubation time may lead to a greater understanding of the differences among prion strains.

  4. Leptin signaling in astrocytes regulates hypothalamic neuronal circuits and feeding.

    PubMed

    Kim, Jae Geun; Suyama, Shigetomo; Koch, Marco; Jin, Sungho; Argente-Arizon, Pilar; Argente, Jesús; Liu, Zhong-Wu; Zimmer, Marcelo R; Jeong, Jin Kwon; Szigeti-Buck, Klara; Gao, Yuanqing; Garcia-Caceres, Cristina; Yi, Chun-Xia; Salmaso, Natalina; Vaccarino, Flora M; Chowen, Julie; Diano, Sabrina; Dietrich, Marcelo O; Tschöp, Matthias H; Horvath, Tamas L

    2014-07-01

    We found that leptin receptors were expressed in hypothalamic astrocytes and that their conditional deletion led to altered glial morphology and synaptic inputs onto hypothalamic neurons involved in feeding control. Leptin-regulated feeding was diminished, whereas feeding after fasting or ghrelin administration was elevated in mice with astrocyte-specific leptin receptor deficiency. These data reveal an active role of glial cells in hypothalamic synaptic remodeling and control of feeding by leptin.

  5. Neuronal androgen receptor regulates insulin sensitivity via suppression of hypothalamic NF-κB-mediated PTP1B expression.

    PubMed

    Yu, I-Chen; Lin, Hung-Yun; Liu, Ning-Chun; Sparks, Janet D; Yeh, Shuyuan; Fang, Lei-Ya; Chen, Lumin; Chang, Chawnshang

    2013-02-01

    Clinical investigations highlight the increased incidence of metabolic syndrome in prostate cancer (PCa) patients receiving androgen deprivation therapy (ADT). Studies using global androgen receptor (AR) knockout mice demonstrate that AR deficiency results in the development of insulin resistance in males. However, mechanisms by which AR in individual organs coordinately regulates insulin sensitivity remain unexplored. Here we tested the hypothesis that functional AR in the brain contributes to whole-body insulin sensitivity regulation and to the metabolic abnormalities developed in AR-deficient male mice. The mouse model selectively lacking AR in the central nervous system and AR-expressing GT1-7 neuronal cells were established and used to delineate molecular mechanisms in insulin signaling modulated by AR. Neuronal AR deficiency leads to reduced insulin sensitivity in middle-aged mice. Neuronal AR regulates hypothalamic insulin signaling by repressing nuclear factor-κB (NF-κB)-mediated induction of protein-tyrosine phosphatase 1B (PTP1B). Hypothalamic insulin resistance leads to hepatic insulin resistance, lipid accumulation, and visceral obesity. The functional deficiency of AR in the hypothalamus leads to male mice being more susceptible to the effects of high-fat diet consumption on PTP1B expression and NF-κB activation. These findings suggest that in men with PCa undergoing ADT, reduction of AR function in the brain may contribute to insulin resistance and visceral obesity. Pharmacotherapies targeting neuronal AR and NF-κB may be developed to combat the metabolic syndrome in men receiving ADT and in elderly men with age-associated hypogonadism.

  6. Neuronal Androgen Receptor Regulates Insulin Sensitivity via Suppression of Hypothalamic NF-κB–Mediated PTP1B Expression

    PubMed Central

    Yu, I-Chen; Lin, Hung-Yun; Liu, Ning-Chun; Sparks, Janet D.; Yeh, Shuyuan; Fang, Lei-Ya; Chen, Lumin; Chang, Chawnshang

    2013-01-01

    Clinical investigations highlight the increased incidence of metabolic syndrome in prostate cancer (PCa) patients receiving androgen deprivation therapy (ADT). Studies using global androgen receptor (AR) knockout mice demonstrate that AR deficiency results in the development of insulin resistance in males. However, mechanisms by which AR in individual organs coordinately regulates insulin sensitivity remain unexplored. Here we tested the hypothesis that functional AR in the brain contributes to whole-body insulin sensitivity regulation and to the metabolic abnormalities developed in AR-deficient male mice. The mouse model selectively lacking AR in the central nervous system and AR-expressing GT1-7 neuronal cells were established and used to delineate molecular mechanisms in insulin signaling modulated by AR. Neuronal AR deficiency leads to reduced insulin sensitivity in middle-aged mice. Neuronal AR regulates hypothalamic insulin signaling by repressing nuclear factor-κB (NF-κB)–mediated induction of protein-tyrosine phosphatase 1B (PTP1B). Hypothalamic insulin resistance leads to hepatic insulin resistance, lipid accumulation, and visceral obesity. The functional deficiency of AR in the hypothalamus leads to male mice being more susceptible to the effects of high-fat diet consumption on PTP1B expression and NF-κB activation. These findings suggest that in men with PCa undergoing ADT, reduction of AR function in the brain may contribute to insulin resistance and visceral obesity. Pharmacotherapies targeting neuronal AR and NF-κB may be developed to combat the metabolic syndrome in men receiving ADT and in elderly men with age-associated hypogonadism. PMID:23139353

  7. A small population of hypothalamic neurons govern fertility: the critical role of VAX1 in GnRH neuron development and fertility maintenance

    PubMed Central

    Hoffmann, Hanne M.; Mellon, Pamela L.

    2017-01-01

    Fertility depends on the correct maturation and function of approximately 800 gonadotropin-releasing hormone (GnRH) neurons in the brain. GnRH neurons are at the apex of the hypothalamic-pituitary-gonadal axis that regulates fertility. In adulthood, GnRH neurons are scattered throughout the anterior hypothalamic area and project to the median eminence, where GnRH is released into the portal vasculature to stimulate release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary. LH and FSH then regulate gonadal steroidogenesis and gametogenesis. Absence of GnRH neurons or inappropriate GnRH release leads to infertility. Despite the critical role of GnRH neurons in fertility, we still have a limited understanding of the genes responsible for proper GnRH neuron development and function in adulthood. GnRH neurons originate in the olfactory placode then migrate into the brain. Homeodomain transcription factors expressed within GnRH neurons or along their migratory path are candidate genes for inherited infertility. Using a combined in vitro and in vivo approach, we have identified Ventral Anterior Homeobox 1 (Vax1) as a novel homeodomain transcription factor responsible for GnRH neuron maturation and fertility. GnRH neuron counts in Vax1 knock-out embryos revealed Vax1 to be required for the presence of GnRH-expressing cells at embryonic day 17.5 (E17.5), but not at E13.5. To localize the effects of Vax1 on fertility, we generated Vax1flox mice and crossed them with Gnrhcre mice to specifically delete Vax1 within GnRH neurons. GnRH staining in Vax1flox/flox:GnRHcre mice show a total absence of GnRH expression in the adult. We performed lineage tracing in Vax1flox/flox:GnRHcre:RosaLacZ mice which proved GnRH neurons to be alive, but incapable of expressing GnRH. The absence of GnRH leads to delayed puberty, hypogonadism and complete infertility in both sexes. Finally, using the immortalized model GnRH neuron cell lines, GN11 and GT1-7, we

  8. A small population of hypothalamic neurons govern fertility: the critical role of VAX1 in GnRH neuron development and fertility maintenance.

    PubMed

    Hoffmann, Hanne M; Mellon, Pamela L

    2016-01-01

    GT1-7, we show that VAX1 is a direct regulator of Gnrh1 transcription by binding key ATTA sites within the Gnrh1 promoter. This study identifies VAX1 as a key transcription factor regulating GnRH expression and establishes VAX1 as a novel candidate gene implicated in heritable infertility.

  9. Hypothalamic leptin-neurotensin-hypocretin neuronal networks in zebrafish.

    PubMed

    Levitas-Djerbi, Talia; Yelin-Bekerman, Laura; Lerer-Goldshtein, Tali; Appelbaum, Lior

    2015-04-01

    Neurotensin (NTS) is a 13 amino acid neuropeptide that is expressed in the hypothalamus. In mammals, NTS-producing neurons that express leptin receptor (LepRb) regulate the function of hypocretin/orexin (HCRT) and dopamine neurons. Thus, the hypothalamic leptin-NTS-HCRT neuronal network orchestrates key homeostatic output, including sleep, feeding, and reward. However, the intricate mechanisms of the circuitry and the unique role of NTS-expressing neurons remain unclear. We studied the NTS neuronal networks in zebrafish and cloned the genes encoding the NTS neuropeptide and receptor (NTSR). Similar to mammals, the ligand is expressed primarily in the hypothalamus, while the receptor is expressed widely throughout the brain in zebrafish. A portion of hypothalamic nts-expressing neurons are inhibitory and some coexpress leptin receptor (lepR1). As in mammals, NTS and HCRT neurons are localized adjacently in the hypothalamus. To track the development and axonal projection of NTS neurons, the NTS promoter was isolated. Transgenesis and double labeling of NTS and HCRT neurons showed that NTS axons project toward HCRT neurons, some of which express ntsr. Moreover, another target of NTS neurons is ntsr-expressing dopaminergeric neurons. These findings suggest structural circuitry between leptin, NTS, and hypocretinergic or dopaminergic neurons and establish the zebrafish as a model to study the role of these neuronal circuits in the regulation of feeding, sleep, and reward.

  10. Cell death mechanisms in GT1-7 GnRH cells exposed to polychlorinated biphenyls PCB74, PCB118, and PCB153

    SciTech Connect

    Dickerson, Sarah M.; Guevara, Esperanza; Woller, Michael J.; Gore, Andrea C.

    2009-06-01

    Exposure to endocrine disrupting chemicals (EDCs) such as polychlorinated biphenyls (PCBs) causes functional deficits in neuroendocrine systems. We used an immortalized hypothalamic GT1-7 cell line, which synthesizes the neuroendocrine peptide gonadotropin-releasing hormone (GnRH), to examine the neurotoxic and endocrine disrupting effects of PCBs and their mechanisms of action. Cells were treated for 1, 4, 8, or 24 h with a range of doses of a representative PCB from each of three classes: coplanar (2,4,4',5-tetrachlorobiphenyl: PCB74), dioxin-like coplanar (2',3,4,4',5' pentachlorobiphenyl: PCB118), non-coplanar (2,2',4,4',5,5'-hexachlorobiphenyl: PCB153), or their combination. GnRH peptide concentrations, cell viability, apoptotic and necrotic cell death, and caspase activation were quantified. In general, GnRH peptide levels were suppressed by high doses and longer durations of PCBs, and elevated at low doses and shorter timepoints. The suppression of GnRH peptide levels was partially reversed in cultures co-treated with the estrogen receptor antagonist ICI 182,780. All PCBs reduced viability and increased both apoptotic and necrotic cell death. Although the effects for the three classes of PCBs were often similar, subtle differences in responses, together with evidence that the combination of PCBs acted slightly different from individual PCBs, suggest that the three tested PCB compounds may act via slightly different or more than one mechanism. These results provide evidence that PCB congeners have endocrine disrupting and/or neurotoxic effects on the hypothalamic GnRH cell line, a finding that has implications for environmental endocrine disruption in animals.

  11. Cell death mechanisms in GT1-7 GnRH cells exposed to polychlorinated biphenyls PCB74, PCB118, and PCB153

    PubMed Central

    Dickerson, Sarah M.; Guevara, Esperanza; Woller, Michael J.; Gore, Andrea C.

    2009-01-01

    Exposure to endocrine-disrupting chemicals (EDCs) such as polychlorinated biphenyls (PCBs) causes functional deficits in neuroendocrine systems. We used an immortalized hypothalamic GT1-7 cell line, which synthesizes the neuroendocrine peptide gonadotropin-releasing hormone (GnRH), to examine the neurotoxic and endocrine disrupting effects of PCBs and their mechanisms of action. Cells were treated for 1, 4, 8, or 24 h with a range of doses of a representative PCB from each of three classes: coplanar (2,4,4′,5-tetrachlorobiphenyl: PCB74), dioxin-like coplanar (2′,3,4,4′,5′ pentachlorobiphenyl: PCB118), non-coplanar (2,2′,4,4′,5,5′-hexachlorobiphenyl: PCB153), or their combination. GnRH peptide concentrations, cell viability, apoptotic and necrotic cell death, and caspase activation were quantified. In general, GnRH peptide levels were suppressed by high doses and longer durations of PCBs, and elevated at low doses and shorter time points. The suppression of GnRH peptide levels was partially reversed in cultures co-treated with the estrogen receptor antagonist ICI 182,780. All PCBs reduced viability and increased both apoptotic and necrotic cell death. Although the effects for the three classes of PCBs were often similar, subtle differences in responses, together with evidence that the combination of PCBs acted slightly differently from individual PCBs, suggest that the three tested PCB compounds may act via slightly different or more than one mechanism. These results provide evidence that PCB congeners have endocrine disrupting and/or neurotoxic effects on the hypothalamic GnRH cell line, a finding that has implications for environmental endocrine disruption in animals. PMID:19362103

  12. Network of hypothalamic neurons that control appetite.

    PubMed

    Sohn, Jong-Woo

    2015-04-01

    The central nervous system (CNS) controls food intake and energy expenditure via tight coordinations between multiple neuronal populations. Specifically, two distinct neuronal populations exist in the arcuate nucleus of hypothalamus (ARH): the anorexigenic (appetite-suppressing) pro-opiomelanocortin (POMC) neurons and the orexigenic (appetite-increasing) neuropeptide Y (NPY)/agouti-related peptide (AgRP) neurons. The coordinated regulation of neuronal circuit involving these neurons is essential in properly maintaining energy balance, and any disturbance therein may result in hyperphagia/obesity or hypophagia/starvation. Thus, adequate knowledge of the POMC and NPY/AgRP neuron physiology is mandatory to understand the pathophysiology of obesity and related metabolic diseases. This review will discuss the history and recent updates on the POMC and NPY/AgRP neuronal circuits, as well as the general anorexigenic and orexigenic circuits in the CNS.

  13. Neurohormones, rikkunshito and hypothalamic neurons interactively control appetite and anorexia.

    PubMed

    Yada, Toshihiko; Kohno, Daisuke; Maejima, Yuko; Sedbazar, Udval; Arai, Takeshi; Toriya, Masako; Maekawa, Fumihiko; Kurita, Hedeharu; Niijima, Akira; Yakabi, Koji

    2012-01-01

    Ghrelin is the orexigenic peptide produced in the periphery, and its plasma level shows remarkable pre/postprandial changes. Ghrelin is considered a pivotal signal to the brain to stimulate feeding. Hence, characterizing the target neurons for ghrelin in the hypothalamic feeding center and the signaling cascade in the target neurons are essential for understanding the mechanisms regulating appetite. Anorexia and cachexia associated with gastric surgery, stress-related diseases, and use of anti-cancer drugs cause the health problems, markedly deteriorating the quality of life. The anorexia involves several neurotransmitters and neuropeptides in the hypothalamic feeding center, in which corticotropin-releasing hormone (CRH), urocortine, serotonin (5HT) and brain-derived neurotrophic factor (BDNF) play a pivotal role. A Japanese herbal medicine, rikkunshito, has been reported to ameliorate the anorexia by promoting the appetite. This review describes 1) the interaction of ghrelin with the orexigenic neuropeptide Y (NPY) neurons in the hypothalamic arcuate nucleus (ARC) and underlying signaling cascade in NPY neurons, 2) the anorectic pathway driven by BDNF-CRH/urocortine and 5HTCRH/ urocortine pathways, 3) the effect of rikkunshito on the interaction of ghrelin and NPY neurons in ARC, and 4) the effect of rikkunshito on the interaction of 5HT on CRH neurons in paraventricular nucleus (PVN).

  14. Molecular interrogation of hypothalamic organization reveals distinct dopamine neuronal subtypes.

    PubMed

    Romanov, Roman A; Zeisel, Amit; Bakker, Joanne; Girach, Fatima; Hellysaz, Arash; Tomer, Raju; Alpár, Alán; Mulder, Jan; Clotman, Frédéric; Keimpema, Erik; Hsueh, Brian; Crow, Ailey K; Martens, Henrik; Schwindling, Christian; Calvigioni, Daniela; Bains, Jaideep S; Máté, Zoltán; Szabó, Gábor; Yanagawa, Yuchio; Zhang, Ming-Dong; Rendeiro, Andre; Farlik, Matthias; Uhlén, Mathias; Wulff, Peer; Bock, Christoph; Broberger, Christian; Deisseroth, Karl; Hökfelt, Tomas; Linnarsson, Sten; Horvath, Tamas L; Harkany, Tibor

    2017-02-01

    The hypothalamus contains the highest diversity of neurons in the brain. Many of these neurons can co-release neurotransmitters and neuropeptides in a use-dependent manner. Investigators have hitherto relied on candidate protein-based tools to correlate behavioral, endocrine and gender traits with hypothalamic neuron identity. Here we map neuronal identities in the hypothalamus by single-cell RNA sequencing. We distinguished 62 neuronal subtypes producing glutamatergic, dopaminergic or GABAergic markers for synaptic neurotransmission and harboring the ability to engage in task-dependent neurotransmitter switching. We identified dopamine neurons that uniquely coexpress the Onecut3 and Nmur2 genes, and placed these in the periventricular nucleus with many synaptic afferents arising from neuromedin S(+) neurons of the suprachiasmatic nucleus. These neuroendocrine dopamine cells may contribute to the dopaminergic inhibition of prolactin secretion diurnally, as their neuromedin S(+) inputs originate from neurons expressing Per2 and Per3 and their tyrosine hydroxylase phosphorylation is regulated in a circadian fashion. Overall, our catalog of neuronal subclasses provides new understanding of hypothalamic organization and function.

  15. Estrogens modulate ventrolateral ventromedial hypothalamic glucose-inhibited neurons.

    PubMed

    Santiago, Ammy M; Clegg, Deborah J; Routh, Vanessa H

    2016-10-01

    Brain regulation of glucose homeostasis is sexually dimorphic; however, the impact sex hormones have on specific neuronal populations within the ventromedial hypothalamic nucleus (VMN), a metabolically sensitive brain region, has yet to be fully characterized. Glucose-excited (GE) and -inhibited (GI) neurons are located throughout the VMN and may play a critical role in glucose and energy homeostasis. Within the ventrolateral portion of the VMN (VL-VMN), glucose sensing neurons and estrogen receptor (ER) distributions overlap. We therefore tested the hypothesis that VL-VMN glucose sensing neurons were sexually dimorphic and regulated by 17β-estradiol (17βE). Electrophysiological recordings of VL-VMN glucose sensing neurons in brain slices isolated from age- and weight-matched female and male mice were performed in the presence and absence of 17βE. We found a new class of VL-VMN GI neurons whose response to low glucose was transient despite continued exposure to low glucose. Heretofore, we refer to these newly identified VL-VMN GI neurons as 'adapting' or AdGI neurons. We found a sexual dimorphic response to low glucose, with male nonadapting GI neurons, but not AdGI neurons, responding more robustly to low glucose than those from females. 17βE blunted the response of both nonadapting GI and AdGI neurons to low glucose in both males and females, which was mediated by activation of estrogen receptor β and inhibition of AMP-activated kinase. In contrast, 17βE had no impact on GE or non-glucose sensing neurons in either sex. These data suggest sex differences and estrogenic regulation of VMN hypothalamic glucose sensing may contribute to the sexual dimorphism in glucose homeostasis.

  16. Few isolated neurons in hypothalamic hamartomas may cause gelastic seizures.

    PubMed

    Waldau, Ben; McLendon, Roger E; Fuchs, Herbert E; George, Timothy M; Grant, Gerald A

    2009-01-01

    Hypothalamic hamartomas (HHs) are congenital, benign masses in the hypothalamus and tuber cinereum that may cause central precocious puberty and gelastic seizures. Nodules of small neurons are thought to be a universal feature of the microarchitecture of HH lesions associated with epilepsy. Here we describe the case of a 5-year-old boy with gelastic seizures who underwent resection of a HH that contained nodules of glial cells, but only few, randomly distributed neurons. HHs that contain few or no neurons have only been reported thus far in cases associated with precocious puberty. This case demonstrates that few solitary neurons in HHs can drive the development of gelastic seizures, and nodules of small neurons may not be a universal feature of HHs associated with epilepsy. This finding is clinically important since hypothalamic hamartomas with rare neurons can easily be misdiagnosed as pilocytic astrocytomas or subependymomas if their presence is overlooked. A neuronal stain is helpful in making the correct diagnosis in these cases.

  17. [Behavioral specialization of cortical and hypothalamic neurons in the rabbit].

    PubMed

    Shevchenko, D G

    1987-01-01

    Behavioural specialization was analyzed of hypothalamic and limbic neurones, with their activity recorded in rabbits during food-acquisition behaviour. The neurones with activity changed during staying of the animal in a definite place of the cage or during behavioural acts, characteristic of a specific behaviour in the cage, are considered as specialized in relation to the most "new" systems, acquired by the rabbit directly during learning of the given behaviour. Neurones with the activity changed with rabbit's turns, i.e. connected with behavioural acts, which the rabbit has not specially learnt, are considered specialized in relation to more "old" inborn systems. Neurones, in which no constant connection with any part of the studied behaviour was observed, are related to the most "ancient" systems. Comparison of the number of hypothalamic and limbic neurones of different groups showed that in the cortex there were some more neurones specialized in relation to behavioural acts, which were formed directly during learning of the rabbit in the experimental cage.

  18. Hypothalamic CRH neurons orchestrate complex behaviours after stress

    PubMed Central

    Füzesi, Tamás; Daviu, Nuria; Wamsteeker Cusulin, Jaclyn I.; Bonin, Robert P.; Bains, Jaideep S.

    2016-01-01

    All organisms possess innate behavioural and physiological programmes that ensure survival. In order to have maximum adaptive benefit, these programmes must be sufficiently flexible to account for changes in the environment. Here we show that hypothalamic CRH neurons orchestrate an environmentally flexible repertoire of behaviours that emerge after acute stress in mice. Optical silencing of CRH neurons disrupts the organization of individual behaviours after acute stress. These behavioural patterns shift according to the environment after stress, but this environmental sensitivity is blunted by activation of PVN CRH neurons. These findings provide evidence that PVN CRH cells are part of a previously unexplored circuit that matches precise behavioural patterns to environmental context following stress. Overactivity in this network in the absence of stress may contribute to environmental ambivalence, resulting in context-inappropriate behavioural strategies. PMID:27306314

  19. Ventromedial hypothalamic neurons control a defensive emotion state.

    PubMed

    Kunwar, Prabhat S; Zelikowsky, Moriel; Remedios, Ryan; Cai, Haijiang; Yilmaz, Melis; Meister, Markus; Anderson, David J

    2015-03-06

    Defensive behaviors reflect underlying emotion states, such as fear. The hypothalamus plays a role in such behaviors, but prevailing textbook views depict it as an effector of upstream emotion centers, such as the amygdala, rather than as an emotion center itself. We used optogenetic manipulations to probe the function of a specific hypothalamic cell type that mediates innate defensive responses. These neurons are sufficient to drive multiple defensive actions, and required for defensive behaviors in diverse contexts. The behavioral consequences of activating these neurons, moreover, exhibit properties characteristic of emotion states in general, including scalability, (negative) valence, generalization and persistence. Importantly, these neurons can also condition learned defensive behavior, further refuting long-standing claims that the hypothalamus is unable to support emotional learning and therefore is not an emotion center. These data indicate that the hypothalamus plays an integral role to instantiate emotion states, and is not simply a passive effector of upstream emotion centers.

  20. Differential involvement of hypothalamic vasopressin neurons in multiple system atrophy.

    PubMed

    Benarroch, Eduardo E; Schmeichel, Ann M; Sandroni, Paola; Low, Phillip A; Parisi, Joseph E

    2006-10-01

    We sought to determine whether there is differential involvement of different groups of hypothalamic arginine-vasopressin (AVP) synthesizing neurons in multiple system atrophy (MSA). Hypothalamus was obtained from five subjects with clinical diagnosis of MSA confirmed neuropathologically and five age-matched controls. Sections were immunostained for AVP, and cells with visible nuclei were counted in the posterior portion of the paraventricular nucleus (PVNp), supraoptic nucleus (SON), magnocellular PVN and suprachiasmatic nucleus (SCN). Sections of the hypothalamus and medulla were also immunostained for tyrosine hydroxylase (TH). There was a significant loss of AVP neurons in the PVNp in MSA compared with controls (17 +/- 3 versus 59 +/- 10 cells/section, P < 0.01). There was preservation of AVP- and TH-immunoreactive neurons in the SON and magnocellular PVN in all MSA cases. In contrast, there was marked depletion of TH-immunoreactive fibres innervating these magnocellular AVP neurons, coincident with a loss of neurons in the A1 area (6 +/- 1 versus 13 +/- 1 cells/section, P < 0.01). There was loss of AVP neurons in the SCN in MSA compared with control cases (14 +/- 3 versus 71 +/- 16 cells/section, P < 0.02). Our results indicate that, in MSA, loss of AVP neurons in the PVNp may contribute to sympathetic failure, whereas loss of catecholaminergic input from the brainstem to the magnocellular AVP neurons may contribute to impaired AVP secretion in response to orthostatic stress. Loss of AVP neurons in the SCN may contribute to impaired circadian regulation of endocrine and autonomic functions.

  1. Direct versus indirect actions of ghrelin on hypothalamic NPY neurons.

    PubMed

    Hashiguchi, Hiroshi; Sheng, Zhenyu; Routh, Vanessa; Gerzanich, Volodymyr; Simard, J Marc; Bryan, Joseph

    2017-01-01

    Assess direct versus indirect action(s) of ghrelin on hypothalamic NPY neurons. Electrophysiology was used to measure ion channel activity in NPY-GFP neurons in slice preparations. Ca2+ imaging was used to monitor ghrelin activation of isolated NPY GFP-labeled neurons. Immunohistochemistry was used to localize Trpm4, SUR1 and Kir6.2 in the hypothalamus. Acylated ghrelin depolarized the membrane potential (MP) of NPY-GFP neurons in brain slices. Depolarization resulted from a decreased input resistance (IR) in ~70% of neurons (15/22) or an increased IR in the remainder (7/22), consistent with the opening or closing of ion channels, respectively. Although tetrodotoxin (TTX) blockade of presynaptic action potentials reduced ghrelin-induced changes in MP and IR, ghrelin still significantly depolarized the MP and decreased IR in TTX-treated neurons, suggesting that ghrelin directly opens cation channel(s) in NPY neurons. In isolated NPY-GFP neurons, ghrelin produced a sustained rise of [Ca2+]c, with an EC50 ~110 pM. Pharmacologic studies confirmed that the direct action of ghrelin was through occupation of the growth hormone secretagogue receptor, GHS-R, and demonstrated the importance of the adenylate cyclase/cAMP/protein kinase A (PKA) and phospholipase C/inositol triphosphate (PLC/IP3) pathways as activators of 5' AMP-activated protein kinase (AMPK). Activation of isolated neurons was not affected by CNQX or TTX, but reducing [Na+]o suppressed activation, suggesting a role for Na+-permeable cation channels. SUR1 and two channel partners, Kir6.2 and Trpm4, were identified immunologically in NPY-GFP neurons in situ. The actions of SUR1 and Trpm4 modulators were informative: like ghrelin, diazoxide, a SUR1 agonist, elevated [Ca2+]c and glibenclamide, a SUR1 antagonist, partially suppressed ghrelin action, while 9-phenanthrol and flufenamic acid, selective Trpm4 antagonists, blocked ghrelin actions on isolated neurons. Ghrelin activation was unaffected by nifedipine and

  2. Tibolone Rapidly Attenuates the GABAB Response in Hypothalamic Neurones

    PubMed Central

    Qiu, Jian; Bosch, Martha A.; Rønnekleiv, Oline K.; Kloosterboer, Helenius J.; Kelly, Martin J.

    2008-01-01

    Tibolone is primarily used for the treatment of climacteric symptoms. Tibolone is rapidly converted into three major metabolites: 3α- and 3β-hydroxy-tibolone (3α- and 3βOH-tibolone), which have oestrogenic effects, and the Δ4-isomer (Δ4-tibolone), which has progestogenic and androgenic effects. Since tibolone is effective in treating climacteric symptoms, the effects on the brain may be explained by the oestrogenic activity of tibolone. Previously using whole-cell patch clamp recording, we found that 17β-oestradiol (E2) rapidly altered GABA neurotransmission in hypothalamic neurones through a membrane oestrogen receptor (mER). E2 reduced the potency of the GABAB receptor agonist baclofen to activate G-protein-coupled, inwardly rectifying K+ channels in hypothalamic neurones. Therefore, we hypothesized that tibolone may have some rapid effects through the mER and sought to elucidate the signalling pathway of tibolone’s action using selective inhibitors and whole cell recording in ovariectomized female guinea pigs and mice. A sub-population of neurones was identified post hoc as proopiomelanocortin (POMC) neurones by immunocytochemical staining. Similar to E2, we have found that tibolone and its active metabolite 3βOH-tibolone rapidly reduced the potency of the GABAB receptor agonist baclofen to activate GIRK channels in POMC neurones. The effects were blocked by the ER antagonist ICI 182,780. Other metabolites of tibolone (3αOH-tibolone and Δ4-tibolone) had no effect. Furthermore, tibolone (and 3βOH-tibolone) was fully efficacious in ERαKO and ERβKO mice to attenuate GABAB responses. The effects of tibolone were blocked by phospholipase C inhibitor U73122. However, in contrast to E2, the effects of tibolone were not blocked by protein kinase C inhibitors or protein kinase A inhibitors. It appears that tibolone (and 3βOH-tibolone) activates phospholipase C leading to PIP2 metabolism and direct alteration of GIRK channel function. Therefore, tibolone

  3. Synaptic contact between median preoptic neurons and subfornical organ neurons projecting to the paraventricular hypothalamic nucleus.

    PubMed

    Kawano, Hitoshi

    2017-04-01

    It is known that the median preoptic nucleus (POMe) sends dense projections to the subfornical organ (SFO). However, the functional significance of these projections have not been well discussed. In this electron microscopic study, we investigated the presence of synapses between POMe-derived axon terminals and SFO neurons that project to the paraventricular hypothalamic nucleus (PVN). After injection of a retrograde tracer, wheat germ agglutinin-conjugated horseradish peroxidase-colloidal gold complex, into the PVN, many labeled neurons were found in the SFO. In contrast, after injection of an anterograde tracer, biotinylated dextran amine, in the POMe, abundant labeled axon varicosities were observed in the SFO. Using electron microscopy, synapses were identified between retrogradely labeled dendrites and cell bodies, and anterogradely labeled axon terminals, indicating that POMe neurons innervate SFO neurons projecting to the PVN. The possibility that POMe neurons play multiple roles in the neuronal circuit responsible for vasopressin release and/or cardiovascular regulation is also discussed.

  4. Ventromedial hypothalamic neurons control a defensive emotion state

    PubMed Central

    Kunwar, Prabhat S; Zelikowsky, Moriel; Remedios, Ryan; Cai, Haijiang; Yilmaz, Melis; Meister, Markus; Anderson, David J

    2015-01-01

    Defensive behaviors reflect underlying emotion states, such as fear. The hypothalamus plays a role in such behaviors, but prevailing textbook views depict it as an effector of upstream emotion centers, such as the amygdala, rather than as an emotion center itself. We used optogenetic manipulations to probe the function of a specific hypothalamic cell type that mediates innate defensive responses. These neurons are sufficient to drive multiple defensive actions, and required for defensive behaviors in diverse contexts. The behavioral consequences of activating these neurons, moreover, exhibit properties characteristic of emotion states in general, including scalability, (negative) valence, generalization and persistence. Importantly, these neurons can also condition learned defensive behavior, further refuting long-standing claims that the hypothalamus is unable to support emotional learning and therefore is not an emotion center. These data indicate that the hypothalamus plays an integral role to instantiate emotion states, and is not simply a passive effector of upstream emotion centers. DOI: http://dx.doi.org/10.7554/eLife.06633.001 PMID:25748136

  5. Membrane-initiated Estrogen Signaling in Hypothalamic Neurons

    PubMed Central

    Kelly, Martin J.; Rønnekleiv, Oline K.

    2008-01-01

    Summary It is well known that many of the actions of 17β-estradiol (E2) in the central nervous system are mediated via intracellular receptor/transcription factors that interact with steroid response elements on target genes. However, there is compelling evidence for membrane steroid receptors for estrogen in hypothalamic and other brain neurons. But it is not well understood how estrogen signals via membrane receptors, and how these signals impact not only membrane excitability but also gene transcription in neurons. Indeed, it has been known for sometime that E2 can rapidly alter neuronal activity within seconds, indicating that some cellular effects can occur via membrane delimited events. In addition, E2 can affect second messenger systems including calcium mobilization and a plethora of kinases to alter cell signaling. Therefore, this review will consider our current knowledge of rapid membrane-initiated and intracellular signaling by E2 in the hypothalamus, the nature of receptors involved and how they contribute to homeostatic functions. PMID:18538919

  6. Excitatory actions of GABA in developing rat hypothalamic neurones.

    PubMed Central

    Chen, G; Trombley, P Q; van den Pol, A N

    1996-01-01

    1. Gramicidin-perforated patch clamp recording was employed to study GABA-mediated responses in rat hypothalamic neurones (n = 102) with an intracellular Cl- concentration unaltered by the pipette solution. 2. In young cultures after 1-7 days in vitro (DIV), GABA induced depolarizing membrane potentials (+16.5 +/- 1.3 mV) that often surpassed the threshold for the firing of action potentials (-42 +/- 1 mV) and resulted in an increase in neuronal activity. The depolarizing responses to GABA in young cultures were dose dependent. The concentration of GABA necessary to evoke the half-maximal depolarization (EC50) was 2.8 microM. In contrast, GABA induced hyperpolarizing membrane potentials (-12.0 +/- 1.4 mV) and a decrease in neuronal activity in older neurones (20-33 DIV). Both the depolarization and the hyperpolarization induced by GABA were blocked by bicuculline, indicating a mediation by GABAA receptors. 3. The reversal potentials of the GABA-evoked currents were between -40 to -50 mV during the first week of culture, and shifted to below -70 mV after 3 weeks of culture. In parallel, neurones that were dissociated from older animals (postnatal day 5) had a more negative reversal potential for the GABA-evoked currents than cells from younger animals (embryonic day 15), suggesting that the negative shift of the reversal potential occurs both in vitro and in vivo. Our data suggest that the mechanism for GABA-induced depolarization is the depolarized Cl- reversal potential found in young but not older neurones. 4. Consistent with the depolarizing response to exogenous application of GABA, some spontaneous depolarizing postsynaptic potentials in young cultures were insensitive to AP5-CNQX, but were eliminated by bicuculline, indicating that synaptically released GABA mediated excitatory synaptic transmission in early development. 5. By combining a rapid computer-controlled delivery of GABA with subthreshold positive current injections into recorded neurones, we found

  7. Optogenetic identification of hypothalamic orexin neuron projections to paraventricular spinally projecting neurons.

    PubMed

    Dergacheva, Olga; Yamanaka, Akihiro; Schwartz, Alan R; Polotsky, Vsevolod Y; Mendelowitz, David

    2017-04-01

    Orexin neurons, and activation of orexin receptors, are generally thought to be sympathoexcitatory; however, the functional connectivity between orexin neurons and a likely sympathetic target, the hypothalamic spinally projecting neurons (SPNs) in the paraventricular nucleus of the hypothalamus (PVN) has not been established. To test the hypothesis that orexin neurons project directly to SPNs in the PVN, channelrhodopsin-2 (ChR2) was selectively expressed in orexin neurons to enable photoactivation of ChR2-expressing fibers while examining evoked postsynaptic currents in SPNs in rat hypothalamic slices. Selective photoactivation of orexin fibers elicited short-latency postsynaptic currents in all SPNs tested (n = 34). These light-triggered responses were heterogeneous, with a majority being excitatory glutamatergic responses (59%) and a minority of inhibitory GABAergic (35%) and mixed glutamatergic and GABAergic currents (6%). Both glutamatergic and GABAergic responses were present in the presence of tetrodotoxin and 4-aminopyridine, suggesting a monosynaptic connection between orexin neurons and SPNs. In addition to generating postsynaptic responses, photostimulation facilitated action potential firing in SPNs (current clamp configuration). Glutamatergic, but not GABAergic, postsynaptic currents were diminished by application of the orexin receptor antagonist almorexant, indicating orexin release facilitates glutamatergic neurotransmission in this pathway. This work identifies a neuronal circuit by which orexin neurons likely exert sympathoexcitatory control of cardiovascular function.NEW & NOTEWORTHY This is the first study to establish, using innovative optogenetic approaches in a transgenic rat model, that there are robust heterogeneous projections from orexin neurons to paraventricular spinally projecting neurons, including excitatory glutamatergic and inhibitory GABAergic neurotransmission. Endogenous orexin release modulates glutamatergic, but not GABAergic

  8. Thyroid hormone is required for hypothalamic neurons regulating cardiovascular functions.

    PubMed

    Mittag, Jens; Lyons, David J; Sällström, Johan; Vujovic, Milica; Dudazy-Gralla, Susi; Warner, Amy; Wallis, Karin; Alkemade, Anneke; Nordström, Kristina; Monyer, Hannah; Broberger, Christian; Arner, Anders; Vennström, Björn

    2013-01-01

    Thyroid hormone is well known for its profound direct effects on cardiovascular function and metabolism. Recent evidence, however, suggests that the hormone also regulates these systems indirectly through the central nervous system. While some of the molecular mechanisms underlying the hormone's central control of metabolism have been identified, its actions in the central cardiovascular control have remained enigmatic. Here, we describe a previously unknown population of parvalbuminergic neurons in the anterior hypothalamus that requires thyroid hormone receptor signaling for proper development. Specific stereotaxic ablation of these cells in the mouse resulted in hypertension and temperature-dependent tachycardia, indicating a role in the central autonomic control of blood pressure and heart rate. Moreover, the neurons exhibited intrinsic temperature sensitivity in patch-clamping experiments, providing a new connection between cardiovascular function and core temperature. Thus, the data identify what we believe to be a novel hypothalamic cell population potentially important for understanding hypertension and indicate developmental hypothyroidism as an epigenetic risk factor for cardiovascular disorders. Furthermore, the findings may be beneficial for treatment of the recently identified patients that have a mutation in thyroid hormone receptor α1.

  9. Thyroid hormone is required for hypothalamic neurons regulating cardiovascular functions

    PubMed Central

    Mittag, Jens; Lyons, David J.; Sällström, Johan; Vujovic, Milica; Dudazy-Gralla, Susi; Warner, Amy; Wallis, Karin; Alkemade, Anneke; Nordström, Kristina; Monyer, Hannah; Broberger, Christian; Arner, Anders; Vennström, Björn

    2012-01-01

    Thyroid hormone is well known for its profound direct effects on cardiovascular function and metabolism. Recent evidence, however, suggests that the hormone also regulates these systems indirectly through the central nervous system. While some of the molecular mechanisms underlying the hormone’s central control of metabolism have been identified, its actions in the central cardiovascular control have remained enigmatic. Here, we describe a previously unknown population of parvalbuminergic neurons in the anterior hypothalamus that requires thyroid hormone receptor signaling for proper development. Specific stereotaxic ablation of these cells in the mouse resulted in hypertension and temperature-dependent tachycardia, indicating a role in the central autonomic control of blood pressure and heart rate. Moreover, the neurons exhibited intrinsic temperature sensitivity in patch-clamping experiments, providing a new connection between cardiovascular function and core temperature. Thus, the data identify what we believe to be a novel hypothalamic cell population potentially important for understanding hypertension and indicate developmental hypothyroidism as an epigenetic risk factor for cardiovascular disorders. Furthermore, the findings may be beneficial for treatment of the recently identified patients that have a mutation in thyroid hormone receptor α1. PMID:23257356

  10. Activation of Strychnine-Sensitive Glycine Receptors by Shilajit on Preoptic Hypothalamic Neurons of Juvenile Mice.

    PubMed

    Bhattarai, Janardhan Prasad; Cho, Dong Hyu; Han, Seong Kyu

    2016-02-29

    Shilajit, a mineral pitch, has been used in Ayurveda and Siddha system of medicine to treat many human ailments, and is reported to contain at least 85 minerals in ionic form. This study examined the possible mechanism of Shilajit action on preoptic hypothalamic neurons using juvenile mice. The hypothalamic neurons are the key regulator of many hormonal systems. In voltage clamp mode at a holding potential of -60 mV, and under a high chloride pipette solution, Shilajit induced dose-dependent inward current. Shilajit-induced inward currents were reproducible and persisted in the presence of 0.5 μM tetrodotoxin (TTX) suggesting a postsynaptic action of Shilajit on hypothalamic neurons. The currents induced by Shilajit were almost completely blocked by 2 μM strychnine (Stry), a glycine receptor antagonist. In addition, Shilajit-induced inward currents were partially blocked by bicuculline. Under a gramicidin-perforated patch clamp mode, Shilajit induced membrane depolarization on juvenile neurons. These results show that Shilajit affects hypothalamic neuronal activities by activating the Stry-sensitive glycine receptor with α₂/α₂β subunit. Taken together, these results suggest that Shilajit contains some ingredients with possible glycine mimetic activities and might influence hypothalamic neurophysiology through activation of Stry-sensitive glycine receptor-mediated responses on hypothalamic neurons postsynaptically.

  11. Fertility-Regulating Kiss1 Neurons Arise from Hypothalamic Pomc-Expressing Progenitors

    PubMed Central

    Sanz, Elisenda; Quintana, Albert; Deem, Jennifer D.; Steiner, Robert A.; Palmiter, Richard D.

    2015-01-01

    Hypothalamic neuronal populations are central regulators of energy homeostasis and reproductive function. However, the ontogeny of these critical hypothalamic neuronal populations is largely unknown. We developed a novel approach to examine the developmental pathways that link specific subtypes of neurons by combining embryonic and adult ribosome-tagging strategies in mice. This new method shows that Pomc-expressing precursors not only differentiate into discrete neuronal populations that mediate energy balance (POMC and AgRP neurons), but also into neurons critical for puberty onset and the regulation of reproductive function (Kiss1 neurons). These results demonstrate a developmental link between nutrient-sensing and reproductive neuropeptide synthesizing neuronal populations and suggest a potential pathway that could link maternal nutrition to reproductive development in the offspring. PMID:25855171

  12. Crucial role of zebrafish prox1 in hypothalamic catecholaminergic neurons development

    PubMed Central

    Pistocchi, Anna; Gaudenzi, Germano; Carra, Silvia; Bresciani, Erica; Del Giacco, Luca; Cotelli, Franco

    2008-01-01

    Background Prox1, the vertebrate homolog of prospero in Drosophila melanogaster, is a divergent homeogene that regulates cell proliferation, fate determination and differentiation during vertebrate embryonic development. Results Here we report that, in zebrafish, prox1 is widely expressed in several districts of the Central Nervous System (CNS). Specifically, we evidenced prox1 expression in a group of neurons, already positive for otp1, located in the hypothalamus at the level of the posterior tuberculum (PT). Prox1 knock-down determines the severe loss of hypothalamic catecholaminergic (CA) neurons, identified by tyrosine hydroxylase (TH) expression, and the synergistic prox1/otp1 overexpression induces the appearance of hypothalamic supernumerary TH-positive neurons and ectopic TH-positive cells on the yolk epitelium. Conclusion Our findings indicate that prox1 activity is crucial for the proper development of the otp1-positive hypothalamic neuronal precursors to their terminal CA phenotype. PMID:18331627

  13. Activation of hypothalamic gono-like neurons in female rats during estrus☆

    PubMed Central

    Ren, Xiaoxuan; Wang, Shaojun; Rong, Peijing; Zhu, Bing

    2012-01-01

    In mammals, gonadal function is controlled by the activity of hypothalamic gonadotropin-releasing hormone neurons, which control the secretion of adenohypophyseal and gonadal hormones. However, there are a number of unanswered questions in relation to gonadal function. It is currently unknown how erotogenic stimulation of the genitals influences the subpopulation of hypothalamic medial preoptic area neurons, antidromically identified as projecting to the median eminence at different periods of the estrous cycle. Additionally, the distinctiveness of hypothalamic medial preoptic area neurons, with respect to methods of feedback control by exogenous hormones, is also unknown. In this study, spontaneous discharges from individual neurons encountered within the medial preoptic area, gono-like neurons, were recorded extracellularly using glass microelectrodes. To confirm the cellular and histochemical properties of the recording units, antidromic stimulation was performed using a side-by-side bipolar stimulating electrode placed into the median eminence, alongside microiontophoretic injections of the conventional tracer, horseradish peroxidase. In addition, further immunohistochemical analyses were performed. Results showed that elevated gono-neuron activity was accompanied by increased background activity and greater responses to erotogenic stimuli during estrus. Application of clitoral traction stimulation resulted in increased activation of the gono-like neurons. This neuronal activity was noticeably inhibited by β-estradiol administration. Immunohistochemical analyses revealed the presence of gonadotropin-releasing hormone-reactive protein in hypothalamic cells in which electrophysiological recordings were taken. Thus, medial preoptic area neurons represent the subset of hypothalamic gonadotropin-releasing hormone neurons described from brain slices in vitro, and might serve as a useful physiological model to form the basis of future in vivo studies. PMID:25337091

  14. InsR/FoxO1 signaling curtails hypothalamic POMC neuron number.

    PubMed

    Plum, Leona; Lin, Hua V; Aizawa, Kumiko S; Liu, Yitian; Accili, Domenico

    2012-01-01

    Insulin receptor (InsR) signaling through transcription factor FoxO1 is important in the development of hypothalamic neuron feeding circuits, but knowledge about underlying mechanisms is limited. To investigate the role of InsR/FoxO1 signaling in the development and maintenance of these circuits, we surveyed the pool of hypothalamic neurons expressing Pomc mRNA in different mouse models of impaired hypothalamic InsR signaling. InsR ablation in the entire hypothalamus did not affect Pomc-neuron number at birth, but resulted in a 25% increase, most notably in the middle arcuate nucleus region, in young adults. Selective restoration of InsR expression in POMC neurons in these mice partly reversed the abnormality, resulting in a 10% decrease compared to age-matched controls. To establish whether FoxO1 signaling plays a role in this process, we examined POMC neuron number in mice with POMC-specific deletion of FoxO1, and detected a 23% decrease in age-matched animals, consistent with a cell-autonomous role of InsR/FoxO1 signaling in regulating POMC neuron number, distinct from its established role to activate Pomc transcription. These changes in Pomc cells occurred in the absence of marked changes in humoral factors or hypothalamic NPY neurons.

  15. MCT2 Expression and Lactate Influx in Anorexigenic and Orexigenic Neurons of the Arcuate Nucleus

    PubMed Central

    Cortes-Campos, Christian; Elizondo, Roberto; Carril, Claudio; Martínez, Fernando; Boric, Katica; Nualart, Francisco; Garcia-Robles, Maria Angeles

    2013-01-01

    Hypothalamic neurons of the arcuate nucleus control food intake, releasing orexigenic and anorexigenic neuropeptides in response to changes in glucose concentration. Several studies have suggested that the glucosensing mechanism is governed by a metabolic interaction between neurons and glial cells via lactate flux through monocarboxylate transporters (MCTs). Hypothalamic glial cells (tanycytes) release lactate through MCT1 and MCT4; however, similar analyses in neuroendocrine neurons have yet to be undertaken. Using primary rat hypothalamic cell cultures and fluorimetric assays, lactate incorporation was detected. Furthermore, the expression and function of MCT2 was demonstrated in the hypothalamic neuronal cell line, GT1-7, using kinetic and inhibition assays. Moreover, MCT2 expression and localization in the Sprague Dawley rat hypothalamus was analyzed using RT-PCR, in situ hybridization and Western blot analyses. Confocal immunohistochemistry analyses revealed MCT2 localization in neuronal but not glial cells. Moreover, MCT2 was localized to ∼90% of orexigenic and ∼60% of anorexigenic neurons as determined by immunolocalization analysis of AgRP and POMC with MCT2-positives neurons. Thus, MCT2 distribution coupled with lactate uptake by hypothalamic neurons suggests that hypothalamic neurons control food intake using lactate to reflect changes in glucose levels. PMID:23638108

  16. Hypothalamic TLR2 triggers sickness behavior via a microglia-neuronal axis

    PubMed Central

    Jin, Sungho; Kim, Jae Geun; Park, Jeong Woo; Koch, Marco; Horvath, Tamas L.; Lee, Byung Ju

    2016-01-01

    Various pathophysiologic mechanisms leading to sickness behaviors have been proposed. For example, an inflammatory process in the hypothalamus has been implicated, but the signaling modalities that involve inflammatory mechanisms and neuronal circuit functions are ill-defined. Here, we show that toll-like receptor 2 (TLR2) activation by intracerebroventricular injection of its ligand, Pam3CSK4, triggered hypothalamic inflammation and activation of arcuate nucleus microglia, resulting in altered input organization and increased activity of proopiomelanocortin (POMC) neurons. These animals developed sickness behavior symptoms, including anorexia, hypoactivity, and hyperthermia. Antagonists of nuclear factor kappa B (NF-κB), cyclooxygenase pathway and melanocortin receptors 3/4 reversed the anorexia and body weight loss induced by TLR2 activation. These results unmask an important role of TLR2 in the development of sickness behaviors via stimulation of hypothalamic microglia to promote POMC neuronal activation in association with hypothalamic inflammation. PMID:27405276

  17. Necdin controls Foxo1 acetylation in hypothalamic arcuate neurons to modulate the thyroid axis.

    PubMed

    Hasegawa, Koichi; Kawahara, Tomohiro; Fujiwara, Kazushiro; Shimpuku, Mayumi; Sasaki, Tsutomu; Kitamura, Tadahiro; Yoshikawa, Kazuaki

    2012-04-18

    The forkhead transcription factor Foxo1 regulates energy homeostasis by modulating gene expression in the hypothalamus. Foxo1 undergoes post-translational modifications such as phosphorylation and acetylation, which modulate its functional activities. Sirtuin1 (Sirt1), a nicotinamide adenine dinucleotide-dependent protein deacetylase, regulates the acetylation status of Foxo1 in mammalian cells. Necdin, a pleiotropic protein required for neuronal development and survival, interacts with both Sirt1 and p53 to facilitate p53 deacetylation. The necdin gene (Ndn), an imprinted gene transcribed only from the paternal allele, is strongly expressed in hypothalamic neurons. Here, we demonstrate that necdin controls the acetylation status of Foxo1 in vivo in hypothalamic arcuate neurons to modulate the thyroid function. Necdin forms a stable ternary complex with Sirt1 and Foxo1, diminishes Foxo1 acetylation, and suppresses the transcriptional activity of Foxo1 in vitro. Paternal Ndn mutant mice express high levels of acetylated Foxo1 and mRNAs encoding agouti-related protein and neuropeptide Y in the hypothalamus in vivo during the juvenile period. The mutant mice exhibit endocrine dysfunction characteristic of hypothalamic hypothyroidism. Chemically induced hyperthyroidism and hypothyroidism lead to hypothalamic responses similar to those under necdin-deficient and excessive conditions, respectively, suggesting that thyroid hormone serves as a negative regulator of this system. These results suggest that necdin regulates Foxo1 acetylation and neuropeptide gene expression in the arcuate neurons to modulate the hypothalamic-pituitary-thyroid axis during development.

  18. Leptin signaling in GFAP-expressing adult glia cells regulates hypothalamic neuronal circuits and feeding

    PubMed Central

    Kim1, Jae Geun; Suyama, Shigetomo; Koch, Marco; Jin, Sungho; Argente-Arizon, Pilar; Argente, Jesus; Liu, Zhong-Wu; Zimmer, Marcelo R.; Jeong, Jin Kwon; Szigeti-Buck, Klara; Gao, Yuanqing; Garcia-Caceres, Cristina; Yi, Chun-Xia; Salmaso, Natalina; Vaccarino, Flora M.; Chowen, Julie; Diano, Sabrina; Dietrich, Marcelo O; Tschöp, Matthias H.; Horvath, Tamas L.

    2014-01-01

    We have shown that synaptic re-organization of hypothalamic feeding circuits in response to metabolic shifts involves astrocytes, cells that can directly respond to the metabolic hormone, leptin, in vitro. It is not known whether the role of glia cells in hypothalamic synaptic adaptions is active or passive. Here we show that leptin receptors are expressed in hypothalamic astrocytes and that conditional, adult deletion of leptin receptors in astrocytes leads to altered glial morphology, decreased glial coverage and elevated synaptic inputs onto pro-opiomelanocortin (POMC)- and Agouti-related protein (AgRP)-producing neurons. Leptin-induced suppression of feeding was diminished, while rebound feeding after fasting or ghrelin administration was elevated in mice with astrocyte-specific leptin receptor deficiency. These data unmask an active role of glial cells in the initiation of hypothalamic synaptic plasticity and neuroendocrine control of feeding by leptin. PMID:24880214

  19. Autophagy in hypothalamic AgRP neurons regulates food intake and energy balance

    PubMed Central

    Kaushik, Susmita; Rodriguez-Navarro, Jose Antonio; Arias, Esperanza; Kiffin, Roberta; Sahu, Srabani; Schwartz, Gary J.; Cuervo, Ana Maria; Singh, Rajat

    2011-01-01

    SUMMARY Macroautophagy is a lysosomal degradative pathway that maintains cellular homeostasis by turning over cellular components. Here, we demonstrate a role for autophagy in hypothalamic agouti-related peptide (AgRP) neurons in the regulation of food intake and energy balance. We show that starvation-induced hypothalamic autophagy mobilizes neuron-intrinsic lipids to generate endogenous free fatty acids, which in turn regulate AgRP levels. The functional consequences of inhibiting autophagy are the failure to upregulate AgRP in response to starvation, and constitutive increases in hypothalamic levels of pro-opiomelanocortin and its cleavage product α-melanocyte stimulating hormone that typically contribute to a lean phenotype. We propose a new conceptual framework for considering how autophagy-regulated lipid metabolism within hypothalamic neurons may modulate neuropeptide levels to have immediate effects on food intake, as well as long-term effects on energy homeostasis. Regulation of hypothalamic autophagy could become an effective intervention in conditions such as obesity and the metabolic syndrome. PMID:21803288

  20. Sleep-waking discharge patterns of ventrolateral preoptic/anterior hypothalamic neurons in rats.

    PubMed

    Szymusiak, R; Alam, N; Steininger, T L; McGinty, D

    1998-08-24

    Numerous lesion, stimulation and recording studies in experimental animals demonstrate the importance of neurons within the preoptic/anterior hypothalamic area (POA) in the regulation of sleep induction and sleep maintenance. Recently, a discrete cluster of cells in the ventrolateral POA (vlPOA) of rats was found to exhibit elevated c-fos gene expression during sleep, indicating that these neurons are strongly activated during nonREM and/or REM sleep stages. We examined neuronal discharge during wakefulness and sleep throughout the dorsal to ventral extent of the lateral POA in rats, using chronic microwire technique. We found that neurons with elevated discharge rates during sleep, compared to waking, were localized to the vlPOA. As a group, vlPOA neurons displayed elevated discharge rates during both nonREM and REM sleep. Discharge of vlPOA neurons reflected the depth of sleep, i.e., discharge rates increased significantly from light to deep nonREM sleep. During recovery sleep following 12-14 h of sleep deprivation, vlPOA neurons displayed increased sleep-related discharge, compared to baseline sleep. Neurons in the vlPOA displaying increased neuronal discharge during sleep were located in the same area where neurons exhibit increased c-fos gene expression during sleep. Such neurons are likely components of a rostral hypothalamic mechanism that regulates sleep onset and sleep maintenance.

  1. [Effect of the intermittent hypoxic training on the functioning of peptidergic neurons of the paraventricular hypothalamic nucleus and brain stem neurons in rats].

    PubMed

    Abramov, A V

    1998-03-01

    Internittent hypoxic training (IHT) increased the quantity and secretory activity of peptidergic neurons of the paraventricular hypothalamic nucleus (PHN) and activated neurons of the dorsal motor nucleus of n.vagus. These structures seem to take part in realisation of the IHT activating effect on condition of the pancreatic delta-cells. The effect involves insulin-stimulating and insuloprotective effects realised via hypothalamic and neuro-conducting ways of regulation of the endocrine pancreas with a direct participation of hypothalamic neuropeptides.

  2. Lesions of hypothalamic mammillary body desynchronise milk-ejection bursts of rat bilateral supraoptic oxytocin neurones.

    PubMed

    Wang, Y-F; Negoro, H; Higuchi, T

    2013-01-01

    Successful milk ejection depends on a bolus release of oxytocin, which results from the synchronised burst firing of magnocellular oxytocin neurones in several hypothalamic nuclei. Despite extensive studies of the mechanism underlying the burst synchrony of oxytocin neurones in the same nucleus, brain regions controlling burst synchronisation among different nuclei remain elusive. We hypothesised that some structures in the ventroposterior hypothalamus may function as the major component of neural circuits controlling burst synchronisation of bilateral oxytocin neurones. To test this hypothesis, we recorded burst firing of bilateral oxytocin neurones in the two supraoptic nuclei after microsurgical disconnection of different hypothalamic regions in anaesthetised lactating rats. The results obtained showed that the interhemispheric section of the caudal part of the hypothalamus but not the rostral hypothalamus resulted in burst desynchronisation. The difference in burst onset time between paired bursts of bilateral oxytocin neurones was 129.2 ± 34.7 s, which is significantly (P < 0.01) longer than that of sham-lesioned controls (0.24 ± 0.02 s). Hypothalamic lesions leading to the desynchronisation involved the mammillary body, supramammillary nucleus and tuberomammillary nucleus in the ventroposterior hypothalamus. Consistently, electrolytic lesion of the median part of this mammillary body region also desynchronised the burst of bilateral oxytocin neurones and disrupted milk ejections. These results indicate that the mammillary body region is critically involved in the burst synchronisation of bilateral oxytocin neurones during suckling and possibly functions as the major component of a putative synchronisation centre. © 2012 British Society for Neuroendocrinology.

  3. Microglia Dictate the Impact of Saturated Fat Consumption on Hypothalamic Inflammation and Neuronal Function

    PubMed Central

    Valdearcos, Martin; Robblee, Megan M.; Benjamin, Daniel I.; Nomura, Daniel K.; Xu, Allison W.; Koliwad, Suneil K.

    2014-01-01

    Diets rich in saturated fat produce inflammation, gliosis, and neuronal stress in the mediobasal hypothalamus (MBH). Here we show that microglia mediate this process and its functional impact. Although microglia and astrocytes accumulate in the MBH of mice fed a diet rich in saturated fatty acids (SFAs), only the microglia undergo inflammatory activation, along with a build-up of hypothalamic SFAs. Enteric gavage specifically with SFAs reproduces microglial activation and neuronal stress in the MBH, and SFA treatment activates murine microglia, but not astrocytes, in culture. Moreover, depleting microglia abrogates SFA-induced inflammation in hypothalamic slices. Remarkably, depleting microglia from the MBH of mice abolishes inflammation and neuronal stress induced by excess SFA consumption, and in this context, microglial depletion enhances leptin signaling and reduces food intake. We thus show that microglia sense SFAs and orchestrate an inflammatory process in the MBH that alters neuronal function when SFA consumption is high. PMID:25497089

  4. Leptin Acts via Lateral Hypothalamic Area Neurotensin Neurons to Inhibit Orexin Neurons by Multiple GABA-Independent Mechanisms

    PubMed Central

    Goforth, Paulette B.; Leinninger, Gina M.; Patterson, Christa M.

    2014-01-01

    The adipocyte-derived hormone leptin modulates neural systems appropriately for the status of body energy stores. Leptin inhibits lateral hypothalamic area (LHA) orexin (OX; also known as hypocretin)-producing neurons, which control feeding, activity, and energy expenditure, among other parameters. Our previous results suggest that GABAergic LHA leptin receptor (LepRb)-containing and neurotensin (Nts)-containing (LepRbNts) neurons lie in close apposition with OX neurons and control Ox mRNA expression. Here, we show that, similar to leptin, activation of LHA Nts neurons by the excitatory hM3Dq DREADD (designer receptor exclusively activated by designer drugs) hyperpolarizes membrane potential and suppresses action potential firing in OX neurons in mouse hypothalamic slices. Furthermore, ablation of LepRb from Nts neurons abrogated the leptin-mediated inhibition, demonstrating that LepRbNts neurons mediate the inhibition of OX neurons by leptin. Leptin did not significantly enhance GABAA-mediated inhibitory synaptic transmission, and GABA receptor antagonists did not block leptin-mediated inhibition of OX neuron activity. Rather, leptin diminished the frequency of spontaneous EPSCs onto OX neurons. Furthermore, leptin indirectly activated an ATP-sensitive potassium (KATP) channel in OX neurons, which was required for the hyperpolarization of OX neurons by leptin. Although Nts did not alter OX activity, galanin, which is coexpressed in LepRbNts neurons, inhibited OX neurons, whereas the galanin receptor antagonist M40 (galanin-(1–12)-Pro3-(Ala-Leu)2-Ala amide) prevented the leptin-induced hyperpolarization of OX cells. These findings demonstrate that leptin indirectly inhibits OX neurons by acting on LHA LepRbNts neurons to mediate two distinct GABA-independent mechanisms of inhibition: the presynaptic inhibition of excitatory neurotransmission and the opening of KATP channels. PMID:25143620

  5. Firing Behavior and Network Activity of Single Neurons in Human Epileptic Hypothalamic Hamartoma

    PubMed Central

    Steinmetz, Peter N.; Wait, Scott D.; Lekovic, Gregory P.; Rekate, Harold L.; Kerrigan, John F.

    2013-01-01

    Objective: Human hypothalamic hamartomas (HH) are intrinsically epileptogenic and are associated with treatment-resistant gelastic seizures. The basic cellular mechanisms responsible for seizure onset within HH are unknown. We used intra-operative microwire recordings of single neuron activity to measure the spontaneous firing rate of neurons and the degree of functional connection between neurons within the tumor. Technique: Fourteen patients underwent transventricular endoscopic resection of HH for treatment-resistant epilepsy. Prior to surgical resection, single neuron recordings from bundled microwires (total of nine contacts) were obtained from HH tissue. Spontaneous activity was recorded for two or three 5-min epochs under steady-state general anesthesia. Off-line analysis included cluster analysis of single unit activity and probability analysis of firing relationships between pairs of neurons. Results: Altogether, 222 neurons were identified (mean 6 neurons per recording epoch). Cluster analysis of single neuron firing utilizing a mixture of Gaussians model identified two distinct populations on the basis of firing rate (median firing frequency 0.6 versus 15.0 spikes per second; p < 10−5). Cluster analysis identified three populations determined by levels of burst firing (median burst indices of 0.015, 0.18, and 0.39; p < 10−15). Unbiased analysis of spontaneous single unit behavior showed that 51% of all possible neuron pairs within each recording epoch had a significant level of firing synchrony (p < 10−15). The subgroup of neurons with higher median firing frequencies was more likely to demonstrate synchronous firing (p < 10−7). Conclusion: Hypothalamic hamartoma tissue in vivo contains neurons which fire spontaneously. The activity of single neurons is diverse but distributes into at least two electrophysiological phenoytpes. Functional linkage between single neurons suggests that HH neurons exist within local networks that may

  6. Hypothalamic glucose-sensing: role of Glia-to-neuron signaling.

    PubMed

    Tonon, M C; Lanfray, D; Castel, H; Vaudry, H; Morin, F

    2013-12-01

    The hypothalamus senses hormones and nutrients in order to regulate energy balance. In particular, detection of hypothalamic glucose levels has been shown to regulate both feeding behavior and peripheral glucose homeostasis, and impairment of this regulatory system is believed to be involved in the development of obesity and diabetes. Several data clearly demonstrate that glial cells are key elements in the perception of glucose, constituting with neurons a "glucose-sensing unit". Characterization of this interplay between glia and neurons represents an exciting challenge, and will undoubtedly contribute to identify new candidates for therapeutic intervention. The purpose of this review is to summarize the current data that stress the importance of glia in central glucose-sensing. The nature of the glia-to-neuron signaling is discussed, with a special focus on the endozepine ODN, a potent anorexigenic peptide that is highly expressed in hypothalamic glia.

  7. Differential effects of histamine on the activity of hypothalamic dopaminergic neurons in the rat.

    PubMed

    Fleckenstein, A E; Lookingland, K J; Moore, K E

    1994-01-01

    The effect of intracerebroventricular administration of histamine on hypothalamic dopaminergic neuronal activity was estimated in male rats by measuring concentrations of dopamine and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in brain regions containing terminals or perikarya of these neurons. Three distinct, regionally specific neurochemical responses were apparent. In the median eminence and intermediate lobe of the pituitary, histamine affected neither DOPAC nor dopamine concentrations, suggesting no effect on tuberoinfundibular or periventricular-hypophysial dopaminergic neuronal activity. In the medial zona incerta and in the dorsomedial, rostral periventricular and medial preoptic hypothalamic nuclei, histamine effected a dose- and time-related increase in both DOPAC and dopamine concentrations; these effects were blocked by destruction of noradrenergic neurons projecting to these regions, suggesting that these changes are attributable to noradrenergic neuronal activation, and that histamine does not affect the activity of incertohypothalamic or periventricular-preoptic dopaminergic neurons located in these brain regions. In the suprachiasmatic, caudal periventricular and paraventricular hypothalamic nuclei, histamine effected a dose- and time-related increase in DOPAC, but not dopamine, concentrations; these effects were blocked by the H1 antagonist mepyramine, but not the H2 antagonist zolantidine. Destruction of noradrenergic neurons projecting to these regions did not prevent the histamine-induced increases in DOPAC concentrations. These data indicate that histamine increases the activity of dopaminergic neurons projecting to the suprachiasmatic, caudal periventricular and paraventricular nuclei via an action at H1 receptors. Overall, these results reveal that i.c.v. administration of histamine differentially affects the activity of the various dopaminergic neuronal systems of the rat hypothalamus.

  8. Neurogenin 3 mediates sex chromosome effects on the generation of sex differences in hypothalamic neuronal development

    PubMed Central

    Scerbo, María J.; Freire-Regatillo, Alejandra; Cisternas, Carla D.; Brunotto, Mabel; Arevalo, Maria A.; Garcia-Segura, Luis M.; Cambiasso, María J.

    2014-01-01

    The organizational action of testosterone during critical periods of development is the cause of numerous sex differences in the brain. However, sex differences in neuritogenesis have been detected in primary neuronal hypothalamic cultures prepared before the peak of testosterone production by fetal testis. In the present study we assessed the hypothesis of that cell-autonomous action of sex chromosomes can differentially regulate the expression of the neuritogenic gene neurogenin 3 (Ngn3) in male and female hypothalamic neurons, generating sex differences in neuronal development. Neuronal cultures were prepared from male and female E14 mouse hypothalami, before the fetal peak of testosterone. Female neurons showed enhanced neuritogenesis and higher expression of Ngn3 than male neurons. The silencing of Ngn3 abolished sex differences in neuritogenesis, decreasing the differentiation of female neurons. The sex difference in Ngn3 expression was determined by sex chromosomes, as demonstrated using the four core genotypes mouse model, in which a spontaneous deletion of the testis-determining gene Sry from the Y chromosome was combined with the insertion of the Sry gene onto an autosome. In addition, the expression of Ngn3, which is also known to mediate the neuritogenic actions of estradiol, was increased in the cultures treated with the hormone, but only in those from male embryos. Furthermore, the hormone reversed the sex differences in neuritogenesis promoting the differentiation of male neurons. These findings indicate that Ngn3 mediates both cell-autonomous actions of sex chromosomes and hormonal effects on neuritogenesis. PMID:25071448

  9. Glut4 expression defines an insulin-sensitive hypothalamic neuronal population.

    PubMed

    Ren, Hongxia; Yan, Shijun; Zhang, Baifang; Lu, Taylor Y; Arancio, Ottavio; Accili, Domenico

    2014-07-01

    Insulin signaling in the CNS modulates satiety and glucose metabolism, but insulin target neurons are poorly defined. We have previously shown that ablation of insulin receptors (InsR) in Glut4-expressing tissues results in systemic abnormalities of insulin action. We propose that Glut4 neurons constitute an insulin-sensitive neuronal subset. We determined their gene expression profiles using flow-sorted hypothalamic Glut4 neurons. Gene ontology analyses demonstrated that Glut4 neurons are enriched in olfacto-sensory receptors, M2 acetylcholine receptors, and pathways required for the acquisition of insulin sensitivity. Following genetic ablation of InsR, transcriptome profiling of Glut4 neurons demonstrated impairment of the insulin, peptide hormone, and cAMP signaling pathways, with a striking upregulation of anion homeostasis pathway. Accordingly, hypothalamic InsR-deficient Glut4 neurons showed reduced firing activity. The molecular signature of Glut4 neurons is consistent with a role for this neural population in the integration of olfacto-sensory cues with hormone signaling to regulate peripheral metabolism.

  10. Pharmacological properties of GABAA receptors in rat hypothalamic neurons expressing the epsilon-subunit.

    PubMed

    Sergeeva, Olga A; Andreeva, Nadja; Garret, Maurice; Scherer, Annette; Haas, Helmut L

    2005-01-05

    The pharmacological properties and functional role of native GABA(A) receptors (GABA(A)Rs) were investigated in rat hypothalamic neurons expressing the epsilon-subunit with the help of whole-cell patch-clamp recording and single-cell reverse transcription-PCR. Two cell groups were identified: histaminergic tuberomamillary and orexinergic/hypocretinergic neurons. Approximately 25% of histaminergic and 70% of orexinergic neurons contained mRNA encoding for the epsilon-subunit. Double-immunofluorescence staining revealed a somatic localization of this protein in these two neuronal groups. Constitutive activity, diazepam modulation, fast desensitization of maximal currents, and activation by propofol (6-98 microm) of GABA(A)Rs did not correlate with epsilon-subunit expression. Propofol at 3-12 microm potentiated GABA-mediated currents similarly in all neurons. However, noise variance analysis of GABA-mediated currents enhanced by propofol revealed a significant difference between epsilon-positive and epsilon-negative neurons. The former displayed no difference between control and potentiated responses, and, in the latter, noise was decreased in the presence of propofol. Spontaneous IPSCs recorded in cultured hypothalamic neurons were prolonged in the presence of propofol in all epsilon-negative neurons, whereas propofol-resistant IPSCs were recorded in epsilon-positive cells. The infrequent expression of the epsilon-subunit may be a key factor in the recently discovered central role of the tuberomamillary nucleus in anesthesia.

  11. Identification of hypothalamic neuron-derived neurotrophic factor as a novel factor modulating appetite.

    PubMed

    Byerly, Mardi S; Swanson, Roy D; Semsarzadeh, Nina N; McCulloh, Patrick S; Kwon, Kiwook; Aja, Susan; Moran, Timothy H; Wong, G William; Blackshaw, Seth

    2013-06-15

    Disruption of finely coordinated neuropeptide signals in the hypothalamus can result in altered food intake and body weight. We identified neuron-derived neurotrophic factor (NENF) as a novel secreted protein through a large-scale screen aimed at identifying novel secreted hypothalamic proteins that regulate food intake. We observed robust Nenf expression in hypothalamic nuclei known to regulate food intake, and its expression was altered under the diet-induced obese (DIO) condition relative to the fed state. Hypothalamic Nenf mRNA was regulated by brain-derived neurotrophic factor (BDNF) signaling, itself an important regulator of appetite. Delivery of purified recombinant BDNF into the lateral cerebral ventricle decreased hypothalamic Nenf expression, while pharmacological inhibition of trkB signaling increased Nenf mRNA expression. Furthermore, recombinant NENF administered via an intracerebroventricular cannula decreased food intake and body weight and increased hypothalamic Pomc and Mc4r mRNA expression. Importantly, the appetite-suppressing effect of NENF was abrogated in obese mice fed a high-fat diet, demonstrating a diet-dependent modulation of NENF function. We propose the existence of a regulatory circuit involving BDNF, NENF, and melanocortin signaling. Our study validates the power of using an integrated experimental and bioinformatic approach to identify novel CNS-derived proteins with appetite-modulating function and reveals NENF as an important central modulator of food intake.

  12. Understanding how discrete populations of hypothalamic neurons orchestrate complicated behavioral states

    PubMed Central

    Graebner, Allison K.; Iyer, Manasi; Carter, Matthew E.

    2015-01-01

    A major question in systems neuroscience is how a single population of neurons can interact with the rest of the brain to orchestrate complex behavioral states. The hypothalamus contains many such discrete neuronal populations that individually regulate arousal, feeding, and drinking. For example, hypothalamic neurons that express hypocretin (Hcrt) neuropeptides can sense homeostatic and metabolic factors affecting wakefulness and orchestrate organismal arousal. Neurons that express agouti-related protein (AgRP) can sense the metabolic needs of the body and orchestrate a state of hunger. The organum vasculosum of the lamina terminalis (OVLT) can detect the hypertonicity of blood and orchestrate a state of thirst. Each hypothalamic population is sufficient to generate complicated behavioral states through the combined efforts of distinct efferent projections. The principal challenge to understanding these brain systems is therefore to determine the individual roles of each downstream projection for each behavioral state. In recent years, the development and application of temporally precise, genetically encoded tools has greatly improved our understanding of the structure and function of these neural systems. This review will survey recent advances in our understanding of how these individual hypothalamic populations can orchestrate complicated behavioral states due to the combined efforts of individual downstream projections. PMID:26300745

  13. Hypoxia and hypercapnia inhibit hypothalamic orexin neurons in rats.

    PubMed

    Dergacheva, Olga; Yamanaka, Akihiro; Schwartz, Alan R; Polotsky, Vsevolod Y; Mendelowitz, David

    2016-11-01

    Evidence of impaired function of orexin neurons has been found in individuals with cardiorespiratory disorders, such as obstructive sleep apnea (OSA) and sudden infant death syndrome (SIDS), but the mechanisms responsible are unknown. Individuals with OSA and SIDS experience repetitive breathing cessations and/or rebreathing of expired air, resulting in hypoxia/hypercapnia (H/H). In this study, we examined the responses of fluorescently identified rat orexin neurons in the lateral hypothalamus to acute H/H to test if and how these neurons alter their activity and function during this challenge. Experiments were conducted in an in vitro slice preparation using voltage-clamp and current-clamp configurations. H/H (10 min) induced hyperpolarization, accompanied by rapid depression, and finally, cessation of firing activity in orexin neurons. Hypoxia alone had similar but less potent effects. H/H did not alter the frequency of inhibitory glycinergic postsynaptic currents. The frequency of GABAergic currents was diminished but only at 8-10 min of H/H. In contrast, the frequency of excitatory glutamatergic postsynaptic events was diminished as early as 2-4 min of H/H. In the presence of glutamatergic receptor blockers, the inhibitory effects of H/H on the firing activity and membrane potential of orexin neurons persisted but to a lesser extent. In conclusion, both direct alteration of postsynaptic membrane properties and diminished glutamatergic neurotransmission likely contribute to the inhibition of orexin neurons by H/H. These mechanisms could be responsible for the decreased function of orexin in individuals at risk for OSA and SIDS. Copyright © 2016 the American Physiological Society.

  14. Hypothalamic neuron projection to autonomic preganglionic levels related with glucose metabolism: a fluorescent labelling study in the rat.

    PubMed

    Portillo, F; Carrasco, M; Vallo, J J

    1996-06-07

    The location of hypothalamic paraventricular neurons projecting to sympathetic preganglionic levels and related to the autonomic regulation of various organs involved in glucose metabolism (OGM) was determined by ipsilateral injections of two fluorescent tracers, Diamidino Yellow into the left dorsal motor nucleus of the vagus and Fast Blue into the left intermediolateral cell column of the T8-T9 spinal cord. Hypothalamospinal neurons were mainly located in the dorsal part of the paraventricular hypothalamic nucleus (PVH) and the hypothalamobulbar neurons were most abundant in the ventral, medial and extreme lateral parts of the PVH. No double-labelled neurons were found in the hypothalamus. These results can help the knowledge of the neural hypothalamic network related with the autonomic hypothalamic control.

  15. Neuronal glucoprivation enhances hypothalamic histamine turnover in rats.

    PubMed

    Oohara, A; Yoshimatsu, H; Kurokawa, M; Oishi, R; Saeki, K; Sakata, T

    1994-08-01

    Histamine (HA) turnover in the rat hypothalamus following insufficient energy supply due to glucoprivation was examined after administration of insulin or 2-deoxy-D-glucose (2-DG). HA turnover was assessed by accumulation of tele-methylhistamine (t-MH), a major metabolite of brain HA, following administration of pargyline. Intraperitoneal injection of 1, 2, and 4 U/kg of insulin, which had no influence on steady-state levels of HA and t-MH, increased pargyline-induced accumulation of t-MH. Accumulation of t-MH due to pargyline was inversely related to the concomitant plasma glucose concentration after different doses of insulin. The level of t-MH accumulated by pargyline did not change compared with that of controls, when a euglycemic condition was maintained or insulin at a dose of 6 mU per rat was infused into the third cerebroventricle. Intracerebroventricular infusion of 24 mumol per rat of 2-DG, which had no influence on steady-state levels of HA and t-MH, increased the level of t-MH enhanced by pargyline. The results indicate that an increase in hypothalamic HA turnover in response to glucoprivation may be involved in homeostatic regulation of energy metabolism in the brain.

  16. Depolarizing Actions of Hydrogen Sulfide on Hypothalamic Paraventricular Nucleus Neurons

    PubMed Central

    Khademullah, C. Sahara; Ferguson, Alastair V.

    2013-01-01

    Hydrogen sulfide (H2S) is a novel neurotransmitter that has been shown to influence cardiovascular functions as well and corticotrophin hormone (CRH) secretion. Since the paraventricular nucleus of the hypothalamus (PVN) is a central relay center for autonomic and endocrine functions, we sought to investigate the effects of H2S on the neuronal population of the PVN. Whole cell current clamp recordings were acquired from the PVN neurons and sodium hydrosulfide hydrate (NaHS) was bath applied at various concentrations (0.1, 1, 10, and 50 mM). NaHS (1, 10, and 50 mM) elicited a concentration-response relationship from the majority of recorded neurons, with almost exclusively depolarizing effects following administration. Cells responded and recovered from NaHS administration quickly and the effects were repeatable. Input differences from baseline and during the NaHS-induced depolarization uncovered a biphasic response, implicating both a potassium and non-selective cation conductance. The results from the neuronal population of the PVN shed light on the possible physiological role that H2S has in autonomic and endocrine function. PMID:23691233

  17. Anorexia and impaired glucose metabolism in mice with hypothalamic ablation of Glut4 neurons.

    PubMed

    Ren, Hongxia; Lu, Taylor Y; McGraw, Timothy E; Accili, Domenico

    2015-02-01

    The central nervous system (CNS) uses glucose independent of insulin. Nonetheless, insulin receptors and insulin-responsive glucose transporters (Glut4) often colocalize in neurons (Glut4 neurons) in anatomically and functionally distinct areas of the CNS. The apparent heterogeneity of Glut4 neurons has thus far thwarted attempts to understand their function. To answer this question, we used Cre-dependent, diphtheria toxin-mediated cell ablation to selectively remove basal hypothalamic Glut4 neurons and investigate the resulting phenotypes. After Glut4 neuron ablation, mice demonstrate altered hormone and nutrient signaling in the CNS. Accordingly, they exhibit negative energy balance phenotype characterized by reduced food intake and increased energy expenditure, without locomotor deficits or gross neuronal abnormalities. Glut4 neuron ablation affects orexigenic melanin-concentrating hormone neurons but has limited effect on neuropeptide Y/agouti-related protein and proopiomelanocortin neurons. The food intake phenotype can be partially normalized by GABA administration, suggesting that it arises from defective GABAergic transmission. Glut4 neuron-ablated mice show peripheral metabolic defects, including fasting hyperglycemia and glucose intolerance, decreased insulin levels, and elevated hepatic gluconeogenic genes. We conclude that Glut4 neurons integrate hormonal and nutritional cues and mediate CNS actions of insulin on energy balance and peripheral metabolism.

  18. Bicarbonate contributes to GABAA receptor-mediated neuronal excitation in surgically resected human hypothalamic hamartomas.

    PubMed

    Kim, Do-Young; Fenoglio, Kristina A; Kerrigan, John F; Rho, Jong M

    2009-01-01

    The role of bicarbonate (HCO(3)(-)) in GABA(A) receptor-mediated depolarization of human hypothalamic hamartoma (HH) neurons was investigated using cellular electrophysiological and calcium imaging techniques. Activation of GABA(A) receptors with muscimol (30 microM) provoked neuronal excitation in over 70% of large (18-22 microM) HH neurons in HCO(3)(-) buffer. Subsequent perfusion of HCO(3)(-)-free HEPES buffer produced partial suppression of muscimol-induced excitation. Additionally, 53% of large HH neurons under HCO(3)(-)-free conditions exhibited reduced intracellular calcium accumulation by muscimol. These results suggest that HCO(3)(-) efflux through GABA(A) receptors on a subpopulation of large HH neurons may contribute to membrane depolarization and subsequent activation of L-type calcium channels.

  19. Activation of synaptic and extrasynaptic glycine receptors by taurine in preoptic hypothalamic neurons.

    PubMed

    Bhattarai, Janardhan Prasad; Park, Soo Joung; Chun, Sang Woo; Cho, Dong Hyu; Han, Seong Kyu

    2015-11-03

    Taurine is an essential amino-sulfonic acid having a fundamental function in the brain, participating in both cell volume regulation and neurotransmission. Using a whole cell voltage patch clamp technique, the taurine-activated neurotransmitter receptors in the preoptic hypothalamic area (PHA) neurons were investigated. In the first set of experiments, different concentrations of taurine were applied on PHA neurons. Taurine-induced responses were concentration-dependent. Taurine-induced currents were action potential-independent and sensitive to strychnine, suggesting the involvement of glycine receptors. In addition, taurine activated not only α-homomeric, but also αβ-heteromeric glycine receptors in PHA neurons. Interestingly, a low concentration of taurine (0.5mM) activated glycine receptors, whereas a higher concentration (3mM) activated both glycine and gamma-aminobutyric acid A (GABAA) receptors in PHA neurons. These results suggest that PHA neurons are influenced by taurine and respond via glycine and GABAA receptors.

  20. Monosodium glutamate-sensitive hypothalamic neurons contribute to the control of bone mass

    NASA Technical Reports Server (NTRS)

    Elefteriou, Florent; Takeda, Shu; Liu, Xiuyun; Armstrong, Dawna; Karsenty, Gerard

    2003-01-01

    Using chemical lesioning we previously identified hypothalamic neurons that are required for leptin antiosteogenic function. In the course of these studies we observed that destruction of neurons sensitive to monosodium glutamate (MSG) in arcuate nuclei did not affect bone mass. However MSG treatment leads to hypogonadism, a condition inducing bone loss. Therefore the normal bone mass of MSG-treated mice suggested that MSG-sensitive neurons may be implicated in the control of bone mass. To test this hypothesis we assessed bone resorption and bone formation parameters in MSG-treated mice. We show here that MSG-treated mice display the expected increase in bone resorption and that their normal bone mass is due to a concomitant increase in bone formation. Correction of MSG-induced hypogonadism by physiological doses of estradiol corrected the abnormal bone resorptive activity in MSG-treated mice and uncovered their high bone mass phenotype. Because neuropeptide Y (NPY) is highly expressed in MSG-sensitive neurons we tested whether NPY regulates bone formation. Surprisingly, NPY-deficient mice had a normal bone mass. This study reveals that distinct populations of hypothalamic neurons are involved in the control of bone mass and demonstrates that MSG-sensitive neurons control bone formation in a leptin-independent manner. It also indicates that NPY deficiency does not affect bone mass.

  1. An ATF4-ATG5 signaling in hypothalamic POMC neurons regulates obesity.

    PubMed

    Xiao, Yuzhong; Deng, Yalan; Yuan, Feixiang; Xia, Tingting; Liu, Hao; Li, Zhigang; Chen, Shanghai; Liu, Zhixue; Ying, Hao; Liu, Yi; Zhai, Qiwei; Guo, Feifan

    2017-03-28

    ATF4 (activating transcription factor 4) is an important transcription factor that has many biological functions, while its role in hypothalamic POMC (pro-opiomelanocortin-alpha) neurons in the regulation of energy homeostasis has not been explored. We recently discovered that mice with an Atf4 deletion specific to POMC neurons (PAKO mice) are lean and have higher energy expenditure. Furthermore, these mice are resistant to high-fat diet (HFD)-induced obesity and obesity-related metabolic disorders. Mechanistically, we found the expression of ATG5 (autophagy related 5) is upregulated in POMC neurons of PAKO mice, and ATF4 regulates ATG5 expression by binding directly to its promoter. Mice with Atf4 and Atg5 double knockout in POMC neurons have reduced energy expenditure and gain more fat mass compared with PAKO mice under a HFD. Finally, the effect of Atf4 knockout in POMC neurons is possibly mediated by enhanced ATG5-dependent macroautophagy/autophagy and α-melanocyte-stimulating hormone (α-MSH) production in the hypothalamus. Together, this work not only identifies a beneficial role for ATF4 in hypothalamic POMC neurons in the regulation of obesity, but also provides a new potential therapeutic target for obesity and obesity-related metabolic diseases.

  2. Monosodium glutamate-sensitive hypothalamic neurons contribute to the control of bone mass

    NASA Technical Reports Server (NTRS)

    Elefteriou, Florent; Takeda, Shu; Liu, Xiuyun; Armstrong, Dawna; Karsenty, Gerard

    2003-01-01

    Using chemical lesioning we previously identified hypothalamic neurons that are required for leptin antiosteogenic function. In the course of these studies we observed that destruction of neurons sensitive to monosodium glutamate (MSG) in arcuate nuclei did not affect bone mass. However MSG treatment leads to hypogonadism, a condition inducing bone loss. Therefore the normal bone mass of MSG-treated mice suggested that MSG-sensitive neurons may be implicated in the control of bone mass. To test this hypothesis we assessed bone resorption and bone formation parameters in MSG-treated mice. We show here that MSG-treated mice display the expected increase in bone resorption and that their normal bone mass is due to a concomitant increase in bone formation. Correction of MSG-induced hypogonadism by physiological doses of estradiol corrected the abnormal bone resorptive activity in MSG-treated mice and uncovered their high bone mass phenotype. Because neuropeptide Y (NPY) is highly expressed in MSG-sensitive neurons we tested whether NPY regulates bone formation. Surprisingly, NPY-deficient mice had a normal bone mass. This study reveals that distinct populations of hypothalamic neurons are involved in the control of bone mass and demonstrates that MSG-sensitive neurons control bone formation in a leptin-independent manner. It also indicates that NPY deficiency does not affect bone mass.

  3. A Thalamo-Hypothalamic Pathway That Activates Oxytocin Neurons in Social Contexts in Female Rats.

    PubMed

    Cservenák, Melinda; Keller, Dávid; Kis, Viktor; Fazekas, Emese A; Öllös, Hanna; Lékó, András H; Szabó, Éva R; Renner, Éva; Usdin, Ted B; Palkovits, Miklós; Dobolyi, Árpád

    2017-02-01

    Oxytocin is released from neurons in the paraventricular hypothalamic nucleus (PVN) in mothers upon suckling and during adult social interactions. However, neuronal pathways that activate oxytocin neurons in social contexts are not yet established. Neurons in the posterior intralaminar complex of the thalamus (PIL), which contain tuberoinfundibular peptide 39 (TIP39) and are activated by pup exposure in lactating mothers, provide a candidate projection. Innervation of oxytocin neurons by TIP39 neurons was examined by double labeling in combination with electron microscopy and retrograde tract-tracing. Potential classic neurotransmitters in TIP39 neurons were investigated by in situ hybridization histochemistry. Neurons activated after encounter with a familiar conspecific female in a familiar environment were mapped with the c-Fos technique. PVN and the supraoptic nucleus oxytocin neurons were closely apposed by an average of 2.0 and 0.4 TIP39 terminals, respectively. Asymmetric (presumed excitatory) synapses were found between TIP39 terminals and cell bodies of oxytocin neurons. In lactating rats, PIL TIP39 neurons were retrogradely labeled from the PVN. TIP39 neurons expressed vesicular glutamate transporter 2 but not glutamic acid decarboxylase 67. PIL contained a markedly increased number of c-Fos-positive neurons in response to social encounter with a familiar conspecific female. Furthermore, the PIL received ascending input from the spinal cord and the inferior colliculus. Thus, TIP39 neurons in the PIL may receive sensory input in response to social interactions and project to the PVN to innervate and excite oxytocin neurons, suggesting that the PIL-PVN projection contributes to the activation of oxytocin neurons in social contexts. Copyright © 2017 by the Endocrine Society.

  4. Epigenomic and metabolic responses of hypothalamic POMC neurons to gestational nicotine exposure in adult offspring.

    PubMed

    Silva, Jose P; Lambert, Guerline; van Booven, Derek; Wahlestedt, Claes

    2016-09-08

    Epidemiological and animal studies have reported that prenatal nicotine exposure (PNE) leads to obesity and type-2 diabetes in offspring. Central leptin-melanocortin signaling via hypothalamic arcuate proopiomelanocortin (POMC) neurons is crucial for the regulation of energy and glucose balance. Furthermore, hypothalamic POMC neurons were recently found to mediate the anorectic effects of nicotine through activation of acetylcholine receptors. Here, we hypothesized that PNE impairs leptin-melanocortinergic regulation of energy balance in first-generation offspring by altering expression of long non-coding RNAs (lncRNAs) putatively regulating development and/or function of hypothalamic POMC neurons. C57BL/6J females were exposed ad libitum to nicotine through drinking water and crossed with C57BL/6J males. Nicotine exposure was sustained during pregnancy and discontinued at parturition. Offspring development was monitored from birth into adulthood. From the age of 8 weeks, central leptin-melanocortin signaling, diabetes, and obesity susceptibility were assessed in male offspring fed a low-fat or high-fat diet for 16 weeks. Nicotine-exposed and non-exposed C57BL/6J females were also crossed with C57BL/6J males expressing the enhanced green fluorescent protein specifically in POMC neurons. Transgenic male offspring were subjected to laser microdissections and RNA sequencing (RNA-seq) analysis of POMC neurons for determination of nicotine-induced gene expression changes and regulatory lncRNA/protein-coding gene interactions. Contrary to expectation based on previous studies, PNE did not impair but rather enhanced leptin-melanocortinergic regulation of energy and glucose balance via POMC neurons in offspring. RNA-seq of laser microdissected POMC neurons revealed only one consistent change, upregulation of Gm15851, a lncRNA of yet unidentified function, in nicotine-exposed offspring. RNA-seq further suggested 82 cis-regulatory lncRNA/protein-coding gene interactions

  5. Effects of hypothalamic thermal stimuli on sympathetic neurones innervating skin and skeletal muscle of the cat hindlimb.

    PubMed

    Grewe, W; Jänig, W; Kümmel, H

    1995-10-01

    1. Postganglionic neurones supplying hairless and hairy skin of the cat hindlimb were analysed for their responses to thermal stimuli applied to the anterior hypothalamus and spinal cord in anaesthetized and artificially ventilated cats. Activity was recorded from multi- and single-unit bundles which were isolated from peripheral nerves. The neurones were functionally identified as cutaneous vasoconstrictor (CVC) and muscle vasoconstrictor (MVC) neurones. Activity in sudomotor (SM) neurones was either monitored indirectly by recording the phasic negative deflections of the skin potential from the surface of the hairless skin, or in some experiments additionally by recording activity directly from the SM axons. 2. The activity in forty-one out of forty-four multi-unit and six out of six single-unit CVC bundles was inhibited, in a graded manner, by hypothalamic warming. An increase in the temperature of the surface of hairless skin followed the decrease in activity of the CVC neurones supplying it. Large changes in skin temperature only followed decreases in CVC activity of more than 40%. Cooling of the hypothalamus had only weak transient effects on CVC neurones. 3. Simultaneous warming of hypothalamus and spinal cord had multiplicative effects on the activity in CVC neurones. Subthreshold warming of one structure increased the response to warming of the other one and reduced the threshold temperature. 4. SM neurones were not affected by hypothalamic warming, but activated during hypothalamic cooling. 5. MVC neurones were weakly activated during hypothalamic warming only if arterial blood pressure decreased, otherwise they were unaffected. It is likely that this activation was due to secondary unloading of arterial baroreceptors. 6. Two silent postganglionic neurones projecting to skin were activated during hypothalamic warming. These neurones may have had a vasodilatory function. 7. Rhythmicity of the activity in CVC neurones, related to the cycle of artificial

  6. Effects of hypothalamic thermal stimuli on sympathetic neurones innervating skin and skeletal muscle of the cat hindlimb.

    PubMed Central

    Grewe, W; Jänig, W; Kümmel, H

    1995-01-01

    1. Postganglionic neurones supplying hairless and hairy skin of the cat hindlimb were analysed for their responses to thermal stimuli applied to the anterior hypothalamus and spinal cord in anaesthetized and artificially ventilated cats. Activity was recorded from multi- and single-unit bundles which were isolated from peripheral nerves. The neurones were functionally identified as cutaneous vasoconstrictor (CVC) and muscle vasoconstrictor (MVC) neurones. Activity in sudomotor (SM) neurones was either monitored indirectly by recording the phasic negative deflections of the skin potential from the surface of the hairless skin, or in some experiments additionally by recording activity directly from the SM axons. 2. The activity in forty-one out of forty-four multi-unit and six out of six single-unit CVC bundles was inhibited, in a graded manner, by hypothalamic warming. An increase in the temperature of the surface of hairless skin followed the decrease in activity of the CVC neurones supplying it. Large changes in skin temperature only followed decreases in CVC activity of more than 40%. Cooling of the hypothalamus had only weak transient effects on CVC neurones. 3. Simultaneous warming of hypothalamus and spinal cord had multiplicative effects on the activity in CVC neurones. Subthreshold warming of one structure increased the response to warming of the other one and reduced the threshold temperature. 4. SM neurones were not affected by hypothalamic warming, but activated during hypothalamic cooling. 5. MVC neurones were weakly activated during hypothalamic warming only if arterial blood pressure decreased, otherwise they were unaffected. It is likely that this activation was due to secondary unloading of arterial baroreceptors. 6. Two silent postganglionic neurones projecting to skin were activated during hypothalamic warming. These neurones may have had a vasodilatory function. 7. Rhythmicity of the activity in CVC neurones, related to the cycle of artificial

  7. Anorexia and Impaired Glucose Metabolism in Mice With Hypothalamic Ablation of Glut4 Neurons

    PubMed Central

    Ren, Hongxia; Lu, Taylor Y.; McGraw, Timothy E.

    2015-01-01

    The central nervous system (CNS) uses glucose independent of insulin. Nonetheless, insulin receptors and insulin-responsive glucose transporters (Glut4) often colocalize in neurons (Glut4 neurons) in anatomically and functionally distinct areas of the CNS. The apparent heterogeneity of Glut4 neurons has thus far thwarted attempts to understand their function. To answer this question, we used Cre-dependent, diphtheria toxin–mediated cell ablation to selectively remove basal hypothalamic Glut4 neurons and investigate the resulting phenotypes. After Glut4 neuron ablation, mice demonstrate altered hormone and nutrient signaling in the CNS. Accordingly, they exhibit negative energy balance phenotype characterized by reduced food intake and increased energy expenditure, without locomotor deficits or gross neuronal abnormalities. Glut4 neuron ablation affects orexigenic melanin-concentrating hormone neurons but has limited effect on neuropeptide Y/agouti-related protein and proopiomelanocortin neurons. The food intake phenotype can be partially normalized by GABA administration, suggesting that it arises from defective GABAergic transmission. Glut4 neuron–ablated mice show peripheral metabolic defects, including fasting hyperglycemia and glucose intolerance, decreased insulin levels, and elevated hepatic gluconeogenic genes. We conclude that Glut4 neurons integrate hormonal and nutritional cues and mediate CNS actions of insulin on energy balance and peripheral metabolism. PMID:25187366

  8. Relative number and distribution of murine hypothalamic proopiomelanocortin neurons innervating distinct target sites.

    PubMed

    King, Connie M; Hentges, Shane T

    2011-01-01

    Proopiomelanocortin (POMC) neurons send projections widely throughout the brain consistent with their role in regulating numerous homeostatic processes and mediating analgesia and reward. Recent data suggest that POMC neurons located in the rostral and caudal extents of the arcuate nucleus of the hypothalamus may mediate selective actions, however it is not clear if POMC neurons in these regions of the arcuate nucleus innervate specific target sites. In the present study, fluorescent microspheres and cholera toxin B were used to retrogradely label POMC neurons in POMC-DsRed transgenic mice. The number and location of POMC cells projecting to the supraoptic nucleus, periaqueductal gray, ventral tegmental area, paraventricular nucleus, lateral hypothalamic nucleus, amygdala and the dosal vagal complex was determined. Tracer injected unilaterally labeled POMC neurons in both sides of the arcuate nucleus. While the total number of retrogradely labeled cells in the arcuate nucleus varied by injection site, less than 10% of POMC neurons were labeled with tracer injected into any target area. Limited target sites appear to be preferentially innervated by POMC neurons that reside in the rostral or caudal extremes of the arcuate nucleus, whereas the majority of target sites are innervated by diffusely distributed POMC neurons. The modest number of cells projecting to each target site indicates that relatively few POMC neurons may mediate potent and specific physiologic responses and therefore disturbed signaling in a very few POMC neurons may have significant consequences.

  9. Relative Number and Distribution of Murine Hypothalamic Proopiomelanocortin Neurons Innervating Distinct Target Sites

    PubMed Central

    King, Connie M.; Hentges, Shane T.

    2011-01-01

    Proopiomelanocortin (POMC) neurons send projections widely throughout the brain consistent with their role in regulating numerous homeostatic processes and mediating analgesia and reward. Recent data suggest that POMC neurons located in the rostral and caudal extents of the arcuate nucleus of the hypothalamus may mediate selective actions, however it is not clear if POMC neurons in these regions of the arcuate nucleus innervate specific target sites. In the present study, fluorescent microspheres and cholera toxin B were used to retrogradely label POMC neurons in POMC-DsRed transgenic mice. The number and location of POMC cells projecting to the supraoptic nucleus, periaqueductal gray, ventral tegmental area, paraventricular nucleus, lateral hypothalamic nucleus, amygdala and the dosal vagal complex was determined. Tracer injected unilaterally labeled POMC neurons in both sides of the arcuate nucleus. While the total number of retrogradely labeled cells in the arcuate nucleus varied by injection site, less than 10% of POMC neurons were labeled with tracer injected into any target area. Limited target sites appear to be preferentially innervated by POMC neurons that reside in the rostral or caudal extremes of the arcuate nucleus, whereas the majority of target sites are innervated by diffusely distributed POMC neurons. The modest number of cells projecting to each target site indicates that relatively few POMC neurons may mediate potent and specific physiologic responses and therefore disturbed signaling in a very few POMC neurons may have significant consequences. PMID:21991375

  10. Near-Perfect Synaptic Integration by Nav1.7 in Hypothalamic Neurons Regulates Body Weight.

    PubMed

    Branco, Tiago; Tozer, Adam; Magnus, Christopher J; Sugino, Ken; Tanaka, Shinsuke; Lee, Albert K; Wood, John N; Sternson, Scott M

    2016-06-16

    Neurons are well suited for computations on millisecond timescales, but some neuronal circuits set behavioral states over long time periods, such as those involved in energy homeostasis. We found that multiple types of hypothalamic neurons, including those that oppositely regulate body weight, are specialized as near-perfect synaptic integrators that summate inputs over extended timescales. Excitatory postsynaptic potentials (EPSPs) are greatly prolonged, outlasting the neuronal membrane time-constant up to 10-fold. This is due to the voltage-gated sodium channel Nav1.7 (Scn9a), previously associated with pain-sensation but not synaptic integration. Scn9a deletion in AGRP, POMC, or paraventricular hypothalamic neurons reduced EPSP duration, synaptic integration, and altered body weight in mice. In vivo whole-cell recordings in the hypothalamus confirmed near-perfect synaptic integration. These experiments show that integration of synaptic inputs over time by Nav1.7 is critical for body weight regulation and reveal a mechanism for synaptic control of circuits regulating long term homeostatic functions.

  11. Physical exercise decreases neuronal activity in the posterior hypothalamic area of spontaneously hypertensive rats.

    PubMed

    Beatty, Joseph A; Kramer, Jeffery M; Plowey, Edward D; Waldrop, Tony G

    2005-02-01

    Recently, physical exercise has been shown to significantly alter neurochemistry and neuronal function and to increase neurogenesis in discrete brain regions. Although we have documented that physical exercise leads to molecular changes in the posterior hypothalamic area (PHA), the impact on neuronal activity is unknown. The purpose of the present study was to determine whether neuronal activity in the PHA is altered by physical exercise. Spontaneously hypertensive rats (SHR) were allowed free access to running wheels for a period of 10 wk (exercised group) or no wheel access at all (nonexercised group). Single-unit extracellular recordings were made in anesthetized in vivo whole animal preparations or in vitro brain slice preparations. The spontaneous firing rates of PHA neurons in exercised SHR in vivo were significantly lower (8.5 +/- 1.6 Hz, n = 31 neurons) compared with that of nonexercised SHR in vivo (13.7 +/- 1.8 Hz, n = 38 neurons; P < 0.05). In addition, PHA neurons that possessed a cardiac-related rhythm in exercised SHR fired significantly lower (6.0 +/- 1.8 Hz, n = 11 neurons) compared with nonexercised SHR (12.1 +/- 2.4 Hz, n = 18 neurons; P < 0.05). Similarly, the spontaneous in vitro firing rates of PHA neurons from exercised SHR were significantly lower (3.5 +/- 0.3 Hz, n = 67 neurons) compared with those of nonexercised SHR (5.6 +/- 0.5 Hz, n = 58 neurons; P < 0.001). Both the in vivo and in vitro findings support the hypothesis that physical exercise can lower spontaneous activity of neurons in a cardiovascular regulatory region of the brain. Thus physical exercise may alter central neural control of cardiovascular function by inducing lasting changes in neuronal activity.

  12. 'Homing' of Lucifer Yellow liposomes into hypothalamic neurons: a combined neuroanatomical Golgi and tracing technique.

    PubMed

    Thunnissen, I E; Marani, E; Rietveld, W J

    1984-12-01

    Liposomes are combined with Lucifer Yellow in order to evoke neuronal uptake of this fluorescent dye in the medial basal hypothalamus. Lucifer Yellow liposomes are preferentially taken up by hypothalamic neurons. The dye spreads into the dendrites and axons, producing Golgi-revealing views of several neurons near the injection site in which both untrapped and liposome-entrapped Lucifer Yellow has been microiontophoretically administered. The capriciousness of the labeled neurons makes it possible to study the dendritic arborization and spines, while the axon with its collaterals can be followed to their targets. Moreover, the dye is also taken up retrogradely. When retrograde uptake over great distances occurs, the Golgi-like appearance is missing, because only then is perikaryal labeling found.

  13. Colocalization of vasopressin and oxytocin in hypothalamic magnocellular neurons in water-deprived rats.

    PubMed

    Telleria-Diaz, A; Grinevich, V V; Jirikowski, G F

    2001-01-01

    The posterior lobe hormones vasopressin and oxytocin are expressed in mutually-exclusive sets of magnocellular hypothamalic neurons. However, under certain functional conditions a partial coexpression has been observed. In the present study we subjected adult rats to long-term osmotic stress by water deprivation for up to 3 days. After 3 days, a marked reduction of vasopressin immunostaining was observed in the paraventricular and supraoptic nuclei as compared with controls. Coexistence of oxytocin and vasopressin occurred in a portion of the magnocellular neurons. Many fibers of the hypothalamic-neurohypophyseal tract contained both peptides. Rehydration for 24 h after 3 days of thirsting resulted in a light recovery of vasopressin immunoreactivity with almost none magnocellular neurons containing both nonapeptides. Our findings indicate that magnocellular hypothalamo neurohypophysial neurons are capable of oxytocin and vasopressin coexpression upon extended osmotic stress.

  14. Endothelial HIF-1α Enables Hypothalamic Glucose Uptake to Drive POMC Neurons.

    PubMed

    Varela, Luis; Suyama, Shigetomo; Huang, Yan; Shanabrough, Marya; Tschöp, Matthias H; Gao, Xiao-Bing; Giordano, Frank J; Horvath, Tamas L

    2017-06-01

    Glucose is the primary driver of hypothalamic proopiomelanocortin (POMC) neurons. We show that endothelial hypoxia-inducible factor 1α (HIF-1α) controls glucose uptake in the hypothalamus and that it is upregulated in conditions of undernourishment, during which POMC neuronal activity is decreased. Endothelium-specific knockdown of HIF-1α impairs the ability of POMC neurons to adapt to the changing metabolic environment in vivo, resulting in overeating after food deprivation in mice. The impaired functioning of POMC neurons was reversed ex vivo or by parenchymal glucose administration. These observations indicate an active role for endothelial cells in the central control of metabolism and suggest that central vascular impairments may cause metabolic disorders. © 2017 by the American Diabetes Association.

  15. Nitric oxide mediates selective degeneration of hypothalamic orexin neurons through dysfunction of protein disulfide isomerase.

    PubMed

    Obukuro, Kanae; Nobunaga, Mizuki; Takigawa, Moeko; Morioka, Hiroshi; Hisatsune, Akinori; Isohama, Yoichiro; Shimokawa, Hiroaki; Tsutsui, Masato; Katsuki, Hiroshi

    2013-07-31

    We addressed the role of nitric oxide (NO) in orexin neuron degeneration that has been observed under various pathological conditions. Administration of an NO donor NOC18 (50 nmol) into the third ventricle of mice resulted in a significant decrease of orexin-immunoreactive (-IR) neurons, in contrast to a modest change in melanin-concentrating hormone-IR neurons. In addition, NOC18 promoted formation of orexin-A-IR aggregates within orexin neurons. An endoplasmic reticulum stress inducer tunicamycin replicated the effect of NOC18 with regard to decrease of orexin-IR neurons and formation of aggregates. We also found that NOC18 caused an increase in S-nitrosation of protein disulfide isomerase (PDI) and a decrease in PDI activity in hypothalamic tissues. Moreover, PDI inhibitors, such as cystamine and securinine, caused a selective decrease of orexin neurons and promoted formation of orexin-A-IR aggregates. Aggregate formation in orexin-IR neurons was also induced by local injection of small interfering RNA targeting PDI. Interestingly, sleep deprivation for 7 consecutive days induced a selective decrease of orexin-IR neurons, which was preceded by aggregate formation in orexin-IR neurons and an increase in S-nitrosated PDI in the hypothalamus. Activity of neuronal NO synthase (nNOS)-positive neurons in the lateral hypothalamus as assessed by c-Fos expression was elevated in response to sleep deprivation. Finally, sleep deprivation-induced decrease of orexin-IR neurons, formation of aggregates, and S-nitrosation of PDI were not observed in nNOS knock-out mice. These results indicate that nNOS-derived NO may mediate specific pathological events in orexin neurons, including neuropeptide misfolding via S-nitrosation and inactivation of PDI.

  16. Molecular and cellular regulation of hypothalamic melanocortin neurons controlling food intake and energy metabolism.

    PubMed

    Koch, M; Horvath, T L

    2014-07-01

    The brain receives and integrates environmental and metabolic information, transforms these signals into adequate neuronal circuit activities, and generates physiological behaviors to promote energy homeostasis. The responsible neuronal circuitries show lifetime plasticity and guaranty metabolic health and survival. However, this highly evolved organization has become challenged nowadays by chronic overload with nutrients and reduced physical activity, which results in an ever-increasing number of obese individuals worldwide. Research within the last two decades has aimed to decipher the responsible molecular and cellular mechanisms for regulation of the hypothalamic melanocortin neurons, which have a key role in the control of food intake and energy metabolism. This review maps the central connections of the melanocortin system and highlights its global position and divergent character in physiological and pathological metabolic events. Moreover, recently uncovered molecular and cellular processes in hypothalamic neurons and glial cells that drive plastic morphological and physiological changes in these cells, and account for regulation of food intake and energy metabolism, are brought into focus. Finally, potential functional interactions between metabolic disorders and psychiatric diseases are discussed.

  17. Hypothalamic neuronal histamine modulates febrile response but not anorexia induced by lipopolysaccharide.

    PubMed

    Chiba, Seiichi; Itateyama, Emi; Oka, Kyoko; Masaki, Takayuki; Sakata, Toshiie; Yoshimatsu, Hironobu

    2005-05-01

    This study examined the contribution of hypothalamic neuronal histamine (HA) to the anorectic and febrile responses induced by lipopolysaccharide (LPS), an exogenous pyrogen, and the endogenous pyrogens interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha). Intraperitoneal (ip) injection of LPS, IL-1beta, or TNF-alpha suppressed 24-hr cumulative food intake and increased rectal temperature in rats. To analyze the histaminergic contribution, rats were pretreated with intracerebroventricular (icv) injection of 2.44 mmol/kg or ip injection of 244 mmol/kg of alpha-fluoromethylhistidine (FMH), a suicide inhibitor of histidine decarboxylase (HDC), to deplete neural HA. The depletion of neural HA augmented the febrile response to ip injection of LPS and IL-1beta and alleviated the anorectic response to ip injection of IL-1beta. However, the depletion of neural HA did not modify the LPS-induced anorectic response or TNF-alpha-induced febrile and anorectic responses. Consistent with these results, the rate of hypothalamic HA turnover, assessed by the accumulation of tele-methylhistamine (t-MH), was elevated with ip injections of LPS and IL-1beta, but unaffected by TNF-alpha at equivalent doses. This suggests that (i) LPS and IL-1beta activate hypothalamic neural HA turnover; (ii) hypothalamic neural HA suppresses the LPS- and IL-1beta-induced febrile responses and accelerates the IL-1beta-induced anorectic response; and (iii) TNF-alpha modulates the febrile and anorectic responses via a neural HA-independent pathway. Therefore, hypothalamic neural HA is involved in the IL-1beta-dominant pathway, rather than the TNF-alpha-dominant pathway, preceding the systemic inflammatory response induced by exogenous pyrogens, such as LPS. Further research on this is needed.

  18. Activation of neurons in the hypothalamic dorsomedial nucleus via hypothalamic projections of the nucleus of the solitary tract following refeeding of fasted rats.

    PubMed

    Renner, Eva; Szabó-Meltzer, Kinga I; Puskás, Nela; Tóth, Zsuzsanna E; Dobolyi, Arpád; Palkovits, Miklós

    2010-01-01

    We report that satiation evokes neuronal activity in the ventral subdivision of the hypothalamic dorsomedial nucleus (DMH) as indicated by increased c-fos expression in response to refeeding in fasted rats. The absence of significant Fos activation following food presentation without consumption suggests that satiation but not craving for food elicits the activation of ventral DMH neurons. The distribution pattern of the prolactin-releasing peptide (PrRP)-immunoreactive (ir) network showed remarkable correlations with the distribution of activated neurons within the DMH. The PrRP-ir fibers and terminals were immunolabeled with tyrosine hydroxylase, suggesting their origin in lower brainstem instead of local, hypothalamic PrRP cells. PrRP-ir fibers arising from neurons of the nucleus of the solitary tract could be followed to the hypothalamus. Unilateral transections of these fibers at pontine and caudal hypothalamic levels resulted in a disappearance of the dense PrRP-ir network in the ventral DMH while PrRP immunoreactivity was increased in transected fibers caudal to the knife cuts as well as in perikarya of the nucleus of the solitary tract ipsilateral to the transections. In accord with these changes, the number of Fos-expressing neurons following refeeding declined in the ipsilateral but remained high in the contralateral DMH. However, the Fos response in the ventral DMH was not attenuated following chemical lesion (neonatal monosodium glutamate treatment) of the hypothalamic arcuate nucleus, another possible source of DMH inputs. These findings suggest that PrRP projections from the nucleus of the solitary tract contribute to the activation of ventral DMH neurons during refeeding, possibly by transferring information on cholecystokinin-mediated satiation.

  19. Local synaptic release of glutamate from neurons in the rat hypothalamic arcuate nucleus.

    PubMed Central

    Belousov, A B; van den Pol, A N

    1997-01-01

    1. The hypothalamic arcuate nucleus (ARC) contains neuroendocrine neurons that regulate endocrine secretions by releasing substances which control anterior pituitary hormonal release into the portal blood stream. Many neuroactive substances have been identified in the ARC, but the existence of excitatory neurons in the ARC and the identity of an excitatory transmitter have not been investigated physiologically. 2. In the present experiments using whole-cell current- and voltage-clamp recording of neurons from cultures and slices of the ARC, we demonstrate for the first time that some of the neurons in the ARC secrete glutamate as their transmitter. 3. Using microdrop stimulation of presynaptic neurons in ARC slices, we found that local axons from these glutamatergic neurons make local synaptic contact with other neurons in the ARC and that all evoked excitatory postsynaptic potentials could be blocked by the selective ionotropic glutamate receptor antagonists 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; 10 microM) and D,L-2-amino-5-phosphonovalerate (AP5; 100 microM). To determine the identity of ARC neurons postsynaptic to local glutamatergic neurons, we used antidromic stimulation to reveal that many of these cells were neuroendocrine neurons by virtue of their maintaining axon terminals in the median eminence. 4. In ARC cultures, postsynaptic potentials, both excitatory and inhibitory, were virtually eliminated by the glutamate receptor antagonists AP5 and CNQX, underlining the functional importance of glutamate within this part of the neuroendocrine brain. 5. GABA was secreted by a subset of ARC neurons from local axons. The GABAA receptor antagonist bicuculline released glutamatergic neurons from chronic inhibition mediated by synaptically released GABA, resulting in further depolarization and an increase in the amplitude and frequency of glutamate-mediated excitatory postsynaptic potentials. Images Figure 1 PMID:9130170

  20. Thermal stimulation of hypothalamic neurones in unanaesthetized rabbits

    PubMed Central

    Hellon, R. F.

    1967-01-01

    1. A technique has been devised for recording unit activity in the anterior hypothalamus of conscious rabbits during the controlled displacement of local temperature by 1-2° C. The region at 1 and 2 mm from the mid line was explored. 2. All the units studied showed spontaneous activity before thermal stimulation with a mean rate of 9 impulses/sec (range 1/16 sec to 65/sec). 3. Twenty-seven (10%) of the recorded neurones showed a change in firing rate which could be related to the temperature changes. Twenty-one of the cells were `warm-sensitive' and were excited when temperature was raised or inhibited when it was lowered. The other six units were `cold-sensitive' and showed the opposite type of response. 4. Apart from this directional grouping, it was possible to classify the responses into four categories: A, five cells whose firing rate was always proportional to local temperature over a range from 2° C below to 2° C above body temperature; B, six cells whose average level of firing changed during the period of observation, but whose sensitivity to temperature was not affected; C, eight cells which showed a threshold and were only affected by temperature above or below a certain level; D, four cells whose changes in frequency either led or lagged behind the temperature changes. 5. The positions of these sensitive units in the hypothalamus did not show any apparent pattern, except that 75% of them were found 1 mm lateral to the mid line; the remaining 25% were 2 mm lateral. PMID:6065885

  1. Caffeine inhibits hypothalamic A1R to excite oxytocin neuron and ameliorate dietary obesity in mice

    PubMed Central

    Wu, Liufeng; Meng, Jia; Shen, Qing; Zhang, Yi; Pan, Susu; Chen, Zhuo; Zhu, Ling-Qiang; Lu, Youming; Huang, Yuan; Zhang, Guo

    2017-01-01

    Caffeine, an antagonist of the adenosine receptor A1R, is used as a dietary supplement to reduce body weight, although the underlying mechanism is unclear. Here, we report that adenosine level in the cerebrospinal fluid, and hypothalamic expression of A1R, are increased in the diet-induced obesity (DIO) mouse. We find that mice with overexpression of A1R in the neurons of paraventricular nucleus (PVN) of the hypothalamus are hyperphagic, have glucose intolerance and high body weight. Central or peripheral administration of caffeine reduces the body weight of DIO mice by the suppression of appetite and increasing of energy expenditure. We also show that caffeine excites oxytocin expressing neurons, and blockade of the action of oxytocin significantly attenuates the effect of caffeine on energy balance. These data suggest that caffeine inhibits A1Rs expressed on PVN oxytocin neurons to negatively regulate energy balance in DIO mice. PMID:28654087

  2. Cell type-specific transcriptomics of hypothalamic energy-sensing neuron responses to weight-loss.

    PubMed

    Henry, Fredrick E; Sugino, Ken; Tozer, Adam; Branco, Tiago; Sternson, Scott M

    2015-09-02

    Molecular and cellular processes in neurons are critical for sensing and responding to energy deficit states, such as during weight-loss. Agouti related protein (AGRP)-expressing neurons are a key hypothalamic population that is activated during energy deficit and increases appetite and weight-gain. Cell type-specific transcriptomics can be used to identify pathways that counteract weight-loss, and here we report high-quality gene expression profiles of AGRP neurons from well-fed and food-deprived young adult mice. For comparison, we also analyzed Proopiomelanocortin (POMC)-expressing neurons, an intermingled population that suppresses appetite and body weight. We find that AGRP neurons are considerably more sensitive to energy deficit than POMC neurons. Furthermore, we identify cell type-specific pathways involving endoplasmic reticulum-stress, circadian signaling, ion channels, neuropeptides, and receptors. Combined with methods to validate and manipulate these pathways, this resource greatly expands molecular insight into neuronal regulation of body weight, and may be useful for devising therapeutic strategies for obesity and eating disorders.

  3. Cell type-specific transcriptomics of hypothalamic energy-sensing neuron responses to weight-loss

    PubMed Central

    Henry, Fredrick E; Sugino, Ken; Tozer, Adam; Branco, Tiago; Sternson, Scott M

    2015-01-01

    Molecular and cellular processes in neurons are critical for sensing and responding to energy deficit states, such as during weight-loss. Agouti related protein (AGRP)-expressing neurons are a key hypothalamic population that is activated during energy deficit and increases appetite and weight-gain. Cell type-specific transcriptomics can be used to identify pathways that counteract weight-loss, and here we report high-quality gene expression profiles of AGRP neurons from well-fed and food-deprived young adult mice. For comparison, we also analyzed Proopiomelanocortin (POMC)-expressing neurons, an intermingled population that suppresses appetite and body weight. We find that AGRP neurons are considerably more sensitive to energy deficit than POMC neurons. Furthermore, we identify cell type-specific pathways involving endoplasmic reticulum-stress, circadian signaling, ion channels, neuropeptides, and receptors. Combined with methods to validate and manipulate these pathways, this resource greatly expands molecular insight into neuronal regulation of body weight, and may be useful for devising therapeutic strategies for obesity and eating disorders. DOI: http://dx.doi.org/10.7554/eLife.09800.001 PMID:26329458

  4. Distribution of hypothalamic vasoactive intestinal peptide immunoreactive neurons in the male native Thai chicken.

    PubMed

    Kamkrathok, Boonyarit; Sartsoongnoen, Natagarn; Prakobsaeng, Nattiya; Rozenboim, Israel; Porter, Tom E; Chaiseha, Yupaporn

    2016-08-01

    Avian prolactin (PRL) secretion is under stimulatory control by the PRL-releasing factor (PRF), vasoactive intestinal peptide (VIP). The neuroendocrine regulation of the avian reproductive system has been extensively studied in females. However, there are limited data in males. The aim of this study was to elucidate the VIPergic system and its relationship to PRL and testosterone (T) in the male native Thai chicken. The distributions of VIP-immunoreactive (-ir) neurons and fibers were determined by immunohistochemistry. Changes in VIP-ir neurons within the nucleus inferioris hypothalami (IH) and nucleus infundibuli hypothalami (IN) areas were compared across the reproductive stages. Plasma levels of PRL and T were determined by enzyme-linked immunosorbent assay and then compared across the reproductive stages. The results revealed that the highest accumulations of VIP-ir neurons were concentrated only within the IH-IN, and VIP-ir neurons were not detected within other hypothalamic nuclei. Within the IH-IN, VIP-ir neurons were low in premature and aging males and markedly increased in mature males. Changes in VIP-ir neurons within the IH-IN were directly mirrored with changes in PRL and T levels across the reproductive stages. These results suggested that VIP neurons in the IH-IN play a regulatory role in year-round reproductive activity in males. The present study also provides additional evidence that VIP is the PRF in non-seasonal, continuously breeding equatorial species.

  5. Hypothalamic dopaminergic neurons in an animal model of seasonal affective disorder.

    PubMed

    Deats, Sean P; Adidharma, Widya; Yan, Lily

    2015-08-18

    Light has profound effects on mood regulation as exemplified in seasonal affective disorder (SAD) and the therapeutic benefits of light therapy. However, the underlying neural pathways through which light regulates mood are not well understood. Our previous work has developed the diurnal grass rat, Arvicanthis niloticus, as an animal model of SAD. Following housing conditions of either 12:12 h dim light:dark (DLD) or 8:16 h short photoperiod (SP), which mimic the lower light intensity or short day-length of winter, respectively, grass rats exhibit an increase in depression-like behavior compared to those housed in a 12:12 h bright light:dark (BLD) condition. Furthermore, we have shown that the orexinergic system is involved in mediating the effects of light on mood and anxiety. To explore other potential neural substrates involved in the depressive phenotype, the present study examined hypothalamic dopaminergic (DA) and somatostatin (SST) neurons in the brains of grass rats housed in DLD, SP and BLD. Using immunostaining for tyrosine hydroxylase (TH) and SST, we found that the number of TH- and SST-ir cells in the hypothalamus was significantly lower in the DLD and SP groups compared to the BLD group. We also found that treating BLD animals with a selective orexin receptor 1 (OX1R) antagonist SB-334867 significantly reduced the number of hypothalamic TH-ir cells. The present study suggests that the hypothalamic DA neurons are sensitive to daytime light deficiency and are regulated by an orexinergic pathway. The results support the hypothesis that the orexinergic pathways mediate the effects of light on other neuronal systems that collectively contribute to light-dependent changes in the affective state.

  6. Hypothalamic Dopaminergic Neurons in an Animal Model of Seasonal Affective Disorder

    PubMed Central

    Deats, Sean P.; Adidharma, Widya; Yan, Lily

    2015-01-01

    Light has profound effects on mood regulation as exemplified in Seasonal Affective Disorder (SAD) and the therapeutic benefits of light therapy. However, the underlying neural pathways through which light regulates mood are not well understood. Our previous work has developed the diurnal grass rat, Arvicanthis niloticus, as an animal model of SAD. Following housing conditions of either 12:12hr Dim Light:Dark (DLD) or 8:16hr Short Photoperiod (SP), which mimic the lower light intensity or short day-length of winter, respectively, grass rats exhibit an increase in depression-like behavior compared to those housed in a 12:12hr Bright Light:Dark (BLD) condition. Furthermore, we revealed that the orexinergic system is involved in mediating the effects of light on mood and anxiety. To explore other potential neural substrates involved in the depressive phenotype, the present study examined hypothalamic dopaminergic (DA) and somatostatin (SST) neurons in the brains of grass rats housed in DLD, SP and BLD. Using immunostaining for tyrosine hydroxylase (TH) and SST, we found that the number of TH- and SST-ir cells in the hypothalamus was significantly lower in the DLD and SP groups compared to the BLD group. We also found that treating BLD animals with a selective orexin receptor 1 (OX1R) antagonist SB-334867 significantly reduced the number of hypothalamic TH-ir cells. The present study suggests that the hypothalamic DA neurons are sensitive to daytime light deficiency and are regulated by an orexinergic pathway. The results support the hypothesis that the orexinergic pathways mediate the effects of light on other neuronal systems that collectively contribute to light-dependent changes in the affective state. PMID:26116821

  7. Islet 1 specifies the identity of hypothalamic melanocortin neurons and is critical for normal food intake and adiposity in adulthood

    PubMed Central

    Nasif, Sofia; de Souza, Flavio S. J.; González, Laura E.; Yamashita, Miho; Orquera, Daniela P.; Rubinstein, Marcelo

    2015-01-01

    Food intake and body weight regulation depend on proper expression of the proopiomelanocortin gene (Pomc) in a group of neurons located in the mediobasal hypothalamus of all vertebrates. These neurons release POMC-encoded melanocortins, which are potent anorexigenic neuropeptides, and their absence from mice or humans leads to hyperphagia and severe obesity. Although the pathophysiology of hypothalamic POMC neurons is well understood, the genetic program that establishes the neuronal melanocortinergic phenotype and maintains a fully functional neuronal POMC phenotype throughout adulthood remains unknown. Here, we report that the early expression of the LIM-homeodomain transcription factor Islet 1 (ISL1) in the developing hypothalamus promotes the terminal differentiation of melanocortinergic neurons and is essential for hypothalamic Pomc expression since its initial onset and throughout the entire lifetime. We detected ISL1 in the prospective hypothalamus just before the onset of Pomc expression and, from then on, Pomc and Isl1 coexpress. ISL1 binds in vitro and in vivo to critical homeodomain binding DNA motifs present in the neuronal Pomc enhancers nPE1 and nPE2, and mutations of these sites completely disrupt the ability of these enhancers to drive reporter gene expression to hypothalamic POMC neurons in transgenic mice and zebrafish. ISL1 is necessary for hypothalamic Pomc expression during mouse and zebrafish embryogenesis. Furthermore, conditional Isl1 inactivation from POMC neurons impairs Pomc expression, leading to hyperphagia and obesity. Our results demonstrate that ISL1 specifies the identity of hypothalamic melanocortin neurons and is required for melanocortin-induced satiety and normal adiposity throughout the entire lifespan. PMID:25825735

  8. IL-6 ameliorates defective leptin sensitivity in DIO ventromedial hypothalamic nucleus neurons.

    PubMed

    Larsen, Louise; Le Foll, Christelle; Dunn-Meynell, Ambrose A; Levin, Barry E

    2016-10-01

    Rats selectively bred to develop diet-induced obesity (DIO) have an early onset reduction in the sensitivity of their ventromedial hypothalamic nucleus (VMN) neurons to leptin compared with diet-resistant (DR) rats. This reduced sensitivity includes decreased leptin receptor (Lepr-b) mRNA expression, leptin receptor binding, leptin-induced phosphorylation of STAT3 (pSTAT3), and impaired leptin excitation (LepE) of VMN neurons. When administered exogenously, the pancreatic peptide, amylin, acts synergistically to reduce food intake and body weight in obese, leptin-resistant DIO rats by increasing VMN leptin signaling, likely by stimulation of microglia IL-6, which acts on its receptor to increase leptin-induced pSTAT3. Here, we demonstrate that incubation of cultured VMN neurons of outbred rats with IL-6 increases their leptin sensitivity. Control, dissociated DIO VMN neurons express 66% less Lepr-b and 75% less Bardet Biedl Syndrome-6 (BBS6) mRNA and have reduced leptin-induced activation of LepE neurons compared with DR neurons. Incubation for 4 days with IL-6 increased DIO neuron Lepr-b expression by 77% and BBS6 by 290% and corrected their defective leptin activation of LepE neurons to DR levels. Since BBS6 enhances trafficking of Lepr-b to the cell membrane, the increases in Lepr-b and BBS6 expression appear to account for correction of the reduced leptin excitation of DIO LepE neurons to that of control DR rats. These data support prior findings suggesting that IL-6 mediates the leptin-sensitizing effects of amylin on VMN neurons and that the inherent leptin resistance of DIO rats can be effectively reversed at a cellular level by IL-6.

  9. Forskolin delays the ethanol-induced desensitization of hypothalamic beta-endorphin neurons in primary cultures.

    PubMed

    Boyadjieva, N; Reddy, B V; Sarkar, D K

    1997-05-01

    Ethanol and its metabolite acetaldehyde have been shown to stimulate immunoreactive beta-endorphin (IR-beta-EP) secretion from hypothalamic neurons in primary cultures. Also, chronic ethanol and acetal-dehyde have been shown to cause the development of tolerance and desensitization of these neurons. In this study, we determined some of the cellular events leading to desensitization of the function of beta-endorphin (beta-EP) secretory neurons. The fetal hypothalamic cells were treated with various doses of ethanol (25 and 50 mM) or acetaldehyde (6.25, 12.5, and 25 mM) for 6 hr or treated with these drugs at 12 hr intervals for 72 hr. Determination of IR-beta-EP concentrations in the media revealed that ethanol increased IR-beta-EP secretion from these cultures for 12 hr, after this period, the cultured cells did not respond to ethanol. Acetaldehyde stimulated IR-beta-EP secretion from this culture for a period of 48 hr, but the IR-beta-EP secretory response to acetaldehyde reduced gradually with time during the first 48-hr period and reached the basal level at 72 hr. The desensitization of beta-EP neurons 12 hr after treatment with alcohol did not seem to be related to the loss of viable cells, because chronic ethanol exposures did not produce any effect on cell viability. However, reduced IR- beta-EP secretory response to acetaldehyde with time was associated with the time-dependent increase in cell death. Pretreatment of cultures with a cAMP analog, forskolin, increased the activity of functional beta-EP neurons and delayed the ethanol desensitization effects on these neurons. Pretreatment of forskolin did not delay the acetaldehyde desensitization of beta-EP neurons, but protected these cells from acetaldehyde toxicity. These results suggest that (i) chronic treatment with ethanol desensitizes beta-EP-secreting neurons due to reduced cellular functions and (ii) chronic acetaldehyde reduces beta-EP neurotransmission due to cell death. Furthermore, data suggest

  10. Developmental programming of hypothalamic neuronal circuits: impact on energy balance control

    PubMed Central

    Gali Ramamoorthy, Thanuja; Begum, Ghazala; Harno, Erika; White, Anne

    2015-01-01

    The prevalence of obesity in adults and children has increased globally at an alarming rate. Mounting evidence from both epidemiological studies and animal models indicates that adult obesity and associated metabolic disorders can be programmed by intrauterine and early postnatal environment- a phenomenon known as “fetal programming of adult disease.” Data from nutritional intervention studies in animals including maternal under- and over-nutrition support the developmental origins of obesity and metabolic syndrome. The hypothalamic neuronal circuits located in the arcuate nucleus controlling appetite and energy expenditure are set early in life and are perturbed by maternal nutritional insults. In this review, we focus on the effects of maternal nutrition in programming permanent changes in these hypothalamic circuits, with experimental evidence from animal models of maternal under- and over-nutrition. We discuss the epigenetic modifications which regulate hypothalamic gene expression as potential molecular mechanisms linking maternal diet during pregnancy to the offspring's risk of obesity at a later age. Understanding these mechanisms in key metabolic genes may provide insights into the development of preventative intervention strategies. PMID:25954145

  11. Developmental programming of hypothalamic neuronal circuits: impact on energy balance control.

    PubMed

    Gali Ramamoorthy, Thanuja; Begum, Ghazala; Harno, Erika; White, Anne

    2015-01-01

    The prevalence of obesity in adults and children has increased globally at an alarming rate. Mounting evidence from both epidemiological studies and animal models indicates that adult obesity and associated metabolic disorders can be programmed by intrauterine and early postnatal environment- a phenomenon known as "fetal programming of adult disease." Data from nutritional intervention studies in animals including maternal under- and over-nutrition support the developmental origins of obesity and metabolic syndrome. The hypothalamic neuronal circuits located in the arcuate nucleus controlling appetite and energy expenditure are set early in life and are perturbed by maternal nutritional insults. In this review, we focus on the effects of maternal nutrition in programming permanent changes in these hypothalamic circuits, with experimental evidence from animal models of maternal under- and over-nutrition. We discuss the epigenetic modifications which regulate hypothalamic gene expression as potential molecular mechanisms linking maternal diet during pregnancy to the offspring's risk of obesity at a later age. Understanding these mechanisms in key metabolic genes may provide insights into the development of preventative intervention strategies.

  12. To ingest or rest? Specialized roles of lateral hypothalamic area neurons in coordinating energy balance

    PubMed Central

    Brown, Juliette A.; Woodworth, Hillary L.; Leinninger, Gina M.

    2015-01-01

    Survival depends on an organism’s ability to sense nutrient status and accordingly regulate intake and energy expenditure behaviors. Uncoupling of energy sensing and behavior, however, underlies energy balance disorders such as anorexia or obesity. The hypothalamus regulates energy balance, and in particular the lateral hypothalamic area (LHA) is poised to coordinate peripheral cues of energy status and behaviors that impact weight, such as drinking, locomotor behavior, arousal/sleep and autonomic output. There are several populations of LHA neurons that are defined by their neuropeptide content and contribute to energy balance. LHA neurons that express the neuropeptides melanin-concentrating hormone (MCH) or orexins/hypocretins (OX) are best characterized and these neurons play important roles in regulating ingestion, arousal, locomotor behavior and autonomic function via distinct neuronal circuits. Recently, another population of LHA neurons containing the neuropeptide Neurotensin (Nts) has been implicated in coordinating anorectic stimuli and behavior to regulate hydration and energy balance. Understanding the specific roles of MCH, OX and Nts neurons in harmonizing energy sensing and behavior thus has the potential to inform pharmacological strategies to modify behaviors and treat energy balance disorders. PMID:25741247

  13. Metabolic regulation of lateral hypothalamic glucose-inhibited orexin neurons may influence midbrain reward neurocircuitry.

    PubMed

    Sheng, Zhenyu; Santiago, Ammy M; Thomas, Mark P; Routh, Vanessa H

    2014-09-01

    Lateral hypothalamic area (LHA) orexin neurons modulate reward-based feeding by activating ventral tegmental area (VTA) dopamine (DA) neurons. We hypothesize that signals of peripheral energy status influence reward-based feeding by modulating the glucose sensitivity of LHA orexin glucose-inhibited (GI) neurons. This hypothesis was tested using electrophysiological recordings of LHA orexin-GI neurons in brain slices from 4 to 6week old male mice whose orexin neurons express green fluorescent protein (GFP) or putative VTA-DA neurons from C57Bl/6 mice. Low glucose directly activated ~60% of LHA orexin-GFP neurons in both whole cell and cell attached recordings. Leptin indirectly reduced and ghrelin directly enhanced the activation of LHA orexin-GI neurons by glucose decreases from 2.5 to 0.1mM by 53±12% (n=16, P<0.001) and 41±24% (n=8, P<0.05), respectively. GABA or neurotensin receptor blockade prevented leptin's effect on glucose sensitivity. Fasting increased activation of LHA orexin-GI neurons by decreased glucose, as would be predicted by these hormonal effects. We also evaluated putative VTA-DA neurons in a novel horizontal slice preparation containing the LHA and VTA. Decreased glucose increased the frequency of spontaneous excitatory post-synaptic currents (sEPSCs; 125 ± 40%, n=9, P<0.05) and action potentials (n=9; P<0.05) in 45% (9/20) of VTA DA neurons. sEPSCs were completely blocked by AMPA and NMDA glutamate receptor antagonists (CNQX 20 μM, n=4; APV 20μM, n=4; respectively), demonstrating that these sEPSCs were mediated by glutamatergic transmission onto VTA DA neurons. Orexin-1 but not 2 receptor antagonism with SB334867 (10μM; n=9) and TCS-OX2-29 (2μM; n=5), respectively, blocks the effects of decreased glucose on VTA DA neurons. Thus, decreased glucose increases orexin-dependent excitatory glutamate neurotransmission onto VTA DA neurons. These data suggest that the glucose sensitivity of LHA orexin-GI neurons links metabolic state and reward

  14. Stress and Sucrose Intake Modulate Neuronal Activity in the Anterior Hypothalamic Area in Rats

    PubMed Central

    Mitra, Arojit; Guèvremont, Geneviève; Timofeeva, Elena

    2016-01-01

    The anterior hypothalamic area (AHA) is an important integrative relay structure for a variety of autonomic, endocrine, and behavioral responses including feeding behavior and response to stress. However, changes in the activity of the AHA neurons during stress and feeding in freely moving rats are not clear. The present study investigated the firing rate and burst activity of neurons in the central nucleus of the AHA (cAHA) during sucrose intake in non-stressful conditions and after acute stress in freely behaving rats. Rats were implanted with micro-electrodes into the cAHA, and extracellular multi-unit activity was recorded during 1-h access to 10% sucrose in non-stressful conditions or after acute foot shock stress. Acute stress significantly reduced sucrose intake, total sucrose lick number, and lick frequency in licking clusters, and increased inter-lick intervals. At the cluster start (CS) of sucrose licking, the cAHA neurons increased (CS-excited, 20% of the recorded neurons), decreased (CS-inhibited, 42% of the neurons) or did not change (CS-nonresponsive, 38% of the neurons) their firing rate. Stress resulted in a significant increase in the firing rate of the CS-inhibited neurons by decreasing inter-spike intervals within the burst firing of these neurons. This increase in the stress-induced firing rate of the CS-inhibited neurons was accompanied by a disruption of the correlation between the firing rate of CS-inhibited and CS-nonresponsive neurons that was observed in non-stressful conditions. Stress did not affect the firing rate of the CS-excited and CS-nonresponsive neurons. However, stress changed the pattern of burst firing of the CS-excited and CS-nonresponsive neurons by decreasing and increasing the burst number in the CS-excited and CS-nonresponsive neurons, respectively. These results suggest that the cAHA neurons integrate the signals related to stress and intake of palatable food and play a role in the stress- and eating-related circuitry

  15. Investigation of the ontogenetic patterns of rat hypothalamic dopaminergic neurone morphology and function in vitro.

    PubMed

    Murray, H E; Gillies, G E

    1993-12-01

    Using fetal rat hypothalamic cells in primary culture maintained in a serum-free defined medium we have investigated the morphological and functional development of the dopamine (DA)-containing neurones intrinsic to the hypothalamus. Immunocytochemical studies demonstrated the presence of three morphologically distinct subtypes of tyrosine hydroxylase-immunopositive neurones. On day 3 in vitro unipolar, bipolar and multipolar cell types were apparent. The latter two subtypes persisted to later days in culture and increased both in perikarya size and neurite length. All subtypes have been shown to have correlates in vivo. Biochemical studies employing [3H]DA demonstrated a time- and temperature-dependent uptake mechanism within the cultures which was significantly attenuated by the uptake inhibitors benztropine and nomifensine in a dose-dependent manner. [3H]DA was also released under both basal and 56 mmol K+/l-stimulated conditions and the magnitude of the response was reduced by exclusion of calcium from the release medium. The amount of [3H]DA accumulated and released by the cultural cells increased with the age of the culture, suggesting functional maturation of the DA-containing neurones within this preparation. The role of oestradiol-17 beta in regulating hypothalamic dopaminergic function was also investigated both indirectly with the use of [3H]DA and by direct measurement of endogenously synthesized DA using high-performance liquid chromatography coupled with electrochemical detection. Both uptake and release of [3H] and release of endogenous DA were significantly modulated by the concentration of steroid in the defined medium. These results demonstrate that hypothalamic dopaminergic neurones, when maintained in primary culture, undergo morphological and functional maturation which have several correlates in vivo. In addition, we have demonstrated that at least one sub-population of dopaminergic neurones within this preparation is responsive to oestradiol

  16. Odour-induced analgesia mediated by hypothalamic orexin neurons in mice

    PubMed Central

    Tashiro, Shogo; Yamaguchi, Ran; Ishikawa, Sodemi; Sakurai, Takeshi; Kajiya, Katsuko; Kanmura, Yuichi; Kuwaki, Tomoyuki; Kashiwadani, Hideki

    2016-01-01

    Various folk remedies employ certain odorous compounds with analgesic effects. In fact, linalool, a monoterpene alcohol found in lavender extracts, has been found to attenuate pain responses via subcutaneous, intraperitoneal, intrathecal, and oral administration. However, the analgesic effects of odorous compounds mediated by olfaction have not been thoroughly examined. We performed behavioural pain tests under odourant vapour exposure in mice. Among six odourant molecules examined, linalool significantly increased the pain threshold and attenuated pain behaviours. Olfactory bulb or epithelium lesion removed these effects, indicating that olfactory sensory input triggered the effects. Furthermore, immunohistochemical analysis revealed that linalool activated hypothalamic orexin neurons, one of the key mediators for pain processing. Formalin tests in orexin neuron-ablated and orexin peptide-deficient mice showed orexinergic transmission was essential for linalool odour-induced analgesia. Together, these findings reveal central analgesic circuits triggered by olfactory input in the mammalian brain and support a potential therapeutic approach for treating pain with linalool odour stimulation. PMID:27845440

  17. Lateral hypothalamic area stimulation excites neurons in the region of the subfornical organ with efferent projections to the hypothalamic paraventricular nucleus in the rat.

    PubMed

    Tanaka, J; Kaba, H; Saito, H; Seto, K

    1986-07-30

    Fifteen neurons in the region of the subfornical organ (SFO) were antidromically activated by electrical stimulation of the paraventricular nucleus (PVN) in the rat. Electrical stimulation of the lateral hypothalamic area (LHA) excited the activity of 9 of the identified units, but did not affect the remaining units. The excitatory response of the identified units was blocked by microiontophoretically (MIPh) applied saralasin (Sar), an angiotensin II (ANGII) antagonist, but not by atropine (Atr), a muscarinic antagonist. These results suggest that the LHA has an excitatory influence on the activity of neurons in the region of the SFO with efferent projections to the PVN and that the influence may be mediated by ANGII receptors.

  18. Somatic nonhomologous crossing-over between neuropeptide genes in rat hypothalamic neurons.

    PubMed Central

    Mohr, E; Peters, A; Morris, J F; Richter, D

    1994-01-01

    Molecular biological and immunocytochemical data demonstrate nonhomologous crossing-over between the closely linked vasopressin (VP) and oxytocin (OT) genes in rat hypothalamic neuroendocrine neurons. Reverse transcription of hypothalamic total RNA from wild-type or homozygous Brattleboro aged rats combined with polymerase chain reaction (PCR) amplifications in the presence of appropriate 5' forward and 3' reverse primers deduced from the VP and OT cDNA sequences yielded PCR products that, upon cloning and sequencing, revealed several hybrid transcripts. They encode the N-terminal part of the VP precursor fused to the C-terminal part of the OT precursor (VP/OT transcripts) and vice versa (OT/VP transcripts). VP/OT hybrid precursor proteins have been identified immunocytochemically in enlarged cisternae of the rough endoplasmic reticulum, yet there is no evidence that the products can be secreted from affected cells. Recombination appears to be a rather frequent genetic event affecting about 0.06-0.1% of the rat vasopressinergic magnocellular neurons in aged rats. Images PMID:7972073

  19. A septal-hypothalamic pathway drives orexin neurons which is necessary for conditioned cocaine preference

    PubMed Central

    Sartor, Gregory C.; Aston-Jones, Gary

    2012-01-01

    Orexins (also called hypocretins) have been shown to be importantly involved in reward and addiction, but little is known about the circuitry that regulates orexin neuronal activity during drug-seeking behaviors. Here, we examined inputs to the lateral hypothalamic (LH) orexin cell field from the lateral septum (LS) using tract-tracing and Fos immunohistochemistry after cocaine (10mg/kg) conditioned place preference (CPP) in Sprague Dawley rats. We found that neurons in rostral LS (LSr) that project to LH are Fos-activated in proportion to cocaine CPP, and that inhibition of LSr neurons with local baclofen and muscimol microinjection (0.3/0.03 nmol) blocks expression of Fos in LH orexin cells and cocaine preference. In addition, using local inactivation in LS and orexin antisense Morpholinos in LH, we found that LSr influences on LH orexin neurons are critical for the expression of cocaine preference. These results indicate that LSr activates LH orexin neurons during cocaine place preference, and that this circuit is essential for expression of cocaine place preference. PMID:22457508

  20. Synaptic glutamate release by ventromedial hypothalamic neurons is part of the neurocircuitry that prevents hypoglycemia.

    PubMed

    Tong, Qingchun; Ye, ChianPing; McCrimmon, Rory J; Dhillon, Harveen; Choi, Brian; Kramer, Melissa D; Yu, Jia; Yang, Zongfang; Christiansen, Lauryn M; Lee, Charlotte E; Choi, Cheol Soo; Zigman, Jeffrey M; Shulman, Gerald I; Sherwin, Robert S; Elmquist, Joel K; Lowell, Bradford B

    2007-05-01

    The importance of neuropeptides in the hypothalamus has been experimentally established. Due to difficulties in assessing function in vivo, the roles of the fast-acting neurotransmitters glutamate and GABA are largely unknown. Synaptic vesicular transporters (VGLUTs for glutamate and VGAT for GABA) are required for vesicular uptake and, consequently, synaptic release of neurotransmitters. Ventromedial hypothalamic (VMH) neurons are predominantly glutamatergic and express VGLUT2. To evaluate the role of glutamate release from VMH neurons, we generated mice lacking VGLUT2 selectively in SF1 neurons (a major subset of VMH neurons). These mice have hypoglycemia during fasting secondary to impaired fasting-induced increases in the glucose-raising pancreatic hormone glucagon and impaired induction in liver of mRNAs encoding PGC-1alpha and the gluconeogenic enzymes PEPCK and G6Pase. Similarly, these mice have defective counterregulatory responses to insulin-induced hypoglycemia and 2-deoxyglucose (an antimetabolite). Thus, glutamate release from VMH neurons is an important component of the neurocircuitry that functions to prevent hypoglycemia.

  1. Single Cell Transcriptomics of Hypothalamic Warm Sensitive Neurons that Control Core Body Temperature and Fever Response

    PubMed Central

    Eberwine, James; Bartfai, Tamas

    2011-01-01

    We report on an ‘unbiased’ molecular characterization of individual, adult neurons, active in a central, anterior hypothalamic neuronal circuit, by establishing cDNA libraries from each individual, electrophysiologically identified warm sensitive neuron (WSN). The cDNA libraries were analyzed by Affymetrix microarray. The presence and frequency of cDNAs was confirmed and enhanced with Illumina sequencing of each single cell cDNA library. cDNAs encoding the GABA biosynthetic enzyme. GAD1 and of adrenomedullin, galanin, prodynorphin, somatostatin, and tachykinin were found in the WSNs. The functional cellular and in vivo studies on dozens of the more than 500 neurotransmitter -, hormone- receptors and ion channels, whose cDNA was identified and sequence confirmed, suggest little or no discrepancy between the transcriptional and functional data in WSNs; whenever agonists were available for a receptor whose cDNA was identified, a functional response was found.. Sequencing single neuron libraries permitted identification of rarely expressed receptors like the insulin receptor, adiponectin receptor2 and of receptor heterodimers; information that is lost when pooling cells leads to dilution of signals and mixing signals. Despite the common electrophysiological phenotype and uniform GAD1 expression, WSN- transcriptomes show heterogenity, suggesting strong epigenetic influence on the transcriptome. Our study suggests that it is well-worth interrogating the cDNA libraries of single neurons by sequencing and chipping. PMID:20970451

  2. Zebrafish adult-derived hypothalamic neurospheres generate gonadotropin-releasing hormone (GnRH) neurons

    PubMed Central

    Cortés-Campos, Christian; Letelier, Joaquín; Ceriani, Ricardo; Whitlock, Kathleen E.

    2015-01-01

    ABSTRACT Gonadotropin-releasing hormone (GnRH) is a hypothalamic decapeptide essential for fertility in vertebrates. Human male patients lacking GnRH and treated with hormone therapy can remain fertile after cessation of treatment suggesting that new GnRH neurons can be generated during adult life. We used zebrafish to investigate the neurogenic potential of the adult hypothalamus. Previously we have characterized the development of GnRH cells in the zebrafish linking genetic pathways to the differentiation of neuromodulatory and endocrine GnRH cells in specific regions of the brain. Here, we developed a new method to obtain neural progenitors from the adult hypothalamus in vitro. Using this system, we show that neurospheres derived from the adult hypothalamus can be maintained in culture and subsequently differentiate glia and neurons. Importantly, the adult derived progenitors differentiate into neurons containing GnRH and the number of cells is increased through exposure to either testosterone or GnRH, hormones used in therapeutic treatment in humans. Finally, we show in vivo that a neurogenic niche in the hypothalamus contains GnRH positive neurons. Thus, we demonstrated for the first time that neurospheres can be derived from the hypothalamus of the adult zebrafish and that these neural progenitors are capable of producing GnRH containing neurons. PMID:26209533

  3. Lateral Hypothalamic Area Glutamatergic Neurons and Their Projections to the Lateral Habenula Regulate Feeding and Reward

    PubMed Central

    Stamatakis, Alice M.; Van Swieten, Maaike; Basiri, Marcus L.; Blair, Grace A.; Kantak, Pranish

    2016-01-01

    The overconsumption of calorically dense, highly palatable foods is thought to be a major contributor to the worldwide obesity epidemic; however, the precise neural circuits that directly regulate hedonic feeding remain elusive. Here, we show that lateral hypothalamic area (LHA) glutamatergic neurons, and their projections to the lateral habenula (LHb), negatively regulate the consumption of palatable food. Genetic ablation of LHA glutamatergic neurons increased daily caloric intake and produced weight gain in mice that had access to a high-fat diet, while not altering general locomotor activity. Anterior LHA glutamatergic neurons send a functional glutamatergic projection to the LHb, a brain region involved in processing aversive stimuli and negative reward prediction outcomes. Pathway-specific, optogenetic stimulation of glutamatergic LHA-LHb circuit resulted in detectable glutamate-mediated EPSCs as well as GABA-mediated IPSCs, although the net effect of neurotransmitter release was to increase the firing of most LHb neurons. In vivo optogenetic inhibition of LHA-LHb glutamatergic fibers produced a real-time place preference, whereas optogenetic stimulation of LHA-LHb glutamatergic fibers had the opposite effect. Furthermore, optogenetic inhibition of LHA-LHb glutamatergic fibers acutely increased the consumption of a palatable liquid caloric reward. Collectively, these results demonstrate that LHA glutamatergic neurons are well situated to bidirectionally regulate feeding and potentially other behavioral states via their functional circuit connectivity with the LHb and potentially other brain regions. SIGNIFICANCE STATEMENT In this study, we show that the genetic ablation of LHA glutamatergic neurons enhances caloric intake. Some of these LHA glutamatergic neurons project to the lateral habenula, a brain area important for generating behavioral avoidance. Optogenetic stimulation of this circuit has net excitatory effects on postsynaptic LHb neurons. This is the

  4. Nutrient sensing and insulin signaling in neuropeptide-expressing immortalized, hypothalamic neurons: A cellular model of insulin resistance.

    PubMed

    Fick, Laura J; Belsham, Denise D

    2010-08-15

    Obesity and type 2 diabetes mellitus represent a significant global health crisis. These two interrelated diseases are typified by perturbed insulin signaling in the hypothalamus. Using novel hypothalamic cell lines, we have begun to elucidate the molecular and intracellular mechanisms involved in the hypothalamic control of energy homeostasis and insulin resistance. In this review, we present evidence of insulin and glucose signaling pathways that lead to changes in neuropeptide gene expression. We have identified some of the molecular mechanisms involved in the control of de novo hypothalamic insulin mRNA expression. And finally, we have defined key mechanisms involved in the etiology of cellular insulin resistance in hypothalamic neurons that may play a fundamental role in cases of high levels of insulin or saturated fatty acids, often linked to the exacerbation of obesity and diabetes.

  5. Prenatal programming by testosterone of hypothalamic metabolic control neurones in the ewe.

    PubMed

    Sheppard, K M; Padmanabhan, V; Coolen, L M; Lehman, M N

    2011-05-01

    Ewes treated prenatally with testosterone develop metabolic deficits, including insulin resistance, in addition to reproductive dysfunctions that collectively mimic polycystic ovarian syndrome (PCOS), a common endocrine disease in women. We hypothesised that metabolic deficits associated with prenatal testosterone excess involve alterations in arcuate nucleus (ARC) neurones that contain either agouti-related peptide (AgRP) or pro-opiomelanocortin (POMC). Characterisation of these neurones in the ewe showed that immunoreactive AgRP and POMC neurones were present in separate populations in the ARC, that AgRP and POMC neurones co-expressed either neuropeptide Y or cocaine- and amphetamine-regulated transcript, respectively, and that each population had a high degree of co-localisation with androgen receptors. Examination of the effect of prenatal testosterone exposure on the number of AgRP and POMC neurones in adult ewes showed that prenatal testosterone excess significantly increased the number of AgRP but not POMC neurones compared to controls; this increase was restricted to the middle division of the ARC, was mimicked by prenatal treatment with dihydrotestosterone, a non-aromatisable androgen, and was blocked by co-treatment of prenatal testosterone with the anti-androgen, flutamide. The density of AgRP fibre immunoreactivity in the preoptic area, paraventricular nucleus, lateral hypothalamus and dorsomedial hypothalamic nucleus was also increased by prenatal testosterone exposure. Thus, ewes that were exposed to androgens during foetal life showed alterations in the number of AgRP-immunoreactive neurones and the density of fibre immunoreactivity in their projection areas, suggestive of permanent prenatal programming of metabolic circuitry that may, in turn, contribute to insulin resistance and an increased risk of obesity in this model of PCOS. © 2011 The Authors. Journal of Neuroendocrinology © 2011 Blackwell Publishing Ltd.

  6. On diamond surface properties and interactions with neurons.

    PubMed

    Ariano, P; Budnyk, O; Dalmazzo, S; Lovisolo, D; Manfredotti, Ch; Rivolo, P; Vittone, E

    2009-10-01

    In this paper we report about the role the diamond surface morphology and atomic termination plays in the survival and viability of neuronal cells, which represent an appropriate experimental model for the development of cell-based biosensors. The samples we have investigated were both CVD homoepitaxial diamond films and nanocrystalline diamond layers deposited on quartz substrates. Different surface terminations were induced through exposure to atomic hydrogen and to intense UV irradiation. GT1-7 cells, a neuronal line of hypothalamic origin, were plated directly onto the diamond surfaces without exogenous adhesion molecules, in order to correlate the surface topography and chemistry to cell growth and viability. The cell density on nanocrystalline diamonds after 48 h from plating was approximately 55% of the control on plastic dishes, whatever is the atomic termination of the surface, whereas the performances of homoepitaxial samples in terms of cell growth depend on surface termination and were significantly lower, 30%.

  7. Distribution of osmoregulatory peptides and neuronal-glial configuration in the hypothalamic magnocellular nuclei of desert rodents.

    PubMed

    Ouali-Hassenaoui, Saliha; Bendjelloul, Mounira; Dekar, Aicha; Theodosis, Dionysia

    2011-12-01

    The desert rodents Psammomys obesus and Gerbillus tarabuli live under extreme conditions and overcome food and water shortage by modes of food and fluid intake specific to each species. Using immunohistochemistry and electron microscopy, we found that the hypothalamic magnocellular nuclei, and in particular, their vasopressinergic component, is highly and similarly developed in Psammomys and Gerbillus. In comparison to other rodents, the hypothalamus in both species contains more magnocellular VP neurons that, together with oxytocin neurons, accumulate in distinct and extensive nuclei. As in dehydrated rodents, many magnocellular neurons contained both neuropeptides. A striking feature of the hypothalamic magnocellular system of Psammomys and Gerbillus was its display of ultrastructural properties related to heightened neurosecretion, namely, a significant reduction in glial coverage of neuronal somata and dendrites in the hypothalamic nuclei. There were many neuronal elements whose surfaces were directly juxtaposed and shared the same synapses. Their magnocellular nuclei also showed a high level of sialylated isoform of the Neural Cell Adhesion Molecule (PSA-NCAM) that underlies their capacity for neuronal and glial plasticity. These species thus offer striking models of structural neuronal and glial plasticity linked to natural conditions of heightened neurosecretion.

  8. Neurotrophin-3 potentiates excitatory GABAergic synaptic transmission in cultured developing hypothalamic neurones of the rat

    PubMed Central

    Gao, Xiao-Bing; van den Pol, A N

    1999-01-01

    Neurotrophin-3 (NT-3) supports the survival and differentiation of neurones in the central and peripheral nervous systems through a number of mechanisms that occur in a matter of hours or days. NT-3 may also have a more rapid mode of action that influences synaptic activity in mature neurones. In the present study, the effect of NT-3 on developing GABAergic synapses was investigated in 3- to 7-day-old cultures of rat hypothalamic neurones with whole-cell patch-clamp recording. NT-3 induced a substantial dose-dependent potentiation of the frequency of spontaneous postsynaptic currents (sPSCs; 160 %) in developing neurones during a period when GABA evoked inward (depolarizing) current, as determined with gramicidin-perforated patch recordings. The NT-3 effect was long lasting; continued enhancement was found > 30 min after NT-3 wash-out. NT-3 evoked a substantial 202 % increase in total GABA-mediated inward current, measured as the time-current integral. Action potential frequency was also increased by NT-3 (to 220 %). The frequency of GABA-mediated miniature postsynaptic currents in developing neurones in the presence of tetrodotoxin was potentiated (to 140 %) by NT-3 with no change in the mean amplitude, suggesting a presynaptic locus of the effect. In striking contrast to immature neurones, when more mature neurones were studied, NT-3 did not enhance the frequency of GABA-mediated spontaneous postsynaptic currents (sPSCs), but instead evoked a slight (16 %) decrease. The frequency of miniature post-synaptic currents was also slightly decreased (16 %) by the NT-3, with no change in amplitude. These results were recorded during a later period of neuronal maturity when GABA would evoke outward (hyperpolarizing) currents. NT-3 had no effect on the mean amplitude of GABA-evoked postsynaptic currents in either developing or mature neurones. Intracellular application of K252a, a non-selective tyrosine kinase inhibitor, did not block the NT-3 effect postsynaptically. In

  9. Depressed basal hypothalamic neuronal activity in type-1 diabetic mice is correlated with proinflammatory secretion of HMBG1.

    PubMed

    Thinschmidt, Jeffrey S; Colon-Perez, Luis M; Febo, Marcelo; Caballero, Sergio; King, Michael A; White, Fletcher A; Grant, Maria B

    2016-02-26

    We recently found indicators of hypothalamic inflammation and neurodegeneration linked to the loss of neuroprotective factors including insulin-like growth factor (IGF-1) and IGF binding protein-2 (IGFBP-3) in mice made diabetic using streptozotocin (STZ). In the current work, a genetic model of type-1 diabetes (Ins2(Akita) mouse) was used to evaluate changes in neuronal activity and concomitant changes in the proinflammatory mediator high-mobility group box-1 (HMBG1). We found basal hypothalamic neuronal activity as indicated by manganese-enhanced magnetic resonance imaging (MEMRI) was significantly decreased in 8 months old, but not 2 months old Ins2(Akita) diabetic mice compared to controls. In tissue from the same animals we evaluated the expression of HMBG1 using immunohistochemistry and confocal microscopy. We found decreased HMBG1 nuclear localization in the paraventricular nucleus of the hypothalamus (PVN) in 8 months old, but not 2 months old diabetic animals indicating nuclear release of the protein consistent with an inflammatory state. Adjacent thalamic regions showed little change in HMBG1 nuclear localization and neuronal activity as a result of diabetes. This work extends our previous findings demonstrating changes consistent with hypothalamic neuroinflammation in STZ treated animals, and shows active inflammatory processes are correlated with changes in basal hypothalamic neuronal activity in Ins2(Akita) mice.

  10. Interactions between Kisspeptin Neurons and Hypothalamic Tuberoinfundibular Dopaminergic Neurons in Aged Female Rats

    PubMed Central

    Iwata, Kinuyo; Ikehara, Masaaki; Kunimura, Yuyu; Ozawa, Hitoshi

    2016-01-01

    Kisspeptin neurons in the arcuate nucleus (ARC) regulate prolactin secretion, and are in physical contact with tuberoinfundibular dopaminergic (TIDA) neurons, which inhibit prolactin secretion. Prolactin levels in the blood are increased with advancing age in rats; therefore, we investigated the interactions with TIDA neurons and kisspeptin neurons in aged female rats (24 months of age), relative to those of young adult female rats (9–10 weeks of age). Plasma prolactin levels in the aged rats were significantly higher than those of young adult rats. Tyrosine hydroxylase (TH)-immunoreactive (ir) cell bodies and kisspeptin-ir nerve fibers were found in the dorsomedial ARC of both groups. The number of TH-ir cell bodies in the dorsomedial ARC did not differ significantly between groups. Additionally, no significant differences in the number of TH-ir cells in contact with kisspeptin-ir fibers was observed between groups. However, the number of kisspeptin-ir or Kiss1 mRNA-expressing cells in the ARC was significantly reduced in the aged rats compared with that of the young rats. These results suggest that the contacts between TIDA neurons and kisspeptin neurons are maintained after reproductive senescence, while production of kisspeptin in the ARC decreases significantly during aging. PMID:28127107

  11. Hypothalamic Vasopressinergic Projections Innervate Central Amygdala GABAergic Neurons: Implications for Anxiety and Stress Coping.

    PubMed

    Hernández, Vito S; Hernández, Oscar R; Perez de la Mora, Miguel; Gómora, María J; Fuxe, Kjell; Eiden, Lee E; Zhang, Limei

    2016-01-01

    The arginine-vasopressin (AVP)-containing hypothalamic magnocellular neurosecretory neurons (VPMNNs) are known for their role in hydro-electrolytic balance control via their projections to the neurohypophysis. Recently, projections from these same neurons to hippocampus, habenula and other brain regions in which vasopressin infusion modulates contingent social and emotionally-affected behaviors, have been reported. Here, we present evidence that VPMNN collaterals also project to the amygdaloid complex, and establish synaptic connections with neurons in central amygdala (CeA). The density of AVP innervation in amygdala was substantially increased in adult rats that had experienced neonatal maternal separation (MS), consistent with our previous observations that MS enhances VPMNN number in the paraventricular (PVN) and supraoptic (SON) nuclei of the hypothalamus. In the CeA, V1a AVP receptor mRNA was only observed in GABAergic neurons, demonstrated by complete co-localization of V1a transcripts in neurons expressing Gad1 and Gad2 transcripts in CeA using the RNAscope method. V1b and V2 receptor mRNAs were not detected, using the same method. Water-deprivation (WD) for 24 h, which increased the metabolic activity of VPMNNs, also increased anxiety-like behavior measured using the elevated plus maze (EPM) test, and this effect was mimicked by bilateral microinfusion of AVP into the CeA. Anxious behavior induced by either WD or AVP infusion was reversed by CeA infusion of V1a antagonist. VPMNNs are thus a newly discovered source of CeA inhibitory circuit modulation, through which both early-life and adult stress coping signals are conveyed from the hypothalamus to the amygdala.

  12. Hypothalamic Vasopressinergic Projections Innervate Central Amygdala GABAergic Neurons: Implications for Anxiety and Stress Coping

    PubMed Central

    Hernández, Vito S.; Hernández, Oscar R.; Perez de la Mora, Miguel; Gómora, María J.; Fuxe, Kjell; Eiden, Lee E.; Zhang, Limei

    2016-01-01

    The arginine-vasopressin (AVP)-containing hypothalamic magnocellular neurosecretory neurons (VPMNNs) are known for their role in hydro-electrolytic balance control via their projections to the neurohypophysis. Recently, projections from these same neurons to hippocampus, habenula and other brain regions in which vasopressin infusion modulates contingent social and emotionally-affected behaviors, have been reported. Here, we present evidence that VPMNN collaterals also project to the amygdaloid complex, and establish synaptic connections with neurons in central amygdala (CeA). The density of AVP innervation in amygdala was substantially increased in adult rats that had experienced neonatal maternal separation (MS), consistent with our previous observations that MS enhances VPMNN number in the paraventricular (PVN) and supraoptic (SON) nuclei of the hypothalamus. In the CeA, V1a AVP receptor mRNA was only observed in GABAergic neurons, demonstrated by complete co-localization of V1a transcripts in neurons expressing Gad1 and Gad2 transcripts in CeA using the RNAscope method. V1b and V2 receptor mRNAs were not detected, using the same method. Water-deprivation (WD) for 24 h, which increased the metabolic activity of VPMNNs, also increased anxiety-like behavior measured using the elevated plus maze (EPM) test, and this effect was mimicked by bilateral microinfusion of AVP into the CeA. Anxious behavior induced by either WD or AVP infusion was reversed by CeA infusion of V1a antagonist. VPMNNs are thus a newly discovered source of CeA inhibitory circuit modulation, through which both early-life and adult stress coping signals are conveyed from the hypothalamus to the amygdala. PMID:27932956

  13. Glucokinase inhibitor glucosamine stimulates feeding and activates hypothalamic neuropeptide Y and orexin neurons.

    PubMed

    Zhou, Ligang; Yueh, Chen-Yu; Lam, Daniel D; Shaw, Jill; Osundiji, Mayowa; Garfield, Alastair S; Evans, Mark; Heisler, Lora K

    2011-09-12

    Maintaining glucose levels within the appropriate physiological range is necessary for survival. The identification of specific neuronal populations, within discreet brain regions, sensitive to changes in glucose concentration has led to the hypothesis of a central glucose-sensing system capable of directly modulating feeding behaviour. Glucokinase (GK) has been identified as a glucose-sensor responsible for detecting such changes both within the brain and the periphery. We previously reported that antagonism of centrally expressed GK by administration of glucosamine (GSN) was sufficient to induce protective glucoprivic feeding in rats. Here we examine a neurochemical mechanism underlying this effect and report that GSN stimulated food intake is highly correlated with the induction of the neuronal activation marker cFOS within two nuclei with a demonstrated role in central glucose sensing and appetite, the arcuate nucleus of the hypothalamus (ARC) and lateral hypothalamic area (LHA). Furthermore, GSN stimulated cFOS within the ARC was observed in orexigenic neurons expressing the endogenous melanocortin receptor antagonist agouti-related peptide (AgRP) and neuropeptide Y (NPY), but not those expressing the anorectic endogenous melanocortin receptor agonist alpha-melanocyte stimulating hormone (α-MSH). In the LHA, GSN stimulated cFOS was found within arousal and feeding associated orexin/hypocretin (ORX), but not orexigenic melanin-concentrating hormone (MCH) expressing neurons. Our data suggest that GK within these specific feeding and arousal related populations of AgRP/NPY and ORX neurons may play a modulatory role in the sensing of and appetitive response to hypoglycaemia. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Dopamine/Tyrosine Hydroxylase Neurons of the Hypothalamic Arcuate Nucleus Release GABA, Communicate with Dopaminergic and Other Arcuate Neurons, and Respond to Dynorphin, Met-Enkephalin, and Oxytocin

    PubMed Central

    Zhang, Xiaobing

    2015-01-01

    We employ transgenic mice with selective expression of tdTomato or cre recombinase together with optogenetics to investigate whether hypothalamic arcuate (ARC) dopamine/tyrosine hydroxylase (TH) neurons interact with other ARC neurons, how they respond to hypothalamic neuropeptides, and to test whether these cells constitute a single homogeneous population. Immunostaining with dopamine and TH antisera was used to corroborate targeted transgene expression. Using whole-cell recording on a large number of neurons (n = 483), two types of neurons with different electrophysiological properties were identified in the dorsomedial ARC where 94% of TH neurons contained immunoreactive dopamine: bursting and nonbursting neurons. In contrast to rat, the regular oscillations of mouse bursting neurons depend on a mechanism involving both T-type calcium and A-type potassium channel activation, but are independent of gap junction coupling. Optogenetic stimulation using cre recombinase-dependent ChIEF-AAV-DJ expressed in ARC TH neurons evoked postsynaptic GABA currents in the majority of neighboring dopamine and nondopamine neurons, suggesting for the first time substantial synaptic projections from ARC TH cells to other ARC neurons. Numerous met-enkephalin (mENK) and dynorphin-immunoreactive boutons appeared to contact ARC TH neurons. mENK inhibited both types of TH neuron through G-protein coupled inwardly rectifying potassium currents mediated by δ and μ opioid receptors. Dynorphin-A inhibited both bursting and nonbursting TH neurons by activating κ receptors. Oxytocin excited both bursting and nonbursting neurons. These results reveal a complexity of TH neurons that communicate extensively with neurons within the ARC. SIGNIFICANCE STATEMENT Here, we show that the great majority of mouse hypothalamic arcuate nucleus (ARC) neurons that synthesize TH in the dorsomedial ARC also contain immunoreactive dopamine, and show either bursting or nonbursting electrical activity. Unlike

  15. The fatty acid synthase inhibitor cerulenin and feeding, like leptin, activate hypothalamic pro-opiomelanocortin (POMC) neurons.

    PubMed

    Shu, I-Wei; Lindenberg, Daniel L; Mizuno, Tooru M; Roberts, James L; Mobbs, Charles V

    2003-09-19

    Hypothalamic POMC neurons mediate catabolic responses such as decreased food intake and increased energy expenditure by, in part, monitoring levels of metabolic factors such as glucose, insulin and leptin. Recently, fatty acid synthase inhibitors were reported to reduce body weight, inhibit food intake, and increase metabolic rate, possibly by acting on hypothalamic neurons through a mechanism involving malonyl-CoA accumulation. Given the observation that leptin mediates similar catabolic effects by, in part, activating hypothalamic POMC neurons, it is possible that other catabolic signals such as feeding and fatty acid synthase inhibition may also activate POMC neurons. To test this hypothesis, hypothalamic sections from mice that were fed or injected with the fatty acid synthase inhibitor cerulenin were examined for Fos (a marker for neuronal activation) and POMC product immunoreactivity and compared with similarly processed sections from leptin-injected mice. Feeding increased Fos immunoreactivity in the lateral peri-arcuate area of the hypothalamus of both wild-type and leptin-deficient ob/ob mice (P<0.05), indicating that nutritional activation of the hypothalamus can be leptin-independent. Furthermore, feeding significantly induced Fos immunoreactivity in neurons expressing POMC (P<0.003), indicating that feeding, like leptin, activates POMC neurons. Injection with cerulenin, like feeding and leptin, also increased Fos immunoreactivity in the lateral peri-arcuate area (P<0.03) and, more specifically, in neurons expressing POMC. In contrast, injection with cerulenin had no grossly observable effects on cortical Fos immunoreactivity and appeared to suppress fasting-induced Fos immunoreactivity by about 35% (although the decrease did not reach statistical significance) in the medial arcuate nucleus, an area associated with anabolic responses such as increased food intake. Injection with cerulenin also decreased Fos immunoreactivity in the granular layer of the

  16. Effects of tamoxifen on neuronal morphology, connectivity and biochemistry of hypothalamic ventromedial neurons: Impact on the modulators of sexual behavior.

    PubMed

    Sá, Susana I; Teixeira, Natércia; Fonseca, Bruno M

    2017-09-28

    Tamoxifen (TAM) is a selective estrogen receptor modulator, widely used in the treatment and prevention of estrogen-dependent breast cancer. Although with great clinical results, women on TAM therapy still report several side effects, such as sexual dysfunction, which impairs quality of life. The anatomo-functional substrates of the human sexual behavior are still unknown; however, these same substrates are very well characterized in the rodent female sexual behavior, which has advantage of being a very simple reflexive response, dependent on the activation of estrogen receptors (ERs) in the ventrolateral division of the hypothalamic ventromedial nucleus (VMNvl). In fact, in the female rodent, the sexual behavior is triggered by increasing circulation levels of estradiol that changes the nucleus neurochemistry and modulates its intricate neuronal network. Therefore, we considered of notice the examination of the possible neurochemical alterations and the synaptic plasticity impairment in VMNvl neurons of estradiol-primed female rats treated with TAM that may be in the basis of this neurological disorder. Accordingly, we used stereological and biochemical methods to study the action of TAM in axospinous and axodendritic synaptic plasticity and on ER expression. The administration of TAM changed the VMNvl neurochemistry by reducing ERα mRNA and increasing ERβ mRNA expression. Furthermore, present results show that TAM induced neuronal atrophy and reduced synaptic connectivity, favoring electrical inactivity. These data suggest that these cellular and molecular changes may be a possible neuronal mechanism of TAM action in the disruption of the VMNvl network, leading to the development of behavioral disorders. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. GABA-mediated oxytocinergic inhibition in dorsal horn neurons by hypothalamic paraventricular nucleus stimulation.

    PubMed

    Rojas-Piloni, Gerardo; López-Hidalgo, Mónica; Martínez-Lorenzana, Guadalupe; Rodríguez-Jiménez, Javier; Condés-Lara, Miguel

    2007-03-16

    In anaesthetized rats, we tested whether the unit activity of dorsal horn neurons that receive nociceptive input is modulated by electrical stimulation of the hypothalamic paraventricular nucleus (PVN). An electrophysiological mapping of dorsal horn neurons at L3-L4 let us choose cells responding to a receptive field located in the toes region of the left hindpaw. Dorsal horn neurons were classified according to their response properties to peripheral stimulation. Wide Dynamic Range (WDR) cells responding to electrical stimulation of the peripheral receptive field and presenting synaptic input of Adelta, Abeta, and C-fibers were studied. Suspected interneurons that are typically silent and lack peripheral receptive field responses were also analyzed. PVN electrical stimulation inhibits Adelta (-55.0+/-10.2%), C-fiber (-73.1+/-6.7%), and post-discharge (-75.0+/-8.9%) peripheral activation in WDR cells, and silent interneurons were activated. So, this last type of interneuron was called a PVN-ON cell. In WDR cells, the inhibition of peripheral responses caused by PVN stimulation was blocked by intrathecal administration of a specific oxytocin antagonist or bicuculline. However, PVN-ON cell activation was blocked by the same specific oxytocin antagonist, but not by bicuculline. Our results suggest that PVN stimulation inhibits nociceptive peripheral-evoked responses in WDR neurons by a descending oxytocinergic pathway mediated by GABAergic PVN-ON cells. We discuss our observation that the PVN electrical stimulation selectively inhibits Adelta and C-fiber activity without affecting Abeta fibers. We conclude that Adelta and C-fibers receive a presynaptic inhibition mediated by GABA.

  18. β-Arrestin Regulates Estradiol Membrane-Initiated Signaling in Hypothalamic Neurons

    PubMed Central

    Wong, Angela M.; Abrams, Matthew C.; Micevych, Paul E.

    2015-01-01

    Estradiol (E2) action in the nervous system is the result of both direct nuclear and membrane-initiated signaling (EMS). E2 regulates membrane estrogen receptor-α (ERα) levels through opposing mechanisms of EMS-mediated trafficking and internalization. While ß-arrestin-mediated mERα internalization has been described in the cortex, a role of ß-arrestin in EMS, which underlies multiple physiological processes, remains undefined. In the arcuate nucleus of the hypothalamus (ARH), membrane-initiated E2 signaling modulates lordosis behavior, a measure of female sexually receptivity. To better understand EMS and regulation of ERα membrane levels, we examined the role of ß-arrestin, a molecule associated with internalization following agonist stimulation. In the present study, we used an immortalized neuronal cell line derived from embryonic hypothalamic neurons, the N-38 line, to examine whether ß-arrestins mediate internalization of mERα. β-arrestin-1 (Arrb1) was found in the ARH and in N-38 neurons. In vitro, E2 increased trafficking and internalization of full-length ERα and ERαΔ4, an alternatively spliced isoform of ERα, which predominates in the membrane. Treatment with E2 also increased phosphorylation of extracellular-signal regulated kinases 1/2 (ERK1/2) in N-38 neurons. Arrb1 siRNA knockdown prevented E2-induced ERαΔ4 internalization and ERK1/2 phosphorylation. In vivo, microinfusions of Arrb1 antisense oligodeoxynucleotides (ODN) into female rat ARH knocked down Arrb1 and prevented estradiol benzoate-induced lordosis behavior compared with nonsense scrambled ODN (lordosis quotient: 3 ± 2.1 vs. 85.0 ± 6.0; p < 0.0001). These results indicate a role for Arrb1 in both EMS and internalization of mERα, which are required for the E2-induction of female sexual receptivity. PMID:25803606

  19. Magel2 Is Required for Leptin-Mediated Depolarization of POMC Neurons in the Hypothalamic Arcuate Nucleus in Mice

    PubMed Central

    Mercer, Rebecca E.; Michaelson, Sheldon D.; Chee, Melissa J. S.; Atallah, Tanya A.

    2013-01-01

    Prader-Willi Syndrome is the most common syndromic form of human obesity and is caused by the loss of function of several genes, including MAGEL2. Mice lacking Magel2 display increased weight gain with excess adiposity and other defects suggestive of hypothalamic deficiency. We demonstrate Magel2-null mice are insensitive to the anorexic effect of peripherally administered leptin. Although their excessive adiposity and hyperleptinemia likely contribute to this physiological leptin resistance, we hypothesized that Magel2 may also have an essential role in intracellular leptin responses in hypothalamic neurons. We therefore measured neuronal activation by immunohistochemistry on brain sections from leptin-injected mice and found a reduced number of arcuate nucleus neurons activated after leptin injection in the Magel2-null animals, suggesting that most but not all leptin receptor–expressing neurons retain leptin sensitivity despite hyperleptinemia. Electrophysiological measurements of arcuate nucleus neurons expressing the leptin receptor demonstrated that although neurons exhibiting hyperpolarizing responses to leptin are present in normal numbers, there were no neurons exhibiting depolarizing responses to leptin in the mutant mice. Additional studies demonstrate that arcuate nucleus pro-opiomelanocortin (POMC) expressing neurons are unresponsive to leptin. Interestingly, Magel2-null mice are hypersensitive to the anorexigenic effects of the melanocortin receptor agonist MT-II. In Prader-Willi Syndrome, loss of MAGEL2 may likewise abolish leptin responses in POMC hypothalamic neurons. This neural defect, together with increased fat mass, blunted circadian rhythm, and growth hormone response pathway defects that are also linked to loss of MAGEL2, could contribute to the hyperphagia and obesity that are hallmarks of this disorder. PMID:23341784

  20. Kisspeptin neurones do not directly signal to RFRP-3 neurones but RFRP-3 may directly modulate a subset of hypothalamic kisspeptin cells in mice.

    PubMed

    Poling, M C; Quennell, J H; Anderson, G M; Kauffman, A S

    2013-10-01

    The neuropeptides kisspeptin (encoded by Kiss1) and RFamide-related peptide-3 (also known as GnIH; encoded by Rfrp) are potent stimulators and inhibitors, respectively, of reproduction. Whether kisspeptin or RFRP-3 might act directly on each other's neuronal populations to indirectly modulate reproductive status is unknown. To examine possible interconnectivity of the kisspeptin and RFRP-3 systems, we performed double-label in situ hybridisation (ISH) for the RFRP-3 receptors, Gpr147 and Gpr74, in hypothalamic Kiss1 neurones of adult male and female mice, as well as double-label ISH for the kisspeptin receptor, Kiss1r, in Rfrp-expressing neurones of the hypothalamic dorsal-medial nucleus (DMN). Only a very small proportion (5-10%) of Kiss1 neurones of the anteroventral periventricular region expressed Gpr147 or Gpr74 in either sex, whereas higher co-expression (approximately 25%) existed in Kiss1 neurones in the arcuate nucleus. Thus, RFRP-3 could signal to a small, primarily arcuate, subset of Kiss1 neurones, a conclusion supported by the finding of approximately 35% of arcuate kisspeptin cells receiving RFRP-3-immunoreactive fibre contacts. By contrast to the former situation, no Rfrp neurones co-expressed Kiss1r in either sex, and Tacr3, the receptor for neurokinin B (NKB; a neuropeptide co-expressed with arcuate kisspeptin neurones) was found in <10% of Rfrp neurones. Moreover, kisspeptin-immunoreactive fibres did not readily appose RFRP-3 cells in either sex, further excluding the likelihood that kisspeptin neurones directly communicate to RFRP-3 neurones. Lastly, despite abundant NKB in the DMN region where RFRP-3 soma reside, NKB was not co-expressed in the majority of Rfrp neurones. Our results suggest that RFRP-3 may modulate a small proportion of kisspeptin-producing neurones in mice, particularly in the arcuate nucleus, whereas kisspeptin neurones are unlikely to have any direct reciprocal actions on RFRP-3 neurones. © 2013 British Society for

  1. Corticotropin releasing factor excites neurons of posterior hypothalamic nucleus to produce tachycardia in rats.

    PubMed

    Gao, He-Ren; Zhuang, Qian-Xing; Li, Bin; Li, Hong-Zhao; Chen, Zhang-Peng; Wang, Jian-Jun; Zhu, Jing-Ning

    2016-02-01

    Corticotropin releasing factor (CRF), a peptide hormone involved in the stress response, holds a key position in cardiovascular regulation. Here, we report that the central effect of CRF on cardiovascular activities is mediated by the posterior hypothalamic nucleus (PH), an important structure responsible for stress-induced cardiovascular changes. Our present results demonstrate that CRF directly excites PH neurons via two CRF receptors, CRFR1 and CRFR2, and consequently increases heart rate (HR) rather than the mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA). Bilateral vagotomy does not influence the tachycardia response to microinjection of CRF into the PH, while β adrenergic receptor antagonist propranolol almost totally abolishes the tachycardia. Furthermore, microinjecting CRF into the PH primarily increases neuronal activity of the rostral ventrolateral medulla (RVLM) and rostral ventromedial medulla (RVMM), but does not influence that of the dorsal motor nucleus of the vagus nerve (DMNV). These findings suggest that the PH is a critical target for central CRF system in regulation of cardiac activity and the PH-RVLM/RVMM-cardiac sympathetic nerve pathways, rather than PH-DMNV-vagus pathway, may contribute to the CRF-induced tachycardia.

  2. Corticotropin releasing factor excites neurons of posterior hypothalamic nucleus to produce tachycardia in rats

    PubMed Central

    Gao, He-Ren; Zhuang, Qian-Xing; Li, Bin; Li, Hong-Zhao; Chen, Zhang-Peng; Wang, Jian-Jun; Zhu, Jing-Ning

    2016-01-01

    Corticotropin releasing factor (CRF), a peptide hormone involved in the stress response, holds a key position in cardiovascular regulation. Here, we report that the central effect of CRF on cardiovascular activities is mediated by the posterior hypothalamic nucleus (PH), an important structure responsible for stress-induced cardiovascular changes. Our present results demonstrate that CRF directly excites PH neurons via two CRF receptors, CRFR1 and CRFR2, and consequently increases heart rate (HR) rather than the mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA). Bilateral vagotomy does not influence the tachycardia response to microinjection of CRF into the PH, while β adrenergic receptor antagonist propranolol almost totally abolishes the tachycardia. Furthermore, microinjecting CRF into the PH primarily increases neuronal activity of the rostral ventrolateral medulla (RVLM) and rostral ventromedial medulla (RVMM), but does not influence that of the dorsal motor nucleus of the vagus nerve (DMNV). These findings suggest that the PH is a critical target for central CRF system in regulation of cardiac activity and the PH-RVLM/RVMM-cardiac sympathetic nerve pathways, rather than PH-DMNV-vagus pathway, may contribute to the CRF-induced tachycardia. PMID:26831220

  3. Postsynaptic Depolarization Enhances GABA Drive to Dorsomedial Hypothalamic Neurons through Somatodendritic Cholecystokinin Release.

    PubMed

    Crosby, Karen M; Baimoukhametova, Dinara V; Bains, Jaideep S; Pittman, Quentin J

    2015-09-23

    Somatodendritically released peptides alter synaptic function through a variety of mechanisms, including autocrine actions that liberate retrograde transmitters. Cholecystokinin (CCK) is a neuropeptide expressed in neurons in the dorsomedial hypothalamic nucleus (DMH), a region implicated in satiety and stress. There are clear demonstrations that exogenous CCK modulates food intake and neuropeptide expression in the DMH, but there is no information on how endogenous CCK alters synaptic properties. Here, we provide the first report of somatodendritic release of CCK in the brain in male Sprague Dawley rats. CCK is released from DMH neurons in response to repeated postsynaptic depolarizations, and acts in an autocrine fashion on CCK2 receptors to enhance postsynaptic NMDA receptor function and liberate the retrograde transmitter, nitric oxide (NO). NO subsequently acts presynaptically to enhance GABA release through a soluble guanylate cyclase-mediated pathway. These data provide the first demonstration of synaptic actions of somatodendritically released CCK in the hypothalamus and reveal a new form of retrograde plasticity, depolarization-induced potentiation of inhibition. Significance statement: Somatodendritic signaling using endocannabinoids or nitric oxide to alter the efficacy of afferent transmission is well established. Despite early convincing evidence for somatodendritic release of neurohypophysial peptides in the hypothalamus, there is only limited evidence for this mode of release for other peptides. Here, we provide the first evidence for somatodendritic release of the satiety peptide cholecystokinin (CCK) in the brain. We also reveal a new form of synaptic plasticity in which postsynaptic depolarization results in enhancement of inhibition through the somatodendritic release of CCK.

  4. NF-κB Activation in Hypothalamic Pro-opiomelanocortin Neurons Is Essential in Illness- and Leptin-induced Anorexia*

    PubMed Central

    Jang, Pil-Geum; Namkoong, Cherl; Kang, Gil Myoung; Hur, Man-Wook; Kim, Seung-Whan; Kim, Geun Hyang; Kang, Yeoungsup; Jeon, Min-Jae; Kim, Eun Hee; Lee, Myung-Shik; Karin, Michael; Baik, Ja-Hyun; Park, Joong-Yeol; Lee, Ki-Up; Kim, Young-Bum; Kim, Min-Seon

    2010-01-01

    Anorexia and weight loss are prevalent in infectious diseases. To investigate the molecular mechanisms underlying these phenomena, we established animal models of infection-associated anorexia by administrating bacterial and viral products, lipopolysaccharide (LPS) and human immunodeficiency virus-1 transactivator protein (Tat). In these models, we found that the nuclear factor-κB (NF-κB), a pivotal transcription factor for inflammation-related proteins, was activated in the hypothalamus. In parallel, administration of LPS and Tat increased hypothalamic pro-inflammatory cytokine production, which was abrogated by inhibition of hypothalamic NF-κB. In vitro, NF-κB activation directly stimulated the transcriptional activity of pro-opiomelanocortin (POMC), a precursor of anorexigenic melanocortin, and mediated the stimulatory effects of LPS, Tat, and pro-inflammatory cytokines on POMC transcription, implying the involvement of NF-κB in controlling feeding behavior. Consistently, hypothalamic injection of LPS and Tat caused a significant reduction in food intake and body weight, which was prevented by blockade of NF-κB and melanocortin. Furthermore, disruption of IκB kinase-β, an upstream kinase of NF-κB, in POMC neurons attenuated LPS- and Tat-induced anorexia. These findings suggest that infection-associated anorexia and weight loss are mediated via NF-κB activation in hypothalamic POMC neurons. In addition, hypothalamic NF-κB was activated by leptin, an important anorexigenic hormone, and mediates leptin-stimulated POMC transcription, indicating that hypothalamic NF-κB also serves as a downstream signaling pathway of leptin. PMID:20097762

  5. Brain-derived neurotrophic factor but not neurotrophin-3 enhances differentiation of somatostatin neurons in hypothalamic cultures.

    PubMed

    Loudes, C; Petit, F; Kordon, C; Faivre-Bauman, A

    2000-09-01

    The present work investigated whether neurotrophins could differentially affect in vitro growth and maturation of two related subsets of hypothalamic neurons, hypophysiotropic somatostatin (SRIH) neurons projecting from the periventricular area and arcuate SRIH interneurons. For this purpose, the hypothalamus of 17-day-old rat fetuses was sampled and separated into a ventral and a dorsal fragment containing respectively periventricular and arcuate regions. Each fragment was dissociated and seeded separately in defined medium. Brain-derived neurotrophic factor (BDNF) or neurotrophin-3 (NT-3), two important members of the neurotrophin family involved in neuronal differentiation and plasticity, were added to the cultures at seeding time. After 6 or 11 days in vitro, neurons were labeled with an anti-SRIH antiserum and submitted to morphometric analysis. In parallel, SRIH mRNA was estimated by semiquantitative reverse-transcriptase-polymerase chain reaction, and neuronal SRIH content, basal and depolarisation-stimulated releases measured by radioimmunoassay. The response of control, non-labeled neurons was estimated by neuronal counts and by assaying glutamic acid decarboxylase, a marker of a large majority of hypothalamic neurons. BDNF markedly increased the size and the branching number of SRIH periventricular cell bodies. Expression of SRIH mRNA, as well as SRIH content and release into the culture medium, were also stimulated by the neurotrophin. Non-SRIH neurons were not affected by the treatment. Under the same conditions, arcuate neurons exhibited a weak, mostly transient response to BDNF. NT-3 was ineffective on either neuronal subset. Immunoneutralization of Trk receptors provided further evidence for BDNF effect specificity. The results indicate that BDNF is a selective activator of the differentiation of hypophysiotropic SRIH neurons in the periventricular area of the hypothalamus.

  6. Hypothalamic UDP Increases in Obesity and Promotes Feeding via P2Y6-Dependent Activation of AgRP Neurons.

    PubMed

    Steculorum, Sophie M; Paeger, Lars; Bremser, Stephan; Evers, Nadine; Hinze, Yvonne; Idzko, Marco; Kloppenburg, Peter; Brüning, Jens C

    2015-09-10

    Activation of orexigenic AgRP-expressing neurons in the arcuate nucleus of the hypothalamus potently promotes feeding, thus defining new regulators of AgRP neuron activity could uncover potential novel targets for obesity treatment. Here, we demonstrate that AgRP neurons express the purinergic receptor 6 (P2Y6), which is activated by uridine-diphosphate (UDP). In vivo, UDP induces ERK phosphorylation and cFos expression in AgRP neurons and promotes action potential firing of these neurons in brain slice recordings. Consequently, central application of UDP promotes feeding, and this response is abrogated upon pharmacologic or genetic inhibition of P2Y6 as well as upon pharmacogenetic inhibition of AgRP neuron activity. In obese animals, hypothalamic UDP content is elevated as a consequence of increased circulating uridine concentrations. Collectively, these experiments reveal a potential regulatory pathway in obesity, where peripheral uridine increases hypothalamic UDP concentrations, which in turn can promote feeding via PY6-dependent activation of AgRP neurons. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Fermentable carbohydrate alters hypothalamic neuronal activity and protects against the obesogenic environment.

    PubMed

    Anastasovska, Jelena; Arora, Tulika; Sanchez Canon, Gina J; Parkinson, James R C; Touhy, Kieran; Gibson, Glen R; Nadkarni, Nachiket A; So, Po-Wah; Goldstone, Anthony P; Thomas, E Louise; Hankir, Mohammed K; Van Loo, Jan; Modi, Neena; Bell, Jimmy D; Frost, Gary

    2012-05-01

    Obesity has become a major global health problem. Recently, attention has focused on the benefits of fermentable carbohydrates on modulating metabolism. Here, we take a system approach to investigate the physiological effects of supplementation with oligofructose-enriched inulin (In). We hypothesize that supplementation with this fermentable carbohydrate will not only lead to changes in body weight and composition, but also to modulation in neuronal activation in the hypothalamus. Male C57BL/6 mice were maintained on a normal chow diet (control) or a high fat (HF) diet supplemented with either oligofructose-enriched In or corn starch (Cs) for 9 weeks. Compared to HF+Cs diet, In supplementation led to significant reduction in average daily weight gain (mean ± s.e.m.: 0.19 ± 0.01 g vs. 0.26 ± 0.02 g, P < 0.01), total body adiposity (24.9 ± 1.2% vs. 30.7 ± 1.4%, P < 0.01), and lowered liver fat content (11.7 ± 1.7% vs. 23.8 ± 3.4%, P < 0.01). Significant changes were also observed in fecal bacterial distribution, with increases in both Bifidobacteria and Lactobacillius and a significant increase in short chain fatty acids (SCFA). Using manganese-enhanced MRI (MEMRI), we observed a significant increase in neuronal activation within the arcuate nucleus (ARC) of animals that received In supplementation compared to those fed HF+Cs diet. In conclusion, we have demonstrated for the first time, in the same animal, a wide range of beneficial metabolic effects following supplementation of a HF diet with oligofructose-enriched In, as well as significant changes in hypothalamic neuronal activity.

  8. Suckling and genital stroking induces Fos expression in hypothalamic oxytocinergic neurons of rabbit pups.

    PubMed

    Caba, Mario; Rovirosa, Maria J; Silver, Rae

    2003-07-12

    Maternal behaviour in the rabbit is unusual among mammals because the doe visits her litter to nurse once every 24 h. In the present study we examined the consequences of milk intake on oxytocinergic (OT) and vasopressinergic (AVP) neurons of the supraoptic (SON) and paraventricular (PVN) nuclei of 7-day-old pups before suckling, after suckling and following anogenital stroking in un-nursed pups. To determine neuronal activation we assessed the expression of the Fos protein combined with antibodies against OT and AVP at two levels in the SON (supraoptic rostral, SOr, and supraoptic retrochiasmatic, SOrch), and three levels in the PVN (anterior, PVab; medial PVm and caudal, PVc). Daily nursing bouts lasted only 228+/-6 s throughout the observed 7 days, and pups ingested up to 34.95+/-9.0% of their body weight in milk on day 7, the day of perfusion. Suckling induced a significant increase in the number of double-labeled Fos/OT cells in both subdivisions of the SON (P<0.01) and in PVab and PVm (P<0.01). The effect in the SON was related to suckling, as it was not seen in stroked, un-nursed pups, which showed Fos increases only in PVab and PVm. All regions in the SON and PVN showed significant increases in the number of Fos/AVP neurons after suckling or stroking but, contrary to OT, the number of double-labeled Fos/AVP cells was very low. In conclusion, our results show that the oxytocinergic system of the SON and PVN is differentially activated by suckling of milk and anogenital stroking, and that the vagal-hypothalamic axis is mature in 7-day-old rabbits.

  9. Adenovirus-mediated gene delivery to hypothalamic magnocellular neurons in mice

    NASA Technical Reports Server (NTRS)

    Vasquez, E. C.; Beltz, T. G.; Meyrelles, S. S.; Johnson, A. K.

    1999-01-01

    Vasopressin is synthesized by magnocellular neurons in supraoptic (SON) and paraventricular (PVN) hypothalamic nuclei and released by their axon terminals in the neurohypophysis (NH). With its actions as an antidiuretic hormone and vasoactive agent, vasopressin plays a pivotal role in the control of body fluids and cardiovascular homeostasis. Because of its well-defined neurobiology and functional importance, the SON/PVN-NH system is ideal to establish methods for gene transfer of genetic material into specific pathways in the mouse central nervous system. In these studies, we compared the efficiency of transferring the gene lacZ, encoding for beta-galactosidase (beta-gal), versus a gene encoding for green fluorescent protein by using replication-deficient adenovirus (Ad) vectors in adult mice. Transfection with viral concentrations up to 2 x 10(7) plaque-forming units per coverslip of NH, PVN, and SON in dissociated, cultured cells caused efficient transfection without cytotoxicity. However, over an extended period of time, higher levels (50% to 75% of the cells) of beta-gal expression were detected in comparison with green fluorescent protein (5% to 50% of the cells). With the use of a stereotaxic approach, the pituitary glands of mice were injected with Ad (4 x 10(6) plaque-forming units). In material from these animals, we were able to visualize the expression of the beta-gal gene in the NH and in magnocellular neurons of both the PVN and SON. The results of these experiments indicate that Ad-Rous sarcoma virus promoter-beta-gal is taken up by nerve terminals at the injection site (NH) and retrogradely transported to the soma of the neurons projecting to the NH. We conclude that the application of these experimental approaches will provide powerful tools for physiological studies and potential approaches to deliver therapeutic genes to treat diseases.

  10. Tuberal hypothalamic neurons secreting the satiety molecule Nesfatin-1 are critically involved in paradoxical (REM) sleep homeostasis.

    PubMed

    Jego, Sonia; Salvert, Denise; Renouard, Leslie; Mori, Masatomo; Goutagny, Romain; Luppi, Pierre-Hervé; Fort, Patrice

    2012-01-01

    The recently discovered Nesfatin-1 plays a role in appetite regulation as a satiety factor through hypothalamic leptin-independent mechanisms. Nesfatin-1 is co-expressed with Melanin-Concentrating Hormone (MCH) in neurons from the tuberal hypothalamic area (THA) which are recruited during sleep states, especially paradoxical sleep (PS). To help decipher the contribution of this contingent of THA neurons to sleep regulatory mechanisms, we thus investigated in rats whether the co-factor Nesfatin-1 is also endowed with sleep-modulating properties. Here, we found that the disruption of the brain Nesfatin-1 signaling achieved by icv administration of Nesfatin-1 antiserum or antisense against the nucleobindin2 (NUCB2) prohormone suppressed PS with little, if any alteration of slow wave sleep (SWS). Further, the infusion of Nesfatin-1 antiserum after a selective PS deprivation, designed for elevating PS needs, severely prevented the ensuing expected PS recovery. Strengthening these pharmacological data, we finally demonstrated by using c-Fos as an index of neuronal activation that the recruitment of Nesfatin-1-immunoreactive neurons within THA is positively correlated to PS but not to SWS amounts experienced by rats prior to sacrifice. In conclusion, this work supports a functional contribution of the Nesfatin-1 signaling, operated by THA neurons, to PS regulatory mechanisms. We propose that these neurons, likely releasing MCH as a synergistic factor, constitute an appropriate lever by which the hypothalamus may integrate endogenous signals to adapt the ultradian rhythm and maintenance of PS in a manner dictated by homeostatic needs. This could be done through the inhibition of downstream targets comprised primarily of the local hypothalamic wake-active orexin- and histamine-containing neurons.

  11. Central NUCB2/Nesfatin-1-expressing neurones belong to the hypothalamic-brainstem circuitry activated by hypoglycaemia.

    PubMed

    Bonnet, M S; Djelloul, M; Tillement, V; Tardivel, C; Mounien, L; Trouslard, J; Troadec, J-D; Dallaporta, M

    2013-01-01

    Nesfatin-1 is a recently identified 82 amino acid peptide shown to have an anorexigenic effect on rodents when administrered centrally and peripherally. Nesfatin-1 is expressed not only in neurones of various brain areas, including the hypothalamic and brainstem nuclei, but also in peripheral organs, such as the stomach and the pancreas. Nesfatinergic neurones were reported to participate in the regulation of satiety signals and in the responses to other stimuli, including restraint stress, abdominal surgery, and lipopolysaccharide-induced inflammation. The present study aimed to investigate whether NUCB2/nesfatin-1 expressing neurones also take part in the central signalling activated in response to hypoglycaemia and therefore are involved in central glucose sensing. Using immunolabelling methods based on the detection of the neuronal activation marker c-Fos and of nesfatin-1, we showed that peripheral injection of insulin induced a strong activation of nesfatin-1-expressing neurones in the brain vagal-regulatory nuclei, including the arcuate nucleus, paraventricular nucleus, lateral hypothalamic area, dorsal motor nucleus of the vagus (DMNX) and nucleus of the tractus solitarius. In response to intracellular glucopaenia induced by i.p. or i.c.v. 2-deoxyglucose injection, the c-Fos/nesfatin-1 colocalisations observed at the hypothalamic and brainstem levels were similar to those observed after insulin-induced hypoglycaemia. Moreover, using Fluorogold as a retrograde tracer, we showed that nesfatinergic preganglionic DMNX neurones activated by hypoglycaemia target the stomach and the pancreas. Taken together, these results suggest that a subpopulation of nesfatinergic neurones belongs to the central network activated by hypoglycaemia, and that nesfatin-1 participates in the triggering of physiological and hormonal counter-regulations observed in response to hypoglycaemia. © 2012 British Society for Neuroendocrinology.

  12. Tuberal Hypothalamic Neurons Secreting the Satiety Molecule Nesfatin-1 Are Critically Involved in Paradoxical (REM) Sleep Homeostasis

    PubMed Central

    Jego, Sonia; Salvert, Denise; Renouard, Leslie; Mori, Masatomo; Goutagny, Romain; Luppi, Pierre-Hervé; Fort, Patrice

    2012-01-01

    The recently discovered Nesfatin-1 plays a role in appetite regulation as a satiety factor through hypothalamic leptin-independent mechanisms. Nesfatin-1 is co-expressed with Melanin-Concentrating Hormone (MCH) in neurons from the tuberal hypothalamic area (THA) which are recruited during sleep states, especially paradoxical sleep (PS). To help decipher the contribution of this contingent of THA neurons to sleep regulatory mechanisms, we thus investigated in rats whether the co-factor Nesfatin-1 is also endowed with sleep-modulating properties. Here, we found that the disruption of the brain Nesfatin-1 signaling achieved by icv administration of Nesfatin-1 antiserum or antisense against the nucleobindin2 (NUCB2) prohormone suppressed PS with little, if any alteration of slow wave sleep (SWS). Further, the infusion of Nesfatin-1 antiserum after a selective PS deprivation, designed for elevating PS needs, severely prevented the ensuing expected PS recovery. Strengthening these pharmacological data, we finally demonstrated by using c-Fos as an index of neuronal activation that the recruitment of Nesfatin-1-immunoreactive neurons within THA is positively correlated to PS but not to SWS amounts experienced by rats prior to sacrifice. In conclusion, this work supports a functional contribution of the Nesfatin-1 signaling, operated by THA neurons, to PS regulatory mechanisms. We propose that these neurons, likely releasing MCH as a synergistic factor, constitute an appropriate lever by which the hypothalamus may integrate endogenous signals to adapt the ultradian rhythm and maintenance of PS in a manner dictated by homeostatic needs. This could be done through the inhibition of downstream targets comprised primarily of the local hypothalamic wake-active orexin- and histamine-containing neurons. PMID:23300698

  13. Depolarization of surface-attached hypothalamic mouse neurons studied by acoustic wave (thickness shear mode) detector.

    PubMed

    Cheung, Shilin; Fick, Laura J; Belsham, Denise D; Thompson, Michael

    2010-02-01

    Isolation of neurons from animal tissue is an important aspect of understanding basic biochemical processes such as the action of hormones and neurotransmitters. In the present work, the focus is on an effort to evaluate the utility of acoustic wave physics for the study of such cells. Immortalised hypothalamic neuronal cells from mouse embryos were cultured on the surface of the gold electrode of a 9.0 MHz thickness-shear mode acoustic wave sensor. These cells, which are clonal, are imposed on the surface of the device at a confluence in the range of 80-100%. The coated sensor is incorporated into a flow-injection configuration such that electrolytes can be introduced in order to examine their effects through measurement by network analysis. Both series resonance frequency, fs, and motional resistance, R(m), were measured in a number of experiments involving the injection of KCl and NaCl into the sensor-neuron system. The various responses to these electrolytes were interpreted in terms of changes in cellular structure associated with the depolarization process. The sensor-neuron system was found to elicit different responses to the addition of KCl and NaCl. Preliminary findings indicate that the TSM sensor does not purely measure changes in the membrane potential upon KCl addition. Typical changes in fs for 15 mM, 30 mM and 60 mM KCl additions were 54 +/- 15, 80 +/- 26 and 142 +/- 58 Hz (mean +/- standard deviation) respectively. Typical changes in R(m) for these KCl additions were 7 +/- 3, 13 +/- 4 and 23 +/- 6 Omega, respectively. These results were concluded after 17 runs at each concentration. Despite the large relative standard deviations, the dependence of f(s) and R(m) with respect to concentration was apparent. Controls performed by coating the TSM sensor with laminin or a cell attachment matrix showed no significant changes in either f(s) or R(m) for the same solutions tested on the sensor-neuron system.

  14. Influence of leptin and GABAB-receptor agonist and antagonist on neurons of the hypothalamic infundibular nucleus in the chicken.

    PubMed

    Bogatyrev, S; Yakimova, K S; Tzschentke, B

    2017-04-01

    In birds and mammals, the neuroendocrine regulation of energy balance is conserved in many aspects. Despite significant similarities between the two groups, differences in the regulatory mechanisms were detected. The present study was performed to carry out investigations of the influence of human leptin and GABAB-receptor agonist and antagonist on the firing rate of neurons of the Nucleus infundibuli hypothalami in brain slices from juvenile chickens. For the first time, we demonstrated a clear, dose-related change in the firing rate of hypothalamic neurons in juvenile chickens after the acute application of recombinant human leptin (1, 10, and 100 nM). All investigated neurons increased their subsequent firing rate. Application of GABAB-receptor agonist baclofen (1 µM) blocked, while antagonist CGP 35348 (10 µM) increased the spontaneous neuronal activity. Simultaneous application of baclofen and leptin reduced the effect observed from single leptin application. This was not found after simultaneously application of leptin and CGP. Altogether, our results indicate that in bird brain slices, and exemplarily in those of the chicken, hypothalamic neurons show mammalian-like responsiveness after acute leptin and GABA application. GABAB-mechanisms involved in GABA release play a likely important role in the leptin-mediated effects on NI neurons via functional leptin receptors.

  15. Effect of acute ethanol on beta-endorphin secretion from rat fetal hypothalamic neurons in primary cultures

    SciTech Connect

    Sarkar, D.K.; Minami, S. )

    1990-01-01

    To characterize the effect of ethanol on the hypothalamic {beta}-endorphin-containing neurons, rat fetal hypothalamic neurons were maintained in primary culture, and the secretion of {beta}-endorphin ({beta}-EP) was determined after ethanol challenges. Constant exposure to ethanol at doses of 6-50 mM produced a dose-dependent increase in basal secretion of {beta}-EP from these cultured cells. These doses of ethanol did not produce any significant effect on cell viability, DNA or protein content. The stimulated secretion of {beta}-EP following constant ethanol exposure is short-lasting. However, intermittent ethanol exposures maintained the ethanol stimulatory action on {beta}-EP secretion for a longer time. The magnitude of the {beta}-EP response to 50 mM ethanol is similar to that of the {beta}-EP response to 56 mM of potassium. Ethanol-stimulated {beta}-EP secretion required extracellular calcium and was blocked by a calcium channel blocker; a sodium channel blocker did not affect ethanol-stimulated secretion. These results suggest that the neuron culture system is a useful model for studying the cellular mechanisms involved in the ethanol-regulated hypothalamic opioid secretion.

  16. Sex difference in physical activity, energy expenditure and obesity driven by a subpopulation of hypothalamic POMC neurons.

    PubMed

    Burke, Luke K; Doslikova, Barbora; D'Agostino, Giuseppe; Greenwald-Yarnell, Megan; Georgescu, Teodora; Chianese, Raffaella; Martinez de Morentin, Pablo B; Ogunnowo-Bada, Emmanuel; Cansell, Celine; Valencia-Torres, Lourdes; Garfield, Alastair S; Apergis-Schoute, John; Lam, Daniel D; Speakman, John R; Rubinstein, Marcelo; Low, Malcolm J; Rochford, Justin J; Myers, Martin G; Evans, Mark L; Heisler, Lora K

    2016-03-01

    Obesity is one of the primary healthcare challenges of the 21st century. Signals relaying information regarding energy needs are integrated within the brain to influence body weight. Central among these integration nodes are the brain pro-opiomelanocortin (POMC) peptides, perturbations of which disrupt energy balance and promote severe obesity. However, POMC neurons are neurochemically diverse and the crucial source of POMC peptides that regulate energy homeostasis and body weight remains to be fully clarified. Given that a 5-hydroxytryptamine 2c receptor (5-HT2CR) agonist is a current obesity medication and 5-HT2CR agonist's effects on appetite are primarily mediated via POMC neurons, we hypothesized that a critical source of POMC regulating food intake and body weight is specifically synthesized in cells containing 5-HT2CRs. To exclusively manipulate Pomc synthesis only within 5-HT2CR containing cells, we generated a novel 5-HT 2C R (CRE) mouse line and intercrossed it with Cre recombinase-dependent and hypothalamic specific reactivatable Pomc (NEO) mice to restrict Pomc synthesis to the subset of hypothalamic cells containing 5-HT2CRs. This provided a means to clarify the specific contribution of a defined subgroup of POMC peptides in energy balance and body weight. Here we transform genetically programed obese and hyperinsulinemic male mice lacking hypothalamic Pomc with increased appetite, reduced physical activity and compromised brown adipose tissue (BAT) into lean, healthy mice via targeted restoration of Pomc function only within 5-HT2CR expressing cells. Remarkably, the same metabolic transformation does not occur in females, who despite corrected feeding behavior and normalized insulin levels remain physically inactive, have lower energy expenditure, compromised BAT and develop obesity. These data provide support for the functional heterogeneity of hypothalamic POMC neurons, revealing that Pomc expression within 5-HT2CR expressing neurons is sufficient

  17. Sex difference in physical activity, energy expenditure and obesity driven by a subpopulation of hypothalamic POMC neurons

    PubMed Central

    Burke, Luke K.; Doslikova, Barbora; D'Agostino, Giuseppe; Greenwald-Yarnell, Megan; Georgescu, Teodora; Chianese, Raffaella; Martinez de Morentin, Pablo B.; Ogunnowo-Bada, Emmanuel; Cansell, Celine; Valencia-Torres, Lourdes; Garfield, Alastair S.; Apergis-Schoute, John; Lam, Daniel D.; Speakman, John R.; Rubinstein, Marcelo; Low, Malcolm J.; Rochford, Justin J.; Myers, Martin G.; Evans, Mark L.; Heisler, Lora K.

    2016-01-01

    Objective Obesity is one of the primary healthcare challenges of the 21st century. Signals relaying information regarding energy needs are integrated within the brain to influence body weight. Central among these integration nodes are the brain pro-opiomelanocortin (POMC) peptides, perturbations of which disrupt energy balance and promote severe obesity. However, POMC neurons are neurochemically diverse and the crucial source of POMC peptides that regulate energy homeostasis and body weight remains to be fully clarified. Methods Given that a 5-hydroxytryptamine 2c receptor (5-HT2CR) agonist is a current obesity medication and 5-HT2CR agonist's effects on appetite are primarily mediated via POMC neurons, we hypothesized that a critical source of POMC regulating food intake and body weight is specifically synthesized in cells containing 5-HT2CRs. To exclusively manipulate Pomc synthesis only within 5-HT2CR containing cells, we generated a novel 5-HT2CRCRE mouse line and intercrossed it with Cre recombinase-dependent and hypothalamic specific reactivatable PomcNEO mice to restrict Pomc synthesis to the subset of hypothalamic cells containing 5-HT2CRs. This provided a means to clarify the specific contribution of a defined subgroup of POMC peptides in energy balance and body weight. Results Here we transform genetically programed obese and hyperinsulinemic male mice lacking hypothalamic Pomc with increased appetite, reduced physical activity and compromised brown adipose tissue (BAT) into lean, healthy mice via targeted restoration of Pomc function only within 5-HT2CR expressing cells. Remarkably, the same metabolic transformation does not occur in females, who despite corrected feeding behavior and normalized insulin levels remain physically inactive, have lower energy expenditure, compromised BAT and develop obesity. Conclusions These data provide support for the functional heterogeneity of hypothalamic POMC neurons, revealing that Pomc expression within 5-HT2CR

  18. Effects of oleic acid on distinct populations of neurons in the hypothalamic arcuate nucleus are dependent on extracellular glucose levels.

    PubMed

    Wang, R; Cruciani-Guglielmacci, C; Migrenne, S; Magnan, C; Cotero, V E; Routh, V H

    2006-03-01

    Pharmacological manipulation of fatty acid metabolism in the hypothalamic arcuate nucleus (ARC) alters energy balance and glucose homeostasis. Thus, we tested the hypotheses that distinctive populations of ARC neurons are oleic acid (OA) sensors that exhibit a glucose dependency, independent of whether some of these OA sensors are also glucose-sensing neurons. We used patch-clamp recordings to investigate the effects of OA on ARC neurons in brain slices from 14- to 21-day-old Sprague-Dawley (SD) rats. Additionally, we recorded spontaneous discharge rate in ARC neurons in 8-wk-old fed and fasted SD rats in vivo. Patch-clamp studies showed that in 2.5 mM glucose 12 of 94 (13%) ARC neurons were excited by 2 microM OA (OA-excited or OAE neurons), whereas six of 94 (6%) were inhibited (OA-inhibited2.5 or OAI2.5 neurons). In contrast, in 0.1 mM glucose, OA inhibited six of 20 (30%) ARC neurons (OAI0.1 neurons); none was excited. None of the OAI0.1 neurons responded to OA in 2.5 mM glucose. Thus OAI2.5 and OAI0.1 neurons are distinct. Similarly, in seven of 20 fed rats (35%) the overall response was OAE-like, whereas in three of 20 (15%) it was OAI-like. In contrast, in fasted rats only OAI-like response were observed (three of 15; 20%). There was minimal overlap between OA-sensing neurons and glucose-sensing neurons. In conclusion, OA regulated three distinct subpopulations of ARC neurons in a glucose-dependent fashion. These data suggest that an interaction between glucose and fatty acids regulates OA sensing in ARC neurons.

  19. Negative Regulation of Leptin-induced Reactive Oxygen Species (ROS) Formation by Cannabinoid CB1 Receptor Activation in Hypothalamic Neurons.

    PubMed

    Palomba, Letizia; Silvestri, Cristoforo; Imperatore, Roberta; Morello, Giovanna; Piscitelli, Fabiana; Martella, Andrea; Cristino, Luigia; Di Marzo, Vincenzo

    2015-05-29

    The adipocyte-derived, anorectic hormone leptin was recently shown to owe part of its regulatory effects on appetite-regulating hypothalamic neuropeptides to the elevation of reactive oxygen species (ROS) levels in arcuate nucleus (ARC) neurons. Leptin is also known to exert a negative regulation on hypothalamic endocannabinoid levels and hence on cannabinoid CB1 receptor activity. Here we investigated the possibility of a negative regulation by CB1 receptors of leptin-mediated ROS formation in the ARC. Through pharmacological and molecular biology experiments we report data showing that leptin-induced ROS accumulation is 1) blunted by arachidonyl-2'-chloroethylamide (ACEA) in a CB1-dependent manner in both the mouse hypothalamic cell line mHypoE-N41 and ARC neuron primary cultures, 2) likewise blocked by a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist, troglitazone, in a manner inhibited by T0070907, a PPAR-γ antagonist that also inhibited the ACEA effect on leptin, 3) blunted under conditions of increased endocannabinoid tone due to either pharmacological or genetic inhibition of endocannabinoid degradation in mHypoE-N41 and primary ARC neuronal cultures from MAGL(-/-) mice, respectively, and 4) associated with reduction of both PPAR-γ and catalase activity, which are reversed by both ACEA and troglitazone. We conclude that CB1 activation reverses leptin-induced ROS formation and hence possibly some of the ROS-mediated effects of the hormone by preventing PPAR-γ inhibition by leptin, with subsequent increase of catalase activity. This mechanism might underlie in part CB1 orexigenic actions under physiopathological conditions accompanied by elevated hypothalamic endocannabinoid levels. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Mecamylamine pretreatment counteracts cigarette smoke induced changes in hypothalamic catecholamine neuron systems and in anterior pituitary function.

    PubMed

    Andersson, K

    1985-11-01

    We have studied the effects of acute, intermittent exposure to tobacco smoke on discrete hypothalamic CA nerve terminal networks and on neuroendocrine function by means of quantitative histofluorimetrical determinations of catecholamine (CA) fluorescence in sections of rat brain and by radioimmunoassay procedures for hormones. Acute intermittent exposure to cigarette smoke induced a lowering of NA levels and increased NA turnover in discrete hypothalamic nerve terminal regions. This exposure also induced increases in DA turnover in the median eminence. The cigarette smoke lowered TSH, prolactin, LH and FSH serum levels, but induced an increase in serum corticosterone concentrations. To determine if the above mentioned changes in neuroendocrine function were nicotine mediated, a cholinergic nicotine-like blocking agent, mecamylamine, was administered prior to exposure to cigarette smoke. Pretreatment with mecamylamine (1.0 mg kg-1) counteracted the cigarette smoke induced changes in CA levels and turnover in all hypothalamic CA nerve terminal regions as well as the changes in serum levels of the pituitary hormones and corticosterone. It is suggested that acute intermittent exposure to cigarette smoke, via its nicotine component, lowers TSH, prolactin, LH and FSH secretion at least in part through activation of the tubero-infundibular DA neurons. Furthermore, the nicotine component of the cigarette smoke is suggested to induce the increase in corticosterone serum levels via increasing NA turnover in the paraventricular hypothalamic nucleus.

  1. Differential role of hypothalamic orexin/hypocretin neurons in reward seeking motivated by cocaine versus palatable food.

    PubMed

    Martin-Fardon, Rémi; Cauvi, Gabrielle; Kerr, Tony M; Weiss, Friedbert

    2016-08-24

    Hypothalamic orexin/hypocretin (Orx/Hcrt) neurons are thought to mediate both food-reinforced behaviors and behavior motivated by drugs of abuse. However, the relative role of the Orx/Hcrt system in behavior motivated by food versus drugs of abuse remains unclear. This investigation addressed this question by contrasting hypothalamic Orx/Hcrt neuronal activation associated with reinstatement of reward seeking induced by stimuli conditioned to cocaine (COC) versus highly palatable food reward, sweetened condensed milk (SCM). Orx/Hcrt neuronal activation in the lateral hypothalamus, dorsomedial hypothalamus and perifornical area, determined by dual c-fos/orx immunocytochemistry, was quantified in rat brains, following reinstatement of reward seeking induced by a discriminative stimulus (S(+) ) conditioned to COC or SCM. The COC S(+) and SCM S(+) initially produced the same magnitude of reward seeking. However, over four subsequent tests, behavior induced by the SCM S(+) decreased to extinction levels, whereas reinstatement induced by the COC S(+) perseverated at undiminished levels. Following both the first and fourth tests, the percentage of Orx/Hcrt cells expressing Fos was significantly increased in all hypothalamic subregions in rats tested with the COC S(+) but not rats tested with the SCM S(+) . These findings point toward a role for the Orx/Hcrt system in perseverating, compulsive-like COC seeking but not behavior motivated by palatable food. Moreover, analysis of the Orx/Hcrt recruitment patterns suggests that failure of Orx/Hcrt neurons in the lateral hypothalamus to respond to inhibitory inputs from Orx/Hcrt neurons in the dorsomedial hypothalamus/perifornical area may contribute to the perseverating nature of COC seeking.

  2. GABAergic regulation of the perifornical-lateral hypothalamic neurons during non-rapid eye movement sleep in rats

    PubMed Central

    Alam, Md. Noor; Kumar, Sunil; Suntsova, Natalia; Bashir, Tariq; Szymusiak, Ronald; McGinty, Dennis

    2010-01-01

    The perifornical-lateral hypothalamic area (PF-LHA) has been implicated in the regulation of behavioral arousal. The PF-LHA predominantly contains neurons that are active during behavioral and cortical activation and quiescent during non-rapid eye movement (nonNREM) sleep, i.e., are nonREM-off neurons. Some in vitro and in vivo studies indicate that PF-LHA neurons, including hypocretin-expressing neurons, are under GABAergic control. However, a role of GABA in suppressing the discharge of PF-LHA neurons during spontaneous nonREM sleep has not been confirmed. We recorded the sleep-wake discharge profiles of PF-LHA neurons and simultaneously assessed the contributions of local GABAA receptor activation and blockade on their wake- and nonREM sleep-related discharge activities by delivering GABAA receptor agonist, muscimol (500nm, 5μM, and 10μM) and its antagonist, bicuculline (5μM, 10μM, and 20μM), adjacent to the recorded neurons via reverse microdialysis. Muscimol dose-dependently decreased the discharge of PF-LHA neurons including nonREM-off neurons. Muscimol-induced suppression of discharge during nonREM sleep was significantly weaker than the suppression produced during waking. In the presence of bicuculline, PF-LHA neurons, including nonREM-off neurons, exhibited elevated discharge, which was dose-dependent and was significantly higher during nonREM sleep, compared to waking. These results suggest that GABAA receptor mediated increased GABAergic tone contributes to the suppression of PF-LHA neurons, including nonREM-off neurons, during spontaneous nonREM sleep. PMID:20188152

  3. Distribution of Hypophysiotropic Thyrotropin-Releasing Hormone (TRH)-Synthesizing Neurons in the Hypothalamic Paraventricular Nucleus of the Mouse

    PubMed Central

    Kádár, Andrea; Sánchez, Edith; Wittmann, Gábor; Singru, Praful S.; Füzesi, Tamás; Marsili, Alessandro; Larsen, P. Reed; Liposits, Zsolt; Lechan, Ronald M.; Fekete, Csaba

    2010-01-01

    Hypophysiotropic thyrotropin-releasing hormone (TRH) neurons, the central regulators of the hypothalamus-pituitary-thyroid axis, are located in the hypothalamic paraventricular nucleus (PVN) in a partly overlapping distribution with non-hypophysiotropic TRH neurons. The distribution of hypophysiotropic TRH neurons in the rat PVN is well understood, but the localization of these neurons is unknown in mice. To determine the distribution and phenotype of hypophysiotropic TRH neurons in mice, double- and triple-labeling experiments were performed on sections of intact mice, and mice treated intravenously and intraperitonially with the retrograde tracer Fluoro-Gold. TRH neurons were located in all parts of the PVN except the periventricular zone. Hypophysiotropic TRH neurons were observed only at the mid level of the PVN, primarily in the compact part. In the this part of the PVN, TRH-neurons were intermingled with oxytocin and vasopressin neurons, but based on their size, the TRH neurons were parvocellular and did not contain magnocellular neuropeptides. Co-localization of TRH and CART were observed only in areas where hypophysiotropic TRH neurons were located. In accordance with the morphological observations, hypothyroidism increased TRH mRNA content of neurons only at the mid level of the PVN. These data demonstrate that the distribution of hypophysiotropic TRH neurons in mice is vastly different from the pattern in rats, with a dominant occurrence of these neurosecretory cells in the compact part and adjacent regions at the mid level of the PVN. Furthermore, our data demonstrate that the organization of the PVN is markedly different in mice and rats. PMID:20737594

  4. Hypothalamic gonadotropin-releasing hormone (GnRH) receptor neurons fire in synchrony with the female reproductive cycle.

    PubMed

    Schauer, Christian; Tong, Tong; Petitjean, Hugues; Blum, Thomas; Peron, Sophie; Mai, Oliver; Schmitz, Frank; Boehm, Ulrich; Leinders-Zufall, Trese

    2015-08-01

    Gonadotropin-releasing hormone (GnRH) controls mammalian reproduction via the hypothalamic-pituitary-gonadal (hpg) axis, acting on gonadotrope cells in the pituitary gland that express the GnRH receptor (GnRHR). Cells expressing the GnRHR have also been identified in the brain. However, the mechanism by which GnRH acts on these potential target cells remains poorly understood due to the difficulty of visualizing and identifying living GnRHR neurons in the central nervous system. We have developed a mouse strain in which GnRHR neurons express a fluorescent marker, enabling the reliable identification of these cells independent of the hormonal status of the animal. In this study, we analyze the GnRHR neurons of the periventricular hypothalamic nucleus in acute brain slices prepared from adult female mice. Strikingly, we find that the action potential firing pattern of these neurons alternates in synchrony with the estrous cycle, with pronounced burst firing during the preovulatory period. We demonstrate that GnRH stimulation is sufficient to trigger the conversion from tonic to burst firing in GnRHR neurons. Furthermore, we show that this switch in the firing pattern is reversed by a potent GnRHR antagonist. These data suggest that endogenous GnRH acts on GnRHR neurons and triggers burst firing in these cells during late proestrus and estrus. Our data have important clinical implications in that they indicate a novel mode of action for GnRHR agonists and antagonists in neurons of the central nervous system that are not part of the classical hpg axis.

  5. Orexin-A suppresses postischemic glucose intolerance and neuronal damage through hypothalamic brain-derived neurotrophic factor.

    PubMed

    Harada, Shinichi; Yamazaki, Yui; Tokuyama, Shogo

    2013-01-01

    Orexin-A (a glucose-sensing neuropeptide in the hypothalamus) and brain-derived neurotrophic factor (BDNF; a member of the neurotrophin family) play roles in many physiologic functions, including regulation of glucose metabolism. We previously showed that the development of postischemic glucose intolerance is one of the triggers of ischemic neuronal damage. The aim of this study was to determine whether there was an interaction between orexin-A and BDNF functions in the hypothalamus after cerebral ischemic stress. Male ddY mice were subjected to 2 hours of middle cerebral artery occlusion (MCAO). Neuronal damage was estimated by histologic and behavioral analyses. Expression of protein levels was analyzed by Western blot. Small interfering RNA directed BDNF, orexin-A, and SB334867 [N-(2-methyl-6-benzoxazolyl)-N'-1,5-naphthyridin-4-yl urea; a specific orexin-1 receptor antagonist] were administered directly into the hypothalamus. The level of hypothalamic orexin-A, detected by immunohistochemistry, was decreased on day 1 after MCAO. Intrahypothalamic administration of orexin-A (1 or 5 pmol/mouse) significantly and dose-dependently suppressed the development of postischemic glucose intolerance on day 1 and development of neuronal damage on day 3. The MCAO-induced decrease in insulin receptor levels in the liver and skeletal muscle on day 1 was recovered to control levels by orexin-A, and this effect of orexin-A was reversed by the administration of SB334867 as well as by hypothalamic BDNF knockdown. These results suggest that suppression of postischemic glucose intolerance by orexin-A assists in the prevention of cerebral ischemic neuronal damage. In addition, hypothalamic BDNF may play an important role in this effect of orexin-A.

  6. Evidence that hypothalamic RFamide related peptide-3 neurones are not leptin-responsive in mice and rats.

    PubMed

    Rizwan, M Z; Harbid, A A; Inglis, M A; Quennell, J H; Anderson, G M

    2014-04-01

    Leptin, a permissive hormonal regulator of fertility, provides information about the body's energy reserves to the hypothalamic gonadotrophin-releasing hormone (GnRH) neuronal system that drives reproduction. Leptin does not directly act on GnRH neurones, and the neuronal pathways that it uses remain unclear. RFamide-related peptide-3 (RFRP-3) neurones project to GnRH neurones and primarily inhibit their activity. We tested whether leptin could act via RFRP-3 neurones to potentially modulate GnRH activity. First, the effects of leptin deficiency or high-fat diet-induced obesity on RFRP-3 cell numbers and gene expression were assessed in male and female mice. There was no significant difference in Rfrp mRNA levels or RFRP-3-immunoreactive cell counts in wild-type versus leptin-deficient ob/ob animals, or in low-fat versus high-fat diet fed wild-type mice. Second, the presence of leptin-induced signalling in RFRP-3 neurones was examined in male and female wild-type mice and rats. Dual label immunohistochemistry revealed leptin-induced phosphorylated signal transducer and activator of transcription-3 in close proximity to RFRP-3 neurones, although there was very little (2-13%) colocalisation and no significant differences between vehicle and leptin-treated animals. Furthermore, we were unable to detect leptin receptor mRNA in a semi-purified RFRP-3 cell preparation. Because GABA neurones form critical leptin-responsive GnRH inputs, we also determined whether RFRP-3 and GABA cells were colocalised. No such colocalisation was detected. These results support the concept that leptin has little or no effects on RFRP-3 neurones, and that these neurones are unlikely to be an important neuronal pathway for the metabolic regulation of fertility by leptin. © 2014 British Society for Neuroendocrinology.

  7. Estrogen-induced dendritic spine elimination on female rat ventromedial hypothalamic neurons that project to the periaqueductal gray.

    PubMed

    Calizo, Lyngine H; Flanagan-Cato, Loretta M

    2002-06-03

    Neurons of the ventromedial hypothalamic nucleus (VMH) that project to the periaqueductal gray (PAG) form a crucial segment of the motor pathway that produces the lordosis posture, the hallmark of female rat sexual behavior. One suggested mechanism through which estrogen facilitates lordosis is by remodeling synaptic connectivity within the VMH. For instance, estrogen alters VMH dendritic spine density. Little is known, however, about the local VMH microcircuitry governing lordosis nor how estrogen alters synaptic connectivity within this local circuit to facilitate sexual behavior. The goal of this study was to define better the neuron types within the VMH microcircuitry and to examine whether estrogen alters synaptic connectivity, as measured by dendritic spine density, on VMH projection neurons. A retrograde tracer was injected into the PAG of ovariectomized rats treated with vehicle or estradiol. Retrogradely labeled VMH neurons were filled with Lucifer yellow, then immunostained for estrogen receptor-alpha (ER alpha). VMH neurons that project to the PAG had more dendrites than functionally unidentified neurons. Additionally, VMH projection neurons could be subdivided into those located within the cluster of ER alpha-containing neurons and those medial to the cluster. Estrogen decreased spine density by 57% on the long primary dendrites of VMH projection neurons located within the ER alpha cluster but not on projection neurons medial to the cluster. Only 4% of the VMH projection neurons expressed ER alpha. These results suggest that estrogen may facilitate sexual behavior by decreasing spines selectively, via an indirect mechanism, on a subset of VMH neurons that project to the PAG. Copyright 2002 Wiley-Liss, Inc.

  8. Area-specific analysis of the distribution of hypothalamic neurons projecting to the rat ventral tegmental area, with special reference to the GABAergic and glutamatergic efferents

    PubMed Central

    Kalló, Imre; Molnár, Csilla S.; Szöke, Sarolta; Fekete, Csaba; Hrabovszky, Erik; Liposits, Zsolt

    2015-01-01

    The ventral tegmental area (VTA) is a main regulator of reward and integrates a wide scale of hormonal and neuronal information. Feeding-, energy expenditure-, stress, adaptation- and reproduction-related hypothalamic signals are processed in the VTA and influence the reward processes. However, the neuroanatomical origin and chemical phenotype of neurons mediating these signals to the VTA have not been fully characterized. In this study we have systematically mapped hypothalamic neurons that project to the VTA using the retrograde tracer Choleratoxin B subunit (CTB) and analyzed their putative gamma-aminobutyric acid (GABA) and/or glutamate character with in situ hybridization in male rats. 23.93 ± 3.91% of hypothalamic neurons projecting to the VTA was found in preoptic and 76.27 ± 4.88% in anterior, tuberal and mammillary hypothalamic regions. Nearly half of the retrogradely-labeled neurons in the preoptic, and more than one third in the anterior, tuberal and mammillary hypothalamus appeared in medially located regions. The analyses of vesicular glutamate transporter 2 (VGLUT2) and glutamate decarboxylase 65 (GAD65) mRNA expression revealed both amino acid markers in different subsets of retrogradely-labeled hypothalamic neurons, typically with the predominance of the glutamatergic marker VGLUT2. About one tenth of CTB-IR neurons were GAD65-positive even in hypothalamic nuclei expressing primarily VGLUT2. Some regions were populated mostly by GAD65 mRNA-containing retrogradely-labeled neurons. These included the perifornical part of the lateral hypothalamus where 58.63 ± 19.04% of CTB-IR neurons were GABAergic. These results indicate that both the medial and lateral nuclear compartments of the hypothalamus provide substantial input to the VTA. Furthermore, colocalization studies revealed that these projections not only use glutamate but also GABA for neurotransmission. These GABAergic afferents may underlie important inhibitory mechanism to fine-tune the

  9. Human recombinant factor VIIa may improve heat intolerance in mice by attenuating hypothalamic neuronal apoptosis and damage.

    PubMed

    Hsu, Chuan-Chih; Chen, Sheng-Hsien; Lin, Cheng-Hsien; Yung, Ming-Chi

    2014-10-01

    Intolerance to heat exposure is believed to be associated with hypothalamo-pituitary-adrenocortical (HPA) axis impairment [reflected by decreases in blood concentrations of both adrenocorticotrophic-hormone (ACTH) and corticosterone]. The purpose of this study was to determine the effect of human recombinant factor VIIa (rfVIIa) on heat intolerance, HPA axis impairment, and hypothalamic inflammation, ischemic and oxidative damage, and apoptosis in mice under heat stress. Immediately after heat stress (41.2 °C for 1 h), mice were treated with vehicle (1 mL/kg of body weight) or rfVIIa (65-270 µg/kg of body weight) and then returned to room temperature (26 °C). Mice still alive on day 4 of heat exposure were considered survivors. Cellular ischemia markers (e.g., glutamate, lactate-to-pyruvate ratio), oxidative damage markers (e.g., nitric oxide metabolite, hydroxyl radials), and pro-inflammatory cytokines (e.g., interleukin-6, interleukin-1β, tumor necrosis factor-α) in hypothalamus were determined. In addition, blood concentrations of both ACTH and corticosterone were measured. Hypothalamic cell damage was assessed by determing the neuronal damage scores, whereas the hypothalamic cell apoptosis was determined by assessing the numbers of cells stained with terminal deoxynucleotidyl transferase-mediated αUTP nick-end labeling, caspase-3-positive cells, and platelet endothelial cell adhesion molecula-1-positive cells in hypothalamus. Compared with vehicle-treated heated mice, rfVIIa-treated heated mice had significantly higher fractional survival (8/10 vs 1/10), lesser thermoregulatory deficit (34.1 vs 24.8 °C), lesser extents of ischemic, oxidative, and inflammatory markers in hypothalamus, lesser neuronal damage scores and apoptosis in hypothalamus, and lesser HPA axis impairment. Human recombinant factor VIIa appears to exert a protective effect against heatstroke by attenuating hypothalamic cell apoptosis (due to ischemic, inflammatory, and oxidative damage

  10. Hypocretin/Orexin excites hypocretin neurons via a local glutamate neuron-A potential mechanism for orchestrating the hypothalamic arousal system.

    PubMed

    Li, Ying; Gao, Xiao Bing; Sakurai, Takeshi; van den Pol, Anthony N

    2002-12-19

    Neurons that release hypocretin/orexin modulate sleep, arousal, and energy homeostasis; the absence of hypocretin results in narcolepsy. Here we present data on the physiological characteristics of these cells, identified with GFP in transgenic mouse brain slices. Hypocretin-1 and -2 depolarized hypocretin neurons by 15mV and evoked an increase in spike frequency (+366% from a 1-3 Hz baseline). The mechanism for this appears to be hypocretin-mediated excitation of local glutamatergic neurons that regulate hypocretin neuron activity, in part by presynaptic facilitation of glutamate release. This represents a possible mechanism for orchestrating the output of the diffuse hypothalamic arousal system. No direct effect of hypocretin on membrane properties of hypocretin cells was detected. Norepinephrine and serotonin, transmitters of other arousal systems, decreased spike frequency and evoked outward currents, whereas acetylcholine and histamine had little effect.

  11. Lateral hypothalamic orexin and melanin-concentrating hormone neurons provide direct input to gonadotropin-releasing hormone neurons in the human

    PubMed Central

    Skrapits, Katalin; Kanti, Vivien; Savanyú, Zsófia; Maurnyi, Csilla; Szenci, Ottó; Horváth, András; Borsay, Beáta Á.; Herczeg, László; Liposits, Zsolt; Hrabovszky, Erik

    2015-01-01

    Hypophysiotropic projections of gonadotropin-releasing hormone (GnRH)-synthesizing neurons form the final common output way of the hypothalamus in the neuroendocrine control of reproduction. Several peptidergic neuronal systems of the medial hypothalamus innervate human GnRH cells and mediate crucially important hormonal and metabolic signals to the reproductive axis, whereas much less is known about the contribution of the lateral hypothalamic area to the afferent control of human GnRH neurons. Orexin (ORX)- and melanin-concentrating hormone (MCH)-synthesizing neurons of this region have been implicated in diverse behavioral and autonomic processes, including sleep and wakefulness, feeding and other functions. In the present immunohistochemical study, we addressed the anatomical connectivity of these neurons to human GnRH cells in post-mortem hypothalamic samples obtained from autopsies. We found that 38.9 ± 10.3% and 17.7 ± 3.3% of GnRH-immunoreactive (IR) perikarya in the infundibular nucleus of human male subjects received ORX-IR and MCH-IR contacts, respectively. On average, each 1 mm segment of GnRH dendrites received 7.3 ± 1.1 ORX-IR and 3.7 ± 0.5 MCH-IR axo-dendritic appositions. Overall, the axo-dendritic contacts dominated over the axo-somatic contacts and represented 80.5 ± 6.4% of ORX-IR and 76.7 ± 4.6% of MCH-IR inputs to GnRH cells. Based on functional evidence from studies of laboratory animals, the direct axo-somatic and axo-dendritic input from ORX and MCH neurons to the human GnRH neuronal system may convey critical metabolic and other homeostatic signals to the reproducive axis. In this study, we also report the generation and characterization of new antibodies for immunohistochemical detection of GnRH neurons in histological sections. PMID:26388735

  12. Age-dependent changes in amino acid phenotype and the role of glutamate release from hypothalamic proopiomelanocortin neurons.

    PubMed

    Dennison, Christina S; King, Connie M; Dicken, Matthew S; Hentges, Shane T

    2016-04-15

    Hypothalamic proopiomelanocortin (POMC) neurons are important regulators of energy balance. Recent studies indicate that in addition to their peptides, POMC neurons can release either the amino acid (AA) transmitter gamma-aminobutyric acid (GABA) or glutamate. A small subset of POMC neurons appears to have a dual AA phenotype based on coexpression of mRNA for the vesicular glutamate transporter (vGlut2) and the GABA synthetic enzyme Gad67. To determine whether the colocalization of GABAergic and glutamatergic markers may be indicative of a switch in AA transmitter phenotype, fluorescent in situ hybridization was used to detect vGlut2 and Gad mRNA in POMC neurons during early postnatal development. The percentage of POMC neurons expressing vGlut2 mRNA in POMC neurons progressively decreased from ∼40% at day 1 to less than 10% by 8 weeks of age, whereas Gad67 was only expressed in ∼10% of POMC neurons at day 1 and increased until ∼45% of POMC neurons coexpressed Gad67 at 8 weeks of age. To determine whether the expression of vGlut2 may play a role in energy balance regulation, genetic deletion of vGlut2 in POMC neurons was accomplished using Cre-lox technology. Male, but not female, mice lacking vGlut2 in POMC neurons were unable to maintain energy balance to the same extent as control mice when fed a high-fat diet. Altogether, the results indicate that POMC neurons are largely glutamatergic early in life and that the release of glutamate from these cells is involved in sex- and diet-specific regulation of energy balance.

  13. Leptin Activates Oxytocin Neurons of the Hypothalamic Paraventricular Nucleus in Both Control and Diet-Induced Obese Rodents

    PubMed Central

    Perello, Mario; Raingo, Jesica

    2013-01-01

    The adipocyte-derived hormone leptin acts in the brain to reduce body weight and fat mass. Recent studies suggest that parvocellular oxytocin (OXT) neurons of the hypothalamic paraventricular nucleus (PVN) can mediate body weight reduction through inhibition of food intake and increased energy expenditure. However, the role of OXT neurons of the PVN as a primary target of leptin has not been investigated. Here, we studied the potential role of OXT neurons of the PVN in leptin-mediated effects on body weight regulation in fasted rats. We demonstrated that intracerebroventricular (ICV) leptin activates STAT3 phosphorylation in OXT neurons of the PVN, showed that this occurs in a subpopulation of OXT neurons that innervate the nucleus of the solitary tract (NTS), and provided further evidence suggesting a role of OXT to mediate leptin’s actions on body weight. In addition, our results indicated that OXT neurons are responsive to ICV leptin and mediate leptin effects on body weight in diet induced obese (DIO) rats, which are resistant to the anorectic effects of the hormone. Thus, we conclude that leptin targets a specific subpopulation of parvocellular OXT neurons of the PVN, and that this action may be important for leptin’s ability to reduce body weight in both control and obese rats. PMID:23527232

  14. Effect of copper on extracellular levels of key pro-inflammatory molecules in hypothalamic GN11 and primary neurons.

    PubMed

    Spisni, Enzo; Valerii, Maria Chiara; Manerba, Marcella; Strillacci, Antonio; Polazzi, Elisabetta; Mattia, Toni; Griffoni, Cristiana; Tomasi, Vittorio

    2009-07-01

    Copper dyshomeostasis is responsible for the neurological symptoms observed in the genetically inherited copper-dependent disorders (e.g., Menkes' and Wilson's diseases), but it has been also shown to have an important role in neurodegenerative diseases such as Alzheimer disease, prion diseases, Parkinson's disease and amyotrophic lateral sclerosis. It is widely accepted that increased extracellular copper levels contribute to neuronal pathogenic process by increasing the production of dangerous radical oxygen species, but the existence of other molecular mechanisms explaining copper neurotoxicity has not been investigated yet. By using a cellular model based on hypothalamic GN11 cultured neurons exposed to copper supplementation and by analysing the cell conditioned media, we try here to identify new molecular events explaining the association between extracellular copper accumulation and neuronal damages. We show here that increased extracellular copper levels produce a wide complex of alterations in the neuronal extracellular environment. In particular, copper affects the secretion of molecules involved in the protection of neurons against oxidative stress, such as cyclophilin A (CypA), or of molecules capable of shifting neuronal cells towards a pro-inflammatory state, such as IL-1alpha, IL-12, Rantes, neutrophil gelatinase-associated lipocalin (NGAL) and secreted protein acidic and rich in cysteine (SPARC). Copper pro-inflammatory properties have been confirmed by using primary neurons.

  15. Classical and Membrane-Initiated Estrogen Signaling in an In Vitro Model of Anterior Hypothalamic Kisspeptin Neurons

    PubMed Central

    Wong, Angela M.; Kathiresan, Anupama S. Q.; Micevych, Paul E.

    2015-01-01

    The neuropeptide kisspeptin is essential for sexual maturation and reproductive function. In particular, kisspeptin-expressing neurons in the anterior rostral periventricular area of the third ventricle are generally recognized as mediators of estrogen positive feedback for the surge release of LH, which stimulates ovulation. Estradiol induces kisspeptin expression in the neurons of the rostral periventricular area of the third ventricle but suppresses kisspeptin expression in neurons of the arcuate nucleus that regulate estrogen-negative feedback. To focus on the intracellular signaling and response to estradiol underlying positive feedback, we used mHypoA51 cells, an immortalized line of kisspeptin neurons derived from adult female mouse hypothalamus. mHypoA51 neurons express estrogen receptor (ER)-α, classical progesterone receptor (PR), and kisspeptin, all key elements of estrogen-positive feedback. As with kisspeptin neurons in vivo, 17β-estradiol (E2) induced kisspeptin and PR in mHypoA51s. The ERα agonist, 1,3,5-Tris(4-hydroxyphenyl)-4-propyl-1H-pyrazole, produced similar increases in expression, indicating that these events were mediated by ERα. However, E2-induced PR up-regulation required an intracellular ER, whereas kisspeptin expression was stimulated through a membrane ER activated by E2 coupled to BSA. These data suggest that anterior hypothalamic kisspeptin neurons integrate both membrane-initiated and classical nuclear estrogen signaling to up-regulate kisspeptin and PR, which are essential for the LH surge. PMID:25730107

  16. Endoplasmic Reticulum Stress PERK-ATF4-CHOP Pathway Is Associated with Hypothalamic Neuronal Injury in Different Durations of Stress in Rats

    PubMed Central

    Yi, Shanyong; Shi, Weibo; Wang, He; Ma, Chunling; Zhang, Xiaojing; Wang, Songjun; Cong, Bin; Li, Yingmin

    2017-01-01

    The hypothalamus, which is the initial part of the hypothalamic-pituitary-adrenal (HPA) axis, plays a critical role in regulating stress in the central nervous system. The present study aimed to determine whether endoplasmic reticulum stress in hypothalamic neurons is differentially stimulated by varying durations of stress exposure, which ultimately leads to pathological changes in neurons by affecting HPA axis function. There is a need for better morphological evidence of the mechanisms involved in stress-induced neuron injury. A stress model was established in rats by restraining for 8 h and forced ice-water swimming for 5 min each day. The stress-inducing process lasted for 1, 3, 7, 14, and 21 days. Enzyme-linked immunosorbent assay (ELISA) was used to assay serum glucocorticoid levels. Thionine staining was used to observe morphological changes in hypothalamic neurons. Immunohistochemistry and microscopy-based multicolor tissue cytometry (MMTC) was used to detect changes in expression of endoplasmic reticulum stress protein GRP78, ATF4, and CHOP. Serum glucocorticoid levels significantly increased after 3 days of stress exposure and the levels peaked by 7 days. By 21 days, however, the levels were significantly decreased. Thionine staining revealed that prolonged stress exposure resulted in hypothalamic neurons with edema, a lack of Nissl bodies, and pyknotic neurons. Immunohistochemistry and MMTC showed that increasing stress periods significantly decreased GRP78 expression, although ATF4 and CHOP protein expression significantly increased. Stress resulted in pathological changes and significant dynamic changes because of endoplasmic reticulum stress in rat hypothalamic neurons. These results suggested that the endoplasmic reticulum stress PERK-ATF4-CHOP pathway may be associated with hypothalamic neuronal injury. PMID:28392758

  17. A1 receptor mediated adenosinergic regulation of perifornical-lateral hypothalamic area neurons in freely behaving rats

    PubMed Central

    Rai, Seema; Kumar, Sunil; Alam, Md. Aftab; Szymusiak, Ronald; McGinty, Dennis; Alam, Md. Noor

    2010-01-01

    The perifornical-lateral hypothalamic area (PF-LHA) plays a central role in the regulation of behavioral arousal. The PF-LHA contains several neuronal types including wake-active hypocretin (HCRT) neurons that have been implicated in the promotion and/or maintenance of behavioral arousal. Adenosine is an endogenous sleep factor and recent evidence suggests that activation and blockade of adenosine A1 receptors within the PF-LHA promote and suppress sleep, respectively. Although, an in vitro study indicates that adenosine inhibits HCRT neurons via A1 receptor, the in vivo effects of A1 receptor mediated adenosinergic transmission on PF-LHA neurons including HCRT neurons are not known. First, we determined the effects of N6-cyclopentyladenosine (CPA), an adenosine A1 receptor agonist, on the sleep-wake discharge activity of the PF-LHA neurons recorded via microwires placed adjacent to the microdialysis probe used for its delivery. Second, we determined the effects of CPA and that of an A1 receptor antagonist, 1,3-dipropyl-8-phenylxanthine (CPDX) into the PF-LHA on cFos-protein immunoreactivity (Fos-IR) in HCRT and non-HCRT neurons around the microdialysis probe used for their delivery. The effect of CPA was studied in rats that were kept awake during lights-off phase, whereas the effect of CPDX was examined in undisturbed rats during lights-on phase. CPA significantly suppressed the sleep-wake discharge activity of PF-LHA neurons. Doses of CPA (50μM) and CPDX (50μM) that suppressed and induced arousal, respectively, in our earlier study (Alam et al., 2009), significantly suppressed and increased Fos-IR in HCRT and non-HCRT neurons. These findings suggest that wake-promoting PF-LHA system is subject to increased endogenous adenosinergic inhibition and that adenosine acting via A1 receptors, in part, inhibits HCRT neurons to promote sleep. PMID:20109537

  18. Somato-Dendritic Localization and Signaling by Leptin Receptors in Hypothalamic POMC and AgRP Neurons

    PubMed Central

    Ha, Sangdeuk; Baver, Scott; Huo, Lihong; Gata, Adriana; Hairston, Joyce; Huntoon, Nicholas; Li, Wenjing; Zhang, Thompson; Benecchi, Elizabeth J.; Ericsson, Maria; Hentges, Shane T.; Bjørbæk, Christian

    2013-01-01

    Leptin acts via neuronal leptin receptors to control energy balance. Hypothalamic pro-opiomelanocortin (POMC) and agouti-related peptide (AgRP)/Neuropeptide Y (NPY)/GABA neurons produce anorexigenic and orexigenic neuropeptides and neurotransmitters, and express the long signaling form of the leptin receptor (LepRb). Despite progress in the understanding of LepRb signaling and function, the sub-cellular localization of LepRb in target neurons has not been determined, primarily due to lack of sensitive anti-LepRb antibodies. Here we applied light microscopy (LM), confocal-laser scanning microscopy (CLSM), and electron microscopy (EM) to investigate LepRb localization and signaling in mice expressing a HA-tagged LepRb selectively in POMC or AgRP/NPY/GABA neurons. We report that LepRb receptors exhibit a somato-dendritic expression pattern. We further show that LepRb activates STAT3 phosphorylation in neuronal fibers within several hypothalamic and hindbrain nuclei of wild-type mice and rats, and specifically in dendrites of arcuate POMC and AgRP/NPY/GABA neurons of Leprb+/+ mice and in Leprbdb/db mice expressing HA-LepRb in a neuron specific manner. We did not find evidence of LepRb localization or STAT3-signaling in axon-fibers or nerve-terminals of POMC and AgRP/NPY/GABA neurons. Three-dimensional serial EM-reconstruction of dendritic segments from POMC and AgRP/NPY/GABA neurons indicates a high density of shaft synapses. In addition, we found that the leptin activates STAT3 signaling in proximity to synapses on POMC and AgRP/NPY/GABA dendritic shafts. Taken together, these data suggest that the signaling-form of the leptin receptor exhibits a somato-dendritic expression pattern in POMC and AgRP/NPY/GABA neurons. Dendritic LepRb signaling may therefore play an important role in leptin’s central effects on energy balance, possibly through modulation of synaptic activity via post-synaptic mechanisms. PMID:24204898

  19. Hypothalamic Orexin-A Neurons Are Involved in the Response of the Brain Stress System to Morphine Withdrawal

    PubMed Central

    Laorden, M. Luisa; Ferenczi, Szilamér; Pintér-Kübler, Bernadett; González-Martín, Laura L.; Lasheras, M. Carmen; Kovács, Krisztina J.; Milanés, M. Victoria; Núñez, Cristina

    2012-01-01

    Both the hypothalamus-pituitary-adrenal (HPA) axis and the extrahypothalamic brain stress system are key elements of the neural circuitry that regulates the negative states during abstinence from chronic drug exposure. Orexins have recently been hypothesized to modulate the extended amygdala and to contribute to the negative emotional state associated with dependence. This study examined the impact of chronic morphine and withdrawal on the lateral hypothalamic (LH) orexin A (OXA) gene expression and activity as well as OXA involvement in the brain stress response to morphine abstinence. Male Wistar rats received chronic morphine followed by naloxone to precipitate withdrawal. The selective OX1R antagonist SB334867 was used to examine whether orexins' activity is related to somatic symptoms of opiate withdrawal and alterations in HPA axis and extended amygdala in rats dependent on morphine. OXA mRNA was induced in the hypothalamus during morphine withdrawal, which was accompanied by activation of OXA neurons in the LH. Importantly, SB334867 attenuated the somatic symptoms of withdrawal, and reduced morphine withdrawal-induced c-Fos expression in the nucleus accumbens (NAc) shell, bed nucleus of stria terminalis, central amygdala and hypothalamic paraventricular nucleus, but did not modify the HPA axis activity. These results highlight a critical role of OXA signalling, via OX1R, in activation of brain stress system to morphine withdrawal and suggest that all orexinergic subpopulations in the lateral hypothalamic area contribute in this response. PMID:22590628

  20. Sex differences in the responses of orexin neurons in the lateral hypothalamic area and feeding behavior to fasting.

    PubMed

    Funabashi, Toshiya; Hagiwara, Hiroko; Mogi, Kazutaka; Mitsushima, Dai; Shinohara, Kazuyuki; Kimura, Fukuko

    2009-09-29

    Because there are sex differences in feeding-related behavior and orexin neurons are involved in feeding, we looked for a possible sex difference in the response of orexin neurons in the lateral hypothalamic area to fasting, using the phosphorylated cyclic AMP response element-binding protein (pCREB) as a marker of neural activity. Intact male and female rats at proestrus, estrus, or diestrus, were fed normally or fasted for 48h. After fasting, they were intravenously injected with saline or glucose and subjected to immunohistochemical processing for the detection of orexin and pCREB. In the rats fed normally and injected with saline, only a small population of orexin neurons expressed pCREB in both male and female rats. However, fasting increased the number of orexin neurons with pCREB (double-stained cells) in female rats regardless of the estrous day but not in male rats, revealing a significant sex difference in the response of orexin neurons to fasting. Glucose injection in fasted rats decreased the number of double-stained cells in female rats, and the magnitude of glucose-dependent decrease was greater at proestrus and estrus than at diestrus 2. We also found that female rats, but not male rats, showed an increase in total food intake after fasting (rebound feeding). We speculate that the demonstrated sex differences in the response of orexin neurons to fasting reflect the vulnerability of feeding mechanisms in females.

  1. Enhanced astroglial GABA uptake attenuates tonic GABAA inhibition of the presympathetic hypothalamic paraventricular nucleus neurons in heart failure.

    PubMed

    Pandit, Sudip; Jo, Ji Yoon; Lee, Sang Ung; Lee, Young Jae; Lee, So Yeong; Ryu, Pan Dong; Lee, Jung Un; Kim, Hyun-Woo; Jeon, Byeong Hwa; Park, Jin Bong

    2015-08-01

    γ-Aminobutyric acid (GABA) generates persistent tonic inhibitory currents (Itonic) and conventional inhibitory postsynaptic currents in the hypothalamic paraventricular nucleus (PVN) via activation of GABAA receptors (GABAARs). We investigated the pathophysiological significance of astroglial GABA uptake in the regulation of Itonic in the PVN neurons projecting to the rostral ventrolateral medulla (PVN-RVLM). The Itonic of PVN-RVLM neurons were significantly reduced in heart failure (HF) compared with sham-operated (SHAM) rats. Reduced Itonic sensitivity to THIP argued for the decreased function of GABAAR δ subunits in HF, whereas similar Itonic sensitivity to benzodiazepines argued against the difference of γ2 subunit-containing GABAARs in SHAM and HF rats. HF Itonic attenuation was reversed by a nonselective GABA transporter (GAT) blocker (nipecotic acid, NPA) and a GAT-3 selective blocker, but not by a GAT-1 blocker, suggesting that astroglial GABA clearance increased in HF. Similar and minimal Itonic responses to bestrophin-1 blockade in SHAM and HF neurons further argued against a role for astroglial GABA release in HF Itonic attenuation. Finally, the NPA-induced inhibition of spontaneous firing was greater in HF than in SHAM PVN-RVLM neurons, whereas diazepam induced less inhibition of spontaneous firing in HF than in SHAM neurons. Overall, our results showed that combined with reduced GABAARs function, the enhanced astroglial GABA uptake-induced attenuation of Itonic in HF PVN-RVLM neurons explains the deficit in tonic GABAergic inhibition and increased sympathetic outflow from the PVN during heart failure.

  2. Prenatal fat exposure and hypothalamic PPAR β/δ: Possible relationship to increased neurogenesis of orexigenic peptide neurons.

    PubMed

    Chang, G-Q; Karatayev, O; Lukatskaya, O; Leibowitz, S F

    2016-05-01

    Gestational exposure to a fat-rich diet, while elevating maternal circulating fatty acids, increases in the offspring's hypothalamus and amygdala the proliferation and density of neurons that express neuropeptides known to stimulate consummatory behavior. To understand the relationship between these phenomena, this study examined in the brain of postnatal offspring (day 15) the effect of prenatal fat exposure on the transcription factor, peroxisome proliferator-activated receptor (PPAR) β/δ, which is sensitive to fatty acids, and the relationship of PPAR β/δ to the orexigenic neuropeptides, orexin, melanin-concentrating hormone, and enkephalin. Prenatal exposure to a fat-rich diet compared to low-fat chow increased the density of cells immunoreactive for PPAR β/δ in the hypothalamic paraventricular nucleus (PVN), perifornical lateral hypothalamus (PFLH), and central nucleus of the amygdala (CeA), but not the hypothalamic arcuate nucleus or basolateral amygdaloid nucleus. It also increased co-labeling of PPAR β/δ with the cell proliferation marker, BrdU, or neuronal marker, NeuN, and the triple labeling of PPAR β/δ with BrdU plus NeuN, indicating an increase in proliferation and density of new PPAR β/δ neurons. Prenatal fat exposure stimulated the double-labeling of PPAR β/δ with orexin or melanin-concentrating hormone in the PFLH and enkephalin in the PVN and CeA and also triple-labeling of PPAR β/δ with BrdU and these neuropeptides, indicating that dietary fat increases the genesis of PPAR β/δ neurons that produce these peptides. These findings demonstrate a close anatomical relationship between PPAR β/δ and the increased proliferation and density of peptide-expressing neurons in the hypothalamus and amygdala of fat-exposed offspring.

  3. A novel floor plate boundary defined by adjacent En1 and Dbx1 microdomains distinguishes midbrain dopamine and hypothalamic neurons.

    PubMed

    Nouri, Navid; Awatramani, Rajeshwar

    2017-03-01

    The mesodiencephalic floor plate (mdFP) is the source of diverse neuron types. Yet, how this structure is compartmentalized has not been clearly elucidated. Here, we identify a novel boundary subdividing the mdFP into two microdomains, defined by engrailed 1 (En1) and developing brain homeobox 1 (Dbx1). Utilizing simultaneous dual and intersectional fate mapping, we demonstrate that this boundary is precisely formed with minimal overlap between En1 and Dbx1 microdomains, unlike many other boundaries. We show that the En1 microdomain gives rise to dopaminergic (DA) neurons, whereas the Dbx1 microdomain gives rise to subthalamic (STN), premammillary (PM) and posterior hypothalamic (PH) populations. To determine whether En1 is sufficient to induce DA neuron production beyond its normal limit, we generated a mouse strain that expresses En1 in the Dbx1 microdomain. In mutants, we observed ectopic production of DA neurons derived from the Dbx1 microdomain, at the expense of STN and PM populations. Our findings provide new insights into subdivisions in the mdFP, and will impact current strategies for the conversion of stem cells into DA neurons.

  4. Nesfatin-1 influences the excitability of gastric distension-responsive neurons in the ventromedial hypothalamic nucleus of rats.

    PubMed

    Feng, Hongzhen; Wang, Qiaoling; Guo, Feifei; Han, Xiaohua; Pang, Mingjie; Sun, Xiangrong; Gong, Yanling; Xu, Luo

    2017-05-04

    The present study investigated the effects of nesfatin-1 on gastric distension (GD)-responsive neurons via an interaction with corticotropin-releasing factor (CRF) receptor signaling in the ventromedial hypothalamic nucleus (VMH), and the potential regulation of these effects by hippocampal projections to VMH. Extracellular single-unit discharges were recorded in VHM following administration of nesfatin-1. The projection of nerve fibers and expression of nesfatin-1 were assessed by retrograde tracing and fluoro-immunohistochemical staining, respectively. Results showed that there were GD-responsive neurons in VMH; Nesfatin-1 administration and electrical stimulation of hippocampal CA1 sub-region altered the firing rate of these neurons. These changes could be partially blocked by pretreatment with the non-selective CRF antagonist astressin-B or an antibody to NUCB2/nesfatin-1. Electrolytic lesion of CA1 hippocampus reduced the effects of nesfatin-1 on VMH GD-responsive neuronal activity. These studies suggest that nesfatin-1 plays an important role in GD-responsive neuronal activity through interactions with CRF signaling pathways in VMH. The hippocampus may participate in the modulation of nesfatin-1-mediated effects in VMH.

  5. Reciprocal connections between CART-immunoreactive, hypothalamic paraventricular neurons and serotonergic dorsal raphe cells in the rat: Light microscopic study.

    PubMed

    Lee, Ji S; Lee, Hyun S

    2014-04-29

    Based on the overlapping physiological roles of cocaine- and amphetamine-regulated transcript (CART) peptides and serotonin, the present study examined the anatomical connection between the hypothalamic paraventricular nucleus (PVN) and the dorsal raphe (DR). The first series of experiments were performed to investigate descending projections from the CART-immunoreactive (CART-ir) PVN to serotonergic DR cells. CART-ir varicosities made contact with serotonergic DR neurons. An anterograde tracing study revealed that varicosities originating from the PVN formed close appositions to serotonergic neuronal profiles along the entire rostro-caudal extent of the DR. A retrograde study demonstrated that CART neurons projecting to the DR were mainly localized in the caudal parvicellular PVN, comprising approximately 3.0%±0.4% (n=8) of total CART cells. A second series of experiments was performed to investigate ascending projections from the DR to CART-ir PVN cells. Serotonin transporter-ir boutons made contact with CART-ir PVN neurons. Anterograde tracing revealed that varicosities originating from the DR formed close appositions to CART-ir PVN cells. Retrograde examination demonstrated that serotonergic neurons projecting to the parvicellular PVN were located along the entire rostro-caudal extent of the DR. The present observation provided an anatomical basis for accumulating evidence in the literature that suggests a functional interaction between the CART and serotonin systems during the regulation of energy balance, emotional behavior, and arousal. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. NEURONAL ACTIVITY AND STRESS DIFFERENTIALLY REGULATE HIPPOCAMPAL AND HYPOTHALAMIC CORTICOTROPIN-RELEASING HORMONE EXPRESSION IN THE IMMATURE RAT

    PubMed Central

    HATALSKI, C. G.; BRUNSON, K. L.; TANTAYANUBUTR, B.; CHEN, Y.; BARAM, T. Z.

    2011-01-01

    Corticotropin-releasing hormone, a major neuromodulator of the neuroendocrine stress response, is expressed in the immature hippocampus, where it enhances glutamate receptor-mediated excitation of principal cells. Since the peptide influences hippocampal synaptic efficacy, its secretion from peptidergic interneuronal terminals may augment hippocampal-mediated functions such as learning and memory. However, whereas information regarding the regulation of corticotropin-releasing hormone’s abundance in CNS regions involved with the neuroendocrine responses to stress has been forthcoming, the mechanisms regulating the peptide’s levels in the hippocampus have not yet been determined. Here we tested the hypothesis that, in the immature rat hippocampus, neuronal stimulation, rather than neuroendocrine challenge, influences the peptide’s expression. Messenger RNA levels of corticotropin-releasing hormone in hippocampal CA1, CA3 and the dentate gyrus, as well as in the hypothalamic paraventricular nucleus, were determined after cold, a physiological challenge that activates the hypothalamic pituitary adrenal system in immature rats, and after activation of hippocampal neurons by hyperthermia. These studies demonstrated that, while cold challenge enhanced corticotropin-releasing hormone messenger RNA levels in the hypothalamus, hippocampal expression of this neuropeptide was unchanged. Secondly, hyperthermia stimulated expression of hippocampal immediate-early genes, as well as of corticotropin-releasing hormone. Finally, the mechanism of hippocampal corticotropin-releasing hormone induction required neuronal stimulation and was abolished by barbiturate administration. Taken together, these results indicate that neuronal stimulation may regulate hippocampal corticotropin-releasing hormone expression in the immature rat, whereas the peptide’s expression in the hypothalamus is influenced by neuroendocrine challenges. PMID:11113306

  7. Imbalanced K+ and Ca2+ subthreshold interactions contribute to increased hypothalamic presympathetic neuronal excitability in hypertensive rats

    PubMed Central

    Sonner, P M; Lee, S; Ryu, P D; Lee, S Y; Stern, J E

    2011-01-01

    We investigated here whether an opposing interplay between the subthreshold currents A-type potassium (IA) and T-type calcium (IT) influences membrane excitability in presympathetic neurones of the hypothalamic paraventricular nucleus (PVN) that innervate the rostral ventrolateral medulla (RVLM). Moreover, we assessed whether a shift in the balance between these two subthreshold currents contributed to increased neuronal activity in hypertension. To this end, we obtained simultaneous electrophysiological recordings, confocal Ca2+ imaging, and single-cell RT-PCR samples from identified PVN-RVLM neurones in sham and renovascular hypertensive rats. Our results indicate that IA and IT, displaying overlapping voltage-dependent and kinetic properties, are present in PVN-RVLM neurones. We found that the relative predominance of each current at hyperpolarized membrane potentials dictates whether PVN-RVLN neurones express a low-threshold spike (LTS) or a transient outward rectification (TOR). Moreover, we report the IA/IT balance to be correlated with the relative expression of Kv4.3 and Cav3.1 subunit mRNA within individual neurones. Pharmacological blockade of IA resulted in an enhanced IT-mediated LTS, as well as LTS-mediated somatodendritic Ca2+ transients. In hypertensive rats, we found a shift in the IT/IA balance, towards an IT predominance, due in part to a diminished Kv4.3 and enhanced Cav3.1 mRNA subunits expression. The imbalanced IT/IA relationship resulted in enhanced LTS, LTS-mediated somatodendritic Ca2+ transients, and increased firing activity in hypertensive rats. Taken together, our results support that a balanced IT/IA interaction influences membrane excitability and Ca2+ dynamics in PVN-RVLM neurones. Moreover, an imbalanced relationship favouring IT results in enhanced neuronal excitability and firing discharge in hypertensive rats, constituting thus a likely mechanism contributing to the characteristic sympathoexcitation observed in this disease. PMID

  8. Regulation of Energy Balance via BDNF Expressed in Nonparaventricular Hypothalamic Neurons.

    PubMed

    Yang, Haili; An, Juan Ji; Sun, Chao; Xu, Baoji

    2016-05-01

    Brain-derived neurotrophic factor (BDNF) expressed in the paraventricular hypothalamus (PVH) has been shown to play a key role in regulating energy intake and energy expenditure. BDNF is also expressed in other hypothalamic nuclei; however, the role in the control of energy balance for BDNF produced in these structures remains largely unknown. We found that deleting the Bdnf gene in the ventromedial hypothalamus (VMH) during embryogenesis using the Sf1-Cre transgene had no effect on body weight in mice. In contrast, deleting the Bdnf gene in the adult VMH using Cre-expressing virus led to significant hyperphagia and obesity. These observations indicate that the lack of a hyperphagia phenotype in the Sf1-Cre/Bdnf mutant mice is likely due to developmental compensation. To investigate the role of BDNF expressed in other hypothalamic areas, we employed the hypothalamus-specific Nkx2.1-Cre transgene to delete the Bdnf gene. We found that the Nkx2.1-Cre transgene could abolish BDNF expression in many hypothalamic nuclei, but not in the PVH, and that the resulting mutant mice developed modest obesity due to reduced energy expenditure. Thus, BDNF produced in the VMH plays a role in regulating energy intake. Furthermore, BDNF expressed in hypothalamic areas other than PVH and VMH is also involved in the control of energy expenditure.

  9. Chronic activation of hypothalamic oxytocin neurons improves cardiac function during left ventricular hypertrophy-induced heart failure.

    PubMed

    Garrott, Kara; Dyavanapalli, Jhansi; Cauley, Edmund; Dwyer, Mary Kate; Kuzmiak-Glancy, Sarah; Wang, Xin; Mendelowitz, David; Kay, Matthew W

    2017-09-01

    A distinctive hallmark of heart failure (HF) is autonomic imbalance, consisting of increased sympathetic activity, and decreased parasympathetic tone. Recent work suggests that activation of hypothalamic oxytocin (OXT) neurons could improve autonomic balance during HF. We hypothesized that a novel method of chronic selective activation of hypothalamic OXT neurons will improve cardiac function and reduce inflammation and fibrosis in a rat model of HF. Two groups of male Sprague-Dawley rats underwent trans-ascending aortic constriction (TAC) to induce left ventricular (LV) hypertrophy that progresses to HF. In one TAC group, OXT neurons in the paraventricular nucleus of the hypothalamus were chronically activated by selective expression and activation of excitatory DREADDs receptors with daily injections of clozapine N-oxide (CNO) (TAC + OXT). Two additional age-matched groups received either saline injections (Control) or CNO injections for excitatory DREADDs activation (OXT NORM). Heart rate (HR), LV developed pressure (LVDP), and coronary flow rate were measured in isolated heart experiments. Isoproterenol (0.01 nM-1.0 µM) was administered to evaluate β-adrenergic sensitivity. We found that increases in cellular hypertrophy and myocardial collagen density in TAC were blunted in TAC + OXT animals. Inflammatory cytokine IL-1β expression was more than twice higher in TAC than all other hearts. LVDP, rate pressure product (RPP), contractility, and relaxation were depressed in TAC compared with all other groups. The response of TAC and TAC + OXT hearts to isoproterenol was blunted, with no significant increase in RPP, contractility, or relaxation. However, HR in TAC + OXT animals increased to match Control at higher doses of isoproterenol. Activation of hypothalamic OXT neurons to elevate parasympathetic tone reduced cellular hypertrophy, levels of IL-1β, and fibrosis during TAC-induced HF in rats. Cardiac contractility parameters were

  10. Simulated GABA synaptic input and L-type calcium channels form functional microdomains in hypothalamic gonadotropin-releasing hormone neurons.

    PubMed

    Hemond, Peter J; O'Boyle, Michael P; Roberts, Carson B; Delgado-Reyes, Alfonso; Hemond, Zoe; Suter, Kelly J

    2012-06-27

    Hypothalamic gonadotropin-releasing hormone (GnRH) neurons integrate the multiple internal and external cues that regulate sexual reproduction. In contrast to other neurons that exhibit extensive dendritic arbors, GnRH neurons usually have a single dendrite with relatively little branching. This largely precludes the integration strategy in which a single dendritic branch serves as a unit of integration. In the present study, we identify a gradient in L-type calcium channels in dendrites of mouse GnRH neurons and its interaction with GABAergic and glutamatergic inputs. Higher levels of L-type calcium channels are in somata/proximal dendrites (i.e., 0-26 μm) and distal dendrites (∼130 μm dendrite length), but intervening midlengths of dendrite (∼27-130 μm) have reduced L-type calcium channels. Using uncaging of GABA, there is a decreasing GABAergic influence along the dendrite and the impact of GABA(A) receptors is dependent on activation of L-type calcium channels. This results in amplification of proximal GABAergic signals and attenuation of distal dendritic signals. Most interestingly, the intervening dendritic regions create a filter through which only relatively high-amplitude, low-frequency GABAergic signaling to dendrites elicits action potentials. The findings of the present study suggest that GnRH dendrites adopt an integration strategy whereby segments of single nonbranching GnRH dendrites create functional microdomains and thus serve as units of integration.

  11. The effect of moxonidine on feeding and body fat in obese Zucker rats: role of hypothalamic NPY neurones

    PubMed Central

    Bing, Chen; King, Peter; Pickavance, Lucy; Brown, Michael; Ziegler, Dieter; Kaan, Elbert; Williams, Gareth

    1999-01-01

    The antihypertensive agent moxonidine, an imidazoline Ii-receptor agonist, also induces hypophagia and lowers body weight in the obese spontaneously hypertensive rat, but the central mediation of this action and the neuronal pathways that moxonidine may interact with are not known. We studied whether moxonidine has anti-obesity effects in the genetically-obese and insulin-resistant fa/fa Zucker rat, and whether these are mediated through inhibition of the hypothalamic neuropeptide Y (NPY) neurones.Lean and obese Zucker rats were given moxonidine (3 mg kg−1 day−1) or saline by gavage for 21 days.Moxonidine decreased food intake throughout by 20% in obese rats (P<0.001) and by 8% in lean rats (P<0.001), and reduced weight gain that final body weight was 15% lower in obese (P<0.001) and 7% lower in lean (P<0.01) rats than their untreated controls. Plasma insulin and leptin levels were decreased in moxonidine-treated obese rats (P<0.01 and P<0.05), but unchanged in treated lean rats. Uncoupling protein-1 gene expression in brown adipose tissue was stimulated by 40–50% (P⩽0.05) in both obese and lean animals given moxonidine. Obese animals given moxonidine showed a 37% reduction in hypothalamic NPY mRNA levels (P=0.01), together with significantly increased NPY concentrations in the paraventricular nucleus (P<0.05), but no changes in the arcuate nucleus or other nuclei; this is consistent with reduced NPY synthesis in the arcuate nucleus and blocked release of NPY in the paraventricular nucleus. In lean animals, moxonidine did not affect NPY levels or NPY mRNA.The hypophagic, thermogenic and anti-obesity effects of moxonidine in obese Zucker rats may be partly due to inhibition of the NPY neurones, whose inappropriate overactivity may underlie obesity in this model. PMID:10369453

  12. Lack of effect of potassium channel openers on ATP-modulated potassium channels recorded from rat ventromedial hypothalamic neurones.

    PubMed Central

    Sellers, A. J.; Boden, P. R.; Ashford, M. L.

    1992-01-01

    1. Single neuronal cells were freshly isolated from the ventromedial hypothalamic nuclei (VMHN) of the rat brain. Currents through ATP-modulated and large conductance (160 and 250 pS) calcium-activated potassium channels were recorded by the cell-attached and excised inside-out patch techniques. 2. BRL38227 (lemakalim; 30-90 microM) applied to the superfusing medium produced no change in firing rate of isolated glucose-receptive VMHN neurones in cell-attached recordings. 3. BRL38227, at concentrations of between 30-100 microM applied to the intracellular (cytoplasmic) aspect of inside-out patches, had no effect on the activity of ATP-sensitive K+ channels in the absence of ATP or in the presence of a sub-maximal inhibitory concentration (3 mM) of ATP. Cromakalim, pinacidil, minoxidil sulphate and diazoxide also produced no effect under these conditions. 4. The potassium channel openers (KCO's) were tested on ATP-activated potassium channels recorded from a further subpopulation of VMHN neurones. Application of BRL38227 (up to and including 100 microM) to this channel in inside-out patches either in the absence of ATP or when activated by 5 mM ATP had no effect on channel activity. Identical results were obtained with cromakalim and pinacidil. 5. BRL38227 had no effect on either of the large conductance (250 pS and 160 pS) calcium-activated potassium channels in VMHN neurones. 6. Intracellular recordings were made from glucose-receptive VMHN neurones in rat brain slices. Cromakalim (50 microM) or diazoxide (60 microM) did not alter the firing rate or passive membrane properties of these neurones demonstrated to be sensitive to tolbutamide (0.1 mM).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1467829

  13. Rbpj-κ mediated Notch signaling plays a critical role in development of hypothalamic Kisspeptin neurons

    PubMed Central

    Biehl, Matthew J; Raetzman, Lori T

    2015-01-01

    The mammalian arcuate nucleus (ARC) houses neurons critical for energy homeostasis and sexual maturation. Proopiomelanocortin (POMC) and Neuropeptide Y (NPY) neurons function to balance energy intake and Kisspeptin neurons are critical for the onset of puberty and reproductive function. While the physiological roles of these neurons have been well established, their development remains unclear. We have previously shown that Notch signaling plays an important role in cell fate within the ARC of mice. Active Notch signaling prevented neural progenitors from differentiating into feeding circuit neurons, whereas conditional loss of Notch signaling lead to a premature differentiation of these neurons. Presently, we hypothesized that Kisspeptin neurons would similarly be affected by Notch manipulation. To address this, we utilized mice with a conditional deletion of the Notch signaling co-factor Rbpj-κ (Rbpj cKO), or mice persistently expressing the Notch1 intracellular domain (NICD tg) within Nkx2.1 expressing cells of the developing hypothalamus. Interestingly, we found that in both models, a lack of Kisspeptin neurons are observed. This suggests that Notch signaling must be properly titrated for formation of Kisspeptin neurons. These results led us to hypothesize that Kisspeptin neurons of the ARC may arise from a different lineage of intermediate progenitors than NPY neurons and that Notch was responsible for the fate choice between these neurons. To determine if Kisspeptin neurons of the ARC differentiate similarly through a Pomc intermediate, we utilized a genetic model expressing the tdTomato fluorescent protein in all cells that have ever expressed Pomc. We observed some Kisspeptin expressing neurons labeled with the Pomc reporter similar to NPY neurons, suggesting that these distinct neurons can arise from a common progenitor. Finally, we hypothesized that temporal differences leading to premature depletion of progenitors in cKO mice lead to our observed

  14. Stimulation of the Hypothalamic Paraventricular Nucleus Modulates Cardiorespiratory Responses via Oxytocinergic Innervation of Neurons in Pre-Bötzinger Complex

    PubMed Central

    Mack, S.O.; Wu, M.; Kc, P.; Haxhiu, M.A.

    2007-01-01

    Previously we reported that oxytocin (OT)-containing neurons of the hypothalamic paraventricular nucleus (PVN) project to the preBötzinger complex (preBötC) region and phrenic motoneurons innervating the diaphragm (D). The aim of these studies was to determine pathways involved in PVN stimulation-induced changes in upper airway and chest wall pumping muscle activity. In addition, we determined the role of OT-containing neurons in the PVN in mediating increased respiratory output elicited by PVN stimulation. Neuroanatomical experiments, using pseudorabies virus (PRV) as a transneuronal tracer in C8 spinalectomized animals showed that PVN neurons project to hypoglossal motoneurons innervating the genioglossus (GG) muscle. Furthermore, microinjection of the PVN with bicuculline, a GABAA receptor antagonist, significantly increased (P<0.05) peak electromyographic activity of GG (GGEMG) and of DEMG, frequency discharge, and arterial blood pressure (BP) and heart rate. Prior injection of oxytocin antagonist [d-(CH2)5, Tyr(Me)2,Orn8]-vasotocin(OVT) intracisternally or blockade of oxytocin receptors in the preBötC region with oxytocin antagonist L-368,899, diminished GGEMG and DEMG responses and blunted the increase in BP and heart rate to PVN stimulation. These data show that PVN stimulation affects central regulatory mechanisms via the preBötC region controlling both respiratory and cardiovascular functions. The parallel changes induced by PVN stimulation were mediated mainly through an OT-OT receptor signaling pathway. PMID:16857863

  15. High fat diet induces specific pathological changes in hypothalamic orexin neurons in mice.

    PubMed

    Nobunaga, Mizuki; Obukuro, Kanae; Kurauchi, Yuki; Hisatsune, Akinori; Seki, Takahiro; Tsutsui, Masato; Katsuki, Hiroshi

    2014-12-01

    Loss of orexin neurons in the hypothalamus is a prominent feature of narcolepsy and several other neurological conditions. We have recently demonstrated that sleep deprivation stimulates local nitric oxide (NO) production by neuronal NO synthase in the lateral hypothalamus, which leads to selective degeneration of orexin neurons accompanied by formation of orexin-immunoreactive aggregates. Here we analyzed whether lifestyle-related conditions other than sleep deprivation could trigger similar pathological changes in orexin neurons. Four-week-old male C57BL/6 mice were fed with high fat diet (HFD) for 8 weeks. Immunohistochemical analysis revealed that the number of orexin-immunopositive neurons was significantly decreased by HFD intake, whereas the number of melanin-concentrating hormone-immunopositive neurons was unchanged. In addition, HFD promoted formation of intracellular orexin-immunoreactive aggregates in a subset of orexin neurons. We also confirmed that expression of inducible NO synthase (iNOS) in the hypothalamus was upregulated in response to HFD intake. Notably, loss of orexin-immunopositive neurons and formation of orexin-immunoreactive aggregates were not observed in iNOS knockout mice fed with HFD. These results indicate that inappropriate dietary conditions could trigger specific neuropathological events in orexin neurons in an iNOS-dependent manner. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Altered neuronal responses to feeding-relevant peptides as sign of developmental plasticity in the hypothalamic regulatory system of body weight.

    PubMed

    Davidowa, Helga; Li, Yuzhen; Plagemann, Andreas

    2003-01-01

    Neuronal plasticity during the critical postnatal period of development seems to promote a change in the function of the hypothalamic regulatory system of body weight. Rats raised in small litters (SL) of only three pups per mother compared to ten or twelve in control litters (CL) gain significantly more weight than normal rats till weaning and are overweight also in later life. These rats are known to express hyperleptinemia, hyperglycemia and hyperinsulinemia. The review summarizes the results of action of leptin and insulin as well as of several feeding-relevant neuropeptides on neuronal activity of hypothalamic regulatory centres in overweight SL rats compared to controls. The study was performed on brain slices perfused with solution containing 10 mM glucose. Whereas a normally inhibitory action of leptin and insulin on medial arcuate neurons (ArcM) is reduced in SL rats and partly replaced by activation, the normally activating effect of these hormones on ventromedial (VMH) neurons is altered to predominant inhibition. Inhibition of ArcM neurons may decrease the release of the orexigenic neuropeptide Y (NPY) and agouti gene-related protein (AGRP). Thus, the negative feedback by leptin and insulin on food intake is replaced by diminished response and partly positive feedback processes in SL rats. The action of NPY and AGRP as well as of the orexigenic melanin-concentrating hormone on paraventricular (PVH) and VMH neurons is also shaped from activation or bimodal effects to predominant inhibition. Such inhibition of PVH and VMH might lead to reduced energy expenditure in small litter rats. Also the anorexigenic melanocortin alpha-MSH seems to contribute into increased energy storage. These altered responses of hypothalamic neurons in overweight small litter rats might reflect a general mechanism of neurochemical plasticity and "malprogramming" of hypothalamic neuropeptidergic systems leading to a permanently altered regulatory function.

  17. Over-Expression of Leptin Receptors in Hypothalamic POMC Neurons Increases Susceptibility to Diet-Induced Obesity

    PubMed Central

    Gamber, Kevin M.; Huo, Lihong; Ha, Sangdeuk; Hairston, Joyce E.; Greeley, Sarah; Bjørbæk, Christian

    2012-01-01

    Diet-induced obesity (DIO) in rodents is characterized by impaired activation of signal-transducer and activator of transcription 3 (STAT3) by leptin receptors (LepRb) within the hypothalamic arcuate nucleus. This signaling defect likely plays an important role in development of DIO. However, the neuro-chemical identity of the leptin-STAT3 resistant arcuate neurons has not been determined and the underlying mechanisms responsible for development of cellular leptin resistance remain unclear. To investigate this, we first measured arcuate gene expression of known key signaling components of the LepRb signaling pathway and tested whether specifically the critical arcuate pro-opiomelanocortin (POMC) neurons are resistant to LepRb-STAT3 signaling in mice given a high-fat-diet (HFD) compared to mice provided a low-fat control diet (LFD). We found that leptin-dependent STAT3 phosphorylation was decreased within POMC neurons of HFD mice. In addition, Leprb mRNA and suppressor of cytokine signaling 3 (Socs3) mRNA were elevated in the arcuate of HFD mice. To investigate whether increased LepRb expression per se in POMC neurons can influence development of DIO and Socs3 expression, we created mice that over-express LepRb selectively in POMC neurons (POMC-LepRb). No differences in body weight, fat mass or food intake were found between LFD POMC-LepRb mice and LFD controls. Surprisingly, body weight, fat mass and caloric intake of HFD POMC-LepRb mice was markedly higher than HFD control mice. In addition, arcuate Socs3 mRNA was increased in HFD POMC-LepRb mice compared to HFD controls. These data show that specifically POMC neurons of DIO mice are resistant to STAT3 activation by leptin, indicating that those cells might play a role in development of DIO. Furthermore, over-expression of LepRb selectively in POMC neurons increases susceptibility to the development of DIO. We propose a model where over-reactivity of the leptin-LepRb signaling system in arcuate neurons may play

  18. Non-Neuronal Cells in the Hypothalamic Adaptation to Metabolic Signals.

    PubMed

    Freire-Regatillo, Alejandra; Argente-Arizón, Pilar; Argente, Jesús; García-Segura, Luis Miguel; Chowen, Julie A

    2017-01-01

    Although the brain is composed of numerous cell types, neurons have received the vast majority of attention in the attempt to understand how this organ functions. Neurons are indeed fundamental but, in order for them to function correctly, they rely on the surrounding "non-neuronal" cells. These different cell types, which include glia, epithelial cells, pericytes, and endothelia, supply essential substances to neurons, in addition to protecting them from dangerous substances and situations. Moreover, it is now clear that non-neuronal cells can also actively participate in determining neuronal signaling outcomes. Due to the increasing problem of obesity in industrialized countries, investigation of the central control of energy balance has greatly increased in attempts to identify new therapeutic targets. This has led to interesting advances in our understanding of how appetite and systemic metabolism are modulated by non-neuronal cells. For example, not only are nutrients and hormones transported into the brain by non-neuronal cells, but these cells can also metabolize these metabolic factors, thus modifying the signals reaching the neurons. The hypothalamus is the main integrating center of incoming metabolic and hormonal signals and interprets this information in order to control appetite and systemic metabolism. Hence, the factors transported and released from surrounding non-neuronal cells will undoubtedly influence metabolic homeostasis. This review focuses on what is known to date regarding the involvement of different cell types in the transport and metabolism of nutrients and hormones in the hypothalamus. The possible involvement of non-neuronal cells, in particular glial cells, in physiopathological outcomes of poor dietary habits and excess weight gain are also discussed.

  19. Transgenic Mice Overexpressing Amyloid Precursor Protein Exhibit Early Metabolic Deficits and a Pathologically Low Leptin State Associated with Hypothalamic Dysfunction in Arcuate Neuropeptide Y Neurons

    PubMed Central

    Ishii, Makoto; Wang, Gang; Racchumi, Gianfranco; Dyke, Jonathan P.

    2014-01-01

    Weight loss is a prominent early feature of Alzheimer's disease (AD) that often precedes the cognitive decline and clinical diagnosis. While the exact pathogenesis of AD remains unclear, accumulation of amyloid-β (Aβ) derived from the amyloid precursor protein (APP) in the brain is thought to lead to the neuronal dysfunction and death underlying the dementia. In this study, we examined whether transgenic mice overexpressing the Swedish mutation of APP (Tg2576), recapitulating selected features of AD, have hypothalamic leptin signaling dysfunction leading to early body weight deficits. We found that 3-month-old Tg2576 mice, before amyloid plaque formation, exhibit decreased weight with markedly decreased adiposity, low plasma leptin levels, and increased energy expenditure without alterations in feeding behavior. The expression of the orexigenic neuropeptide Y (NPY) in the hypothalamus to the low leptin state was abnormal at basal and fasting conditions. In addition, arcuate NPY neurons exhibited abnormal electrophysiological responses to leptin in Tg2576 hypothalamic slices or wild-type slices treated with Aβ. Finally, the metabolic deficits worsened as Tg2576 mice aged and amyloid burden increased in the brain. These results indicate that excess Aβ can potentially disrupt hypothalamic arcuate NPY neurons leading to weight loss and a pathologically low leptin state early in the disease process that progressively worsens as the amyloid burden increases. Collectively, these findings suggest that weight loss is an intrinsic pathological feature of Aβ accumulation and identify hypothalamic leptin signaling as a previously unrecognized pathogenic site of action for Aβ. PMID:24990930

  20. Non-Neuronal Cells in the Hypothalamic Adaptation to Metabolic Signals

    PubMed Central

    Freire-Regatillo, Alejandra; Argente-Arizón, Pilar; Argente, Jesús; García-Segura, Luis Miguel; Chowen, Julie A.

    2017-01-01

    Although the brain is composed of numerous cell types, neurons have received the vast majority of attention in the attempt to understand how this organ functions. Neurons are indeed fundamental but, in order for them to function correctly, they rely on the surrounding “non-neuronal” cells. These different cell types, which include glia, epithelial cells, pericytes, and endothelia, supply essential substances to neurons, in addition to protecting them from dangerous substances and situations. Moreover, it is now clear that non-neuronal cells can also actively participate in determining neuronal signaling outcomes. Due to the increasing problem of obesity in industrialized countries, investigation of the central control of energy balance has greatly increased in attempts to identify new therapeutic targets. This has led to interesting advances in our understanding of how appetite and systemic metabolism are modulated by non-neuronal cells. For example, not only are nutrients and hormones transported into the brain by non-neuronal cells, but these cells can also metabolize these metabolic factors, thus modifying the signals reaching the neurons. The hypothalamus is the main integrating center of incoming metabolic and hormonal signals and interprets this information in order to control appetite and systemic metabolism. Hence, the factors transported and released from surrounding non-neuronal cells will undoubtedly influence metabolic homeostasis. This review focuses on what is known to date regarding the involvement of different cell types in the transport and metabolism of nutrients and hormones in the hypothalamus. The possible involvement of non-neuronal cells, in particular glial cells, in physiopathological outcomes of poor dietary habits and excess weight gain are also discussed. PMID:28377744

  1. Reduced fasting-induced activation of hypothalamic arcuate neurons is associated with hyperleptinemia and increased leptin sensitivity in obese mice.

    PubMed

    Becskei, Csilla; Lutz, Thomas A; Riediger, Thomas

    2010-08-01

    Fasting increases c-Fos expression in neuropeptide Y (NPY) neurons of the hypothalamic arcuate nucleus (ARC) in lean, but not in hyperleptinemic mice with late-onset obesity (LOO). Although obesity is associated with leptin resistance, we hypothesized that under fasting conditions, leptin sensitivity might be restored and that hyperleptinemia may counteract the neuronal response to fasting. We investigated whether the reduced fasting response of ARC neurons in LOO is paralleled by an increase in leptin sensitivity, as measured by leptin-induced STAT-3 phosphorylation. To assess leptin's role in the modulation of the fasting-induced ARC activation, we investigated c-Fos responses and hormone and metabolite levels in hyperleptinemic diet-induced obese (DIO) and in leptin-deficient ob/ob mice. Leptin induced a stronger STAT-3 phosphorylation in fasted LOO and lean mice than in ad libitum-fed animals. Similar to LOO, hyperleptinemic DIO mice showed no c-Fos response after fasting, while ob/ob mice showed a stronger response than lean control mice. Mimicking hyperleptinemia by repeated leptin injections in lean mice during fasting attenuated the fasting-induced c-Fos expression. Our findings indicate that high leptin levels prevent the fasting-induced activation of ARC neurons in mice. Moreover, leptin sensitivity is dynamic in obese subjects and depends on the feeding status. During short-term increases in leptin sensitivity, e.g., during fasting, leptin signaling appears to be effective, even in hyperleptinemic obesity. As reflected by the blockade of the fasting-induced ARC activation, fasting seems to interfere with the responsiveness of the ARC to signals related to the status of energy intake.

  2. Chronic intermittent hypoxia increases sympathetic control of blood pressure: role of neuronal activity in the hypothalamic paraventricular nucleus.

    PubMed

    Sharpe, Amanda L; Calderon, Alfredo S; Andrade, Mary Ann; Cunningham, J Thomas; Mifflin, Steven W; Toney, Glenn M

    2013-12-01

    Like humans with sleep apnea, rats exposed to chronic intermittent hypoxia (CIH) experience arterial hypoxemias and develop hypertension characterized by exaggerated sympathetic nerve activity (SNA). To gain insights into the poorly understood mechanisms that initiate sleep apnea/CIH-associated hypertension, experiments were performed in rats exposed to CIH for only 7 days. Compared with sham-treated normoxic control rats, CIH-exposed rats (n = 8 rats/group) had significantly increased hematocrit (P < 0.001) and mean arterial pressure (MAP; P < 0.05). Blockade of ganglionic transmission caused a significantly (P < 0.05) greater reduction of MAP in rats exposed to CIH than control rats (n = 8 rats/group), indicating a greater contribution of SNA in the support of MAP even at this early stage of CIH hypertension. Chemical inhibition of neuronal discharge in the hypothalamic paraventricular nucleus (PVN) (100 pmol muscimol) had no effect on renal SNA but reduced lumbar SNA (P < 0.005) and MAP (P < 0.05) more in CIH-exposed rats (n = 8) than control rats (n = 7), indicating that CIH increased the contribution of PVN neuronal activity in the support of lumbar SNA and MAP. Because CIH activates brain regions controlling body fluid homeostasis, the effects of internal carotid artery injection of hypertonic saline were tested and determined to increase lumbar SNA more (P < 0.05) in CIH-exposed rats than in control rats (n = 9 rats/group). We conclude that neurogenic mechanisms are activated early in the development of CIH hypertension such that elevated MAP relies on increased sympathetic tonus and ongoing PVN neuronal activity. The increased sensitivity of Na(+)/osmosensitive circuitry in CIH-exposed rats suggests that early neuroadaptive responses among body fluid regulatory neurons could contribute to the initiation of CIH hypertension.

  3. Lateral Hypothalamic Stimulation Reduces Hyperalgesia Through Spinally Descending Orexin-A Neurons in Neuropathic Pain.

    PubMed

    Wardach, Jacob; Wagner, Monica; Jeong, Younhee; Holden, Janean E

    2016-03-01

    No evidence to date shows that lateral hypothalamic (LH) stimulation produces orexin-A-mediated antinociception in the spinal cord dorsal horn (SCDH) in a model of neuropathic pain. We conducted experiments to examine the effect of orexin-A-mediated LH stimulation in female rats with chronic constriction injury (CCI) on thermal hyperalgesia. Rats receiving carbachol into the LH demonstrated antinociception on both the left CCI and right nonligated paws (p < .05). Rats were given carbachol in the LH followed by intrathecal injection of the orexin-1 (OX1) receptor antagonist SB-334867, which blocked LH-induced antinociception compared with control groups (p < .05) in the left paw, but not in the right paw. These findings support the hypothesis that LH stimulation produces antinociception in rats with thermal hyperalgesia from neuropathic pain via an orexin-A connection between the LH and the SCDH. Identification of this pathway may lead to studies using orexins to manage clinical pain.

  4. Modulation of body temperature and LH secretion by hypothalamic KNDy (kisspeptin, neurokinin B and dynorphin) neurons: A novel hypothesis on the mechanism of hot flushes

    PubMed Central

    Rance, Naomi E.; Dacks, Penny A.; Mittelman-Smith, Melinda A.; Romanovsky, Andrej A.; Krajewski-Hall, Sally J.

    2013-01-01

    Despite affecting millions of individuals, the etiology of hot flushes remains unknown. Here we review the physiology of hot flushes, CNS pathways regulating heat-dissipation effectors, and effects of estrogen on thermoregulation in animal models. Based on the marked changes in hypothalamic kisspeptin, neurokinin B and dynorphin (KNDy) neurons in postmenopausal women, we hypothesize that KNDy neurons play a role in the mechanism of flushes. In the rat, KNDy neurons project to preoptic thermoregulatory areas that express the neurokinin 3 receptor (NK3R), the primary receptor for NKB. Furthermore, activation of NK3R in the median preoptic nucleus, part of the heat-defense pathway, reduces body temperature. Finally, ablation of KNDy neurons reduces cutaneous vasodilatation and partially blocks the effects of estrogen on thermoregulation. These data suggest that arcuate KNDy neurons relay estrogen signals to preoptic structures regulating heat-dissipation effectors, supporting the hypothesis that KNDy neurons participate in the generation of flushes. PMID:23872331

  5. Ionic channels and conductance-based models for hypothalamic neuronal thermosensitivity.

    PubMed

    Wechselberger, Martin; Wright, Chadwick L; Bishop, Georgia A; Boulant, Jack A

    2006-09-01

    Thermoregulatory responses are partially controlled by the preoptic area and anterior hypothalamus (PO/AH), which contains a mixed population of temperature-sensitive and insensitive neurons. Immunohistochemical procedures identified the extent of various ionic channels in rat PO/AH neurons. These included pacemaker current channels [i.e., hyperpolarization-activated cyclic nucleotide-gated channels (HCN)], background potassium leak channels (TASK-1 and TRAAK), and transient receptor potential channel (TRP) TRPV4. PO/AH neurons showed dense TASK-1 and HCN-2 immunoreactivity and moderate TRAAK and HCN-4 immunoreactivity. In contrast, the neuronal cell bodies did not label for TRPV4, but instead, punctate labeling was observed in traversing axons or their terminal endings. On the basis of these results and previous electrophysiological studies, Hodgkin-Huxley-like models were constructed. These models suggest that most PO/AH neurons have the same types of ionic channels, but different levels of channel expression can explain the inherent properties of the various types of temperature-sensitive and insensitive neurons.

  6. Interaction between neuronal uptake inhibitors and presynaptic serotonin autoreceptors in rat hypothalamic slices: comparison of K+ and electrical depolarization.

    PubMed

    Passarelli, F; Galzin, A M; Langer, S Z

    1987-09-01

    In rat hypothalamic slices prelabeled with [3H]-5-hydroxytryptamine ([3H]-5-HT), exposure to the 5-HT receptor agonist lysergic acid diethylamide (0.1-1 microM) or 5-methoxytryptamine (0.1-10 microM) decreased in a concentration-dependent manner the release of 3H-transmitter elicited by high K+ or electrical stimulation. Exposure to the 5-HT autoreceptor antagonist methiothepin (0.1-1 microM) increased in a concentration-dependent manner the K+ stimulation-evoked overflow of [3H]-5-HT and a similar increase was observed under conditions of electrical stimulation. In contrast, exposure to the nontricyclic 5-HT uptake inhibitor citalopram (0.1-1 microM) did not modify by itself the electrically evoked overflow of [3H]-5-HT, but increased in a concentration-dependent manner the release of 3H-transmitter elicited by K+ stimulation. This effect of citalopram on transmitter release was potentiated when the endogenous stores of 5-HT were depleted by pretreatment with para-chlorophenylalanine methyl ester (300 mg/kg i.p.). Citalopram was shown previously to antagonize the inhibition by lysergic acid diethylamide of the electrically evoked release of [3H]-5-HT in rat hypothalamic slices. Yet, this inhibitor of neuronal uptake of 5-HT did not antagonize the effects of lysergic acid diethylamide when the release of [3H]-5-HT was evoked by K+ depolarization. Electrical stimulation represents a more physiological experimental model for transmitter release than exposure to high K+, and therefore the interaction between 5-HT uptake blockade and presynaptic inhibitory 5-HT autoreceptors, observed in the hypothalamus with electrical stimulation but not with K+ depolarization, remains of biological relevance.

  7. Modulation of AgRP-neuronal function by SOCS3 as an initiating event in diet-induced hypothalamic leptin resistance.

    PubMed

    Olofsson, Louise E; Unger, Elizabeth K; Cheung, Clement C; Xu, Allison W

    2013-02-19

    Chronic consumption of a fat-rich diet leads to attenuation of leptin signaling in hypothalamic neurons, a hallmark feature of cellular leptin resistance. To date, little is known about the temporal and spatial dysregulation of neuronal function under conditions of nutrient excess. We show that agouti-related protein (AgRP)-expressing neurons precede proopiomelanocortin neurons in developing diet-induced cellular leptin resistance. High-fat diet-induced up-regulation of suppressor of cytokine signaling-3 (SOCS3) occurs in AgRP neurons before proopiomelanocortin and other hypothalamic neurons. SOCS3 expression in AgRP neurons increases after 2 d of high-fat feeding, but reduces after switching to a low-fat diet for 1 d. Consistently, transgenic overexpression of SOCS3 in AgRP neurons produces metabolic phenotypes resembling those observed after short-term high-fat feeding. We further show that AgRP neurons are the predominant cell type situated outside the blood-brain barrier in the mediobasal hypothalamus. AgRP neurons are more responsive to low levels of circulating leptin, but they are also more prone to development of leptin resistance in response to a small increase in blood leptin concentrations. Collectively, these results suggest that AgRP neurons are able to sense slight changes in plasma metabolic signals, allowing them to serve as first-line responders to fluctuation of energy intake. Furthermore, modulation of SOCS3 expression in AgRP neurons may play a dynamic and physiological role in metabolic fine tuning in response to short-term changes of nutritional status.

  8. Plasticity of hypothalamic dopamine neurons during lactation results in dissociation of electrical activity and release.

    PubMed

    Romanò, Nicola; Yip, Siew H; Hodson, David J; Guillou, Anne; Parnaudeau, Sébastien; Kirk, Siobhan; Tronche, François; Bonnefont, Xavier; Le Tissier, Paul; Bunn, Stephen J; Grattan, Dave R; Mollard, Patrice; Martin, Agnès O

    2013-03-06

    Tuberoinfundibular dopamine (TIDA) neurons are the central regulators of prolactin (PRL) secretion. Their extensive functional plasticity allows a change from low PRL secretion in the non-pregnant state to the condition of hyperprolactinemia that characterizes lactation. To allow this rise in PRL, TIDA neurons are thought to become unresponsive to PRL at lactation and functionally silenced. Here we show that, contrary to expectations, the electrical properties of the system were not modified during lactation and that the neurons remained electrically responsive to a PRL stimulus, with PRL inducing an acute increase in their firing rate during lactation that was identical to that seen in non-pregnant mice. Furthermore, we show a long-term organization of TIDA neuron electrical activity with an harmonization of their firing rates, which remains intact during lactation. However, PRL-induced secretion of dopamine (DA) at the median eminence was strongly blunted during lactation, at least in part attributable to lack of phosphorylation of tyrosine hydroxylase, the key enzyme involved in DA synthesis. We therefore conclude that lactation, rather than involving electrical silencing of TIDA neurons, represents a condition of decoupling between electrical activity at the cell body and DA secretion at the median eminence.

  9. A septal-hypothalamic pathway drives orexin neurons, which is necessary for conditioned cocaine preference.

    PubMed

    Sartor, Gregory C; Aston-Jones, Gary S

    2012-03-28

    Orexins (also called hypocretins) have been shown to be importantly involved in reward and addiction, but little is known about the circuitry that regulates orexin neuronal activity during drug-seeking behaviors. Here, we examined inputs to the lateral hypothalamus (LH) orexin cell field from the lateral septum (LS) using tract-tracing and Fos immunohistochemistry after cocaine (10 mg/kg) conditioned place preference (CPP) in Sprague Dawley rats. We found that neurons in rostral LS (LSr) that project to LH are Fos-activated in proportion to cocaine CPP, and that inhibition of LSr neurons with local baclofen and muscimol microinjection (0.3/0.03 nmol) blocks expression of Fos in LH orexin cells and cocaine preference. In addition, using local inactivation in LS and orexin antisense morpholinos in LH, we found that LSr influences on LH orexin neurons are critical for the expression of cocaine preference. These results indicate that LSr activates LH orexin neurons during cocaine place preference, and that this circuit is essential for expression of cocaine place preference.

  10. Evidence that diet-induced hyperleptinemia, but not hypothalamic gliosis, causes ghrelin resistance in NPY/AgRP neurons of male mice.

    PubMed

    Briggs, Dana I; Lockie, Sarah H; Benzler, Jonas; Wu, Qunli; Stark, Romana; Reichenbach, Alex; Hoy, Andrew J; Lemus, Moyra B; Coleman, Harold A; Parkington, Helena C; Tups, Alex; Andrews, Zane B

    2014-07-01

    High-fat diet (HFD) feeding causes ghrelin resistance in arcuate neuropeptide Y (NPY)/Agouti-related peptide neurons. In the current study, we investigated the time course over which this occurs and the mechanisms responsible for ghrelin resistance. After 3 weeks of HFD feeding, neither peripheral nor central ghrelin increased food intake and or activated NPY neurons as demonstrated by a lack of Fos immunoreactivity or whole-cell patch-clamp electrophysiology. Pair-feeding studies that matched HFD calorie intake with chow calorie intake show that HFD exposure does not cause ghrelin resistance independent of body weight gain. We observed increased plasma leptin in mice fed a HFD for 3 weeks and show that leptin-deficient obese ob/ob mice are still ghrelin sensitive but become ghrelin resistant when central leptin is coadministered. Moreover, ob/ob mice fed a HFD for 3 weeks remain ghrelin sensitive, and the ability of ghrelin to induce action potential firing in NPY neurons was blocked by leptin. We also examined hypothalamic gliosis in mice fed a chow diet or HFD, as well as in ob/ob mice fed a chow diet or HFD and lean controls. HFD-fed mice exhibited increased glial fibrillary acidic protein-positive cells compared with chow-fed mice, suggesting that hypothalamic gliosis may underlie ghrelin resistance. However, we also observed an increase in hypothalamic gliosis in ob/ob mice fed a HFD compared with chow-fed ob/ob and lean control mice. Because ob/ob mice fed a HFD remain ghrelin sensitive, our results suggest that hypothalamic gliosis does not underlie ghrelin resistance. Further, pair-feeding a HFD to match the calorie intake of chow-fed controls did not increase body weight gain or cause central ghrelin resistance; thus, our evidence suggests that diet-induced hyperleptinemia, rather than diet-induced hypothalamic gliosis or HFD exposure, causes ghrelin resistance.

  11. Histaminergic responses by hypothalamic neurons that regulate lordosis and their modulation by estradiol

    PubMed Central

    Dupré, Christophe; Lovett-Barron, Matthew; Pfaff, Donald W.; Kow, Lee-Ming

    2010-01-01

    How do fluctuations in the level of generalized arousal of the brain affect the performance of specific motivated behaviors, such as sexual behaviors that depend on sexual arousal? A great deal of previous work has provided us with two important starting points in answering this question: (i) that histamine (HA) serves generalized CNS arousal and (ii) that heightened electrical activity of neurons in the ventromedial nucleus of the hypothalamus (VMN) is necessary and sufficient for facilitating the primary female sex behavior in laboratory animals, lordosis behavior. Here we used patch clamp recording technology to analyze HA effects on VMN neuronal activity. The results show that HA acting through H1 receptors (H1R) depolarizes these neurons. Further, acute administration of estradiol, an estrogen necessary for lordosis behavior to occur, heightens this effect. Hyperpolarization, which tends to decrease excitability and enhance inhibition, was not affected by acute estradiol or mediated by H1R but was mediated by other HA receptor subtypes, H2 and H3. Sampling of mRNA from individual VMN neurons showed colocalization of expression of H1 receptor mRNA with estrogen receptor (ER)-α mRNA but also revealed ER colocalization with the other HA receptor subtypes and colocalization of different subtypes with each other. The latter finding provides the molecular basis for complex “push-pull” regulation of VMN neuronal excitability by HA. Thus, in the simplest causal route, HA, acting on VMN neurons through H1R provides a mechanism by which elevated states of generalized CNS arousal can foster a specific estrogen-dependent, aroused behavior, sexual behavior. PMID:20562342

  12. Suprachiasmatic nuclei and Circadian rhythms. The role of suprachiasmatic nuclei on rhythmic activity of neurons in the lateral hypothalamic area, ventromedian nuclei and pineal gland

    NASA Technical Reports Server (NTRS)

    Nishino, H.

    1977-01-01

    Unit activity of lateral hypothalamic area (LHA) and Ventromedian nuclei (VMN) was recorded in urethane anesthetized male rats. A 5 to 10 sec. a 3-5 min and a circadian rhythmicity were observed. In about 15% of all neurons, spontaneous activity of LHA and VMN showed reciprocal relationships. Subthreshold stimuli applied at a slow rate in the septum and the suprachiasmatic nuclei (SCN) suppressed the rhythms without changing firing rates. On the other hand, stimulation of the optic nerve at a rate of 5 to 10/sec increased firing rates in 1/3 of neurons of SCN. Iontophoretically applied acetylcholine increased 80% of tested neurons of SCN, whereas norepinephrine, dopamine and 5 HT inhibited 64, 60 and 75% of SCN neurons respectively. These inhibitions were much stronger in neurons, the activity of which was increased by optic nerve stimulation. Stimulation of the SCN inhibited the tonic activity in cervical sympathetic nerves.

  13. Hypothalamic neuronal origin of neuropeptide Y (NPY) or cocaine- and amphetamine-regulated transcript (CART) fibers projecting to the tuberomammillary nucleus of the rat.

    PubMed

    Lee, Eun Y; Hwang, Young G; Lee, Hyun S

    2017-02-15

    Based on the importance of tuberomammillary nucleus (TMN) as a target for feeding/arousal-related functions, we aimed in the present study to investigate hypothalamic neuronal origin of neuropeptide Y (NPY) and cocaine- and amphetamine-regulated transcript (CART) fibers projecting to the histaminergic nucleus. In the first series of experiments, we examined NPY (or CART) fiber distribution within the boundary of adenosine deaminase (ADA)-immunoreactive (ir) TMN regions; extensive NPY (or CART)-ir axon terminals were observed in E4 (TMMd), E3 (TMMv), and E2 (TMVr) subdivisions. NPY varicosities co-contained vesicular GABA transporters (vGAT). CART boutons, however, contained either vGAT or vesicular glutamate transporters (vGLU), which suggested dual (or multiple) origins of CART fibers. Based on the previous observation on melanin-concentrating hormone (MCH)-ir neuronal elements in the TMN, their coexistence with CART peptide was examined in detail. In E4 subdivision, approximately 40.8% of MCH-ir somata co-contained CART, but the proportion was reduced to 24.1% in E3 region. In E2 and E1 (TMVc) regions, only MCH-ir axon terminals existed without any MCH-ir somata. In the second series of experiments, we investigated hypothalamic neuronal origin of NPY (or CART) fibers projecting to the TMN. The arcuate nucleus (Arc) was the sole source of hypothalamic NPY fibers projecting to the nucleus. In contrast, CART fibers in the TMN originated from the Arc as well as the other hypothalamic nuclei including the retrochiasmatic nucleus, paraventricular nucleus, lateral hypothalamus (LH), zona incerta (ZI), and dorsal hypothalamic area. Quantitative analysis showed that arcuate CART projection to the TMN occupied approximately 23.5% of the total hypothalamic CART input to the nucleus, while the rest originated mainly from the LH and ZI. The present observations suggested that the TMN might play a key role in energy balance and arousal, by receiving periphery-derived, first

  14. Copper Enhances Zinc-Induced Neurotoxicity and the Endoplasmic Reticulum Stress Response in a Neuronal Model of Vascular Dementia

    PubMed Central

    Tanaka, Ken-ichiro; Kawahara, Masahiro

    2017-01-01

    Zinc (Zn), an essential trace element, is secreted by synaptic vesicles during neuronal excitation and plays several critical roles in neuronal information processing. However, excess Zn ion (Zn2+) is neurotoxic and has a causative role in the pathogenesis of vascular dementia. Here, we investigated the molecular mechanism of Zn2+-induced neurotoxicity by using immortalized hypothalamic neurons (GT1-7 cells), which are more vulnerable than other neuronal cells to Zn2+. We examined the effects of other metal ions on the Zn2+-induced neurotoxicity in these cells and found that sub-lethal concentrations of copper ion (Cu2+) markedly exacerbated Zn2+-induced neurotoxicity. The co-administration of Cu2+ and Zn2+ also significantly increased the expression of genes related to the endoplasmic reticulum's stress response, including CHOP, GADD34, and ATF4. Similar to Zn2+, Cu2+ is stored in presynaptic vesicles and secreted during neuronal excitation. Thus, based on our results, we hypothesize here that Cu2+ interacts with Zn2+ in the synapse to synergistically promote neuronal death and significantly influence the pathogenesis of vascular dementia. PMID:28232787

  15. Application of the Co-culture Membrane System Pointed to a Protective Role of Catestatin on Hippocampal Plus Hypothalamic Neurons Exposed to Oxygen and Glucose Deprivation.

    PubMed

    Mele, Maria; Morelli, Sabrina; Fazzari, Gilda; Avolio, Ennio; Alò, Raffaella; Piscioneri, Antonella; De Bartolo, Loredana; Facciolo, Rosa Maria; Canonaco, Marcello

    2016-11-05

    Depletion of oxygen and glucose even for brief periods is sufficient to cause cerebral ischemia, which is a predominant worldwide cause of motor deficits with the reduction of life quality and subsequently death. Hence, more insights regarding protective measures against ischemic events are becoming a major research goal. Among the many neuronal factors, N-methyl-D-aspartate receptors (NMDAR), orexinergic neuroreceptors (ORXR), and sympatho-inhibitory neuropeptide catestatin (CST) are widely involved with ischemic episodes. In this study, it was possible to induce in vitro ischemic conditions of the hamster (Mesocricetus auratus) hippocampal and hypothalamic neuronal cultures, grown on a newly compartmentalized membrane system, via oxygen and glucose deprivation (OGD). These cultures displayed notably differentiated NMDARergic and ORXergic receptor expression activities along with evident brain-derived neurotrophic factor (BDNF) plus orexin A (ORX-A) secretion, especially under co-cultured conditions. Interestingly, addition of CST in OGD-insulted hippocampal cells accounted for upregulated GluN1 and ORX1R transcripts that in the case of the latter neuroreceptor was very strongly (p < 0.001) increased when co-cultured with hypothalamic cells. Similarly, hypothalamic neurons supplied very evident upregulations of GluN1, ORX1R, and above all of GluN2A transcripts along with increased BDNF and ORX-A secretion in the presence of hippocampal cells. Overall, the preferential CST effects on BDNF plus ORX-A production together with altered NMDAR and ORXR levels, especially in co-cultured hypothalamic cells pointed to ORX-containing neurons as major protective constituents against ischemic damages thus opening new scenarios on the cross-talking roles of CST during ischemic disorders.

  16. Rhythmic patterns of discharge in hypothalamic neurosecretory neurons of cats and dogs.

    PubMed Central

    Yamashita, H; Koizumi, K; Brooks, C M

    1979-01-01

    Recent studies in rats suggest that vasopressin- and oxytocin-secreting neurons in supraoptic nuclei and paraventricular nuclei of the hypothalamus show two different patterns of activity: one a "bursting" or rhythmic pattern and the other, irregular continuous discharges. This possibility was investigated in cats and dogs anesthetized with chloralose or Nembutal by recording electrical activity of single supraoptic and paraventricular neurons. Only some of the "identified" neurosecretory cells showed rhythmic, intermittent discharges ("bursting" cells in rats); the majority showed an irregular continuous firing pattern. Furthermore, the pattern of discharge sometimes changed from one ot the other during long periods of observation. This occurred without apparent stimulus in certain instances; in others, the rhythmic firing was associated with fluctuation in blood pressure and heart rate and was likely to be caused by changes in baroreceptor activity. Possible origins of rhythmic discharges and the physiological importance of such patterns in terms of hormone secretion are discussed. PMID:293755

  17. Src Kinases Regulate Glutamatergic Input to Hypothalamic Presympathetic Neurons and Sympathetic Outflow in Hypertension.

    PubMed

    Qiao, Xin; Zhou, Jing-Jing; Li, De-Pei; Pan, Hui-Lin

    2017-01-01

    The elevated sympathetic outflow associated with hypertension is maintained by increased N-methyl-d-aspartate receptor (NMDAR) activity in the paraventricular nucleus (PVN) of the hypothalamus. Synaptic NMDAR activity is tightly regulated by protein kinases, including the Src family of tyrosine kinases. We determined whether Src kinases play a role in increased NMDAR activity of PVN neurons projecting to the rostral ventrolateral medulla and in elevated sympathetic vasomotor tone in spontaneously hypertensive rats (SHRs). The Src protein level in the PVN was significantly greater in SHRs than in normotensive Wistar-Kyoto (WKY) rats and was not significantly altered by lowering blood pressure with celiac ganglionectomy in SHRs. Inhibition of Src kinase activity with 4-amino-5-(4-chlorophenyl)-7-(dimethylethyl)pyrazolo[3,4-d]pyrimidine (PP2) completely normalized the higher amplitudes of evoked NMDAR-mediated excitatory postsynaptic currents and puff NMDA-elicited currents of rostral ventrolateral medulla-projecting PVN neurons in SHRs. PP2 treatment also attenuated the higher frequency of NMDAR-mediated miniature excitatory postsynaptic currents of these neurons in SHRs. However, PP2 had no effect on NMDAR-excitatory postsynaptic currents or miniature excitatory postsynaptic currents of rostral ventrolateral medulla-projecting PVN neurons in WKY rats. NMDAR activity increased by an Src-activating peptide was blocked by PP2 but not by inhibition of casein kinase 2. In addition, microinjection of PP2 into the PVN not only decreased lumbar sympathetic nerve discharges and blood pressure but also eliminated the inhibitory effect of the NMDAR antagonist on sympathetic nerve activity and blood pressure in SHRs. Collectively, our findings suggest that increased Src kinase activity potentiates presynaptic and postsynaptic NMDAR activity in the PVN and sympathetic vasomotor tone in hypertension. © 2016 American Heart Association, Inc.

  18. Dendritic arbor of neurons in the hypothalamic ventromedial nucleus in female prairie voles (Microtus ochrogaster).

    PubMed

    Ferri, Sarah L; Rohrbach, Carlos J; Way, Samantha E; Curtis, Kathleen S; Curtis, J Thomas; Flanagan-Cato, Loretta M

    2013-01-01

    Female mating behavior in rats is associated with hormone-induced changes in the dendritic arbor of neurons in the ventromedial nucleus of the hypothalamus (VMH), particularly the ventrolateral portion. Regulation of mating behavior in female prairie voles differs substantially from that in rats; therefore, we examined the dendritic morphology of VMH neurons in this species. Sexually naïve adult female prairie voles were housed with a male to activate the females' reproductive endocrine system. Following 48 h of cohabitation, females were tested for evidence of reproductive activation by assessing the level of male sexual interest, after which their brains were processed using Golgi impregnation, which allowed ventrolateral VMH neurons to be visualized and analyzed. Dendritic arborization in the female prairie vole VMH neurons was strikingly similar to that of female rats. The key difference was that in the prairie voles the long primary dendrites extended considerably further than those observed in rats. Although most female voles paired with males exhibited sexual activation, some females did not. These two groups displayed specific differences in their VMH dendrites. In particular, the long primary dendrites were longer in the reproductively active females compared with those in the non-activated females. Overall, dendrite lengths were positively correlated with plasma estradiol levels in females exposed to males, but not in unpaired females. Although causal relationships between the neuroendocrine events, dendrite length, and the outward, behavioral manifestation of reproductive activation cannot be determined from this study, these results suggest an association between ventrolateral VMH dendrite morphology and female mating behavior in prairie voles, akin to what has been observed in female rats.

  19. Hypothalamic melanin concentrating hormone neurons communicate the nutrient value of sugar.

    PubMed

    Domingos, Ana I; Sordillo, Aylesse; Dietrich, Marcelo O; Liu, Zhong-Wu; Tellez, Luis A; Vaynshteyn, Jake; Ferreira, Jozelia G; Ekstrand, Mats I; Horvath, Tamas L; de Araujo, Ivan E; Friedman, Jeffrey M

    2013-12-31

    Sugars that contain glucose, such as sucrose, are generally preferred to artificial sweeteners owing to their post-ingestive rewarding effect, which elevates striatal dopamine (DA) release. While the post-ingestive rewarding effect, which artificial sweeteners do not have, signals the nutrient value of sugar and influences food preference, the neural circuitry that mediates the rewarding effect of glucose is unknown. In this study, we show that optogenetic activation of melanin-concentrating hormone (MCH) neurons during intake of the artificial sweetener sucralose increases striatal dopamine levels and inverts the normal preference for sucrose vs sucralose. Conversely, animals with ablation of MCH neurons no longer prefer sucrose to sucralose and show reduced striatal DA release upon sucrose ingestion. We further show that MCH neurons project to reward areas and are required for the post-ingestive rewarding effect of sucrose in sweet-blind Trpm5(-/-) mice. These studies identify an essential component of the neural pathways linking nutrient sensing and food reward. DOI: http://dx.doi.org/10.7554/eLife.01462.001.

  20. Regulation of hypothalamic neuronal sensing and food intake by ketone bodies and fatty acids.

    PubMed

    Le Foll, Christelle; Dunn-Meynell, Ambrose A; Miziorko, Henri M; Levin, Barry E

    2014-04-01

    Metabolic sensing neurons in the ventromedial hypothalamus (VMH) alter their activity when ambient levels of metabolic substrates, such as glucose and fatty acids (FA), change. To assess the relationship between a high-fat diet (HFD; 60%) intake on feeding and serum and VMH FA levels, rats were trained to eat a low-fat diet (LFD; 13.5%) or an HFD in 3 h/day and were monitored with VMH FA microdialysis. Despite having higher serum levels, HFD rats had lower VMH FA levels but ate less from 3 to 6 h of refeeding than did LFD rats. However, VMH β-hydroxybutyrate (β-OHB) and VMH-to-serum β-OHB ratio levels were higher in HFD rats during the first 1 h of refeeding, suggesting that VMH astrocyte ketone production mediated their reduced intake. In fact, using calcium imaging in dissociated VMH neurons showed that ketone bodies overrode normal FA sensing, primarily by exciting neurons that were activated or inhibited by oleic acid. Importantly, bilateral inhibition of VMH ketone production with a 3-hydroxy-3-methylglutaryl-CoA synthase inhibitor reversed the 3- to 6-h HFD-induced inhibition of intake but had no effect in LFD-fed rats. These data suggest that a restricted HFD intake regimen inhibits caloric intake as a consequence of FA-induced VMH ketone body production by astrocytes.

  1. Hypothalamic melanin concentrating hormone neurons communicate the nutrient value of sugar

    PubMed Central

    Domingos, Ana I; Sordillo, Aylesse; Dietrich, Marcelo O; Liu, Zhong-Wu; Tellez, Luis A; Vaynshteyn, Jake; Ferreira, Jozelia G; Ekstrand, Mats I; Horvath, Tamas L; de Araujo, Ivan E; Friedman, Jeffrey M

    2013-01-01

    Sugars that contain glucose, such as sucrose, are generally preferred to artificial sweeteners owing to their post-ingestive rewarding effect, which elevates striatal dopamine (DA) release. While the post-ingestive rewarding effect, which artificial sweeteners do not have, signals the nutrient value of sugar and influences food preference, the neural circuitry that mediates the rewarding effect of glucose is unknown. In this study, we show that optogenetic activation of melanin-concentrating hormone (MCH) neurons during intake of the artificial sweetener sucralose increases striatal dopamine levels and inverts the normal preference for sucrose vs sucralose. Conversely, animals with ablation of MCH neurons no longer prefer sucrose to sucralose and show reduced striatal DA release upon sucrose ingestion. We further show that MCH neurons project to reward areas and are required for the post-ingestive rewarding effect of sucrose in sweet-blind Trpm5−/− mice. These studies identify an essential component of the neural pathways linking nutrient sensing and food reward. DOI: http://dx.doi.org/10.7554/eLife.01462.001 PMID:24381247

  2. A functional coupling between extrasynaptic NMDA receptors and A-type K+ channels under astrocyte control regulates hypothalamic neurosecretory neuronal activity

    PubMed Central

    Naskar, Krishna; Stern, Javier E

    2014-01-01

    Neuronal activity is controlled by a fine-tuned balance between intrinsic properties and extrinsic synaptic inputs. Moreover, neighbouring astrocytes are now recognized to influence a wide spectrum of neuronal functions. Yet, how these three key factors act in concert to modulate and fine-tune neuronal output is not well understood. Here, we show that in rat hypothalamic magnocellular neurosecretory cells (MNCs), glutamate NMDA receptors (NMDARs) are negatively coupled to the transient, voltage-gated A-type K+ current (IA). We found that activation of NMDARs by extracellular glutamate levels influenced by astrocyte glutamate transporters resulted in a significant inhibition of IA. The NMDAR–IA functional coupling resulted from activation of extrasynaptic NMDARs, was calcium- and protein kinase C-dependent, and involved enhanced steady-state, voltage-dependent inactivation of IA. The NMDAR–IA coupling diminished the latency to the first evoked spike in response to membrane depolarization and increased the total number of evoked action potentials, thus strengthening the neuronal input/output function. Finally, we found a blunted NMDA-mediated inhibition of IA in dehydrated rats. Together, our findings support a novel signalling mechanism that involves a functional coupling between extrasynaptic NMDARs and A-type K+ channels, which is influenced by local astrocytes. We show this signalling complex to play an important role in modulating hypothalamic neuronal excitability, which may contribute to adaptive responses during a sustained osmotic challenge such as dehydration. PMID:24835172

  3. Properties of native P2X receptors in large multipolar neurons dissociated from rat hypothalamic arcuate nucleus.

    PubMed

    Wakamori, Minoru; Sorimachi, Masaru

    2004-04-16

    ATP, the ligand of P2X receptors, is a candidate of neurotransmitter or co-transmitter in the peripheral and the central nervous systems. Anatomical studies have revealed the wide distribution of P2X receptors in the brain. So far, P2X-mediated small synaptic responses have been recorded in some brain regions. To determine the physiological significance of postsynaptic ATP receptors in the brain, we have investigated the P2X responses in rat dissociated hypothalamic arcuate neurons by using the patch-clamp technique. ATP evoked inward currents in a concentration-dependent manner (EC(50)=42 microM) at a holding potential of -70 mV. The current-voltage relationship showed a marked inward rectification starting around -10 mV. Although neither 300 microM alphabeta-methylene-ATP nor 300 microM betagamma-methylene-ATP induced any currents, 100 microM ATPgammaS and 100 microM 2-methylthio-ATP evoked inward currents of which amplitude was about 60% of the control currents evoked by 100 microM ATP. PPADS, one of P2 receptor antagonists, inhibited the ATP-evoked currents in a time- and a concentration-dependent manners (IC(50)=19 microM at 2 min). Permeant Ca(2+) inhibited the ATP-evoked currents in the range of millimolars (IC(50)=7 mM); however, Cd(2+) (1-300 microM), a broad cation channel blocker, facilitated the currents with slow off-response. Zn(2+) in the range of 1-100 microM facilitated the currents whereas Zn(2+) at the concentrations over 100 microM inhibited the currents. These observations suggest that functional P2X receptors are expressed in the hypothalamic arcuate nucleus. The most likely subunit combinations of the P2X receptors are P2X(2)-homomultimer and P2X(2)/P2X(6)-heteromultimer.

  4. Transgenic mice overexpressing amyloid precursor protein exhibit early metabolic deficits and a pathologically low leptin state associated with hypothalamic dysfunction in arcuate neuropeptide Y neurons.

    PubMed

    Ishii, Makoto; Wang, Gang; Racchumi, Gianfranco; Dyke, Jonathan P; Iadecola, Costantino

    2014-07-02

    Weight loss is a prominent early feature of Alzheimer's disease (AD) that often precedes the cognitive decline and clinical diagnosis. While the exact pathogenesis of AD remains unclear, accumulation of amyloid-β (Aβ) derived from the amyloid precursor protein (APP) in the brain is thought to lead to the neuronal dysfunction and death underlying the dementia. In this study, we examined whether transgenic mice overexpressing the Swedish mutation of APP (Tg2576), recapitulating selected features of AD, have hypothalamic leptin signaling dysfunction leading to early body weight deficits. We found that 3-month-old Tg2576 mice, before amyloid plaque formation, exhibit decreased weight with markedly decreased adiposity, low plasma leptin levels, and increased energy expenditure without alterations in feeding behavior. The expression of the orexigenic neuropeptide Y (NPY) in the hypothalamus to the low leptin state was abnormal at basal and fasting conditions. In addition, arcuate NPY neurons exhibited abnormal electrophysiological responses to leptin in Tg2576 hypothalamic slices or wild-type slices treated with Aβ. Finally, the metabolic deficits worsened as Tg2576 mice aged and amyloid burden increased in the brain. These results indicate that excess Aβ can potentially disrupt hypothalamic arcuate NPY neurons leading to weight loss and a pathologically low leptin state early in the disease process that progressively worsens as the amyloid burden increases. Collectively, these findings suggest that weight loss is an intrinsic pathological feature of Aβ accumulation and identify hypothalamic leptin signaling as a previously unrecognized pathogenic site of action for Aβ. Copyright © 2014 the authors 0270-6474/14/349096-11$15.00/0.

  5. Induction and subcellular redistribution of progesterone receptor A and B by tamoxifen in the hypothalamic ventromedial neurons of young adult female Wistar rats.

    PubMed

    Sá, Susana I; Fonseca, Bruno M; Teixeira, Natércia; Madeira, M Dulce

    2016-01-15

    The ventrolateral division of the hypothalamic ventromedial nucleus (VMNvl) is a brain center for estrogen-dependent triggering of female sexual behavior upon progesterone receptor (PR) activation. We examined the agonistic and antagonistic actions of tamoxifen in this nucleus by analyzing its effects on the total number of PR-immunoreactive neurons, PR mRNA and protein levels, and subcellular location of PRs in ovariectomized Wistar rats. The results show that tamoxifen has no agonistic action in the number of PR-immunoreactive neurons, but increases PR expression and labeling in the nucleus and cytoplasm of VMNvl neurons that constitutively express PRs. As an antagonist, tamoxifen partially inhibited the estradiol-dependent increase in the number of PR-immunoreactive neurons and in PR mRNA and protein levels, without interfering with the subcellular location of the protein. We suggest that tamoxifen influence on PR expression in the VMNvl critically depends on the presence or absence of estradiol.

  6. Fasted/fed states regulate postsynaptic hub protein DYNLL2 and glutamatergic transmission in oxytocin neurons in the hypothalamic paraventricular nucleus.

    PubMed

    Suyama, Shigetomo; Kodaira-Hirano, Misato; Otgon-Uul, Zesemdorj; Ueta, Yoichi; Nakata, Masanori; Yada, Toshihiko

    2016-04-01

    The neurons in the hypothalamus regulate food intake and energy metabolism on reception of systemic energy states. Accumulating evidences have indicated that synaptic transmission on the hypothalamic neurons is modulated by the metabolic condition related to fasted/fed states, and that this modulation of synaptic plasticity plays a role in regulation of feeding. It has been shown that oxytocin (Oxt) neurons in the paraventricular nucleus (PVN) of the hypothalamus sense and integrate various peripheral and central signals and thereby induce satiety. However, whether metabolic conditions regulate the synaptic transmission on Oxt neurons in PVN remains unclear. The present study examined whether the fasted/fed states regulate synaptic transmission on Oxt neurons in PVN. The miniature excitatory postsynaptic currents (mEPSCs) onto Oxt neurons in PVN were increased under ad lib fed condition compared to 24h fasted condition. Furthermore, the NMDA receptor-mediated EPSC on Oxt neurons was increased under fed, compared to fasted, condition. In Oxt neurons, dynein light chain 2 (DYNLL2), a protein suggested to be implicated in the NMDA receptor trafficking to the postsynaptic site, was increased under fed, compared to fasted, condition. The present results suggest that feeding increases excitatory synaptic input on PVN Oxt neurons via mechanisms involving DYNLL2 upregulation and NMDA receptor-mediated synaptic reorganization.

  7. Leptin resistance and obesity in mice with deletion of methyl-CpG-binding protein 2 (MeCP2) in hypothalamic pro-opiomelanocortin (POMC) neurons.

    PubMed

    Wang, Xiaorui; Lacza, Zsombor; Sun, Yi E; Han, Weiping

    2014-01-01

    Pro-opiomelanocortin (POMC) neurons in the arcuate nucleus (ARC) regulate energy homeostasis by secreting α-melanocyte-stimulating hormone (α-MSH), derived from POMC precursor, in response to leptin signalling. Expression of Pomc is subject to multiple modes of regulation, including epigenetic regulation. Methyl-CpG-binding protein 2 (MeCP2), a nuclear protein essential for neuronal function, interacts with promoters to influence gene expression. We aim to address whether MeCP2 regulates hypothalamic Pomc expression and to investigate the role of epigenetics, particularly DNA methylation, in this process. We generated a mouse line with MeCP2 specifically deleted in POMC neurons (Mecp2 flox/y /Pomc-Cre [PKO]) and characterised its metabolic phenotypes. We examined the DNA methylation pattern of the Pomc promoter and its impact on hypothalamic gene expression. We also studied the requirement of MeCP2 for, and the effects of, DNA methylation on Pomc promoter activity using luciferase assays. PKO mice are overweight, with increased fat mass resulting from increased food intake and respiratory exchange ratio. PKO mice also exhibit elevated plasma leptin. Deletion of MeCP2 in POMC neurons leads to increased DNA methylation of the hypothalamic Pomc promoter and reduced Pomc expression. Furthermore, in vitro studies show that hypermethylation of the Pomc promoter reduces its transcriptional activity and reveal a functional synergy between MeCP2 and cAMP responsive element binding protein 1 (CREB1) in positively regulating the Pomc promoter. Our results demonstrate that MeCP2 positively regulates Pomc expression in the hypothalamus. Absence of MeCP2 in POMC neurons leads to increased DNA methylation of the Pomc promoter, which, in turn, downregulates Pomc expression, leading to obesity in mice with an accentuating degree of leptin resistance.

  8. Deletion of ATF4 in AgRP Neurons Promotes Fat Loss Mainly via Increasing Energy Expenditure.

    PubMed

    Deng, Jiali; Yuan, Feixiang; Guo, Yajie; Xiao, Yuzhong; Niu, Yuguo; Deng, Yalan; Han, Xiao; Guan, Youfei; Chen, Shanghai; Guo, Feifan

    2017-03-01

    Although many functions of activating transcription factor 4 (ATF4) are identified, a role of ATF4 in the hypothalamus in regulating energy homeostasis is unknown. Here, we generated adult-onset agouti-related peptide neuron-specific ATF4 knockout (AgRP-ATF4 KO) mice and found that these mice were lean, with improved insulin and leptin sensitivity and decreased hepatic lipid accumulation. Furthermore, AgRP-ATF4 KO mice showed reduced food intake and increased energy expenditure, mainly because of enhanced thermogenesis in brown adipose tissue. Moreover, AgRP-ATF4 KO mice were resistant to high-fat diet-induced obesity, insulin resistance, and liver steatosis and maintained at a higher body temperature under cold stress. Interestingly, the expression of FOXO1 was directly regulated by ATF4 via binding to the cAMP-responsive element site on its promoter in hypothalamic GT1-7 cells. Finally, Foxo1 expression was reduced in the arcuate nucleus (ARC) of the hypothalamus of AgRP-ATF4 KO mice, and adenovirus-mediated overexpression of FOXO1 in ARC increased the fat mass in AgRP-ATF4 KO mice. Collectively, our data demonstrate a novel function of ATF4 in AgRP neurons of the hypothalamus in energy balance and lipid metabolism and suggest hypothalamic ATF4 as a potential drug target for treating obesity and its related metabolic disorders. © 2017 by the American Diabetes Association.

  9. Molecular Profiling of Human Induced Pluripotent Stem Cell-Derived Hypothalamic Neurones Provides Developmental Insights into Genetic Loci for Body Weight Regulation.

    PubMed

    Yao, L; Liu, Y; Qiu, Z; Kumar, S; Curran, J E; Blangero, J; Chen, Y; Lehman, D M

    2017-02-01

    Recent data suggest that common genetic risks for metabolic disorders such as obesity may be human-specific and exert effects via the central nervous system. To overcome the limitation of human tissue access for study, we have generated induced human pluripotent stem cell (hiPSC)-derived neuronal cultures that recapture many features of hypothalamic neurones within the arcuate nucleus. In the present study, we have comprehensively characterised this model across development, benchmarked these neurones to in vivo events, and demonstrate a link between obesity risk variants and hypothalamic development. The dynamic transcriptome across neuronal maturation was examined using microarray and RNA sequencing methods at nine time points. K-means clustering of the longitudinal data was conducted to identify co-regulation and microRNA control of biological processes. The transcriptomes were compared with those of 103 samples from 13 brain regions reported in the Genotype-Tissue Expression database (GTEx) using principal components analysis. Genes with proximity to body mass index (BMI)-associated genetic variants were mapped to the developmentally expressed genesets, and enrichment significance was assessed with Fisher's exact test. The human neuronal cultures have a transcriptional and physiological profile of neuropeptide Y/agouti-related peptide arcuate nucleus neurones. The neuronal transcriptomes were highly correlated with adult hypothalamus compared to any other brain region from the GTEx. Also, approximately 25% of the transcripts showed substantial changes in expression across neuronal development and potential co-regulation of biological processes that mirror neuronal development in vivo. These developmentally expressed genes were significantly enriched for genes in proximity to BMI-associated variants. We confirmed the utility of this in vitro human model for studying the development of key hypothalamic neurones involved in energy balance and show that genes at

  10. Sweet Taste Receptor Serves to Activate Glucose- and Leptin-Responsive Neurons in the Hypothalamic Arcuate Nucleus and Participates in Glucose Responsiveness.

    PubMed

    Kohno, Daisuke; Koike, Miho; Ninomiya, Yuzo; Kojima, Itaru; Kitamura, Tadahiro; Yada, Toshihiko

    2016-01-01

    The hypothalamic feeding center plays an important role in energy homeostasis. In the feeding center, whole-body energy signals including hormones and nutrients are sensed, processed, and integrated. As a result, food intake and energy expenditure are regulated. Two types of glucose-sensing neurons exist in the hypothalamic arcuate nucleus (ARC): glucose-excited neurons and glucose-inhibited neurons. While some molecules are known to be related to glucose sensing in the hypothalamus, the mechanisms underlying glucose sensing in the hypothalamus are not fully understood. The sweet taste receptor is a heterodimer of taste type 1 receptor 2 (T1R2) and taste type 1 receptor 3 (T1R3) and senses sweet tastes. T1R2 and T1R3 are distributed in multiple organs including the tongue, pancreas, adipose tissue, and hypothalamus. However, the role of sweet taste receptors in the ARC remains to be clarified. To examine the role of sweet taste receptors in the ARC, cytosolic Ca(2+) concentration ([Ca(2+)]i) in isolated single ARC neurons were measured using Fura-2 fluorescent imaging. An artificial sweetener, sucralose at 10(-5)-10(-2) M dose dependently increased [Ca(2+)]i in 12-16% of ARC neurons. The sucralose-induced [Ca(2+)]i increase was suppressed by a sweet taste receptor inhibitor, gurmarin. The sucralose-induced [Ca(2+)]i increase was inhibited under an extracellular Ca(2+)-free condition and in the presence of an L-type Ca(2+) channel blocker, nitrendipine. Sucralose-responding neurons were activated by high-concentration of glucose. This response to glucose was markedly suppressed by gurmarin. More than half of sucralose-responding neurons were activated by leptin but not ghrelin. Percentages of proopiomelanocortin (POMC) neurons among sucralose-responding neurons and sweet taste receptor expressing neurons were low, suggesting that majority of sucralose-responding neurons are non-POMC neurons. These data suggest that sweet taste receptor-mediated cellular activation

  11. Sweet Taste Receptor Serves to Activate Glucose- and Leptin-Responsive Neurons in the Hypothalamic Arcuate Nucleus and Participates in Glucose Responsiveness

    PubMed Central

    Kohno, Daisuke; Koike, Miho; Ninomiya, Yuzo; Kojima, Itaru; Kitamura, Tadahiro; Yada, Toshihiko

    2016-01-01

    The hypothalamic feeding center plays an important role in energy homeostasis. In the feeding center, whole-body energy signals including hormones and nutrients are sensed, processed, and integrated. As a result, food intake and energy expenditure are regulated. Two types of glucose-sensing neurons exist in the hypothalamic arcuate nucleus (ARC): glucose-excited neurons and glucose-inhibited neurons. While some molecules are known to be related to glucose sensing in the hypothalamus, the mechanisms underlying glucose sensing in the hypothalamus are not fully understood. The sweet taste receptor is a heterodimer of taste type 1 receptor 2 (T1R2) and taste type 1 receptor 3 (T1R3) and senses sweet tastes. T1R2 and T1R3 are distributed in multiple organs including the tongue, pancreas, adipose tissue, and hypothalamus. However, the role of sweet taste receptors in the ARC remains to be clarified. To examine the role of sweet taste receptors in the ARC, cytosolic Ca2+ concentration ([Ca2+]i) in isolated single ARC neurons were measured using Fura-2 fluorescent imaging. An artificial sweetener, sucralose at 10−5–10−2 M dose dependently increased [Ca2+]i in 12–16% of ARC neurons. The sucralose-induced [Ca2+]i increase was suppressed by a sweet taste receptor inhibitor, gurmarin. The sucralose-induced [Ca2+]i increase was inhibited under an extracellular Ca2+-free condition and in the presence of an L-type Ca2+ channel blocker, nitrendipine. Sucralose-responding neurons were activated by high-concentration of glucose. This response to glucose was markedly suppressed by gurmarin. More than half of sucralose-responding neurons were activated by leptin but not ghrelin. Percentages of proopiomelanocortin (POMC) neurons among sucralose-responding neurons and sweet taste receptor expressing neurons were low, suggesting that majority of sucralose-responding neurons are non-POMC neurons. These data suggest that sweet taste receptor-mediated cellular activation mainly

  12. Central action of FGF19 reduces hypothalamic AGRP/NPY neuron activity and improves glucose metabolism.

    PubMed

    Marcelin, Geneviève; Jo, Young-Hwan; Li, Xiaosong; Schwartz, Gary J; Zhang, Ying; Dun, Nae J; Lyu, Rong-Ming; Blouet, Clémence; Chang, Jaw K; Chua, Streamson

    2014-02-01

    Tight control of glucose excursions has been a long-standing goal of treatment for patients with type 2 diabetes mellitus in order to ameliorate the morbidity and mortality associated with hyperglycemia. Fibroblast growth factor (FGF) 19 is a hormone-like enterokine released postprandially that emerged as a potential therapeutic agent for metabolic disorders, including diabetes and obesity. Remarkably, FGF19 treatment has hypoglycemic actions that remain potent in models of genetic and acquired insulin resistance. Here, we provided evidence that the central nervous system responds to FGF19 administered in the periphery. Then, in two mouse models of insulin resistance, leptin-deficiency and high-fat diet feeding, third intra-cerebro-ventricular infusions of FGF19 improved glycemic status, reduced insulin resistance and potentiated insulin signaling in the periphery. In addition, our study highlights a new mechanism of central FGF19 action, involving the suppression of AGRP/NPY neuronal activity. Overall, our work unveils novel regulatory pathways induced by FGF19 that will be useful in the design of novel strategies to control diabetes in obesity.

  13. The effects of experimental gestational hypertension on maternal blood pressure and fluid intake and pre-weanling hypothalamic neuronal activity.

    PubMed

    Arguelles, Juan; Perillan, Carmen; Beltz, Terry G; Xue, Baojian; Badaue-Passos, Daniel; Vega, Jose A; Johnson, Alan Kim

    2017-04-11

    To examine the fetal programming effects of maternal hypertension, natriophilia and hyperreninemia [experimentally induced in rats by partial inter-renal aortic ligature (PAL) prior to mating] fos immunoreactivity was studied in 6-day-old offspring of PAL and control mothers. The purposes of the present set of experiments were twofold. The first was to characterize the effects of PAL on the mother's arterial blood pressure and intake of salt (1.8% NaCl solution) and water over the course of gestation. Second, was to study the pattern of neuronal activation in key brain areas of 6-day-old offspring treated with the dipsogen isoproterenol that were from PAL and control mothers. Beta-adrenergic receptor agonist-treated pups allowed the determination whether there were neuroanatomical correlates within the neural substrates controlling thirst and the enhanced water intake evidenced by the isoproterenol treated pups of PAL mothers. Hydromineral ingestive behavior along with blood pressure and heart rate of PAL (M-PAL) and control (M-sPAL) dams throughout gestation was studied. Higher salt and water intakes along with blood pressures and heart rates were found during gestation and lactation in the M-PAL group. Maternal PAL evoked significantly increased isoproterenol-elicited Fos staining in brain regions (e.g. subfornical organ, organum vasculosum of the lamina terminalis, supraoptic nucleus, hypothalamic paraventricular nucleus and median preoptic nucleus) of 6-day-old pups, which is the age of animals shown enhanced thirst responses in PAL offspring. These results indicate that PAL is compatible with pregnancy, producing a sustained increase in blood pressure and heart rate, along with increased water and salt intake. The present study demonstrates that the neural substrates involved in cardiovascular homeostasis and fluid balance in adult rats are responsive in six-day-old rats, and can be altered by fetal programming.

  14. Effects of embryonic ethanol exposure at low doses on neuronal development, voluntary ethanol consumption and related behaviors in larval and adult zebrafish: Role of hypothalamic orexigenic peptides.

    PubMed

    Sterling, M E; Chang, G-Q; Karatayev, O; Chang, S Y; Leibowitz, S F

    2016-05-01

    Embryonic exposure to ethanol is known to affect neurochemical systems in rodents and increase alcohol drinking and related behaviors in humans and rodents. With zebrafish emerging as a powerful tool for uncovering neural mechanisms of numerous diseases and exhibiting similarities to rodents, the present report building on our rat studies examined in zebrafish the effects of embryonic ethanol exposure on hypothalamic neurogenesis, expression of orexigenic neuropeptides, and voluntary ethanol consumption and locomotor behaviors in larval and adult zebrafish, and also effects of central neuropeptide injections on these behaviors affected by ethanol. At 24h post-fertilization, zebrafish embryos were exposed for 2h to ethanol, at low concentrations of 0.25% and 0.5%, in the tank water. Embryonic ethanol compared to control dose-dependently increased hypothalamic neurogenesis and the proliferation and expression of the orexigenic peptides, galanin (GAL) and orexin (OX), in the anterior hypothalamus. These changes in hypothalamic peptide neurons were accompanied by an increase in voluntary consumption of 10% ethanol-gelatin and in novelty-induced locomotor and exploratory behavior in adult zebrafish and locomotor activity in larvae. After intracerebroventricular injection, these peptides compared to vehicle had specific effects on these behaviors altered by ethanol, with GAL stimulating consumption of 10% ethanol-gelatin more than plain gelatin food and OX stimulating novelty-induced locomotor behavior while increasing intake of food and ethanol equally. These results, similar to those obtained in rats, suggest that the ethanol-induced increase in genesis and expression of these hypothalamic peptide neurons contribute to the behavioral changes induced by embryonic exposure to ethanol.

  15. Effects of embryonic ethanol exposure at low doses on neuronal development, voluntary ethanol consumption and related behaviors in larval and adult zebrafish: Role of hypothalamic orexigenic peptides

    PubMed Central

    Sterling, M.E.; Chang, G.-Q.; Karatayev, O.; Chang, S.Y.; Leibowitz, S.F.

    2016-01-01

    Embryonic exposure to ethanol is known to affect neurochemical systems in rodents and increase alcohol drinking and related behaviors in humans and rodents. With zebrafish emerging as a powerful tool for uncovering neural mechanisms of numerous diseases and exhibiting similarities to rodents, the present report building on our rat studies examined in zebrafish the effects of embryonic ethanol exposure on hypothalamic neurogenesis, expression of orexigenic neuropeptides, and voluntary ethanol consumption and locomotor behaviors in larval and adult zebrafish, and also effects of central neuropeptide injections on these behaviors affected by ethanol. At 24 h post-fertilization, zebrafish embryos were exposed for 2 h to ethanol, at low concentrations of 0.25% and 0.5%, in the tank water. Embryonic ethanol compared to control dose-dependently increased hypothalamic neurogenesis and the proliferation and expression of the orexigenic peptides, galanin (GAL) and orexin (OX), in the anterior hypothalamus. These changes in hypothalamic peptide neurons were accompanied by an increase in voluntary consumption of 10% ethanol-gelatin and in novelty-induced locomotor and exploratory behavior in adult zebrafish and locomotor activity in larvae. After intracerebroventricular injection, these peptides compared to vehicle had specific effects on these behaviors altered by ethanol, with GAL stimulating consumption of 10% ethanol-gelatin more than plain gelatin food and OX stimulating novelty-induced locomotor behavior while increasing intake of food and ethanol equally. These results, similar to those obtained in rats, suggest that the ethanol-induced increase in genesis and expression of these hypothalamic peptide neurons contribute to the behavioral changes induced by embryonic exposure to ethanol. PMID:26778786

  16. Central action of ELABELA reduces food intake and activates arginine vasopressin and corticotropin-releasing hormone neurons in the hypothalamic paraventricular nucleus.

    PubMed

    Santoso, Putra; Maejima, Yuko; Kumamoto, Kensuke; Takenoshita, Seiichi; Shimomura, Kenju

    2015-09-30

    ELABELA (ELA) is a novel hormone consisting of 32 amino acid peptides found in humans as well as other vertebrates and is considered to play an important role in the circulatory system through the apelin receptor (APJ). However, whether ELA also acts in the central nervous system remains unknown. Here, we show that ELA functions as an anorexigenic hormone in adult mouse brain. An intracerebroventricular injection of ELA reduces food intake and activates arginine vasopressin (AVP) and corticotropin-releasing hormone (CRH) neurons in the paraventricular nucleus (PVN), a hypothalamic region that regulates food intake. Cytosolic calcium ([Ca]i) measurement shows that ELA dose dependently increases [Ca]i in single AVP and CRH-immunoreactive neurons isolated from the PVN. Our data suggest that ELA functions as an anorexigenic hormone through activation of AVP and CRH neurons in the PVN.

  17. Insulin directly regulates NPY and AgRP gene expression via the MAPK MEK/ERK signal transduction pathway in mHypoE-46 hypothalamic neurons.

    PubMed

    Mayer, Christopher M; Belsham, Denise D

    2009-08-13

    Insulin plays a key role in the maintenance of nutrient homeostasis through central regulation of neuropeptides. Neuropeptide Y (NPY) and agouti-related peptide (AgRP) are vital orexigenic peptides that are regulated by insulin, although the processes utilized are unknown. Using a hypothalamic, clonal cell line, mHypoE-46, which endogenously expresses NPY, AgRP and the insulin receptor, we studied the mechanisms involved in the regulation of the NPY/AgRP neuron by insulin. We determined that insulin has direct actions on the neurons and acts to repress NPY/AgRP gene expression through a MAPK MEK/ERK-dependent pathway. Transient transfection analysis determined that human NPY and AgRP 5' flanking gene regions were not regulated by insulin in the mouse cell line, while sequence comparison analysis indicated only a 50% sequence similarity between human and mouse NPY and AgRP 5' flanking regions. These experiments indicate that insulin acts directly on specific hypothalamic neurons to regulate neuropeptide transcription.

  18. Chronic growth hormone (GH) hypersecretion induces reciprocal and reversible changes in mRNA levels from hypothalamic GH-releasing hormone and somatostatin neurons in the rat.

    PubMed Central

    Bertherat, J; Timsit, J; Bluet-Pajot, M T; Mercadier, J J; Gourdji, D; Kordon, C; Epelbaum, J

    1993-01-01

    Effects of growth hormone (GH) hypersecretion on somatostatin-(SRIH) and GH-releasing hormone (GHRH) were studied by in situ hybridization and receptor autoradiography in rats bearing a GH-secreting tumor. 6 and 18 wk after tumor induction, animals displayed a sharp increase in body weight and GH plasma levels; pituitary GH content was reduced by 47 and 55%, while that of prolactin and thyrotropin was unchanged. At 18 wk, hypothalamic GHRH and SRIH levels had fallen by 84 and 52%, respectively. In parallel, the density of GHRH mRNA per arcuate neuron was reduced by 52 and 50% at 6 and 18 wk, while SRIH mRNA levels increased by 71 and 83% in the periventricular nucleus (with no alteration in the hilus of the dentate gyrus). The numbers of GHRH- and SRIH-synthetizing neurons in the hypothalamus were not altered in GH-hypersecreting rats. Resection of the tumor restored hypothalamic GHRH and SRIH mRNAs to control levels. GH hypersecretion did not modify 125I-SRIH binding sites on GHRH neurons. Thus, chronic GH hypersecretion affects the expression of the genes encoding for GHRH and SRIH. The effect is long lasting, not desensitizable and reversible. Images PMID:8097209

  19. Stressor-responsive central nesfatin-1 activates corticotropin-releasing hormone, noradrenaline and serotonin neurons and evokes hypothalamic-pituitary-adrenal axis

    PubMed Central

    Yoshida, Natsu; Maejima, Yuko; Sedbazar, Udval; Ando, Akihiko; Kurita, Hideharu; Damdindorj, Boldbaatar; Takano, Eisuke; Gantulga, Darambazar; Iwasaki, Yusaku; Kurashina, Tomoyuki; Onaka, Tatsushi; Dezaki, Katsuya; Nakata, Masanori; Mori, Masatomo; Yada, Toshihiko

    2010-01-01

    A recently discovered satiety molecule, nesfatin-1, is localized in neurons of the hypothalamus and brain stem and colocalized with stress-related substances, corticotropin-releasing hormone (CRH), oxytocin, proopiomelanocortin, noradrenaline (NA) and 5-hydroxytryptamine (5-HT). Intracerebroventricular (icv) administration of nesfatin-1 produces fear-related behaviors and potentiates stressor-induced increases in plasma adrenocorticotropic hormone (ACTH) and corticosterone levels in rats. These findings suggest a link between nesfatin-1 and stress. In the present study, we aimed to further clarify the neuronal network by which nesfatin-1 could induce stress responses in rats. Restraint stress induced c-Fos expressions in nesfatin-1-immunoreactive neurons in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus, and in the nucleus of solitary tract (NTS), locus coeruleus (LC) and dorsal raphe nucleus (DR) in the brain stem, without altering plasma nesfatin-1 levels. Icv nesfatin-1 induced c-Fos expressions in the PVN, SON, NTS, LC, DR and median raphe nucleus, including PVN-CRH, NTS-NA, LC-NA and DR-5-HT neurons. Nesfatin-1 increased cytosolic Ca2+ concentration in the CRH-immunoreactive neurons isolated from PVN. Icv nesfatin-1 increased plasma ACTH and corticosterone levels. These results indicate that the central nesfatin-1 system is stimulated by stress and activates CRH, NA and 5-HT neurons and hypothalamic-pituitary-adrenal axis, evoking both central and peripheral stress responses. PMID:20966530

  20. Morphine withdrawal-induced c-fos expression in the hypothalamic paraventricular nucleus is dependent on the activation of catecholaminergic neurones.

    PubMed

    Laorden, M Luisa; Núñez, Cristina; Almela, Pilar; Milanés, M Victoria

    2002-10-01

    We previously demonstrated that morphine withdrawal induced hyperactivity of noradrenergic pathways innervating the hypothalamic paraventricular nucleus (PVN) in rats, in parallel with an increase in the neurosecretory activity of the hypothalamus-pituitary-adrenocortical (HPA) axis, as evaluated by corticosterone release. These neuroendocrine effects were dependent on stimulation of alpha-adrenoceptors. In the present study, Fos immunostaining was used as a reflection of neuronal activity and combined with immunostaining for tyrosine hydroxylase (TH) for immunohistochemical identification of active neurones during morphine withdrawal. Dependence on morphine was induced by 7-day chronic subcutaneous implantation of six morphine pellets (75 mg). Morphine withdrawal was precipitated by administration of naloxone (5 mg/kg subcutaneously) on day 8. Fos immunoreactivity in the PVN and also in the nucleus tractus solitarius (NTS)-A2 and ventrolateral medulla (VLM)-A1 cell groups, which project to the PVN, increased during morphine withdrawal. Following withdrawal, Fos immunoreactivity was present in most of the TH-positive neurones of the A2 and A1 neurones. In a second study, the effects of administration of adrenoceptor antagonists on withdrawal-induced Fos expression in the PVN were studied. Pre-treatment with alpha1- or alpha2-adrenoceptor antagonists, prazosin (1 mg/kg intraperitoneally) and yohimbine (1 mg/kg intraperitoneally), respectively, 20 min before naloxone administration to morphine-dependent rats markedly reduced Fos expression in the PVN. Similarly, pre-treatment with the beta antagonist, propranolol (3 mg/kg intraperitoneally), significantly prevented withdrawal-induced Fos expression. Collectively, these results suggest the hypothesis that noradrenergic neurones in the brainstem innervating the PVN are active during morphine withdrawal, and that activation of transcriptional responses mediated by Fos in the HPA axis following withdrawal are dependent

  1. Single cell transcriptomics of hypothalamic warm sensitive neurons that control core body temperature and fever response Signaling asymmetry and an extension of chemical neuroanatomy.

    PubMed

    Eberwine, James; Bartfai, Tamas

    2011-03-01

    We report on an 'unbiased' molecular characterization of individual, adult neurons, active in a central, anterior hypothalamic neuronal circuit, by establishing cDNA libraries from each individual, electrophysiologically identified warm sensitive neuron (WSN). The cDNA libraries were analyzed by Affymetrix microarray. The presence and frequency of cDNAs were confirmed and enhanced with Illumina sequencing of each single cell cDNA library. cDNAs encoding the GABA biosynthetic enzyme Gad1 and of adrenomedullin, galanin, prodynorphin, somatostatin, and tachykinin were found in the WSNs. The functional cellular and in vivo studies on dozens of the more than 500 neurotransmitters, hormone receptors and ion channels, whose cDNA was identified and sequence confirmed, suggest little or no discrepancy between the transcriptional and functional data in WSNs; whenever agonists were available for a receptor whose cDNA was identified, a functional response was found. Sequencing single neuron libraries permitted identification of rarely expressed receptors like the insulin receptor, adiponectin receptor 2 and of receptor heterodimers; information that is lost when pooling cells leads to dilution of signals and mixing signals. Despite the common electrophysiological phenotype and uniform Gad1 expression, WSN transcriptomes show heterogeneity, suggesting strong epigenetic influence on the transcriptome. Our study suggests that it is well-worth interrogating the cDNA libraries of single neurons by sequencing and chipping.

  2. Evidence for the exclusive expression of functional homomeric α7 nAChRs in hypothalamic histaminergic tuberomammillary neurons in rats

    PubMed Central

    Tischkau, Shelley; Mhaskar, Yashanad; Uteshev, Victor V.

    2014-01-01

    Hypothalamic histaminergic tuberomammillary (TM) neurons in rats express high densities of nicotinic acetylcholine receptors (nAChRs) whose Ca2+ permeability, kinetic and pharmacological properties are similar to those of heterologous homomeric α7 nAChRs. However, native α7 nAChR subunits can co-assemble with β or α5 nAChR subunits to form functional heteromeric α7-containing α7β or α7α5 nAChRs with kinetics and pharmacology similar to those of α7 homomers. Therefore, although TM nAChRs have been used as an ex vivo model of functional α7 homomers, the molecular makeup of TM nAChRs has not been determined and the expression of functional α7-containing heteromers in TM neurons has not been excluded. To determine the profile of TM nAChR subunit transcripts, we have conducted single-cell qRT-PCR experiments using acutely dissociated TM neurons in rats. TM neurons were found to express transcripts of only principal α3, α6 and α7 nAChR subunits. Transcripts of other known mammalian neuronal subunits (α2, α4-5, α9-10, β2-4) were not detected. In the absence of β and α5 subunits, the expression of functional α7-containing heteromers in TM neurons is highly unlikely because principal α3, α6 and α7 nAChR subunits alone are not known to form functional heteromeric nAChRs. These results support the exclusive expression of native functional α7 homomers in rat TM neurons and introduce these neurons as a unique reliable source of native functional homomeric α7 nAChRs suitable for ex vivo and in vitro pharmacological assays in developing selective α7 nAChR agents. PMID:24486841

  3. Evidence for the exclusive expression of functional homomeric α7 nAChRs in hypothalamic histaminergic tuberomammillary neurons in rats.

    PubMed

    Tischkau, Shelley; Mhaskar, Yashanad; Uteshev, Victor V

    2014-03-20

    Hypothalamic histaminergic tuberomammillary (TM) neurons in rats express high densities of nicotinic acetylcholine receptors (nAChRs) whose Ca(2+) permeability, kinetic and pharmacological properties are similar to those of heterologous homomeric α7 nAChRs. However, native α7 nAChR subunits can co-assemble with β or α5 nAChR subunits to form functional heteromeric α7-containing α7β or α7α5 nAChRs with kinetics and pharmacology similar to those of α7 homomers. Therefore, although TM nAChRs have been used as an ex vivo model of functional α7 homomers, the molecular makeup of TM nAChRs has not been determined and the expression of functional α7-containing heteromers in TM neurons has not been excluded. To determine the profile of TM nAChR subunit transcripts, we have conducted single-cell qRT-PCR experiments using acutely dissociated TM neurons in rats. TM neurons were found to express transcripts of only principal α3, α6 and α7 nAChR subunits. Transcripts of other known mammalian neuronal subunits (α2, α4-5, α9-10, β2-4) were not detected. In the absence of β and α5 subunits, the expression of functional α7-containing heteromers in TM neurons is highly unlikely because principal α3, α6 and α7 nAChR subunits alone are not known to form functional heteromeric nAChRs. These results support the exclusive expression of native functional α7 homomers in rat TM neurons and introduce these neurons as a unique reliable source of native functional homomeric α7 nAChRs suitable for ex vivo and in vitro pharmacological assays in developing selective α7 nAChR agents. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. Protein kinase CK2 contributes to diminished small conductance Ca2+-activated K+ channel activity of hypothalamic pre-sympathetic neurons in hypertension.

    PubMed

    Pachuau, Judith; Li, De-Pei; Chen, Shao-Rui; Lee, Hae-Ahm; Pan, Hui-Lin

    2014-09-01

    Small conductance calcium-activated K(+) (SK) channels regulate neuronal excitability. However, little is known about changes in SK channel activity of pre-sympathetic neurons in the hypothalamic paraventricular nucleus (PVN) in essential hypertension. SK channels, calmodulin, and casein kinase II (CK2) form a molecular complex. Because CK2 is up-regulated in the PVN in spontaneously hypertensive rats (SHRs), we hypothesized that CK2 increases calmodulin phosphorylation and contributes to diminished SK channel activity in PVN pre-sympathetic neurons in SHRs. Perforated whole-cell recordings were performed on retrogradely labeled spinally projecting PVN neurons in Wistar-Kyoto (WKY) rats and SHRs. Blocking SK channels with apamin significantly increased the firing rate of PVN neurons in WKY rats but not in SHRs. CK2 inhibition restored the stimulatory effect of apamin on the firing activity of PVN neurons in SHRs. Furthermore, apamin-sensitive SK currents and depolarization-induced medium after-hyperpolarization potentials of PVN neurons were significantly larger in WKY rats than in SHRs. CK2 inhibition significantly increased the SK channel current and medium after-depolarization potential of PVN neurons in SHRs. In addition, CK2-mediated calmodulin phosphorylation level in the PVN was significantly higher in SHRs than in WKY rats. Although SK3 was detected in the PVN, its expression level did not differ significantly between SHRs and WKY rats. Our findings suggest that CK2-mediated calmodulin phosphorylation is increased and contributes to diminished SK channel function of PVN pre-sympathetic neurons in SHRs. This information advances our understanding of the mechanisms underlying hyperactivity of PVN pre-sympathetic neurons and increased sympathetic vasomotor tone in hypertension. Small conductance calcium-activated K(+) (SK) channels, calmodulin, and protein kinase CK2 form a molecular complex and regulate neuronal excitability. Our study suggests that augmented

  5. Arg-Phe-amide-related peptides influence gonadotropin-releasing hormone neurons.

    PubMed

    Kelestimur, Haluk; Kacar, Emine; Uzun, Aysegul; Ozcan, Mete; Kutlu, Selim

    2013-06-25

    The hypothalamic Arg-Phe-amide-related peptides, gonadotropin-inhibitory hormone and orthologous mammalian peptides of Arg-Phe-amide, may be important regulators of the hypothalamus-pituitary-gonadal reproductive axis. These peptides may modulate the effects of kisspeptins because they are presently recognized as the most potent activators of the hypothalamus-pituitary-gonadal axis. However, their effects on gonadotropin-releasing hormone neurons have not been investigated. In the current study, the GT1-7 cell line-expressing gonadotropin-releasing hormone was used as a model to explore the effects of Arg-Pheamide-related peptides on kisspeptin activation. Intracellular calcium concentration was quantified using the calcium-sensitive dye, fura-2 acetoxymethyl ester. Gonadotropin-releasing hormone released into the medium was detected via enzyme-linked immunosorbent assay. Results showed that 100 nmol/L kisspeptin-10 significantly increased gonadotropin-releasing hormone levels (at 120 minutes of exposure) and intracellular calcium concentrations. Co-treatment of kisspeptin with 1 μmol/L gonadotropin-inhibitory hormone or 1 μmol/L Arg-Phe-amide-related peptide-1 significantly attenuated levels of kisspeptin-induced gonadotropin-releasing hormone but did not affect kisspeptin-induced elevations of intracellular calcium concentration. Overall, the results suggest that gonadotropin-inhibitory hormone and Arg-Phe-amide-related peptide-1 may have inhibitory effects on kisspeptin-activated gonadotropin-releasing hormone neurons independent of the calcium signaling pathway.

  6. Separate populations of neurons within the paraventricular hypothalamic nucleus of the rat project to vagal and thoracic autonomic preganglionic levels and express c-Fos protein induced by lithium chloride.

    PubMed

    Portillo, F; Carrasco, M; Vallo, J J

    1998-03-01

    The role of different hypothalamic nuclei, particularly the paraventricular nucleus (PVN), in the control of food intake and feeding behaviour is well known. It is also well established that lithium chloride (LiCl) causes various disorders in feeding behaviour. In this study, we analyzed the precise distribution of hypothalamic neurons activated by i.p. LiCl administration (LCA neurons) and compared it to that of hypothalamic neurons which project to autonomic preganglionic levels (HAP neurons). We also analysed the possibility that some neurons belong to both populations of nerve cells. To this end, a multiple-labelling technique, using two retrograde fluorescent tracers together with c-Fos-like immunohistochemistry, was performed. Fast Blue was injected in the dorsal motor nucleus of the vagus and Fluorogold (FG) in the thoracic intermedial-lateral cell column, to trace parasympathetic and sympathetic pathways, respectively. LiCl was used as stimulus for c-Fos-like immunohistochemistry. HAP neurons were located mainly in the dorsal, ventral and lateral regions of the parvocellular PVN, while LCA neurons were observed predominantly in the magnocellular region of the PVN rostrally to HAP neurons. A significant number of FG/Fos double-labelled neurons were located in the dorsal parvocellular subnucleus of the PVN (dp) in the LiCl-stimulated rats. We concluded that there is a clear segregation of LCA neurons from HAP neurons within the PVN. The presence of FG/Fos double-labelled neurons in the dp suggests that this nucleus could mediate a sympathetic response after LiCl administration.

  7. Effect of Cholesterol Reduction on Receptor Signaling in Neurons*

    PubMed Central

    Fukui, Kenji; Ferris, Heather A.; Kahn, C. Ronald

    2015-01-01

    Diabetes mellitus is associated with a variety of complications, including alterations in the central nervous system (CNS). We have recently shown that diabetes results in a reduction of cholesterol synthesis in the brain due to decreased insulin stimulation of SREBP2-mediated cholesterol synthesis in neuronal and glial cells. In the present study, we explored the effects of the decrease in cholesterol on neuronal cell function using GT1-7 hypothalamic cells subjected to cholesterol depletion in vitro using three independent methods: 1) exposure to methyl-β-cyclodextrin, 2) treatment with the HMG-CoA reductase inhibitor simvastatin, and 3) shRNA-mediated knockdown of SREBP2. All three methods produced 20–31% reductions in cellular cholesterol content, similar to the decrease in cholesterol synthesis observed in diabetes. All cholesterol-depleted neuron-derived cells, independent of the method of reduction, exhibited decreased phosphorylation/activation of IRS-1 and AKT following stimulation by insulin, insulin-like growth factor-1, or the neurotrophins (NGF and BDNF). ERK phosphorylation/activation was also decreased after methyl-β-cyclodextrin and statin treatment but increased in cells following SREBP2 knockdown. In addition, apoptosis in the presence of amyloid-β was increased. Reduction in cellular cholesterol also resulted in increased basal autophagy and impairment of induction of autophagy by glucose deprivation. Together, these data indicate that a reduction in neuron-derived cholesterol content, similar to that observed in diabetic brain, creates a state of insulin and growth factor resistance that could contribute to CNS-related complications of diabetes, including increased risk of neurodegenerative diseases, such as Alzheimer disease. PMID:26370080

  8. Arcuate hypothalamic AgRP and putative POMC neurons show opposite changes in spiking across multiple timescales

    PubMed Central

    Mandelblat-Cerf, Yael; Ramesh, Rohan N; Burgess, Christian R; Patella, Paola; Yang, Zongfang; Lowell, Bradford B; Andermann, Mark L

    2015-01-01

    Agouti-related-peptide (AgRP) neurons—interoceptive neurons in the arcuate nucleus of the hypothalamus (ARC)—are both necessary and sufficient for driving feeding behavior. To better understand the functional roles of AgRP neurons, we performed optetrode electrophysiological recordings from AgRP neurons in awake, behaving AgRP-IRES-Cre mice. In free-feeding mice, we observed a fivefold increase in AgRP neuron firing with mounting caloric deficit in afternoon vs morning recordings. In food-restricted mice, as food became available, AgRP neuron firing dropped, yet remained elevated as compared to firing in sated mice. The rapid drop in spiking activity of AgRP neurons at meal onset may reflect a termination of the drive to find food, while residual, persistent spiking may reflect a sustained drive to consume food. Moreover, nearby neurons inhibited by AgRP neuron photostimulation, likely including satiety-promoting pro-opiomelanocortin (POMC) neurons, demonstrated opposite changes in spiking. Finally, firing of ARC neurons was also rapidly modulated within seconds of individual licks for liquid food. These findings suggest novel roles for antagonistic AgRP and POMC neurons in the regulation of feeding behaviors across multiple timescales. DOI: http://dx.doi.org/10.7554/eLife.07122.001 PMID:26159614

  9. Deletion of Suppressor of Cytokine Signaling 3 from Forebrain Neurons Delays Infertility and Onset of Hypothalamic Leptin Resistance in Response to a High Caloric Diet.

    PubMed

    McEwen, Hayden J L; Inglis, Megan A; Quennell, Janette H; Grattan, David R; Anderson, Greg M

    2016-07-06

    The cellular processes that cause high caloric diet (HCD)-induced infertility are poorly understood but may involve upregulation of suppressor of cytokine signaling (SOCS-3) proteins that are associated with hypothalamic leptin resistance. Deletion of SOCS-3 from brain cells is known to protect mice from diet-induced obesity, but the effects on HCD-induced infertility are unknown. We used neuron-specific SOCS3 knock-out mice to elucidate this and the effects on regional hypothalamic leptin resistance. As expected, male and female neuron-specific SOCS3 knock-out mice were protected from HCD-induced obesity. While female wild-type mice became infertile after 4 months of HCD feeding, infertility onset in knock-out females was delayed by 4 weeks. Similarly, knock-out mice had delayed leptin resistance development in the medial preoptic area and anteroventral periventricular nucleus, regions important for generation of the surge of GnRH and LH that induces ovulation. We therefore tested whether the suppressive effects of HCD on the estradiol-induced GnRH/LH surge were overcome by neuron-specific SOCS3 knock-out. Although only 20% of control HCD-mice experienced a preovulatory-like LH surge, LH surges could be induced in almost all neuron-specific SOCS3 knock-out mice on this diet. In contrast to females, HCD-fed male mice did not exhibit any fertility decline compared with low caloric diet-fed males despite their resistance to the satiety effects of leptin. These data show that deletion of SOCS3 delays the onset of leptin resistance and infertility in HCD-fed female mice, but given continued HCD feeding this state does eventually occur, presumably in response to other mechanisms inhibiting leptin signal transduction. Obesity is commonly associated with infertility in humans and other animals. Treatments for human infertility show a decreased success rate with increasing body mass index. A hallmark of obesity is an increase in circulating leptin levels; despite this, the

  10. Deletion of Suppressor of Cytokine Signaling 3 from Forebrain Neurons Delays Infertility and Onset of Hypothalamic Leptin Resistance in Response to a High Caloric Diet

    PubMed Central

    McEwen, Hayden J. L.; Inglis, Megan A.; Quennell, Janette H.; Grattan, David R.

    2016-01-01

    The cellular processes that cause high caloric diet (HCD)-induced infertility are poorly understood but may involve upregulation of suppressor of cytokine signaling (SOCS-3) proteins that are associated with hypothalamic leptin resistance. Deletion of SOCS-3 from brain cells is known to protect mice from diet-induced obesity, but the effects on HCD-induced infertility are unknown. We used neuron-specific SOCS3 knock-out mice to elucidate this and the effects on regional hypothalamic leptin resistance. As expected, male and female neuron-specific SOCS3 knock-out mice were protected from HCD-induced obesity. While female wild-type mice became infertile after 4 months of HCD feeding, infertility onset in knock-out females was delayed by 4 weeks. Similarly, knock-out mice had delayed leptin resistance development in the medial preoptic area and anteroventral periventricular nucleus, regions important for generation of the surge of GnRH and LH that induces ovulation. We therefore tested whether the suppressive effects of HCD on the estradiol-induced GnRH/LH surge were overcome by neuron-specific SOCS3 knock-out. Although only 20% of control HCD-mice experienced a preovulatory-like LH surge, LH surges could be induced in almost all neuron-specific SOCS3 knock-out mice on this diet. In contrast to females, HCD-fed male mice did not exhibit any fertility decline compared with low caloric diet-fed males despite their resistance to the satiety effects of leptin. These data show that deletion of SOCS3 delays the onset of leptin resistance and infertility in HCD-fed female mice, but given continued HCD feeding this state does eventually occur, presumably in response to other mechanisms inhibiting leptin signal transduction. SIGNIFICANCE STATEMENT Obesity is commonly associated with infertility in humans and other animals. Treatments for human infertility show a decreased success rate with increasing body mass index. A hallmark of obesity is an increase in circulating leptin

  11. Influence of the hypothalamic paraventricular nucleus on cardiovascular neurones in the rostral ventrolateral medulla of the rat.

    PubMed

    Yang, Z; Coote, J H

    1998-12-01

    1. The question of whether neurones in the paraventricular nucleus (PVN) of the hypothalamus have an excitatory influence on reticulo-spinal vasomotor neurones of the rostral ventrolateral medulla (RVL) has been addressed in this study using anaesthetized rats. 2. Extracellular microelectrode recordings were made from sixty vasomotor neurones in the RVL, identified by their cardiac cycle-related probability of discharge, by the decrease in activity in response to an increase in arterial blood pressure produced by intravenous phenylephrine and by the increase in activity in response to a decrease in blood pressure produced by intravenous nitroprusside. 3. More than 70 % of these RVL vasomotor neurones were identified as spinally projecting by antidromically activating their axons via a stimulating electrode in the lateral funiculus of the T2 or T10 segment of spinal cord. 4. Activation of neurones at different sites in the PVN with a microinjection of d,l-homocysteic acid (DLH) elicited either pressor or depressor responses. 5. At PVN pressor sites fifteen RVL vasomotor neurones were shown to be activated prior to the blood pressure change. A further twenty RVL vasomotor neurones were observed to decrease activity following the blood pressure rise. At PVN depressor sites twelve RVL neurones were inhibited prior to the blood pressure change whereas another thirteen identified RVL neurones increased their discharge following the fall in blood pressure. 6. In three rats single shock electrical stimulation at a PVN pressor site, first identified with DLH, elicited a single or double action potential in thirteen RVL neurones with a latency of 27 +/- 1 ms. 7. It is concluded that PVN neurones may elicit increases in blood pressure via excitatory connections with RVL-spinal vasomotor neurones, and that other PVN neurones may elicit decreases in blood pressure via inhibitory connections with these RVL neurones.

  12. Novel Interaction of Class IIb Histone Deacetylase 6 (HDAC6) with Class IIa HDAC9 Controls Gonadotropin Releasing Hormone (GnRH) Neuronal Cell Survival and Movement.

    PubMed

    Salian-Mehta, Smita; Xu, Mei; McKinsey, Timothy A; Tobet, Stuart; Wierman, Margaret E

    2015-05-29

    The impact of histone deacetylases (HDACs) in the control of gonadotropin releasing hormone (GnRH) neuronal development is unknown. We identified an increase in many HDACs in GT1-7 (differentiated) compared with NLT (undifferentiated) GnRH neuronal cell lines. Increased HDAC9 mRNA and protein and specific deacetylase activity in GT1-7 cells suggested a functional role. Introduction of HDAC9 in NLT cells protected from serum withdrawal induced apoptosis and impaired basal neuronal cell movement. Conversely, silencing of endogenous HDAC9 in GT1-7 cells increased apoptosis and cell movement. Comparison of WT and mutant HDAC9 constructs demonstrated that the HDAC9 pro-survival effects required combined cytoplasmic and nuclear localization, whereas the effects on cell movement required a cytoplasmic site of action. Co-immunoprecipitation demonstrated a novel interaction of HDAC9 selectively with the Class IIb HDAC6. HDAC6 was also up-regulated at the mRNA and protein levels, and HDAC6 catalytic activity was significantly increased in GT1-7 compared with NLT cells. HDAC9 interacted with HDAC6 through its second catalytic domain. Silencing of HDAC6, HDAC9, or both, in GT1-7 cells augmented apoptosis compared with controls. HDAC6 and -9 had additive effects to promote cell survival via modulating the BAX/BCL2 pathway. Silencing of HDAC6 resulted in an activation of movement of GT1-7 cells with induction in acetylation of α-tubulin. Inhibition of HDAC6 and HDAC9 together resulted in an additive effect to increase cell movement but did not alter the acetylation of αtubulin. Together, these studies identify a novel interaction of Class IIa HDAC9 with Class IIb HDAC6 to modulate cell movement and survival in GnRH neurons. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Novel Interaction of Class IIb Histone Deacetylase 6 (HDAC6) with Class IIa HDAC9 Controls Gonadotropin Releasing Hormone (GnRH) Neuronal Cell Survival and Movement*

    PubMed Central

    Salian-Mehta, Smita; Xu, Mei; McKinsey, Timothy A.; Tobet, Stuart; Wierman, Margaret E.

    2015-01-01

    The impact of histone deacetylases (HDACs) in the control of gonadotropin releasing hormone (GnRH) neuronal development is unknown. We identified an increase in many HDACs in GT1-7 (differentiated) compared with NLT (undifferentiated) GnRH neuronal cell lines. Increased HDAC9 mRNA and protein and specific deacetylase activity in GT1-7 cells suggested a functional role. Introduction of HDAC9 in NLT cells protected from serum withdrawal induced apoptosis and impaired basal neuronal cell movement. Conversely, silencing of endogenous HDAC9 in GT1-7 cells increased apoptosis and cell movement. Comparison of WT and mutant HDAC9 constructs demonstrated that the HDAC9 pro-survival effects required combined cytoplasmic and nuclear localization, whereas the effects on cell movement required a cytoplasmic site of action. Co-immunoprecipitation demonstrated a novel interaction of HDAC9 selectively with the Class IIb HDAC6. HDAC6 was also up-regulated at the mRNA and protein levels, and HDAC6 catalytic activity was significantly increased in GT1-7 compared with NLT cells. HDAC9 interacted with HDAC6 through its second catalytic domain. Silencing of HDAC6, HDAC9, or both, in GT1-7 cells augmented apoptosis compared with controls. HDAC6 and -9 had additive effects to promote cell survival via modulating the BAX/BCL2 pathway. Silencing of HDAC6 resulted in an activation of movement of GT1-7 cells with induction in acetylation of α-tubulin. Inhibition of HDAC6 and HDAC9 together resulted in an additive effect to increase cell movement but did not alter the acetylation of αtubulin. Together, these studies identify a novel interaction of Class IIa HDAC9 with Class IIb HDAC6 to modulate cell movement and survival in GnRH neurons. PMID:25873389

  14. Nitric oxide production in the perifornical-lateral hypothalamic area (PF-LHA) and its influences on the modulation of PF-LHA neurons

    PubMed Central

    Kostin, Andrey; Rai, Seema; Kumar, Sunil; Szymusiak, Ronald; McGinty, Dennis; Alam, Md. Noor

    2011-01-01

    The perifornical-lateral hypothalamic area (PF-LHA) is a major wake-promoting structure. It predominantly contains neurons that are active during behavioral and cortical activation. PF-LHA stimulation produces arousal and PF-LHA lesions produce somnolence. Nitric oxide (NO) is a gaseous neurotransmitter that has been implicated in the regulation of multiple pathological and physiological processes including the regulation of sleep. NO levels are higher in the cortex and in the basal forebrain (BF) during arousal. In this study we determined whether NO levels increase in the PF-LHA during prolonged arousal and whether increased NO modulates the discharge activity of PF-LHA neurons. Experiments were conducted during lights-on phase between 8.00 – 20.00h (lights-on at 8.00h). First, we quantified levels of NO metabolites, NO2− and NO3− (collectively called NOx−) in the microdialysis dialysates collected from the PF-LHA during baseline (undisturbed rats), 6h of sleep deprivation (SD), and recovery after SD. We further determined the effects of a NO donor, NOC-18, on the discharge activity of PF-LHA neurons in urethane-anesthetized rats. Overall, SD significantly affected NOx− production in the PF-LHA (one way repeated measures ANOVA, F=7.827, p=0.004). The levels of NOx− increased progressively in animals that were subjected to prolonged arousal as compared to the undisturbed predominantly sleeping animals and decreased during the recovery period. Local application of NOC-18 significantly suppressed the discharge of PF-LHA neurons including a majority of stimulus-on neurons or neurons exhibiting activation during EEG desynchronization. The findings of this study suggest that in the PF-LHA, NO production is elevated during prolonged waking and that NO exerts predominantly inhibitory effects on PF-LHA neurons, especially on those neurons that are active during cortical activation. These findings are consistent with a hypothesis that NO in the PF-LHA plays a

  15. Increased densities of nitric oxide synthase expressing neurons in the temporal cortex and the hypothalamic paraventricular nucleus of polytoxicomanic heroin overdose victims: possible implications for heroin neurotoxicity.

    PubMed

    Bernstein, Hans-Gert; Trübner, Kurt; Krebs, Philipp; Dobrowolny, Henrik; Bielau, Hendrik; Steiner, Johann; Bogerts, Bernhard

    2014-01-01

    Heroin is one of the most dangerous drugs of abuse, which may exert various neurotoxic actions on the brain (such as gray matter loss, neuronal apoptosis, mitochondrial dysfunction, synaptic defects, depression of adult neurogenensis, as well as development of spongiform leucoencephalopathy). Some of these toxic effects are probably mediated by the gas nitric oxide (NO). We studied by morphometric analysis the numerical density of neurons expressing neuronal nitric oxide synthase (nNOS) in cortical and hypothalamic areas of eight heroin overdose victims and nine matched controls. Heroin addicts showed significantly increased numerical densities of nNOS immunoreactive cells in the right temporal cortex and the left paraventricular nucleus. Remarkably, in heroin abusers, but not in controls, we observed not only immunostained interneurons, but also cortical pyramidal cells. Given that increased cellular expression of nNOS was accompanied by elevated NO generation in brains of heroin addicts, these elevated levels of NO might have contributed to some of the known toxic effects of heroin (for example, reduced adult neurogenesis, mitochondrial pathology or disturbances in synaptic functioning).

  16. An In Vitro System Comprising Immortalized Hypothalamic Neuronal Cells (GT1–7 Cells) for Evaluation of the Neuroendocrine Effects of Essential Oils

    PubMed Central

    Mizuno, Dai; Konoha-Mizuno, Keiko; Mori, Miwako; Yamazaki, Kentaro; Haneda, Toshihiro; Koyama, Hironari; Kawahara, Masahiro

    2015-01-01

    Aromatherapy and plant-based essential oils are widely used as complementary and alternative therapies for symptoms including anxiety. Furthermore, it was reportedly effective for the care of several diseases such as Alzheimer's disease and depressive illness. To investigate the pharmacological effects of essential oils, we developed an in vitro assay system using immortalized hypothalamic neuronal cells (GT1–7 cells). In this study, we evaluated the effects of essential oils on neuronal death induced by hydrogen peroxide (H2O2), aluminum, zinc, or the antagonist of estrogen receptor (tamoxifen). Among tests of various essential oils, we found that H2O2-induced neuronal death was attenuated by the essential oils of damask rose, eucalyptus, fennel, geranium, ginger, kabosu, mandarin, myrrh, and neroli. Damask rose oil had protective effects against aluminum-induced neurotoxicity, while geranium and rosemary oil showed protective activity against zinc-induced neurotoxicity. In contrast, geranium oil and ginger oil enhanced the neurotoxicity of tamoxifen. Our in vitro assay system could be useful for the neuropharmacological and endocrine pharmacological studies of essential oils. PMID:26576190

  17. Redistribution of NMDA Receptors in Estrogen-Receptor-β-Containing Paraventricular Hypothalamic Neurons following Slow-Pressor Angiotensin II Hypertension in Female Mice with Accelerated Ovarian Failure

    PubMed Central

    Marques-Lopes, Jose; Tesfaye, Ephrath; Israilov, Sigal; Van Kempen, Tracey A.; Wang, Gang; Glass, Michael J.; Pickel, Virginia M.; Iadecola, Costantino; Waters, Elizabeth M.; Milner, Teresa A.

    2017-01-01

    Hypertension in male and aging female rodents is associated with glutamate-dependent plasticity in the hypothalamus, but existing models have failed to capture distinct transitional menopausal phases that could have a significant impact on the synaptic plasticity and emergent hypertension. In rodents, accelerated ovarian failure (AOF) induced by systemic injection of 4-vinylcyclohexane diepoxide mimics the estrogen fluctuations seen in human menopause including the perimenopause transition (peri-AOF) and postmenopause (post-AOF). Thus, we used the mouse AOF model to determine the impact of slow-pressor angiotensin II (AngII) administration on blood pressure and on the subcellular distribution of obligatory N-methyl-D-aspartate (NMDA) receptor GluN1 subunits in the paraventricular hypothalamic nucleus (PVN), a key estrogen-responsive cardiovascular regulatory area. Estrogen-sensitive neuronal profiles were identified in mice expressing enhanced green fluorescent protein under the promoter for estrogen receptor (ER) β, a major ER in the PVN. Slow-pressor AngII increased arterial blood pressure in mice at peri- and post-AOF time points. In control oil-injected (nonhypertensive) mice, AngII decreased the total number of GluN1 in ERβ-containing PVN dendrites. In contrast, AngII resulted in a reapportionment of GluN1 from the cytoplasm to the plasma membrane of ERβ-containing PVN dendrites in peri-AOF mice. Moreover, in post-AOF mice, AngII increased total GluN1, dendritic size and radical production in ERβ-containing neurons. These results indicate that unique patterns of hypothalamic glutamate receptor plasticity and dendritic structure accompany the elevated blood pressure in peri- and post-AOF time points. Our findings suggest the possibility that distinct neurobiological processes are associated with the increased blood pressure during perimenopausal and postmenopausal periods. PMID:27078860

  18. Effect of anorexinergic peptides, cholecystokinin (CCK) and cocaine and amphetamine regulated transcript (CART) peptide, on the activity of neurons in hypothalamic structures of C57Bl/6 mice involved in the food intake regulation.

    PubMed

    Pirnik, Zdeno; Maixnerová, Jana; Matysková, Resha; Koutová, Darja; Zelezná, Blanka; Maletínská, Lenka; Kiss, Alexander

    2010-01-01

    The hypothalamus plays an important role in food consumption, receiving information about energy balance via hormonal, metabolic, and neural inputs. Its neurons produce neuropeptides influencing energy balance. Especially important to regulation of food consumption are certain hypothalamic structures, including the arcuate (ARC) and ventromedial (VMN) nuclei and the lateral hypothalamic area (LHA). We determined the impact of cholecystokinin (CCK) and cocaine and amphetamine regulated transcript (CART) peptide, on activity of ARC and VMN neurons and hypocretin (Hcrt) synthesizing neurons in LHA. ARC is an integrative nucleus regulating food consumption, VMN is considered to be a satiety centre, and LHA a hunger sensing centre. After overnight fasting, male C57Bl/6 mice received intraperitoneal injection of (i.p.) saline (SAL) or CCK (4microg/kg) or intracerebroventricular injection of (i.c.v.) CART peptide (0.1microg/mice) or CCK (i.p.) followed by CART peptide (i.c.v.) 5min later. Sixty minutes later, the presence of Fos or Fos/Hcrt immunostaining indicated activity of ARC and VMN neurons, as well as of Hcrt cells in LHA. CCK alone did not influence neuronal activity in any of the nuclei studied. CART peptide stimulated neurons in ARC and VMN (p<0.01) but decreased Hcrt neuronal activity in LHA (p<0.05). Co-administration of both peptides synergistically stimulated ARC neurons (p<0.01) and asynergistically inhibited LHA Hcrt neurons (p<0.01). Results indicate that CCK may modify the effect of CART peptide and thus substantially influence activity of neurons in hypothalamic structures involved in regulation of food intake.

  19. Prenatal exposure to ethanol stimulates hypothalamic CCR2 chemokine receptor system: Possible relation to increased density of orexigenic peptide neurons and ethanol drinking in adolescent offspring.

    PubMed

    Chang, G-Q; Karatayev, O; Leibowitz, S F

    2015-12-03

    Clinical and animal studies indicate that maternal consumption of ethanol during pregnancy increases alcohol drinking in the offspring. Possible underlying mechanisms may involve orexigenic peptides, which are stimulated by prenatal ethanol exposure and themselves promote drinking. Building on evidence that ethanol stimulates neuroimmune factors such as the chemokine CCL2 that in adult rats is shown to colocalize with the orexigenic peptide, melanin-concentrating hormone (MCH) in the lateral hypothalamus (LH), the present study sought to investigate the possibility that CCL2 or its receptor CCR2 in LH is stimulated by prenatal ethanol exposure, perhaps specifically within MCH neurons. Our paradigm of intraoral administration of ethanol to pregnant rats, at low-to-moderate doses (1 or 3g/kg/day) during peak hypothalamic neurogenesis, caused in adolescent male offspring twofold increase in drinking of and preference for ethanol and reinstatement of ethanol drinking in a two-bottle choice paradigm under an intermittent access schedule. This effect of prenatal ethanol exposure was associated with an increased expression of MCH and density of MCH(+) neurons in LH of preadolescent offspring. Whereas CCL2(+) cells at this age were low in density and unaffected by ethanol, CCR2(+) cells were dense in LH and increased by prenatal ethanol, with a large percentage (83-87%) identified as neurons and found to colocalize MCH. Prenatal ethanol also stimulated the genesis of CCR2(+) and MCH(+) neurons in the embryo, which co-labeled the proliferation marker, BrdU. Ethanol also increased the genesis and density of neurons that co-expressed CCR2 and MCH in LH, with triple-labeled CCR2(+)/MCH(+)/BrdU(+) neurons that were absent in control rats accounting for 35% of newly generated neurons in ethanol-exposed rats. With both the chemokine and MCH systems believed to promote ethanol consumption, this greater density of CCR2(+)/MCH(+) neurons in the LH of preadolescent rats suggests that

  20. Prenatal exposure to ethanol stimulates hypothalamic CCR2 chemokine receptor system: Possible relation to increased density of orexigenic peptide neurons and ethanol drinking in adolescent offspring

    PubMed Central

    Chang, G.-Q.; Karatayev, O.; Leibowitz, S. F.

    2015-01-01

    Clinical and animal studies indicate that maternal consumption of ethanol during pregnancy increases alcohol drinking in the offspring. Possible underlying mechanisms may involve orexigenic peptides, which are stimulated by prenatal ethanol exposure and themselves promote drinking. Building on evidence that ethanol stimulates neuroimmune factors such as the chemokine CCL2 that in adult rats is shown to colocalize with the orexigenic peptide, melanin-concentrating hormone (MCH) in the lateral hypothalamus (LH), the present study sought to investigate the possibility that CCL2 or its receptor CCR2 in LH are stimulated by prenatal ethanol exposure, perhaps specifically within MCH neurons. Our paradigm of intraoral administration of ethanol to pregnant rats, at low-to-moderate doses (1 or 3 g/kg/day) during peak hypothalamic neurogenesis, caused in adolescent male offspring two-fold increase in drinking of and preference for ethanol and reinstatement of ethanol drinking in a two-bottle choice paradigm under an intermittent access schedule. This effect of prenatal ethanol exposure was associated with an increased expression of MCH and density of MCH+ neurons in LH of preadolescent offspring. Whereas CCL2+ cells at this age were low in density and unaffected by ethanol, CCR2+ cells were dense in LH and increased by prenatal ethanol, with a large percentage (83–87%) identified as neurons and found to colocalize MCH. Prenatal ethanol also stimulated the genesis of CCR2+ and MCH+ neurons in the embryo, which co-labeled the proliferation marker, BrdU. Ethanol also increased the genesis and density of neurons that co-expressed CCR2 and MCH in LH, with triple-labeled CCR2+/MCH+/BrdU+ neurons that were absent in control rats accounting for 35% of newly generated neurons in ethanol-exposed rats. With both the chemokine and MCH systems believed to promote ethanol consumption, this greater density of CCR2+/MCH+ neurons in the LH of preadolescent rats suggests that these systems

  1. Dual projections of single orexin- or CART-immunoreactive, lateral hypothalamic neurons to the paraventricular thalamic nucleus and nucleus accumbens shell in the rat: Light microscopic study.

    PubMed

    Lee, Eun Y; Lee, Hyun S

    2016-03-01

    The paraventricular thalamic nucleus (PVT) is a major relay station to the limbic forebrain areas such as the nucleus accumbens shell (AcbSh). Both PVT and AcbSh are known to receive feeding/arousal-related peptidergic fibers including orexin (ORX) and cocaine- and amphetamine-regulated transcript (CART) peptide. In the first series of experiments, we examined the peptidergic fiber distribution in the AcbSh; the density of ORX (or CART) fibers in the AcbSh was substantially lower than that in the PVT. At the light microscopic level, ORX (or CART) terminals formed close appositions to choline acetyltransferase (ChAT)-, glutamate decarboxylase (GAD)-, or enkephalin (Enk)-immunoreactive neuronal elements in the AcbSh. In the second series of experiments, we addressed the question of whether single ORX (or CART) cells in the hypothalamus provided divergent axon collaterals to the PVT and AcbSh. ORX neurons with dual projections were found in the medial, central, and lateral subdivisions of the lateral hypothalamus (LH), which amounted to an average of 1.6% of total ORX cells. CART neurons with divergent axon collaterals were observed in the LH, zona incerta, dorsal hypothalamic area, and retrochiasmatic nucleus, which represented a mean of 2.5% of total CART cells. None of arcuate CART cells sent dual projections. These data suggested that a portion of ORX (or CART) neurons in the hypothalamus, via divergent axon collaterals, might concurrently modulate the activity of PVT and AcbSh cells to affect feeding and drug-seeking behaviors. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Lateral hypothalamic area orexin-A influence the firing activity of gastric distension-sensitive neurons and gastric motility in rats.

    PubMed

    Hao, Heling; Luan, Xiao; Guo, Feifei; Sun, Xiangrong; Gong, Yanling; Xu, Luo

    2016-06-01

    The orexins system consists of two G-protein coupled receptors (the orexin-1 and the orexin-2 receptor) and two neuropeptides, orexin-A and orexin-B. Orexin-A is an excitatory neuropeptide that regulates arousal, wakefulness and appetite. Recent studies have shown that orexin-A may promote gastric motility. We aim to explore the effects of orexin-A on the gastric -distension (GD) sensitive neurons and gastric motility in the lateral hypothalamic area (LHA), and the possible regulation by the paraventricular nucleus (PVN). Extracellular single unit discharges were recorded and the gastric motility was monitored by administration of orexin-A into the LHA and electrical stimulation of the PVN. There were GD neurons in the LHA, and administration of orexin-A to the LHA could increase the firing rate of both GD-excitatory (GD-E) and GD-inhibited (GD-I) neurons. The gastric motility was significantly enhanced by injection of orexin-A into the LHA with a dose dependent manner, which could be completely abolished by pre-treatment with orexin-A receptor antagonist SB334867. Electrical stimulation of the PVN could significantly increase the firing rate of GD neurons responsive to orexin-A in the LHA as well as promote gastric motility of rats. However, those effects could be partly blocked by pre-treatment with SB334867 in the LHA. It is suggested that orexin-A plays an important role in promoting gastric motility via LHA. The PVN may be involved in regulation of LHA on gastric motility.

  3. Estrogen Regulation of Gene Expression in GnRH Neurons

    PubMed Central

    Ng, Yewade; Wolfe, Andrew; Novaira, Horacio J.; Radovick, Sally

    2009-01-01

    Estrogen plays an essential role in the regulation of the female reproductive hormone axis and specifically is a major regulator of GnRH neuronal function in the female brain. GnRH neuronal cell lines were used to explore the direct effects of estradiol on gene expression in GnRH neurons. The presence of estrogen receptor (ER) binding sites was established by a receptor binding assay and estrogen receptor α and β mRNA were identified in GN11 cells and ERβ in GT1-7 cells using RT-PCR analysis of mRNA. ERα was more abundantly expressed in GN11 cells than ERβ as assessed by real time PCR. Additionally, GN11 cells expressed significantly more of both ERα and β than GT1-7 cells. Functional studies in GN11 and GT1-7 demonstrated estrogen down regulation of endogenous mouse GnRH mRNA levels using quantitative real-time PCR (qRT-PCR). Correspondingly, estradiol also reduced secretion of GnRH from both the GN11 and GT1-7 cell lines. Since estradiol has been shown to regulate progesterone receptor (PR) expression; similar studies were performed demonstrating an estradiol mediated increase in PR in both cell lines. Estradiol regulation of ER expression was also explored and these studies indicated that estradiol decreased ERα and ERβ mRNA levels in a dose-dependent manner in GN11 and GT1-7 cells. These effects were blocked by the addition of the estrogen receptor antagonist ICI 182,780. Both PPT, a specific ERα agonist, and DPN, a specific ERβ agonist, inhibited GnRH gene expression in GN11 cells, but only DPN inhibited GnRH gene expression in GT1-7 cells, consistent with their undetectable levels of ERα expression. These studies characterize a direct inhibitory effect of estradiol on GnRH in GnRH neurons, and a direct stimulatory effect of estradiol on PR gene expression. In addition, the agonist studies indicate there is a functional overlap of ERα and ERβ regulation in GnRH neurons. These studies may give insight into the molecular regulation of estrogen

  4. Subfornical organ neurons with efferent projections to the hypothalamic paraventricular nucleus: an electrophysiological study in the rat.

    PubMed

    Tanaka, J; Kaba, H; Saito, H; Seto, K

    1985-10-28

    Seventeen neurons in the subfornical organ (SFO) were antidromically activated by electrical stimulation of the paraventricular nucleus (PVN) in the rat. The activity of all identified SFO neurons was excited by microiontophoretically (MIPh) applied angiotensin II (AII) and the effect of AII was blocked by MIPh-applied saralasin (Sar), an AII antagonist, but not by atropine (Atr), a muscarinic antagonist. In these identified SFO neurons, 9 were also excited and 8 were not affected by MIPh-applied acetylcholine (ACh) and the effect of ACh was attenuated by not only MIPh-applied Atr but also by Sar. These results suggest that there are specific AII- and both AII- and ACh-sensitive types of SFO neurons with efferent projections to the PVN.

  5. GHRP-6-induced changes in electrical activity of single cells in the arcuate, ventromedial and periventricular nucleus neurones [correction of nuclei] of a hypothalamic slice preparation in vitro.

    PubMed

    Hewson, A K; Viltart, O; McKenzie, D N; Dyball, R E; Dickson, S L

    1999-12-01

    unresponsive and the remaining three cells (15.8%) were significantly inhibited. Of 19 cells recorded in the periventricular nucleus, 13 (68.4%) were unresponsive to GHRP-6 and six (31.6%) were significantly inhibited. Thus, electrophysiological studies in vitro suggest that: (1) neurones in the hypothalamic arcuate nucleus, ventromedial nucleus and periventricular nucleus show changes in electrical activity in response to GHRP-6; and (2) the arcuate nucleus cells excited by GHRP-6 are also subject to inhibitory control by somatostatin.

  6. Neonatal Leptin Exposure Specifies Innervation of Presympathetic Hypothalamic Neurons and Improves the Metabolic Status of Leptin Deficient Mice

    PubMed Central

    BOUYER, Karine; SIMERLY, Richard B.

    2013-01-01

    The paraventricular nucleus of the hypothalamus (PVH) consists of distinct functional compartments regulating neuroendocrine, behavioral, and autonomic activities that are involved in the homeostatic control of energy balance. These compartments receive synaptic inputs from neurons of the arcuate nucleus (ARH) that contains orexigenic agouti-related peptide (AgRP) and anorexigenic pro-opiomelanocortin (POMC) neuropeptides. The axon outgrowth from the ARH to PVH occurs during a critical postnatal period and is influenced by the adipocyte-derived hormone leptin, which promotes its development. However, little is known about leptin's role in specifying patterns of cellular connectivity in the different compartments of the PVH. To address this question, we utilized retrograde and immunohistochemical labeling to evaluate neuronal inputs onto sympathetic preautonomic and neuroendocrine neurons in PVH of leptin-deficient mice (Lepob/Lepob) exposed to a postnatal leptin treatment. In adult Lepob/Lepob mice, densities of AgRP and αMSH immunoreactive fibers were significantly reduced in neuroendocrine compartments of the PVH, but only AgRP were reduced in all regions containing preautonomic neurons. Moreover, postnatal leptin treatment significantly increased the density of AgRP-containing fibers and peptidergic inputs onto identified preautonomic, but not onto neuroendocrine cells. Neonatal leptin treatment neither rescued αMSH inputs onto neuroendocrine neurons, nor altered cellular ratios of inhibitory and excitatory inputs. These effects were associated with attenuated body weight gain, food intake and improved physiological response to sympathetic stimuli. Together, these results provide evidence that leptin directs cell-type specific patterns of ARH peptidergic inputs onto preautonomic neurons in the PVH, which contribute to normal energy balance regulation. PMID:23303959

  7. Parvalbumin-Neurons of the Ventrolateral Hypothalamic Parvafox Nucleus Receive a Glycinergic Input: A Gene-Microarray Study

    PubMed Central

    Szabolcsi, Viktoria; Albisetti, Gioele W.; Celio, Marco R.

    2017-01-01

    The ventrolateral hypothalamic parvafox (formerly called PV1-Foxb1) nucleus is an anatomical entity of recent discovery and unknown function. With a view to gaining an insight into its putative functional role(s), we conducted a gene-microarray analysis and, armed with the forthcoming data, controlled the results with the Allen databases and the murine BrainStars (B*) database. The parvafox nucleus was specifically sampled by laser-capture microdissection and the transcriptome was subjected to a microarray analysis on Affymetrix chips. Eighty-two relevant genes were found to be potentially more expressed in this brain region than in either the cerebral cortex or the hippocampus. When the expression patterns of these genes were counterchecked in the Allen-Database of in-situ hybridizations and in the B*-microarray database, their localization in the parvafox region was confirmed for thirteen. For nine novel genes, which are particularly interesting because of their possible involvement in neuromodulation, the expression was verified by quantitative real time-PCR. Of particular functional importance may be the occurrence of glycine receptors, the presence of which indicates that the activity of the parvafox nucleus is under ascending inhibitory control. PMID:28167900

  8. Basic fibroblast growth factor priming increases the responsiveness of immortalized hypothalamic luteinizing hormone releasing hormone neurones to neurotrophic factors.

    PubMed

    Gallo, F; Morale, M C; Tirolo, C; Testa, N; Farinella, Z; Avola, R; Beaudet, A; Marchetti, B

    2000-10-01

    The participation of growth factors (GFs) in the regulation of luteinizing hormone releasing hormone (LHRH) neuronal function has recently been proposed, but little is known about the role played by GFs during early LHRH neurone differentiation. In the present study, we have used combined biochemical and morphological approaches to study the ability of a number of GFs normally expressed during brain development, including basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), insulin and insulin-like growth factor I (IGF-I) to induce survival, differentiation, proliferation, and phenotypic expression of immortalized (GT1-1) LHRH neurones in vitro, at early (3-days in vitro, 3-DIV) and late (8-DIV) stages of neuronal differentiation. Comparison of GF-treated vs untreated neurones grown in serum-deprived (SD) medium demonstrated bFGF to be the most potent, and insulin the least active in promoting neuronal differentiation. Thus, at both 3-DIV and 8-DIV, but especially at 8-DIV, bFGF induced the greatest increase in the total length and number of LHRH processes/cell and in growth cone surface area. bFGF was also the most active at 3-DIV, and IGF-I at 8-DIV, in counteracting SD-induced cell death, whereas EGF was the most potent in increasing [3H]thymidine incorporation. All GFs studied decreased the spontaneous release of LHRH from GT1-1 cells when applied at 3-DIV or 8-DIV, except for insulin which was inactive at both time-points and bFGF which was inactive at 8-DIV. Pre-treatment of GT1-1 cells with a suboptimal ('priming') dose of bFGF for 12 h followed by application of the different GFs induced a sharp potentiation of the neurotrophic and proliferative effects of the latter and particularly of those of IGF-I. Moreover, bFGF priming counteracted EGF-induced decrease in LHRH release and significantly stimulated LHRH secretion following IGF-I or insulin application, suggesting that bFGF may sensitize LHRH neurones to differentiating effects of

  9. Water deprivation increases Fos expression in hypothalamic corticotropin-releasing factor neurons induced by right atrial distension in awake rats.

    PubMed

    Benedetti, Mauricio; Rorato, Rodrigo; Castro, Margaret; Machado, Benedito H; Antunes-Rodrigues, Jose; Elias, Lucila L K

    2008-11-01

    Atrial mechanoreceptors, sensitive to stretch, contribute in regulating heart rate and intravascular volume. The information from those receptors reaches the nucleus tractus solitarius and then the paraventricular nucleus (PVN), known to have a crucial role in the regulation of cardiovascular function. Neurons in the PVN synthesize CRF, AVP, and oxytocin (OT). Stimulation of atrial mechanoreceptors was performed in awake rats implanted with a balloon at the junction of the superior vena cava and right atrium. Plasma ACTH, AVP, and OT concentrations and Fos, CRF, AVP, and OT immunolabeling in the PVN were determined after balloon inflation in hydrated and water-deprived rats. The distension of the balloon increased the plasma ACTH concentrations, which were higher in water-deprived than in hydrated rats (P < 0.05). In addition, the distension in the water-deprived group decreased plasma AVP concentrations (P < 0.05), compared with the respective control group. The distension increased the number of Fos- and double-labeled Fos/CRF neurons in the parvocellular PVN, which was higher in the water-deprived than in the hydrated group (P < 0.01). There was no difference in the Fos expression in magnocellular PVN neurons after distension in hydrated and water-deprived groups, compared with respective controls. In conclusion, parvocellular CRF neurons showed an increase of Fos expression induced by stimulation of right atrial mechanoreceptors, suggesting that CRF participates in the cardiovascular reflex adjustments elicited by volume loading. Activation of CRF neurons in the PVN by cardiovascular reflex is affected by osmotic stimulation.

  10. Deletion of Vax1 from Gonadotropin-Releasing Hormone (GnRH) Neurons Abolishes GnRH Expression and Leads to Hypogonadism and Infertility.

    PubMed

    Hoffmann, Hanne M; Trang, Crystal; Gong, Ping; Kimura, Ikuo; Pandolfi, Erica C; Mellon, Pamela L

    2016-03-23

    Hypothalamic gonadotropin-releasing hormone (GnRH) neurons are at the apex of the hypothalamic-pituitary-gonadal axis that regulates mammalian fertility. Herein we demonstrate a critical role for the homeodomain transcription factor ventral anterior homeobox 1 (VAX1) in GnRH neuron maturation and show that Vax1 deletion from GnRH neurons leads to complete infertility in males and females. Specifically, global Vax1 knock-out embryos had normal numbers of GnRH neurons at 13 d of gestation, but no GnRH staining was detected by embryonic day 17. To identify the role of VAX1 specifically in GnRH neuron development,Vax1(flox)mice were generated and lineage tracing performed in Vax1(flox/flox):GnRH(cre):RosaLacZ mice. This identified VAX1 as essential for maintaining expression of Gnrh1 The absence of GnRH staining in adult Vax1(flox/flox):GnRH(cre)mice led to delayed puberty, hypogonadism, and infertility. To address the mechanism by which VAX1 maintains Gnrh1 transcription, the capacity of VAX1 to regulate Gnrh1 transcription was evaluated in the GnRH cell lines GN11 and GT1-7. As determined by luciferase and electrophoretic mobility shift assays, we found VAX1 to be a direct activator of the GnRH promoter through binding to four ATTA sites in the GnRH enhancer (E1) and proximal promoter (P), and able to compete with the homeoprotein SIX6 for occupation of the identified ATTA sites in the GnRH promoter. We conclude that VAX1 is expressed in GnRH neurons where it is required for GnRH neuron expression of GnRH and maintenance of fertility in mice. Infertility classified as idiopathic hypogonadotropic hypogonadism (IHH) is characterized by delayed or absent sexual maturation and low sex steroid levels due to alterations in neuroendocrine control of the hypothalamic-pituitary-gonadal axis. The incidence of IHH is 1-10 cases per 100,000 births. Although extensive efforts have been invested in identifying genes giving rise to IHH, >50% of cases have unknown genetic origins

  11. Effects of chronic restraint stress on social behaviors and the number of hypothalamic oxytocin neurons in male rats.

    PubMed

    Li, Jin; Li, Han-Xia; Shou, Xiao-Jing; Xu, Xin-Jie; Song, Tian-Jia; Han, Song-Ping; Zhang, Rong; Han, Ji-Sheng

    2016-12-01

    Oxytocin (OXT) and vasopressin (AVP) are considered to be related to mammalian social behavior and the regulation of stress responses. The present study investigated the effects of chronic homotypic restraint stress (CHRS) on social behaviors and anxiety, as well as its repercussions on OXT- and AVP-positive neurons in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) nuclei in rat. Male Sprague-Dawley rats receiving CHRS were exposed to repeated restraint stress of 30min per day for 10days. Changes in social approach behaviors were evaluated with the three-chambered social approach task. Changes in anxiety-like behaviors were evaluated in the light-dark box test. The number of neurons expressing oxytocin and/or vasopressin in PVN and SON were examined by immunohistochemistry techniques. The results demonstrated that social approach was increased and anxiety was decreased following 10-day exposure to CHRS. Furthermore, the number of OXT-immunoreactive cells in PVN was increased significantly, whereas no change in SON was seen. The number of AVP immunoreactive cells either in PVN or SON was unaffected. The results of this study suggest that certain types of stress could be effective in the treatment of social dysfunction in persons with mental disorders such as autism, social anxiety disorder. The therapeutic effects may be mediated by changes in the function of OXT neurons in PVN. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Control of energy balance by hypothalamic gene circuitry involving two nuclear receptors, neuron-derived orphan receptor 1 and glucocorticoid receptor.

    PubMed

    Kim, Sun-Gyun; Lee, Bora; Kim, Dae-Hwan; Kim, Juhee; Lee, Seunghee; Lee, Soo-Kyung; Lee, Jae W

    2013-10-01

    Nuclear receptors (NRs) regulate diverse physiological processes, including the central nervous system control of energy balance. However, the molecular mechanisms for the central actions of NRs in energy balance remain relatively poorly defined. Here we report a hypothalamic gene network involving two NRs, neuron-derived orphan receptor 1 (NOR1) and glucocorticoid receptor (GR), which directs the regulated expression of orexigenic neuropeptides agouti-related peptide (AgRP) and neuropeptide Y (NPY) in response to peripheral signals. Our results suggest that the anorexigenic signal leptin induces NOR1 expression likely via the transcription factor cyclic AMP response element-binding protein (CREB), while the orexigenic signal glucocorticoid mobilizes GR to inhibit NOR1 expression by antagonizing the action of CREB. Also, NOR1 suppresses glucocorticoid-dependent expression of AgRP and NPY. Consistently, relative to wild-type mice, NOR1-null mice showed significantly higher levels of AgRP and NPY and were less responsive to leptin in decreasing the expression of AgRP and NPY. These results identify mutual antagonism between NOR1 and GR to be a key rheostat for peripheral metabolic signals to centrally control energy balance.

  13. Residual Ca2+ channel current modulation by megestrol acetate via a G-protein alpha s-subunit in rat hypothalamic neurones.

    PubMed Central

    Costa, A M; Spence, K T; Plata-Salamán, C R; ffrench-Mullen, J M

    1995-01-01

    1. The inhibition of voltage-activated Ca2+ channel currents by the orally active progesterone derivative, megestrol acetate (MA), was examined in freshly dissociated rat ventromedial hypothalamic nucleus (VMN) neurones using the whole-cell voltage-clamp technique with 10 mM Ba2+ as the charge carrier. 2. The steady-state inhibition of the peak high-threshold Ca2+ channel current evoked by depolarization from -80 to -10 mV by MA increased in a concentration-dependent fashion. MA inhibited a fraction of the whole-cell Ca2+ channel current while progesterone had no effect on the peak Ca2+ channel current (7% at 10 microM). The low-threshold Ca2+ (T-type) current, evoked from -100 to -30 mV, was unaffected by MA. 3. Intracellular dialysis with MA had no effect on the Ca2+ channel current. Concomitant extracellular perfusion of MA showed normal inhibitory activity, suggesting that the MA binding site can only be accessed extracellularly. 4. The high-threshold Ca2+ channel current in VMN neurones was found to consist of four pharmacologically distinguishable components: an N-type current, an L-type current, a P-type current, and a residual current. MA had no effect on the N-, L- and P-type Ca2+ channel currents, but inhibited the residual current. 5. In neurones isolated from cholera toxin-treated animals, the MA-induced inhibition of the Ca2+ channel current was significantly diminished, suggesting a G-protein alpha S-subunit involvement. 6. Treatment with antisense phosphothio-oligodeoxynucleotides to the G alpha S-subunit (antisense-G alpha S) significantly reduced the MA-induced inhibition of the Ca2+ channel current. Treatment with either sense-G alpha S or antisense-G alpha 11 had no effect, confirming a G alpha S-subunit involvement. 7. These results suggest that appetite enhancement induced by MA in cachectic patients may in part be due to a novel central nervous system action, that is, inhibition of a fraction of the whole-cell Ca2+ channel current to attenuate

  14. Excitatory amino acid receptors in the periaqueductal gray mediate the cardiovascular response evoked by activation of dorsomedial hypothalamic neurons.

    PubMed

    da Silva, L G; Menezes, R C A; Villela, D C; Fontes, M A P

    2006-01-01

    Neurons in the region of dorsomedial hypothalamus are involved in the organization of the physiological responses to emotional stress. We have recently shown that the cardiovascular response evoked by activation of dorsomedial hypothalamus neurons is largely dependent on a synaptic relay with the lateral/dorsolateral periaqueductal gray region. In this study, we aimed to investigate whether excitatory amino acid receptors at the lateral/dorsolateral periaqueductal gray region are involved in mediating the response evoked by activation of dorsomedial hypothalamus neurons. In conscious rats, the cardiovascular effects produced by microinjection of GABA(A) receptor antagonist, bicuculline methiodide into the dorsomedial hypothalamus were evaluated before and after injection of different excitatory amino acid antagonists into lateral/dorsolateral periaqueductal gray region. Pretreatment of lateral/dorsolateral periaqueductal gray region with the non-selective ionotropic excitatory amino acid receptor antagonist kynurenic acid or with the N-methyl-D-aspartate receptor-selective antagonist, MK-801, largely reduced the tachycardic and pressor effects evoked by activation of dorsomedial hypothalamus neurons by bicuculline methiodide microinjection (heart rate 90 and 74%; blood pressure 81 and 84%, respectively). The non-N-methyl-D-aspartate receptor-selective antagonist 6-cyano-7-nitroquinoxaline-2,3-dione, did not alter the cardiovascular response evoked by dorsomedial hypothalamus activation. In an additional series of experiments, microinjection of the N-methyl-D-aspartate receptor agonist, N-methyl-D-aspartate, into the lateral/dorsolateral periaqueductal gray region, evoked an increase in heart rate and a pressor response that was accompanied by an increase in locomotor activity. These effects were not altered by pretreatment of lateral/dorsolateral periaqueductal gray region neurons with 6-cyano-7-nitroquinoxaline-2,3-dione but were completely abolished by MK-801

  15. Involvement of the Beta-Endorphin Neurons of the Hypothalamic Arcuate Nucleus in Ethanol-Induced Place Preference Conditioning in Mice

    PubMed Central

    Pastor, Raúl; Font, Laura; Miquel, Marta; Phillips, Tamara J.; Aragon, Carlos M.G.

    2014-01-01

    Background Increasing evidence indicates that mu- and delta-opioid receptors are decisively involved in the retrieval of memories underlying conditioned effects of ethanol. The precise mechanism by which these receptors participate in such effects remains unclear. Given the important role of the proopiomelanocortin (POMc)-derived opioid peptide beta-endorphin, an endogenous mu- and delta-opioid receptor agonist, in some of the behavioral effects of ethanol, we hypothesized that beta-endorphin would also be involved in ethanol conditioning. Methods In the present study we treated female Swiss mice with estradiol valerate (EV), which induces a neurotoxic lesion of the beta-endorphin neurons of the hypothalamic arcuate nucleus (ArcN). These mice were compared to saline-treated controls to investigate the role of beta-endorphin in the acquisition, extinction and reinstatement of ethanol (0 or 2 g/kg; i.p.)-induced conditioned place preference (CPP). Results Immunohistochemical analyses confirmed a decreased number of POMc-containing neurons of the ArcN with EV treatment. EV did not affect the acquisition or reinstatement of ethanol-induced CPP, but facilitated its extinction. Behavioral sensitization to ethanol, seen during the conditioning days, was not present in EV-treated animals. Conclusions The present data suggest that ArcN beta-endorphins are involved in the retrieval of conditioned memories of ethanol, and are implicated in the processes that underlie extinction of ethanol-cue associations. Results also reveal a dissociated neurobiology supporting behavioral sensitization to ethanol and its conditioning properties, as a beta-endorphin deficit affected sensitization to ethanol, while leaving acquisition and reinstatement of ethanol-induced CPP unaffected. PMID:22014186

  16. Neurons of the A5 region are required for the tachycardia evoked by electrical stimulation of the hypothalamic defence area in anaesthetized rats.

    PubMed

    López-González, M V; Díaz-Casares, A; Peinado-Aragonés, C A; Lara, J P; Barbancho, M A; Dawid-Milner, M S

    2013-08-01

    In order to assess the possible interactions between the pontine A5 region and the hypothalamic defence area (HDA), we have examined the pattern of double staining for c-Fos protein immunoreactivity (c-Fos-ir) and tyrosine hydroxylase, throughout the rostrocaudal extent of the A5 region in spontaneously breathing anaesthetized male Sprague-Dawley rats during electrical stimulation of the HDA. Activation of the HDA elicited a selective increase in c-Fos-ir with an ipsilateral predominance in catecholaminergic and non-catecholaminergic A5 somata (P < 0.001 in both cases). A second group of experiments was done to examine the importance of the A5 region in modulating the cardiorespiratory response evoked from the HDA. Cardiorespiratory changes were analysed in response to electrical stimulation of the HDA before and after ipsilateral microinjection of muscimol within the A5 region. Stimulation of the HDA evoked an inspiratory facilitatory response, consisting of an increase in respiratory rate (P < 0.001) due to a decrease in expiratory time (P < 0.01). The respiratory response was accompanied by a pressor response (P < 0.001) and tachycardia (P < 0.001). After muscimol microinjection within the A5 region, pressor and heart rate responses to HDA stimulation were reduced (P < 0.01 and P < 0.001, respectively). The respiratory response persisted unchanged. Finally, to confirm functional interactions between the HDA and the A5 region, extracellular recordings of putative A5 neurones were obtained during HDA stimulation. Seventy-five A5 cells were recorded, 35 of which were affected by the HDA (47%). These results indicate that neurones of the A5 region participate in the cardiovascular response evoked from the HDA. The possible mechanisms involved in these interactions are discussed.

  17. Regulation of neurite growth in immortalized mouse hypothalamic neurons and rat hippocampal primary cultures by teneurin C-terminal-associated peptide-1.

    PubMed

    Al Chawaf, A; St Amant, K; Belsham, D; Lovejoy, D A

    2007-02-23

    Teneurins are a highly conserved family of four type II transmembrane proteins that are expressed in the CNS. The protein possesses several functional domains including a unique bioactive 40-41 amino acid sequence at the extracellular terminus. Synthetic versions of this teneurin C-terminal-associated peptide (TCAP) can modulate cyclic AMP accumulation, cell proliferation and teneurin mRNA levels in vitro. Furthermore, i.c.v. injections of TCAP-1 into rat brain induce major changes in acoustic startle response behavior 3 weeks after administration, suggesting that the peptide may act to alter interneuron communication via changes in neurite and axon outgrowth. Synthetic mouse/rat TCAP-1 was used to treat cultured immortalized mouse hypothalamic cells, to determine if TCAP-1 could directly regulate neurite and axon growth. TCAP-1-treated cells showed a significant increase in the length of neurites accompanied by a marked increase in beta-tubulin transcription and translation as determined by real-time PCR and Western blot analysis, respectively. Changes in alpha-actinin-4 transcription and beta-actin protein expression were also noted. Immunofluorescence confocal microscopy using beta-tubulin antiserum showed enhanced resolution of beta-tubulin cytoskeletal elements throughout the cell. In order to determine if the effects of TCAP-1 could be reproduced in primary neuronal cultures, primary cultures of E18 rat hippocampal cells were treated with 100 nM TCAP-1. The TCAP-1-treated hippocampal cultures showed a significant increase in both the number of cells, dendritic branching and the presence of large and fasciculated beta-tubulin immunoreactive axons. These data suggest that TCAP acts, in part, as a functional region of the teneurins to regulate neurite and axonal growth of neurons.

  18. Topography of subnuclei of the hypothalamic paraventricular nucleus in rats and sensitivity of their neurons to insulin defficiency

    SciTech Connect

    Goufman, E.I.

    1985-07-01

    This investigation was undertaken to study the reaction of paraventricular nuclei (PVN) subnuclei to insulin deficiency and to elevation of the blood glucose level under conditions of experimental alloxan diabetes. Experiments were carried out on 15 control and 15 experimental mature male Wistar rats. The state of the carbohydrate metabolism of the diabetic and control animals was judged by the blood glucose and radioimmune insulin levels. The results of these investigations show that both magnocellular and parvocellular neurons of PVN react to alloxan diabetes, which supports the hypothesis that PVN of the hypothalamus participates in the control of carbohydrate metabolism.

  19. Rasd1, a small G protein with a big role in the hypothalamic response to neuronal activation.

    PubMed

    Greenwood, Michael P; Greenwood, Mingkwan; Mecawi, Andre S; Antunes-Rodrigues, José; Paton, Julian F R; Murphy, David

    2016-01-07

    Rasd1 is a member of the Ras family of monomeric G proteins that was first identified as a dexamethasone inducible gene in the pituitary corticotroph cell line AtT20. Using microarrays we previously identified increased Rasd1 mRNA expression in the rat supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus in response to increased plasma osmolality provoked by fluid deprivation and salt loading. RASD1 has been shown to inhibit adenylyl cyclase activity in vitro resulting in the inhibition of the cAMP-PKA-CREB signaling pathway. Therefore, we tested the hypothesis that RASD1 may inhibit cAMP stimulated gene expression in the brain. We show that Rasd1 is expressed in vasopressin neurons of the PVN and SON, within which mRNA levels are induced by hyperosmotic cues. Dexamethasone treatment of AtT20 cells decreased forskolin stimulation of c-Fos, Nr4a1 and phosphorylated CREB expression, effects that were mimicked by overexpression of Rasd1, and inhibited by knockdown of Rasd1. These effects were dependent upon isoprenylation, as both farnesyltransferase inhibitor FTI-277 and CAAX box deletion prevented Rasd1 inhibition of cAMP-induced gene expression. Injection of lentiviral vector into rat SON expressing Rasd1 diminished, whereas CAAX mutant increased, cAMP inducible genes in response to osmotic stress. We have identified two mechanisms of Rasd1 induction in the hypothalamus, one by elevated glucocorticoids in response to stress, and one in response to increased plasma osmolality resulting from osmotic stress. We propose that the abundance of RASD1 in vasopressin expressing neurons, based on its inhibitory actions on CREB phosphorylation, is an important mechanism for controlling the transcriptional responses to stressors in both the PVN and SON. These effects likely occur through modulation of cAMP-PKA-CREB signaling pathway in the brain.

  20. Influence of serial electrical stimulations of perifornical and posterior hypothalamic orexin-containing neurons on regulation of sleep homeostasis and sleep-wakefulness cycle recovery from experimental comatose state and anesthesia-induced deep sleep.

    PubMed

    Chijavadze, E; Chkhartishvili, E; Babilodze, M; Maglakelidze, N; Nachkebia, N

    2013-11-01

    The work was aimed for the ascertainment of following question - whether Orexin-containing neurons of dorsal and lateral hypothalamic, and brain Orexinergic system in general, are those cellular targets which can speed up recovery of disturbed sleep homeostasis and accelerate restoration of sleep-wakefulness cycle phases during some pathological conditions - experimental comatose state and/or deep anesthesia-induced sleep. Study was carried out on white rats. Modeling of experimental comatose state was made by midbrain cytotoxic lesions at intra-collicular level.Animals were under artificial respiration and special care. Different doses of Sodium Ethaminal were used for deep anesthesia. 30 min after comatose state and/or deep anesthesia induced sleep serial electrical stimulations of posterior and/or perifornical hypothalamus were started. Stimulation period lasted for 1 hour with the 5 min intervals between subsequent stimulations applied by turn to the left and right side hypothalamic parts.EEG registration of cortical and hippocampal electrical activity was started immediately after experimental comatose state and deep anesthesia induced sleep and continued continuously during 72 hour. According to obtained new evidences, serial electrical stimulations of posterior and perifornical hypothalamic Orexin-containing neurons significantly accelerate recovery of sleep homeostasis, disturbed because of comatose state and/or deep anesthesia induced sleep. Speed up recovery of sleep homeostasis was manifested in acceleration of coming out from comatose state and deep anesthesia induced sleep and significant early restoration of sleep-wakefulness cycle behavioral states.

  1. GABA type B receptor signaling in proopiomelanocortin neurons protects against obesity, insulin resistance, and hypothalamic inflammation in male mice on a high-fat diet.

    PubMed

    Ito, Yoshihiro; Banno, Ryoichi; Shibata, Miyuki; Adachi, Koichi; Hagimoto, Shigeru; Hagiwara, Daisuke; Ozawa, Yoshiharu; Goto, Motomitsu; Suga, Hidetaka; Sugimura, Yoshihisa; Bettler, Bernhard; Oiso, Yutaka; Arima, Hiroshi

    2013-10-23

    There is evidence suggesting that the GABA system in the arcuate nucleus, where orexigenic neuropeptide Y and agouti-related peptide as well as anorexigenic proopiomelanocortin (POMC) are expressed, plays an important role in energy balance. In this study, we generated POMC-specific GABAB receptor-deficient [knock-out (KO)] mice. Male KO mice on a high-fat diet (HFD) showed mild increases in body weight (BW) at the age of 9 weeks compared to wild-type (WT) mice, and the differences remained significant until 16 weeks old. However, there was no difference in BW in females between genotypes. While food intake was similar between genotypes, oxygen consumption was significantly decreased in the male KO mice. The insulin tolerance test revealed that the male KO mice were less insulin sensitive compared to WT mice at the age of 8 weeks, when there was no significant difference in BW between genotypes. Despite increased BW, POMC mRNA expression in the arcuate nucleus was significantly decreased in the KO mice compared to WT mice at the age of 16 weeks. Furthermore, the expression of TNFα as well as IL-6, proinflammatory markers in the hypothalamus, was significantly increased in the KO mice on a HFD compared to WT mice. This demonstrates that the deletion of GABAB receptors in POMC neurons in the male mice on a HFD results in obesity, insulin resistance, and hypothalamic inflammation. Furthermore, the decreased POMC expression in the obese KO mice suggests that the regulation of POMC expression through GABAB receptors is essential for proper energy balance.

  2. Mu-Opioid Stimulation in Rat Prefrontal Cortex Engages Hypothalamic Orexin/Hypocretin-Containing Neurons, and Reveals Dissociable Roles of Nucleus Accumbens and Hypothalamus in Cortically Driven Feeding

    PubMed Central

    Mena, Jesus D.; Selleck, Ryan A.

    2013-01-01

    Mu-opioid receptor (μOR) stimulation within ventral medial prefrontal cortex (vmPFC) induces feeding and hyperactivity, resulting possibly from recruitment of glutamate signaling in multiple vmPFC projection targets. We tested this hypothesis by analyzing Fos expression in vmPFC terminal fields after intra-vmPFC μOR stimulation, and by examining of the impact of glutamate receptor blockade in two feeding-related targets of vmPFC, the lateral-perifornical hypothalamic area (LH-PeF) and nucleus accumbens shell (Acb shell), upon behavioral effects elicited by intra-vmPFC μOR stimulation in rats. Intra-vmPFC infusion of the μOR agonist, DAMGO, provoked Fos expression in the dorsomedial sector of tuberal hypothalamus (including the perifornical area) and increased the percentage of Fos-expressing hypocretin/orexin-immunoreactive neurons in these zones. NMDA receptor blockade in the LH-PeF nearly eliminated intra-vmPFC DAMGO-induced food intake without altering DAMGO-induced hyperactivity. In contrast, blocking AMPA-type glutamate receptors within the Acb shell (the feeding-relevant subtype in this structure) antagonized intra-vmPFC DAMGO-induced hyperlocomotion but enhanced food intake. Intra-vmPFC DAMGO also elevated the breakpoint for sucrose-reinforced progressive-ratio responding; this effect was significantly enhanced by concomitant AMPA blockade in the Acb shell. Conversely, intra-Acb shell AMPA stimulation reduced breakpoint and increased nonspecific responding on the inactive lever. These data indicate intra-vmPFC μOR signaling jointly modulates appetitive motivation and generalized motoric activation through functionally dissociable vmPFC projection targets. These findings may shed light on the circuitry underlying disorganized appetitive responses in psychopathology; e.g., binge eating and opiate or alcohol abuse, disorders in which μORs and aberrant cortical activation have been implicated. PMID:24259576

  3. Alterations in the subcellular distribution of NADPH oxidase p47phox in hypothalamic paraventricular neurons following slow pressor Angiotensin II hypertension in female mice with accelerated ovarian failure

    PubMed Central

    Van Kempen, Tracey A.; Narayan, Ankita; Waters, Elizabeth M.; Marques-Lopes, Jose; Iadecola, Costantino; Glass, Michael J.; Pickel, Virginia M.; Milner, Teresa A.

    2015-01-01

    At younger ages, women have a lower risk for hypertension than men, but this sexual dimorphism declines with the onset of menopause. These differences are paralleled in rodents following “slow-pressor” angiotensin II (AngII) administration: young male and aged female mice, but not young females, develop hypertension. There is also an established sexual dimorphism both in the cardiovascular response to the neurohypophyseal hormone arginine vasopressin (AVP) and in the expression of oxidative stress. We examined the relationship between AngII-mediated hypertension and the cellular distribution of the superoxide generating NADPH oxidase (NOX) in AVP-expressing hypothalamic paraventricular nucleus (PVN) neurons in “menopausal” female mice. Dual labeling immunoelectron microscopy was used to determine if the subcellular distribution of the organizer/adapter NOX p47phox subunit is altered in PVN dendrites following AngII administered (14 days) during the “postmenopausal” stage of accelerated ovarian failure (AOF) in young female mice treated with 4-vinylcyclohexene diepoxide. Slow-pressor AngII elevated blood pressure in AOF females and induced a significant a significant increase in near plasmalemmal p47phox and a decrease in cytoplasmic p47phox in PVN AVP dendrites. These changes are opposite to those observed in AngII-induced hypertensive male mice (Coleman et al., J. Neuroscience 33: 4308-16, 2013), and may be ascribed in part to baseline differences between young females and males in the near plasmalemmal p47phox on AVP dendrites seen in the present study. These findings highlight fundamental differences in the neural substrates of oxidative stress in the PVN associated with AngII hypertension in postmenopausal females compared with males. PMID:26659944

  4. Recovery of hypothalamic tuberoinfundibular dopamine neurons from acute toxicant exposure is dependent upon protein synthesis and associated with an increase in parkin and ubiquitin carboxy-terminal hydrolase-L1 expression.

    PubMed

    Benskey, Matthew; Behrouz, Bahareh; Sunryd, Johan; Pappas, Samuel S; Baek, Seung-Hoon; Huebner, Marianne; Lookingland, Keith J; Goudreau, John L

    2012-06-01

    Hypothalamic tuberoinfundibular dopamine (TIDA) neurons remain unaffected in Parkinson disease (PD) while there is significant degeneration of midbrain nigrostriatal dopamine (NSDA) neurons. A similar pattern of susceptibility is observed in acute and chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse and rotenone rat models of degeneration. It is not known if the resistance of TIDA neurons is a constitutive or induced cell-autonomous phenotype for this unique subset of DA neurons. In the present study, treatment with a single injection of MPTP (20 mg/kg; s.c.) was employed to examine the response of TIDA versus NSDA neurons to acute injury. An acute single dose of MPTP caused an initial loss of DA from axon terminals of both TIDA and NSDA neurons, with recovery occurring solely in TIDA neurons by 16 h post-treatment. Initial loss of DA from axon terminals was dependent on a functional dopamine transporter (DAT) in NSDA neurons but DAT-independent in TIDA neurons. The active metabolite of MPTP, 1-methyl, 4-phenylpyradinium (MPP+), reached higher concentration and was eliminated slower in TIDA compared to NSDA neurons, which indicates that impaired toxicant bioactivation or distribution is an unlikely explanation for the observed resistance of TIDA neurons to MPTP exposure. Inhibition of protein synthesis prevented TIDA neuron recovery, suggesting that the ability to recover from injury was dependent on an induced, rather than a constitutive cellular mechanism. Further, there were no changes in total tyrosine hydroxylase (TH) expression following MPTP, indicating that up-regulation of the rate-limiting enzyme in DA synthesis does not account for TIDA neuronal recovery. Differential candidate gene expression analysis revealed a time-dependent increase in parkin and ubiquitin carboxyl-terminal hydrolase-L1 (UCH-L1) expression (mRNA and protein) in TIDA neurons during recovery from injury. Parkin expression was also found to increase with incremental

  5. Membrane progesterone receptors: evidence for neuroprotective, neurosteroid signaling and neuroendocrine functions in neuronal cells.

    PubMed

    Thomas, Peter; Pang, Yefei

    2012-01-01

    Membrane progesterone receptors (mPRs) are novel G protein-coupled receptors belonging to the progestin and adipoQ receptor family (PAQR) that mediate a variety of rapid cell surface-initiated progesterone actions in the reproductive system involving activation of intracellular signaling pathways (i.e. nonclassical actions). The mPRs are highly expressed in the brain, but research on their neural functions has only been conducted in a single neuronal cell line, GT1-7 cells, which have negligible nuclear progesterone receptor (PR) expression. GT1-7 cells express mPRα and mPRβ on their plasma membranes which is associated with the presence of high-affinity, specific [(3)H]-progesterone receptor binding. The neurosteroid, allopregnanolone, is an effective ligand for recombinant mPRα with a relative binding affinity of 7.6% that of progesterone. Allopregnanolone acts as a potent mPR agonist on GT1-7 cells, mimicking the progesterone-induced decrease in cAMP accumulation and its antiapoptotic actions at low nanomolar concentrations. The decrease in cAMP levels is associated with rapid progesterone-induced downregulation of GnRH pulsatile secretion from perifused GT1-7 cells. The recent suggestion that mPRs are alkaline ceramidases and mediate sphingolipid signaling is not supported by empirical evidence that TNFα does not bind to mPRs overexpressed in human cells and that exogenous sphingomyelinase is ineffective in mimicking progestin actions through mPRs to induce meiotic maturation of fish oocytes. Taken together, these recent studies indicate that mPRs mediate neuroprotective effects of progesterone and allopregnanolone and are also the likely intermediaries in progesterone-induced inhibition of pulsatile GnRH secretion in GT1-7 cells. Copyright © 2012 S. Karger AG, Basel.

  6. The role of hypothalamic mTORC1 signaling in insulin regulation of food intake, body weight, and sympathetic nerve activity in male mice.

    PubMed

    Muta, Kenjiro; Morgan, Donald A; Rahmouni, Kamal

    2015-04-01

    Insulin action in the brain particularly the hypothalamus is critically involved in the regulation of several physiological processes, including energy homeostasis and sympathetic nerve activity, but the underlying mechanisms are poorly understood. The mechanistic target of rapamycin complex 1 (mTORC1) is implicated in the control of diverse cellular functions, including sensing nutrients and energy status. Here, we examined the role of hypothalamic mTORC1 in mediating the anorectic, weight-reducing, and sympathetic effects of central insulin action. In a mouse hypothalamic cell line (GT1-7), insulin treatment increased mTORC1 activity in a time-dependent manner. In addition, intracerebroventricular (ICV) administration of insulin to mice activated mTORC1 pathway in the hypothalamic arcuate nucleus, a key site of central action of insulin. Interestingly, inhibition of hypothalamic mTORC1 with rapamycin reversed the food intake- and body weight-lowering effects of ICV insulin. Rapamycin also abolished the ability of ICV insulin to cause lumbar sympathetic nerve activation. In GT1-7 cells, we found that insulin activation of mTORC1 pathway requires phosphatidylinositol 3-kinase (PI3K). Consistent with this, genetic disruption of PI3K in mice abolished insulin stimulation of hypothalamic mTORC1 signaling as well as the lumbar sympathetic nerve activation evoked by insulin. These results demonstrate the importance of mTORC1 pathway in the hypothalamus in mediating the action of insulin to regulate energy homeostasis and sympathetic nerve traffic. Our data also highlight the key role of PI3K as a link between insulin receptor and mTORC1 signaling in the hypothalamus.

  7. Membrane Progesterone Receptors (mPRs): Evidence for Neuroprotective, Neurosteroid Signaling and Neuroendocrine Functions in Neuronal Cells

    PubMed Central

    Thomas, Peter; Pang, Yefei

    2012-01-01

    Membrane progesterone receptors (mPRs) are novel G protein-coupled receptors belonging to the progestin and adipoQ receptor family (PAQR) that mediate a variety of rapid, cell surface-initiated progesterone actions in the reproductive system involving activation of intracellular signaling pathways (i.e. nonclassical actions). The mPRs are highly expressed in the brain but research on their neural functions has only been conducted in a single neuronal cell line, GT1-7 cells, which have negligible nuclear progesterone receptor (PR) expression. GT1-7 cells express mPRα and mPRβ on their plasma membranes which is associated with the presence of high affinity, specific [3H]-progesterone receptor binding. The neurosteroid, allopregnanolone, is an effective ligand for recombinant mPRα with a relative binding affinity of 7.6% that of progesterone. Allopregnanolone acts as a potent mPR agonist on GT1-7 cells, mimicking the progesterone-induced decrease in cAMP accumulation and its antiapoptotic actions at low nanomolar concentrations.. The decrease in cAMP levels is associated with rapid progesterone-induced down-regulation of GnRH pulsatile secretion from perifused GT1-7 cells. The recent suggestion that mPRs are alkaline ceramidases and mediate sphingolipid signaling is not supported by empirical evidence that TNFα does not bind to mPRs over expressed in human cells and that exogenous sphingomyelinase is ineffective in mimicking progestin actions through mPRs to induce meiotic maturation of fish oocytes. Taken together, these recent studies indicate that mPRs mediate neuroprotective effects of progesterone and allopregnanolone and are also the likely intermediaries in progesterone-induced inhibition of pulsatile GnRH secretion in GT1-7 cells. PMID:22687885

  8. Supression of the steroid-primed luteinizing hormone surge in the female rat by sodium dimethyldithiocarbamate: Relationship to hypothalamic catecholamines and GnRH neuronal activation

    EPA Science Inventory

    In female rodents, hypothalamic norepinephrine (NE) has a role in stimulating the secretion of gonadotropin-releasing hormone (GnRH) that triggers the ovulatory surge of luteinizing hormone (LH). NE synthesis from dopamine requires the presence of dopamine--hydroxylase (DH) an...

  9. Supression of the steroid-primed luteinizing hormone surge in the female rat by sodium dimethyldithiocarbamate: Relationship to hypothalamic catecholamines and GnRH neuronal activation

    EPA Science Inventory

    In female rodents, hypothalamic norepinephrine (NE) has a role in stimulating the secretion of gonadotropin-releasing hormone (GnRH) that triggers the ovulatory surge of luteinizing hormone (LH). NE synthesis from dopamine requires the presence of dopamine--hydroxylase (DH) an...

  10. Fumonisin B1-induced apoptosis in neuroblastoma, glioblastoma and hypothalamic cell lines.

    PubMed

    Stockmann-Juvala, Helene; Naarala, Jonne; Loikkanen, Jarkko; Vähäkangas, Kirsi; Savolainen, Kai

    2006-08-15

    Fumonisin B(1) (FB(1)) is a mycotoxin produced by Fusarium verticilliodes, which commonly infects corn across the world. Fusarium fungi may also be found in moisture-damaged buildings. In this study, we investigated the role of apoptosis in the toxicity of FB(1) in four different cell lines. Activation of caspase-3-like protease, DNA fragmentation and expression of p53 and Bcl-2 family proteins were studied in mouse GT1-7 hypothalamic, rat C6 glioblastoma, human U-118MG glioblastoma, and human SH-SY5Y neuroblastoma cells exposed to 0.1-100microM FB(1) for 0-144h. Caspase-3-like protease activity increased in all cell lines, except SH-SY5Y, at 48-144h, and internucleosomal DNA fragmentation occurred in all of the cell lines, pointing to a role for apoptosis in the toxicity of FB(1). However, the expressions of p53 or pro- or antiapoptotic Bcl-2 family proteins (Bax, Bcl-2, Bcl-X(L) and Mcl-1) were not affected in any of the cell lines even after prolonged exposure to FB(1) at high doses. The results of this study, together with the results of our previous studies, provide evidence that FB(1) is a potential neurotoxin, but that the toxicity of FB(1) varies between different cell lines. The sensitivity of these cell lines towards FB(1) is as follows: U-118MG>GT1-7>C6>SH-SY5Y cells. These results are consistent with the assumption that cells of glial origin may be more sensitive towards FB(1) than cells of neural origin.

  11. A Mutation in cnot8, Component of the Ccr4-Not Complex Regulating Transcript Stability, Affects Expression Levels of Developmental Regulators and Reveals a Role of Fgf3 in Development of Caudal Hypothalamic Dopaminergic Neurons

    PubMed Central

    Koch, Peter; Löhr, Heiko B.; Driever, Wolfgang

    2014-01-01

    While regulation of the activity of developmental control genes at the transcriptional level as well as by specific miRNA-based degradation are intensively studied, little is known whether general cellular mechanisms controlling mRNA decay may contribute to differential stability of mRNAs of developmental control genes. Here, we investigate whether a mutation in the deadenylation dependent mRNA decay pathway may reveal differential effects on developmental mechanisms, using dopaminergic differentiation in the zebrafish brain as model system. In a zebrafish genetic screen aimed at identifying genes controlling dopaminergic neuron development we isolated the m1061 mutation that selectively caused increased dopaminergic differentiation in the caudal hypothalamus, while other dopaminergic groups were not affected. Positional cloning revealed that m1061 causes a premature stop codon in the cnot8 open reading frame. Cnot8 is a component of the Ccr4-Not complex and displays deadenylase activity, which is required for removal of the poly (A) tail in bulk mRNA turnover. Analyses of expression of developmental regulators indicate that loss of Cnot8 activity results in increased mRNA in situ hybridization signal levels for a subset of developmental control genes. We show that in the area of caudal hypothalamic dopaminergic differentiation, mRNA levels for several components of the FGF signaling pathway, including Fgf3, FGF receptors, and FGF target genes, are increased. Pharmacological inhibition of FGF signaling or a mutation in the fgf3 gene can compensate the gain of caudal hypothalamic dopaminergic neurons in cnot8m1061 mutants, indicating a role for Fgf3 in control of development of this dopaminergic population. The cnot8m1061 mutant phenotype provides an in vivo system to study roles of the Cnot8 deadenylase component of the mRNA decay pathway in vertebrate development. Our data indicate that attenuation of Cnot8 activity differentially affects mRNA levels of

  12. A mutation in cnot8, component of the Ccr4-not complex regulating transcript stability, affects expression levels of developmental regulators and reveals a role of Fgf3 in development of caudal hypothalamic dopaminergic neurons.

    PubMed

    Koch, Peter; Löhr, Heiko B; Driever, Wolfgang

    2014-01-01

    While regulation of the activity of developmental control genes at the transcriptional level as well as by specific miRNA-based degradation are intensively studied, little is known whether general cellular mechanisms controlling mRNA decay may contribute to differential stability of mRNAs of developmental control genes. Here, we investigate whether a mutation in the deadenylation dependent mRNA decay pathway may reveal differential effects on developmental mechanisms, using dopaminergic differentiation in the zebrafish brain as model system. In a zebrafish genetic screen aimed at identifying genes controlling dopaminergic neuron development we isolated the m1061 mutation that selectively caused increased dopaminergic differentiation in the caudal hypothalamus, while other dopaminergic groups were not affected. Positional cloning revealed that m1061 causes a premature stop codon in the cnot8 open reading frame. Cnot8 is a component of the Ccr4-Not complex and displays deadenylase activity, which is required for removal of the poly (A) tail in bulk mRNA turnover. Analyses of expression of developmental regulators indicate that loss of Cnot8 activity results in increased mRNA in situ hybridization signal levels for a subset of developmental control genes. We show that in the area of caudal hypothalamic dopaminergic differentiation, mRNA levels for several components of the FGF signaling pathway, including Fgf3, FGF receptors, and FGF target genes, are increased. Pharmacological inhibition of FGF signaling or a mutation in the fgf3 gene can compensate the gain of caudal hypothalamic dopaminergic neurons in cnot8m1061 mutants, indicating a role for Fgf3 in control of development of this dopaminergic population. The cnot8m1061 mutant phenotype provides an in vivo system to study roles of the Cnot8 deadenylase component of the mRNA decay pathway in vertebrate development. Our data indicate that attenuation of Cnot8 activity differentially affects mRNA levels of

  13. Somatostatin receptor subtypes sst1 and sst2 elicit opposite effects on the response to glutamate of mouse hypothalamic neurones: an electrophysiological and single cell RT-PCR study.

    PubMed

    Lanneau, C; Viollet, C; Faivre-Bauman, A; Loudes, C; Kordon, C; Epelbaum, J; Gardette, R

    1998-01-01

    We have previously shown that somatostatin can either enhance or decrease AMPA/kainate receptor-mediated responses to glutamate in mouse-dissociated hypothalamic neurones grown in vitro. To investigate whether this effect is due to differential activation of somatostatin (SRIF) receptor subtypes, we compared modulation of the response to glutamate by SRIF with that induced by CH-275 and octreotide, two selective agonists of sst1 and sst2/sst5 receptors, respectively. Somatostatin either significantly decreased (49%) or increased (30%) peak currents induced by glutamate, and was ineffective in the remaining cells. Only the decreased response was obtained with octreotide, whereas only increased responses were elicited by CH-275 (47 and 35% of the tested cells, respectively). Mean amplitude variations under somatostatin or octreotide on the one hand, and under somatostatin or CH-275 on the other hand, were equivalent. Pertussis toxin pretreatment significantly decreased the number of cells inhibited by somatostatin or octreotide, but had no effect on the frequency of neurones showing increased sensitivity to glutamate during somatostatin or CH-275 application. About half of the neurones tested by single cell reverse transcriptase polymerase chain reaction (RT-PCR) expressed only one sst receptor (sst1 in 26% and sst2 in 22% of studied cells). Out of the remaining neurones, 34% displayed neither sst1 nor sst2 mRNAs, whereas 18% showed a simultaneous expression of both mRNA subtypes. Expression of sst1 or sst2 mRNA subtypes matched totally with the effects of somatostatin on sensitivity to glutamate in 79% of the neurones processed for PCR after recordings. These data show that pertussis toxin-insensitive activation of the sst1 receptor subtype mediates somatostatin-induced increase in sensitivity to glutamate, whereas decrease in the response to glutamate is linked to pertussis toxin-sensitive activation of the sst2 receptor subtype.

  14. Androgen receptors and estrogen receptors are colocalized in male rat hypothalamic and limbic neurons that express Fos immunoreactivity induced by mating.

    PubMed

    Gréco, B; Edwards, D A; Michael, R P; Clancy, A N

    1998-01-01

    Conversion of testosterone into estradiol is important for male rat sexual behavior, and both steroids probably contribute to mating. The distributions of neurons containing androgen receptors (AR) and estrogen receptors (ER) overlap, and many AR-immunoreactive (AR-ir) neurons express Fos immunoreactivity (Fos-ir) induced by mating. Because mating-induced Fos-ir in the male rat occurs mainly in AR-ir neurons, and because both steroids are important for mating, we hypothesized that (i) AR-ir and ER-ir are colocalized and that (ii) some of these neurons are activated during mating. We examined, in adjacent sections from the medial preoptic area (MPN) through the central tegmental field (CTF), the expression of ER-ir in: (i) AR-ir-containing neurons, and (ii) Fos-ir-expressive neurons. PG21 anti-AR, OA-11-824 anti-c-fos, H222 or 1D5 anti-ER primary antibodies were visualized, respectively, with cyanine-conjugated, fluorescein- or cyanine-conjugated, and fluorescein-conjugated secondary antibodies in male rats which were killed 1 h after ejaculating with a receptive female. In MPN, bed nucleus of the stria terminalis (BNST), and medial amygdala (MEA), 80-90% of ER-ir labeling occurred in AR-ir-positive neurons but only about 30% of AR-ir neurons were ER-ir-positive. No ER-ir was found in the CTF. This suggests the presence of three types of brain neurons sensitive to gonadal steroid hormones: neurons sensitive to androgens only, neurons sensitive to both androgens and estrogens, and neurons sensitive to estrogens only. About 50% of ER-ir labeling occurred in cells expressing mating-induced Fos-ir but only about 30% of Fos-ir neurons were ER-ir-positive. These findings suggest that, in the MPN, at least two different neuronal populations are activated during mating: the first contains AR-ir only and the second contains AR-ir and ER-ir. In the BNST and MEA, at least three hormonally sensitive populations are activated during mating: the two described above plus a third

  15. Activation of the hypothalamic feeding centre upon visual prey detection

    PubMed Central

    Muto, Akira; Lal, Pradeep; Ailani, Deepak; Abe, Gembu; Itoh, Mari; Kawakami, Koichi

    2017-01-01

    The visual system plays a major role in food/prey recognition in diurnal animals, and food intake is regulated by the hypothalamus. However, whether and how visual information about prey is conveyed to the hypothalamic feeding centre is largely unknown. Here we perform real-time imaging of neuronal activity in freely behaving or constrained zebrafish larvae and demonstrate that prey or prey-like visual stimuli activate the hypothalamic feeding centre. Furthermore, we identify prey detector neurons in the pretectal area that project to the hypothalamic feeding centre. Ablation of the pretectum completely abolishes prey capture behaviour and neurotoxin expression in the hypothalamic area also reduces feeding. Taken together, these results suggest that the pretecto-hypothalamic pathway plays a crucial role in conveying visual information to the feeding centre. Thus, this pathway possibly converts visual food detection into feeding motivation in zebrafish. PMID:28425439

  16. ALTERED HYPOTHALAMIC FUNCTION IN DIET-INDUCED OBESITY

    PubMed Central

    Velloso, L A; Schwartz, M W

    2012-01-01

    Energy homeostasis involves a complex network of hypothalamic and extra-hypothalamic neurons that transduce hormonal, nutrient and neuronal signals into responses that ultimately match caloric intake to energy expenditure and thereby promote stability of body fat stores. Growing evidence suggests that rather than reflecting a failure to regulate caloric intake, common forms of obesity involve fundamental changes to this homeostatic system that favor the defense of an elevated level of body adiposity. This article reviews emerging evidence that during high-fat feeding, obesity pathogenesis involves fundamental alteration of hypothalamic systems that regulate food intake and energy expenditure. PMID:21386802

  17. Melanin-concentrating hormone (MCH) immunoreactivity in the brain and pituitary of the dogfish Scyliorhinus canicula. Colocalization with alpha-melanocyte-stimulating hormone (alpha-MSH) in hypothalamic neurons.

    PubMed

    Vallarino, M; Andersen, A C; Delbende, C; Ottonello, I; Eberle, A N; Vaudry, H

    1989-01-01

    The distribution of melanin-concentrating hormone (MCH) in the central nervous system of the dogfish Scyliorhinus canicula was determined by indirect immunofluorescence and peroxidase-anti-peroxidase techniques, using an antiserum raised against synthetic salmon MCH. Three groups of MCH-positive cell bodies were localized in the posterior hypothalamus. The most prominent cell group was detected in the nucleus sacci vasculosi. Scattered MCH-immunoreactive cells were observed in the nucleus tuberculi posterioris and in the nucleus lateralis tuberis. At the pituitary level, the caudal part of the median lobe of the pars distalis contained strongly MCH-positive perikarya. Some of these cells were liquor-contacting-type. Immunoreactive fibers originating from the hypothalamic perikarya projected throughout the dorsal wall of the posterior hypothalamus. Positive fibers were also detected within the thalamus and the central gray of the mesencephalon. The distribution of MCH-containing neurons was compared to that of alpha-MSH-immunoreactive elements using consecutive, 5-micron thick sections. Both MCH- and alpha-MSH-immunoreactive peptides were found in the same neurons of the nucleus sacci vasculosi. These data suggest that MCH and alpha-MSH, two neuropeptides which exert antagonistic activities on skin melanophores, may also act in a coordinate manner in the central nervous system of cartilaginous fish.

  18. Metabolic Benefit of Chronic Caloric Restriction and Activation of Hypothalamic AGRP/NPY Neurons in Male Mice Is Independent of Ghrelin.

    PubMed

    Rogers, Nicole H; Walsh, Heidi; Alvarez-Garcia, Oscar; Park, Seongjoon; Gaylinn, Bruce; Thorner, Michael O; Smith, Roy G

    2016-04-01

    Aging is associated with attenuated ghrelin signaling. During aging, chronic caloric restriction (CR) produces health benefits accompanied by enhanced ghrelin production. Ghrelin receptor (GH secretagogue receptor 1a) agonists administered to aging rodents and humans restore the young adult phenotype; therefore, we tested the hypothesis that the metabolic benefits of CR are mediated by endogenous ghrelin. Three month-old male mice lacking ghrelin (Ghrelin-/-) or ghrelin receptor (Ghsr-/-), and their wild-type (WT) littermates were randomly assigned to 2 groups: ad libitum (AL) fed and CR, where 40% food restriction was introduced gradually to allow Ghrelin-/- and Ghsr-/- mice to metabolically adapt and avoid severe hypoglycemia. Twelve months later, plasma ghrelin, metabolic parameters, ambulatory activity, hypothalamic and liver gene expression, as well as body composition were measured. CR increased plasma ghrelin and des-acyl ghrelin concentrations in WT and Ghsr-/- mice. CR of WT, Ghsr-/-, and Ghrelin-/- mice markedly improved metabolic flexibility, enhanced ambulatory activity, and reduced adiposity. Inactivation of Ghrelin or Ghsr had no effect on AL food intake or food anticipatory behavior. In contrast to the widely held belief that endogenous ghrelin regulates food intake, CR increased expression of hypothalamic Agrp and Npy, with reduced expression of Pomc across genotypes. In the AL context, ablation of ghrelin signaling markedly inhibited liver steatosis, which correlated with reduced Pparγ expression and enhanced Irs2 expression. Although CR and administration of GH secretagogue receptor 1a agonists both benefit the aging phenotype, we conclude the benefits of chronic CR are a consequence of enhanced metabolic flexibility independent of endogenous ghrelin or des-acyl ghrelin signaling.

  19. Age-related alterations in hypothalamic kisspeptin, neurokinin B, and dynorphin neurons and in pulsatile LH release in female and male rats.

    PubMed

    Kunimura, Yuyu; Iwata, Kinuyo; Ishigami, Akihito; Ozawa, Hitoshi

    2017-02-01

    Pulsatile secretion of gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) decreases during aging. Kisspeptin (encoded by Kiss1) neurons in the arcuate nucleus coexpress neurokinin B (Tac3) and dynorphin (Pdyn) and are critical for regulating the GnRH/LH pulse. We therefore examined kisspeptin neurons by histochemistry and pulsatile LH release in rats aged 2-3 (Young), 12-13 (Young-Middle), 19-22 (Late-Middle), and 24-26 (Old) months. Total LH concentrations, sampled for 3 hours, decreased in both sexes with aging. In females, numbers of Tac3 and Pdyn neurons were significantly reduced in all aging rats, and numbers of Kiss1 neurons were significantly reduced in Late-Middle and Old rats. In males, numbers of all 3 neuron-types were significantly decreased in all aging rats. GnRH agonist induced LH release in all animals; however, the increased LH concentration in all aging rats was less than that in Young rats. These results suggest that expression of each gene in kisspeptin neurons may be controlled individually during aging, and that reduction of their expression or change in pituitary responsiveness may cause attenuated pulsatile LH secretion.

  20. [Hypothalamic dysfunction in obesity].

    PubMed

    van de Sande-Lee, Simone; Velloso, Licio A

    2012-08-01

    Obesity, defined as abnormal or excessive fat accumulation that may impair life quality, is one of the major public health problems worldwide. It results from an imbalance between food intake and energy expenditure. The control of energy balance in animals and humans is performed by the central nervous system (CNS) by means of neuroendocrine connections, in which circulating peripheral hormones, such as leptin and insulin, provide signals to specialized neurons of the hypothalamus reflecting body fat stores, and induce appropriate responses to maintain the stability of these stores. The majority of obesity cases are associated with central resistance to both leptin and insulin actions. In experimental animals, high-fat diets can induce an inflammatory process in the hypothalamus, which impairs leptin and insulin intracellular signaling pathways, and results in hyperphagia, decreased energy expenditure and, ultimately, obesity. Recent evidence obtained from neuroimaging studies and assessment of inflammatory markers in the cerebrospinal fluid of obese subjects suggests that similar alterations may be also present in humans. In this review, we briefly present the mechanisms involved with the loss of homeostatic control of energy balance in animal models of obesity, and the current evidence of hypothalamic dysfunction in obese humans.

  1. The role of tanycytes in hypothalamic glucosensing

    PubMed Central

    Elizondo-Vega, Roberto; Cortes-Campos, Christian; Barahona, Maria J; Oyarce, Karina A; Carril, Claudio A; García-Robles, Maria A

    2015-01-01

    Tanycytes are elongated hypothalamic glial cells that cover the basal walls of the third ventricle; their apical regions contact the cerebrospinal fluid (CSF), and their processes reach hypothalamic neuronal nuclei that control the energy status of an organism. These nuclei maintain the balance between energy expenditure and intake, integrating several peripheral signals and triggering cellular responses that modify the feeding behaviour and peripheral glucose homeostasis. One of the most important and well-studied signals that control this process is glucose; however, the mechanism by which this molecule is sensed remains unknown. We along with others have proposed that tanycytes play a key role in this process, transducing changes in CSF glucose concentration to the neurons that control energy status. Recent studies have demonstrated the expression and function of monocarboxylate transporters and canonical pancreatic β cell glucose sensing molecules, including glucose transporter 2 and glucokinase, in tanycytes. These and other data, which will be discussed in this review, suggest that hypothalamic glucosensing is mediated through a metabolic interaction between tanycytes and neurons through lactate. This article will summarize the recent evidence that supports the importance of tanycytes in hypothalamic glucosensing, and discuss the possible mechanisms involved in this process. Finally, it is important to highlight that a detailed analysis of this mechanism could represent an opportunity to understand the evolution of associated pathologies, including diabetes and obesity, and identify new candidates for therapeutic intervention. PMID:26081217

  2. Role of developmental factors in hypothalamic function

    PubMed Central

    Biran, Jakob; Tahor, Maayan; Wircer, Einav; Levkowitz, Gil

    2015-01-01

    The hypothalamus is a brain region which regulates homeostasis by mediating endocrine, autonomic and behavioral functions. It is comprised of several nuclei containing distinct neuronal populations producing neuropeptides and neurotransmitters that regulate fundamental body functions including temperature and metabolic rate, thirst and hunger, sexual behavior and reproduction, circadian rhythm, and emotional responses. The identity, number and connectivity of these neuronal populations are established during the organism’s development and are of crucial importance for normal hypothalamic function. Studies have suggested that developmental abnormalities in specific hypothalamic circuits can lead to obesity, sleep disorders, anxiety, depression and autism. At the molecular level, the development of the hypothalamus is regulated by transcription factors (TF), secreted growth factors, neuropeptides and their receptors. Recent studies in zebrafish and mouse have demonstrated that some of these molecules maintain their expression in the adult brain and subsequently play a role in the physiological functions that are regulated by hypothalamic neurons. Here, we summarize the involvement of some of the key developmental factors in hypothalamic development and function by focusing on the mouse and zebrafish genetic model organisms. PMID:25954163

  3. c-Fos expression in neurons projecting from the preoptic and lateral hypothalamic areas to the ventrolateral periaqueductal gray in relation to sleep states

    PubMed Central

    Hsieh, Kung-Chiao; Gvilia, Irma; Kumar, Sunil; Uschakov, Aaron; McGinty, Dennis; Alam, M. Noor; Szymusiak, Ronald

    2011-01-01

    The ventrolateral division of the periaqueductal gray (vlPAG) and the adjacent deep mesencephalic reticular nucleus have been implicated in the control of sleep. The preoptic hypothalamus, which contains populations of sleep-active neurons, is an important source of afferents to the vlPAG. The perifornical lateral hypothalamus (LH) contains populations of wake-active neurons and also projects strongly to the vlPAG. We examined nonREM and REM sleep-dependent expression of c-Fos protein in preoptic-vlPAG and LH-vlPAG projection neurons identified by retrograde labeling with Fluoro-gold (FG). Separate groups of rats (n=5) were subjected to 3 hours total sleep deprivation (TSD) followed by 1 hour recovery sleep (RS), or to 3 hours of selective REM sleep deprivation (RSD) followed by RS. A third group of rats (n=5) was subjected to TSD without opportunity for RS (awake group). In the median preoptic nucleus (MnPN), the percentage of FG+ neurons that were also Fos+ was higher in TSD-RS animals compared to both RSD-RS rats and awake rats. There were significant correlations between time spent in deep nonREM sleep during the 1-hour prior to sacrifice across groups and the percentage of double-labeled cells in MnPN and ventrolateral preoptic area (VLPO). There were no significant correlations between percentage of double labeled neurons and time spent in REM sleep for any of the preoptic nuclei examined. In the LH, percentage of double-labeled neurons was highest in awake rats, intermediate in TSD-RS rats and lowest in the RSD-RS group. These results suggest that neurons projecting from MnPN and VLPO to the vlPAG are activated during nonREM sleep and support the hypothesis that preoptic neurons provide inhibitory input to vlPAG during sleep. Suppression of excitatory input to the vlPAG from the LH during sleep may have a permissive effect on REM sleep generation. PMID:21601616

  4. Estradiol and Progesterone Differentially Regulate the Dendritic Arbor of Neurons in the Hypothalamic Ventromedial Nucleus of the Female Rat(Rattus norvegicus)

    PubMed Central

    GRIFFIN, GERALD D.; FLANAGAN-CATO, LORETTA M.

    2008-01-01

    The ventromedial nucleus of the hypothalamus (VMH), with its major subdivisions, the dorsomedial and ventrolateral VMH (dmVMH and vlVMH, respectively), has been studied extensively for its role in female sexual behavior. This behavior is controlled by the vlVMH through the cellular actions of estradiol combined with progesterone. Although the effects of treatment with estradiol alone on neuronal morphology in the vlVMH have been examined, much less is known about the combined effects of estradiol and progesterone on neuronal structure. The present study employed Golgi impregnation to investigate the effects of estradiol treatment alone vs. estradiol combined with progesterone treatment on dendritic arbor of VMH neurons. The dendritic arbor of VMH neurons was somewhat different in the vlVMH vs. the dmVMH, with longer and more dendrites in the vlVMH. Estradiol treatment alone caused a marked reduction in the length of long primary dendrites in the vlVMH, but not in the dmVMH. The estradiol-induced retraction of long primary dendrites in the vlVMH was reversed within 4 hours of progesterone treatment. The differences in the dendritic arbors of dmVMH and vlVMH provide further support for the notion that these two regions have different patterns of neural connectivity. In addition, this study is the first to report opposing effects of estradiol alone vs. estradiol plus progesterone on the dendritic arbor of neurons in the vlVMH. These results suggest a structural mechanism for estradiol alone to have a modest effect on mating behavior while setting the stage for its ample expression. PMID:18698598

  5. Passive transfer of narcolepsy: anti-TRIB2 autoantibody positive patient IgG causes hypothalamic orexin neuron loss and sleep attacks in mice.

    PubMed

    Katzav, Aviva; Arango, Maria T; Kivity, Shaye; Tanaka, Susumu; Givaty, Gili; Agmon-Levin, Nancy; Honda, Makoto; Anaya, Juan-Manuel; Chapman, Joab; Shoenfeld, Yehuda

    2013-09-01

    Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness and cataplexy (a sudden weakening of posture muscle tone usually triggered by emotion) caused by the loss of orexin neurons in the hypothalamus. Autoimmune mechanisms are implicated in narcolepsy by increased frequency of specific HLA alleles and the presence of specific autoantibody (anti-Tribbles homolog 2 (TRIB2) antibodies) in the sera of patients with narcolepsy. Presently, we passively transferred narcolepsy to naïve mice by injecting intra-cerebra-ventricularly (ICV) pooled IgG positive for anti-TRIB2 antibodies. Narcolepsy-IgG-injected mice had a loss of the NeuN (neuronal marker), synaptophysin (synaptic marker) and orexin-positive neurons in the lateral hypothalamus area in narcolepsy compared to control-IgG-injected mice and these changes were associated with narcolepsy-like immobility attacks at four weeks post injection and with hyperactivity and long term memory deficits in the staircase and novel object recognition tests. Similar behavioral and cognitive deficits are observed in narcoleptic patients. This is the first report of passive transfer of experimental narcolepsy to naïve mice induced by autoantibodies and supports the autoimmune pathogenesis in narcolepsy.

  6. A Relationship between Reduced Nucleus Accumbens Shell and Enhanced Lateral Hypothalamic Orexin Neuronal Activation in Long-Term Fructose Bingeing Behavior

    PubMed Central

    Rorabaugh, Jacki M.; Stratford, Jennifer M.; Zahniser, Nancy R.

    2014-01-01

    Fructose accounts for 10% of daily calories in the American diet. Fructose, but not glucose, given intracerebroventricularly stimulates homeostatic feeding mechanisms within the hypothalamus; however, little is known about how fructose affects hedonic feeding centers. Repeated ingestion of sucrose, a disaccharide of fructose and glucose, increases neuronal activity in hedonic centers, the nucleus accumbens (NAc) shell and core, but not the hypothalamus. Rats given glucose in the intermittent access model (IAM) display signatures of hedonic feeding including bingeing and altered DA receptor (R) numbers within the NAc. Here we examined whether substituting fructose for glucose in this IAM produces bingeing behavior, alters DA Rs and activates hedonic and homeostatic feeding centers. Following long-term (21-day) exposure to the IAM, rats given 8–12% fructose solutions displayed fructose bingeing but unaltered DA D1R or D2R number. Fructose bingeing rats, as compared to chow bingeing controls, exhibited reduced NAc shell neuron activation, as determined by c-Fos-immunoreactivity (Fos-IR). This activation was negatively correlated with orexin (Orx) neuron activation in the lateral hypothalamus/perifornical area (LH/PeF), a brain region linking homeostatic to hedonic feeding centers. Following short-term (2-day) access to the IAM, rats exhibited bingeing but unchanged Fos-IR, suggesting only long-term fructose bingeing increases Orx release. In long-term fructose bingeing rats, pretreatment with the Ox1R antagonist SB-334867 (30 mg/kg; i.p.) equally reduced fructose bingeing and chow intake, resulting in a 50% reduction in calories. Similarly, in control rats, SB-334867 reduced chow/caloric intake by 60%. Thus, in the IAM, Ox1Rs appear to regulate feeding based on caloric content rather than palatability. Overall, our results, in combination with the literature, suggest individual monosaccharides activate distinct neuronal circuits to promote feeding behavior

  7. Slow-pressor angiotensin II hypertension and concomitant dendritic NMDA receptor trafficking in estrogen receptor β-containing neurons of the mouse hypothalamic paraventricular nucleus are sex and age dependent.

    PubMed

    Marques-Lopes, Jose; Van Kempen, Tracey; Waters, Elizabeth M; Pickel, Virginia M; Iadecola, Costantino; Milner, Teresa A

    2014-09-01

    The incidence of hypertension increases after menopause. Similar to humans, "slow-pressor" doses of angiotensin II (AngII) increase blood pressure in young males, but not in young female mice. However, AngII increases blood pressure in aged female mice, paralleling reproductive hormonal changes. These changes could influence receptor trafficking in central cardiovascular circuits and contribute to hypertension. Increased postsynaptic N-methyl-D-aspartate (NMDA) receptor activity in the hypothalamic paraventricular nucleus (PVN) is crucial for the sympathoexcitation driving AngII hypertension. Estrogen receptors β (ERβs) are present in PVN neurons. We tested the hypothesis that changes in ovarian hormones with age promote susceptibility to AngII hypertension, and influence NMDA receptor NR1 subunit trafficking in ERβ-containing PVN neurons. Transgenic mice expressing enhanced green fluorescent protein (EGFP) in ERβ-containing cells were implanted with osmotic minipumps delivering AngII (600 ng/kg/min) or saline for 2 weeks. AngII increased blood pressure in 2-month-old males and 18-month-old females, but not in 2-month-old females. By electron microscopy, NR1-silver-intensified immunogold (SIG) was mainly in ERβ-EGFP dendrites. At baseline, NR1-SIG density was greater in 2-month-old females than in 2-month-old males or 18-month-old females. After AngII infusion, NR1-SIG density was decreased in 2-month-old females, but increased in 2-month-old males and 18-month-old females. These findings suggest that, in young female mice, NR1 density is decreased in ERβ-PVN dendrites thus reducing NMDA receptor activity and preventing hypertension. Conversely, in young males and aged females, NR1 density is upregulated in ERβ-PVN dendrites and ultimately leads to the neurohumoral dysfunction driving hypertension.

  8. Glucose Alters Per2 Rhythmicity Independent of AMPK, Whereas AMPK Inhibitor Compound C Causes Profound Repression of Clock Genes and AgRP in mHypoE-37 Hypothalamic Neurons

    PubMed Central

    Oosterman, Johanneke E.; Belsham, Denise D.

    2016-01-01

    Specific neurons in the hypothalamus are regulated by peripheral hormones and nutrients to maintain proper metabolic control. It is unclear if nutrients can directly control clock gene expression. We have therefore utilized the immortalized, hypothalamic cell line mHypoE-37, which exhibits robust circadian rhythms of core clock genes. mHypoE-37 neurons were exposed to 0.5 or 5.5 mM glucose, comparable to physiological levels in the brain. Per2 and Bmal1 mRNAs were assessed every 3 hours over 36 hours. Incubation with 5.5 mM glucose significantly shortened the period and delayed the phase of Per2 mRNA levels, but had no effect on Bmal1. Glucose had no significant effect on phospho-GSK3β, whereas AMPK phosphorylation was altered. Thus, the AMPK inhibitor Compound C was utilized, and mRNA levels of Per2, Bmal1, Cryptochrome1 (Cry1), agouti-related peptide (AgRP), carnitine palmitoyltransferase 1C (Cpt1c), and O-linked N-acetylglucosamine transferase (Ogt) were measured. Remarkably, Compound C dramatically reduced transcript levels of Per2, Bmal1, Cry1, and AgRP, but not Cpt1c or Ogt. Because AMPK was not inhibited at the same time or concentrations as the clock genes, we suggest that the effect of Compound C on gene expression occurs through an AMPK-independent mechanism. The consequences of inhibition of the rhythmic expression of clock genes, and in turn downstream metabolic mediators, such as AgRP, could have detrimental effects on overall metabolic processes. Importantly, the effects of the most commonly used AMPK inhibitor Compound C should be interpreted with caution, considering its role in AMPK-independent repression of specific genes, and especially clock gene rhythm dysregulation. PMID:26784927

  9. Glucose Alters Per2 Rhythmicity Independent of AMPK, Whereas AMPK Inhibitor Compound C Causes Profound Repression of Clock Genes and AgRP in mHypoE-37 Hypothalamic Neurons.

    PubMed

    Oosterman, Johanneke E; Belsham, Denise D

    2016-01-01

    Specific neurons in the hypothalamus are regulated by peripheral hormones and nutrients to maintain proper metabolic control. It is unclear if nutrients can directly control clock gene expression. We have therefore utilized the immortalized, hypothalamic cell line mHypoE-37, which exhibits robust circadian rhythms of core clock genes. mHypoE-37 neurons were exposed to 0.5 or 5.5 mM glucose, comparable to physiological levels in the brain. Per2 and Bmal1 mRNAs were assessed every 3 hours over 36 hours. Incubation with 5.5 mM glucose significantly shortened the period and delayed the phase of Per2 mRNA levels, but had no effect on Bmal1. Glucose had no significant effect on phospho-GSK3β, whereas AMPK phosphorylation was altered. Thus, the AMPK inhibitor Compound C was utilized, and mRNA levels of Per2, Bmal1, Cryptochrome1 (Cry1), agouti-related peptide (AgRP), carnitine palmitoyltransferase 1C (Cpt1c), and O-linked N-acetylglucosamine transferase (Ogt) were measured. Remarkably, Compound C dramatically reduced transcript levels of Per2, Bmal1, Cry1, and AgRP, but not Cpt1c or Ogt. Because AMPK was not inhibited at the same time or concentrations as the clock genes, we suggest that the effect of Compound C on gene expression occurs through an AMPK-independent mechanism. The consequences of inhibition of the rhythmic expression of clock genes, and in turn downstream metabolic mediators, such as AgRP, could have detrimental effects on overall metabolic processes. Importantly, the effects of the most commonly used AMPK inhibitor Compound C should be interpreted with caution, considering its role in AMPK-independent repression of specific genes, and especially clock gene rhythm dysregulation.

  10. Delineating the regulation of energy homeostasis using hypothalamic cell models.

    PubMed

    Wellhauser, Leigh; Gojska, Nicole M; Belsham, Denise D

    2015-01-01

    Attesting to its intimate peripheral connections, hypothalamic neurons integrate nutritional and hormonal cues to effectively manage energy homeostasis according to the overall status of the system. Extensive progress in the identification of essential transcriptional and post-translational mechanisms regulating the controlled expression and actions of hypothalamic neuropeptides has been identified through the use of animal and cell models. This review will introduce the basic techniques of hypothalamic investigation both in vivo and in vitro and will briefly highlight the key advantages and challenges of their use. Further emphasis will be place on the use of immortalized models of hypothalamic neurons for in vitro study of feeding regulation, with a particular focus on cell lines proving themselves most fruitful in deciphering fundamental basics of NPY/AgRP, Proglucagon, and POMC neuropeptide function. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Hypothalamic inflammation: a double-edged sword to nutritional diseases

    PubMed Central

    Cai, Dongsheng; Liu, Tiewen

    2015-01-01

    The hypothalamus is one of the master regulators of various physiological processes, including energy balance and nutrient metabolism. These regulatory functions are mediated by discrete hypothalamic regions that integrate metabolic sensing with neuroendocrine and neural controls of systemic physiology. Neurons and non-neuronal cells in these hypothalamic regions act supportively to execute metabolic regulations. Under conditions of brain and hypothalamic inflammation, which may result from overnutrition-induced intracellular stresses or disease-associated systemic inflammatory factors, extracellular and intracellular environments of hypothalamic cells are disrupted, leading to central metabolic dysregulations and various diseases. Recent research has begun to elucidate the effects of hypothalamic inflammation in causing diverse components of metabolic syndrome leading to diabetes and cardiovascular disease. These new understandings have provocatively expanded previous knowledge on the cachectic roles of brain inflammatory response in diseases, such as infections and cancers. This review describes the molecular and cellular characteristics of hypothalamic inflammation in metabolic syndrome and related diseases as opposed to cachectic diseases, and also discusses concepts and potential applications of inhibiting central/hypothalamic inflammation to treat nutritional diseases. PMID:22417140

  12. Increased hypothalamic serotonin turnover in inflammation-induced anorexia.

    PubMed

    Dwarkasing, J T; Witkamp, R F; Boekschoten, M V; Ter Laak, M C; Heins, M S; van Norren, K

    2016-05-20

    Anorexia can occur as a serious complication of disease. Increasing evidence suggests that inflammation plays a major role, along with a hypothalamic dysregulation characterized by locally elevated serotonin levels. The present study was undertaken to further explore the connections between peripheral inflammation, anorexia and hypothalamic serotonin metabolism and signaling pathways. First, we investigated the response of two hypothalamic neuronal cell lines to TNFα, IL-6 and LPS. Next, we studied transcriptomic changes and serotonergic activity in the hypothalamus of mice after intraperitoneal injection with TNFα, IL-6 or a combination of TNFα and IL-6. In vitro, we showed that hypothalamic neurons responded to inflammatory mediators by releasing cytokines. This inflammatory response was associated with an increased serotonin release. Mice injected with TNFα and IL-6 showed decreased food intake, associated with altered expression of inflammation-related genes in the hypothalamus. In addition, hypothalamic serotonin turnover showed to be elevated in treated mice. Overall, our results underline that peripheral inflammation reaches the hypothalamus where it affects hypothalamic serotoninergic metabolism. These hypothalamic changes in serotonin pathways are associated with decreased food intake, providing evidence for a role of serotonin in inflammation-induced anorexia.

  13. Hypothalamic Survival Circuits: Blueprints for Purposive Behaviors

    PubMed Central

    Sternson, Scott M.

    2015-01-01

    Neural processes that direct an animal’s actions toward environmental goals are critical elements for understanding behavior. The hypothalamus is closely associated with motivated behaviors required for survival and reproduction. Intense feeding, drinking, aggressive, and sexual behaviors can be produced by a simple neuronal stimulus applied to discrete hypothalamic regions. What can these “evoked behaviors” teach us about the neural processes that determine behavioral intent and intensity? Small populations of neurons sufficient to evoke a complex motivated behavior may be used as entry points to identify circuits that energize and direct behavior to specific goals. Here, I review recent applications of molecular genetic, optogenetic, and pharmacogenetic approaches that overcome previous limitations for analyzing anatomically complex hypothalamic circuits and their interactions with the rest of the brain. These new tools have the potential to bridge the gaps between neurobiological and psychological thinking about the mechanisms of complex motivated behavior. PMID:23473313

  14. Hypothalamic neuropeptides and the regulation of appetite.

    PubMed

    Parker, Jennifer A; Bloom, Stephen R

    2012-07-01

    Neuropeptides released by hypothalamic neurons play a major role in the regulation of feeding, acting both within the hypothalamus, and at other appetite regulating centres throughout the brain. Where classical neurotransmitters signal only within synapses, neuropeptides diffuse over greater distances affecting both nearby and distant neurons expressing the relevant receptors, which are often extrasynaptic. As well as triggering a behavioural output, neuropeptides also act as neuromodulators: altering the response of neurons to both neurotransmitters and circulating signals of nutrient status. The mechanisms of action of hypothalamic neuropeptides with established roles in feeding, including melanin-concentrating hormone (MCH), the orexins, α-melanocyte stimulating hormone (α-MSH), agouti-gene related protein (AgRP), neuropeptide Y, and oxytocin, are reviewed in this article, with emphasis laid on both their effects on appetite regulating centres throughout the brain, and on examining the evidence for their physiological roles. In addition, evidence for the involvement of several putative appetite regulating hypothalamic neuropeptides is assessed including, ghrelin, cocaine and amphetamine-regulated transcript (CART), neuropeptide W and the galanin-like peptides. This article is part of a Special Issue entitled 'Central control of Food Intake'.

  15. The obesity susceptibility gene Cpe links FoxO1 signaling in hypothalamic pro-opiomelanocortin neurons with regulation of food intake.

    PubMed

    Plum, Leona; Lin, Hua V; Dutia, Roxanne; Tanaka, Jun; Aizawa, Kumiko S; Matsumoto, Michihiro; Kim, Andrea J; Cawley, Niamh X; Paik, Ji-Hye; Loh, Y Peng; DePinho, Ronald A; Wardlaw, Sharon L; Accili, Domenico

    2009-10-01

    Reduced food intake brings about an adaptive decrease in energy expenditure that contributes to the recidivism of obesity after weight loss. Insulin and leptin inhibit food intake through actions in the central nervous system that are partly mediated by the transcription factor FoxO1. We show that FoxO1 ablation in pro-opiomelanocortin (Pomc)-expressing neurons in mice (here called Pomc-Foxo1(-/-) mice) increases Carboxypeptidase E (Cpe) expression, resulting in selective increases of alpha-melanocyte-stimulating hormone (alpha-Msh) and carboxy-cleaved beta-endorphin, the products of Cpe-dependent processing of Pomc. This neuropeptide profile is associated with decreased food intake and normal energy expenditure in Pomc-Foxo1(-/-) mice. We show that Cpe expression is downregulated by diet-induced obesity and that FoxO1 deletion offsets the decrease, protecting against weight gain. Moreover, moderate Cpe overexpression in the arcuate nucleus phenocopies features of the FoxO1 mutation. The dissociation of food intake from energy expenditure in Pomc-Foxo1(-/-) mice represents a model for therapeutic intervention in obesity and raises the possibility of targeting Cpe to develop weight loss medications.

  16. Estrogen Signaling in Hypothalamic Circuits Controling Reproduction

    PubMed Central

    Kelly, Martin J.; Qiu, Jian

    2010-01-01

    It is well known that many of the actions of 17β-estradiol (E2) in the central nervous system are mediated via intracellular receptor/transcription factors that interact with steroid response elements on target genes. However, there is compelling evidence for membrane steroid receptors for estrogen in hypothalamic and other brain neurons. Yet, it is not well understood how estrogen signals via membrane receptors, and how these signals impact not only membrane excitability but also gene transcription in neurons that modulate GnRH neuronal excitability. Indeed, it has been known for sometime that E2 can rapidly alter neuronal activity within seconds, indicating that some cellular effects can occur via membrane delimited events. In addition, E2 can affect second messenger systems including calcium mobilization and a plethora of kinases to alter cell signaling. Therefore, this review will consider our current knowledge of rapid membrane-initiated and intracellular signaling by E2 in hypothalamic neurons critical for reproductive function. PMID:20807512

  17. Hypothalamic obesity in children.

    PubMed

    Bereket, A; Kiess, W; Lustig, R H; Muller, H L; Goldstone, A P; Weiss, R; Yavuz, Y; Hochberg, Z

    2012-09-01

    Hypothalamic obesity is an intractable form of obesity syndrome that was initially described in patients with hypothalamic tumours and surgical damage. However, this definition is now expanded to include obesity developing after a variety of insults, including intracranial infections, infiltrations, trauma, vascular problems and hydrocephalus, in addition to acquired or congenital functional defects in central energy homeostasis in children with the so-called common obesity. The pathogenetic mechanisms underlying hypothalamic obesity are complex and multifactorial. Weight gain results from damage to the ventromedial hypothalamus, which leads, variously, to hyperphagia, a low-resting metabolic rate; autonomic imbalance; growth hormone-, gonadotropins and thyroid-stimulating hormone deficiency; hypomobility; and insomnia. Hypothalamic obesity did not receive enough attention, as evidenced by rarity of studies in this group of patients. A satellite symposium was held during the European Congress of Obesity in May 2011, in Istanbul, Turkey, to discuss recent developments and concepts regarding pathophysiology and management of hypothalamic obesity in children. An international group of leading researchers presented certain aspects of the problem. This paper summarizes the highlights of this symposium. Understanding the central role of the hypothalamus in the regulation of feeding and energy metabolism will help us gain insights into the pathogenesis and management of common obesity. © 2012 The Authors. obesity reviews © 2012 International Association for the Study of Obesity.

  18. Hypothalamic inflammation and gliosis in obesity

    PubMed Central

    Dorfman, Mauricio D.; Thaler, Joshua P.

    2015-01-01

    Structured Abstract Purpose of review Hypothalamic inflammation and gliosis are recently discovered mechanisms that may contribute to obesity pathogenesis. Current research in this area suggests that investigation of these CNS responses may provide opportunities to develop new weight loss treatments. Recent findings In rodents, hypothalamic inflammation and gliosis occur rapidly with high-fat diet consumption prior to significant weight gain. In addition, sensitivity or resistance to diet-induced obesity in rodents generally correlates with the presence or absence of hypothalamic inflammation and reactive gliosis (brain response to injury). Moreover, functional interventions that increase or decrease inflammation in neurons and glia correspondingly alter diet-associated weight gain. However, some conflicting data have recently emerged that question the contribution of hypothalamic inflammation to obesity pathogenesis. However, several studies have detected gliosis and disrupted connectivity in obese humans, highlighting the potential translational importance of this mechanism. Summary There is growing evidence that obesity is associated with brain inflammation in humans, particularly in the hypothalamus where its presence may disrupt body weight control and glucose homeostasis. More work is needed to determine whether this response is common in human obesity and to what extent it can be manipulated for therapeutic benefit. PMID:26192704

  19. Hypothalamic glucose sensing: making ends meet

    PubMed Central

    Routh, Vanessa H.; Hao, Lihong; Santiago, Ammy M.; Sheng, Zhenyu; Zhou, Chunxue

    2014-01-01

    The neuroendocrine system governs essential survival and homeostatic functions. For example, growth is needed for development, thermoregulation maintains optimal core temperature in a changing environment, and reproduction ensures species survival. Stress and immune responses enable an organism to overcome external and internal threats while the circadian system regulates arousal and sleep such that vegetative and active functions do not overlap. All of these functions require a significant portion of the body's energy. As the integrator of the neuroendocrine system, the hypothalamus carefully assesses the energy status of the body in order to appropriately partition resources to provide for each system without compromising the others. While doing so the hypothalamus must ensure that adequate glucose levels are preserved for brain function since glucose is the primary fuel of the brain. To this end, the hypothalamus contains specialized glucose sensing neurons which are scattered throughout the nuclei controlling distinct neuroendocrine functions. We hypothesize that these neurons play a key role in enabling the hypothalamus to partition energy to meet these peripheral survival needs without endangering the brain's glucose supply. This review will first describe the varied mechanisms underlying glucose sensing in neurons within discrete hypothalamic nuclei. We will then evaluate the way in which peripheral energy status regulates glucose sensitivity. For example, during energy deficit such as fasting specific hypothalamic glucose sensing neurons become sensitized to decreased glucose. This increases the gain of the information relay when glucose availability is a greater concern for the brain. Finally, changes in glucose sensitivity under pathological conditions (e.g., recurrent insulin-hypoglycemia, diabetes) will be addressed. The overall goal of this review is to place glucose sensing neurons within the context of hypothalamic control of neuroendocrine function

  20. Hypothalamic regulation of sleep and arousal.

    PubMed

    McGinty, Dennis; Szymusiak, Ronald

    2003-09-01

    The hypnogenic function of the rostral hypothalamic region, particularly the preoptic area (POA) was established previously on the basis of lesion, neuronal unit recording, and neurochemical and thermal stimulation studies. Recent studies have mapped the locations of putative sleep-promoting neurons in the POA using c-Fos immunostaining techniques and confirmed these findings with electrophysiological methods. Segregated groups of sleep-active neurons have been localized in the ventrolateral POA (vlPOA) and median preoptic nucleus (MnPN). MnPN and vlPOA sleep-active neurons express the inhibitory transmitter, GABA. In vlPOA neurons, GABA is co-localized with a second inhibitory transmitter, galanin. Descending projections from these sites terminate in putative arousal-promoting cell groups, including histaminergic, serotonergic, orexinergic, noradrenergic, and cholinergic neurons. These findings suggest the hypothesis that non-REM sleep occurs as a consequence of GABAergic and galaninergic inhibition of arousal-promoting neurons resulting from activation of vlPOA and MnPN sleep-promoting neurons. In support of this hypothesis, it was shown that putative sleep-promoting and arousal-promoting neurons exhibit reciprocal changes in discharge across the sleep-wake cycle and that GABA release in wake-promoting sites increases during nonREM sleep. In addition, some POA sleep-active neurons are warm-sensitive. Local POA warming inhibits discharge of multiple arousal-promoting neuronal groups. POA warming, unit recording, and lesion studies also show that POA regulates the amount of delta EEG activity within nonREM sleep, and index of the depth of sleep. Finally, there is evidence that arousal systems inhibit vlPOA and MnPN neurons and the POA hypnogenic mechanism. Mutually-inhibitory interactions between sleep-promoting and arousal-promoting systems are hypothesized to form a functional sleep-wake switch.

  1. The Role of Hypothalamic Neuropeptides in Neurogenesis and Neuritogenesis

    PubMed Central

    Bakos, Jan; Zatkova, Martina; Bacova, Zuzana; Ostatnikova, Daniela

    2016-01-01

    The hypothalamus is a source of neural progenitor cells which give rise to different populations of specialized and differentiated cells during brain development. Newly formed neurons in the hypothalamus can synthesize and release various neuropeptides. Although term neuropeptide recently undergoes redefinition, small-size hypothalamic neuropeptides remain major signaling molecules mediating short- and long-term effects on brain development. They represent important factors in neurite growth and formation of neural circuits. There is evidence suggesting that the newly generated hypothalamic neurons may be involved in regulation of metabolism, energy balance, body weight, and social behavior as well. Here we review recent data on the role of hypothalamic neuropeptides in adult neurogenesis and neuritogenesis with special emphasis on the development of food intake and social behavior related brain circuits. PMID:26881105

  2. Histaminergic neurons in the hypothalamic thermoregulatory pathways

    SciTech Connect

    Lomax, P.; Green, M.D.

    1981-11-01

    Based on neurochemical and neurophysiological research, especially over the past decade, considerable evidence exists for accepting histamine as a central neurotransmitter alongside the other neuroamines. The data supporting a functional role are not complete, but they do exhibit a consistent pattern in the case of the central thermoregulatory pathways. Thus, the region of the thermoregulatory centers in the rostral hypothalamus contains relatively high concentrations of histamine and the enzyme systems for its synthesis and degradation: degeneration studies indicate histaminergic pathways in the hypothalamus; thermoregulatory changes can be induced by activation of either H/sub 1/ or H/sub 2/ receptors; behavioral studies reveal different functional roles for H/sub 1/ and H/sub 2/ receptors; and the thermoregulatory responses to histamine are detectable across different species, even in nonhomeothermic animals. This evidence supports assigning a transmitter function to histamine in the central thermoregulatory pathways that would appear to be as well-founded as the comparable data amassed for other neuroamines.

  3. Increasing Fatty Acid Oxidation Remodels the Hypothalamic Neurometabolome to Mitigate Stress and Inflammation

    PubMed Central

    McFadden, Joseph W.; Aja, Susan; Li, Qun; Bandaru, Veera V. R.; Kim, Eun-Kyoung; Haughey, Norman J.; Kuhajda, Francis P.; Ronnett, Gabriele V.

    2014-01-01

    Modification of hypothalamic fatty acid (FA) metabolism can improve energy homeostasis and prevent hyperphagia and excessive weight gain in diet-induced obesity (DIO) from a diet high in saturated fatty acids. We have shown previously that C75, a stimulator of carnitine palmitoyl transferase-1 (CPT-1) and fatty acid oxidation (FAOx), exerts at least some of its hypophagic effects via neuronal mechanisms in the hypothalamus. In the present work, we characterized the effects of C75 and another anorexigenic compound, the glycerol-3-phosphate acyltransferase (GPAT) inhibitor FSG67, on FA metabolism, metabolomics profiles, and metabolic stress responses in cultured hypothalamic neurons and hypothalamic neuronal cell lines during lipid excess with palmitate. Both compounds enhanced palmitate oxidation, increased ATP, and inactivated AMP-activated protein kinase (AMPK) in hypothalamic neurons in vitro. Lipidomics and untargeted metabolomics revealed that enhanced catabolism of FA decreased palmitate availability and prevented the production of fatty acylglycerols, ceramides, and cholesterol esters, lipids that are associated with lipotoxicity-provoked metabolic stress. This improved metabolic signature was accompanied by increased levels of reactive oxygen species (ROS), and yet favorable changes in oxidative stress, overt ER stress, and inflammation. We propose that enhancing FAOx in hypothalamic neurons exposed to excess lipids promotes metabolic remodeling that reduces local inflammatory and cell stress responses. This shift would restore mitochondrial function such that increased FAOx can produce hypothalamic neuronal ATP and lead to decreased food intake and body weight to improve systemic metabolism. PMID:25541737

  4. Lef1-dependent hypothalamic neurogenesis inhibits anxiety

    PubMed Central

    Xie, Yuanyuan; Panahi, Samin; Gaynes, John A.; Watters, Harrison N.; Zhou, Dingxi; Xue, Hai-Hui; Fung, Camille M.; Levine, Edward M.; Letsou, Anthea; Brennan, K. C.

    2017-01-01

    While innate behaviors are conserved throughout the animal kingdom, it is unknown whether common signaling pathways regulate the development of neuronal populations mediating these behaviors in diverse organisms. Here, we demonstrate that the Wnt/ß-catenin effector Lef1 is required for the differentiation of anxiolytic hypothalamic neurons in zebrafish and mice, although the identity of Lef1-dependent genes and neurons differ between these 2 species. We further show that zebrafish and Drosophila have common Lef1-dependent gene expression in their respective neuroendocrine organs, consistent with a conserved pathway that has diverged in the mouse. Finally, orthologs of Lef1-dependent genes from both zebrafish and mouse show highly correlated hypothalamic expression in marmosets and humans, suggesting co-regulation of 2 parallel anxiolytic pathways in primates. These findings demonstrate that during evolution, a transcription factor can act through multiple mechanisms to generate a common behavioral output, and that Lef1 regulates circuit development that is fundamentally important for mediating anxiety in a wide variety of animal species. PMID:28837622

  5. Activation of A-type gamma-aminobutyric acid receptors excites gonadotropin-releasing hormone neurons.

    PubMed

    DeFazio, R Anthony; Heger, Sabine; Ojeda, Sergio R; Moenter, Suzanne M

    2002-12-01

    Gamma-aminobutyric acid (GABA), acting through GABA(A) receptors (GABA(A)R), is hypothesized to suppress reproduction by inhibiting GnRH secretion, but GABA actions directly on GnRH neurons are not well established. In green fluorescent protein-identified adult mouse GnRH neurons in brain slices, gramicidin-perforated-patch-clamp experiments revealed the reversal potential (E(GABA)) for current through GABA(A)Rs was depolarized relative to the resting potential. Furthermore, rapid GABA application elicited action potentials in GnRH neurons but not controls. The consequence of GABA(A)R activation depends on intracellular chloride levels, which are maintained by homeostatic mechanisms. Membrane proteins that typically extrude chloride (KCC-2 cotransporter, CLC-2 channel) were absent from the GT1-7 immortalized GnRH cell line and GnRH neurons in situ or were not localized to the proper cell compartment for function. In contrast, GT1-7 cells and some GnRH neurons expressed the chloride-accumulating cotransporter, NKCC-1. Patch-clamp experiments showed that blockade of NKCC hyperpolarized E(GABA) by lowering intracellular chloride. Regardless of reproductive state, rapid GABA application excited GnRH neurons. In contrast, bath application of the GABA(A)R agonist muscimol transiently increased then suppressed firing; suppression persisted 4-15 min. Rapid activation of GABA(A)R thus excites GnRH neurons whereas prolonged activation reduces excitability, suggesting the physiological consequence of synaptic activation of GABA(A)R in GnRH neurons is excitation.

  6. A Hypothalamic Phosphatase Switch Coordinates Energy Expenditure with Feeding.

    PubMed

    Dodd, Garron T; Andrews, Zane B; Simonds, Stephanie E; Michael, Natalie J; DeVeer, Michael; Brüning, Jens C; Spanswick, David; Cowley, Michael A; Tiganis, Tony

    2017-08-01

    Beige adipocytes can interconvert between white and brown-like states and switch between energy storage versus expenditure. Here we report that beige adipocyte plasticity is important for feeding-associated changes in energy expenditure and is coordinated by the hypothalamus and the phosphatase TCPTP. A fasting-induced and glucocorticoid-mediated induction of TCPTP, inhibited insulin signaling in AgRP/NPY neurons, repressed the browning of white fat and decreased energy expenditure. Conversely feeding reduced hypothalamic TCPTP, to increase AgRP/NPY neuronal insulin signaling, white adipose tissue browning and energy expenditure. The feeding-induced repression of hypothalamic TCPTP was defective in obesity. Mice lacking TCPTP in AgRP/NPY neurons were resistant to diet-induced obesity and had increased beige fat activity and energy expenditure. The deletion of hypothalamic TCPTP in obesity restored feeding-induced browning and increased energy expenditure to promote weight loss. Our studies define a hypothalamic switch that coordinates energy expenditure with feeding for the maintenance of energy balance. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Leptin regulates glutamate and glucose transporters in hypothalamic astrocytes

    PubMed Central

    Fuente-Martín, Esther; García-Cáceres, Cristina; Granado, Miriam; de Ceballos, María L.; Sánchez-Garrido, Miguel Ángel; Sarman, Beatrix; Liu, Zhong-Wu; Dietrich, Marcelo O.; Tena-Sempere, Manuel; Argente-Arizón, Pilar; Díaz, Francisca; Argente, Jesús; Horvath, Tamas L.; Chowen, Julie A.

    2012-01-01

    Glial cells perform critical functions that alter the metabolism and activity of neurons, and there is increasing interest in their role in appetite and energy balance. Leptin, a key regulator of appetite and metabolism, has previously been reported to influence glial structural proteins and morphology. Here, we demonstrate that metabolic status and leptin also modify astrocyte-specific glutamate and glucose transporters, indicating that metabolic signals influence synaptic efficacy and glucose uptake and, ultimately, neuronal function. We found that basal and glucose-stimulated electrical activity of hypothalamic proopiomelanocortin (POMC) neurons in mice were altered in the offspring of mothers fed a high-fat diet. In adulthood, increased body weight and fasting also altered the expression of glucose and glutamate transporters. These results demonstrate that whole-organism metabolism alters hypothalamic glial cell activity and suggest that these cells play an important role in the pathology of obesity. PMID:23064363

  8. The organic anion transporting polypeptide 1a5 is a pivotal transporter for the uptake of microcystin-LR by gonadotropin-releasing hormone neurons.

    PubMed

    Ding, Jie; Wang, Jing; Xiang, Zou; Diao, Weiyi; Su, Moxi; Shi, Weiwei; Wan, Ting; Han, Xiaodong

    2017-01-01

    Microcystins (MCs) are widely distributed hepatotoxic polypeptides produced by cyanobacteria. Microcystin-LR (MC-LR) has the broadest distribution and strongest toxicity among more than 80 isoforms of hepatotoxic MCs. MC-LR suppresses the expression of gonadotropin-releasing hormone (GnRH) that is critically required for the release of testosterone, resulting in the induction of male reproductive toxicity. However, the specific mechanisms of the uptake of MC-LR by GnRH-secreting neurons still remain unclear. In this study, GT1-7 cells were exposed to MC-LR in order to determine whether the GnRH-secreting neurons were the target of MC-LR that could induce male reproductive toxicity. Our data demonstrated that at least four organic anion transporting polypeptides (Oatp1a4, Oatp1a5, Oatp5a1, Oatp2b1) were expressed in GnRH neurons at the mRNA level, but only Oatp1a5 was expressed at the protein level. Furthermore, we demonstrated that MC-LR could not be transported into Oatp1a5-deficient GT1-7 cells which were protected from cell viability loss induced by MC-LR. These data suggest that Oatp1a5 may play an important role in the toxic effect of MC-LR on GnRH neurons.

  9. Hypothalamic control of brown adipose tissue thermogenesis

    PubMed Central

    Labbé, Sebastien M.; Caron, Alexandre; Lanfray, Damien; Monge-Rofarello, Boris; Bartness, Timothy J.; Richard, Denis

    2015-01-01

    It has long been known, in large part from animal studies, that the control of brown adipose tissue (BAT) thermogenesis is insured by the central nervous system (CNS), which integrates several stimuli in order to control BAT activation through the sympathetic nervous system (SNS). SNS-mediated BAT activity is governed by diverse neurons found in brain structures involved in homeostatic regulations and whose activity is modulated by various factors including oscillations of energy fluxes. The characterization of these neurons has always represented a challenging issue. The available literature suggests that the neuronal circuits controlling BAT thermogenesis are largely part of an autonomic circuitry involving the hypothalamus, brainstem and the SNS efferent neurons. In the present review, we recapitulate the latest progresses in regards to the hypothalamic regulation of BAT metabolism. We briefly addressed the role of the thermoregulatory pathway and its interactions with the energy balance systems in the control of thermogenesis. We also reviewed the involvement of the brain melanocortin and endocannabinoid systems as well as the emerging role of steroidogenic factor 1 (SF1) neurons in BAT thermogenesis. Finally, we examined the link existing between these systems and the homeostatic factors that modulate their activities. PMID:26578907

  10. Hypothalamic miRNAs: emerging roles in energy balance control.

    PubMed

    Schneeberger, Marc; Gomez-Valadés, Alicia G; Ramirez, Sara; Gomis, Ramon; Claret, Marc

    2015-01-01

    The hypothalamus is a crucial central nervous system area controlling appetite, body weight and metabolism. It consists in multiple neuronal types that sense, integrate and generate appropriate responses to hormonal and nutritional signals partly by fine-tuning the expression of specific batteries of genes. However, the mechanisms regulating these neuronal gene programmes in physiology and pathophysiology are not completely understood. MicroRNAs (miRNAs) are key regulators of gene expression that recently emerged as pivotal modulators of systemic metabolism. In this article we will review current evidence indicating that miRNAs in hypothalamic neurons are also implicated in appetite and whole-body energy balance control.

  11. Amphetamine, an appetite suppressant, decreases neuropeptide Y immunoreactivity in rat hypothalamic paraventriculum.

    PubMed

    Hsieh, Yih-Shou; Yang, Shun-Fa; Kuo, Dong-Yih

    2005-04-15

    Amphetamine (AMPH) is a well-known anorectic agent. The mechanism underlying the anorectic response of AMPH has been attributed to its inhibitory effect on hypothalamic neuropeptide Y (NPY), an orexigenic peptide in the brain. However, there is still lack of genomic or in situ immunohistochemical evidence to prove it. The present study was aimed to assess the molecular mechanism of AMPH anorexia by immunostaining of hypothalamic NPY protein in the area of paraventricular nucleus (PVN) and by detecting the change of hypothalamic NPY mRNA level using RT-PCR. Results revealed that an AMPH treatment might reduce the expression of NPY at both transcriptional and posttranslational levels. Comparatively, a treatment of clomipramine, a serotonin transporter inhibitor, was unable to reduce NPY mRNA level, revealing the noninvolvement of hypothalamic NPY gene in serotonin anorexia. Our results provided genomic and in situ immunohistochemical evidence to confirm the mediation of hypothalamic NPY neurons in the anorectic action of AMPH.

  12. Hypothalamic BOLD response to glucose intake and hypothalamic volume are similar in anorexia nervosa and healthy control subjects

    PubMed Central

    van Opstal, Anna M.; Westerink, Anna M.; Teeuwisse, Wouter M.; van der Geest, Mirjam A. M.; van Furth, Eric F.; van der Grond, Jeroen

    2015-01-01

    Background: Inconsistent findings about the neurobiology of Anorexia Nervosa (AN) hinder the development of effective treatments for this severe mental disorder. Therefore, the need arises for elucidation of neurobiological factors involved in the pathophysiology of AN. The hypothalamus plays a key role in the neurobiological processes that govern food intake and energy homeostasis, processes that are disturbed in anorexia nervosa (AN). The present study will assess the hypothalamic response to energy intake and the hypothalamic structure in patients with AN and healthy controls. Methods: Ten women aged 18–30 years diagnosed with AN and 11 healthy, lean (BMI < 23 kg/m2) women in the same age range were recruited. We used functional magnetic resonance imaging (MRI) to determine function of the hypothalamus in response to glucose. Structural MRI was used to determine differences in hypothalamic volume and local gray matter volume using manual segmentation and voxel-based morphometry. Results: No differences were found in hypothalamic volume and neuronal activity in response to a glucose load between the patients and controls. Whole brain structural analysis showed a significant decrease in gray matter volume in the cingulate cortex in the AN patients, bilaterally. Conclusions: We argue that in spite of various known changes in the hypothalamus the direct hypothalamic response to glucose intake is similar in AN patients and healthy controls. PMID:25999808

  13. Neuropeptide exocytosis involving synaptotagmin-4 and oxytocin in hypothalamic programming of body weight and energy balance.

    PubMed

    Zhang, Guo; Bai, Hua; Zhang, Hai; Dean, Camin; Wu, Qiang; Li, Juxue; Guariglia, Sara; Meng, Qingyuan; Cai, Dongsheng

    2011-02-10

    Hypothalamic neuropeptides play essential roles in regulating energy and body weight balance. Energy imbalance and obesity have been linked to hypothalamic signaling defects in regulating neuropeptide genes; however, it is unknown whether dysregulation of neuropeptide exocytosis could be critically involved. This study discovered that synaptotagmin-4, an atypical modulator of synaptic exocytosis, is expressed most abundantly in oxytocin neurons of the hypothalamus. Synaptotagmin-4 negatively regulates oxytocin exocytosis, and dietary obesity is associated with increased vesicle binding of synaptotagmin-4 and thus enhanced negative regulation of oxytocin release. Overexpressing synaptotagmin-4 in hypothalamic oxytocin neurons and centrally antagonizing oxytocin in mice are similarly obesogenic. Synaptotagmin-4 inhibition prevents against dietary obesity by normalizing oxytocin release and energy balance under chronic nutritional excess. In conclusion, the negative regulation of synaptotagmin-4 on oxytocin release represents a hypothalamic basis of neuropeptide exocytosis in controlling obesity and related diseases. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Single-Cell RNA-Seq Reveals Hypothalamic Cell Diversity.

    PubMed

    Chen, Renchao; Wu, Xiaoji; Jiang, Lan; Zhang, Yi

    2017-03-28

    The hypothalamus is one of the most complex brain structures involved in homeostatic regulation. Defining cell composition and identifying cell-type-specific transcriptional features of the hypothalamus is essential for understanding its functions and related disorders. Here, we report single-cell RNA sequencing results of adult mouse hypothalamus, which defines 11 non-neuronal and 34 neuronal cell clusters with distinct transcriptional signatures. Analyses of cell-type-specific transcriptomes reveal gene expression dynamics underlying oligodendrocyte differentiation and tanycyte subtypes. Additionally, data analysis provides a comprehensive view of neuropeptide expression across hypothalamic neuronal subtypes and uncover Crabp1(+) and Pax6(+) neuronal populations in specific hypothalamic sub-regions. Furthermore, we found food deprivation exhibited differential transcriptional effects among the different neuronal subtypes, suggesting functional specification of various neuronal subtypes. Thus, the work provides a comprehensive transcriptional perspective of adult hypothalamus, which serves as a valuable resource for dissecting cell-type-specific functions of this complex brain region.

  15. [Hypothalamic involvement in multiple sclerosis].

    PubMed

    Darlix, A; Mathey, G; Monin, M-L; Sauvée, M; Braun, M; Schaff, J-L; Debouverie, M

    2012-05-01

    Hypothalamic involvement is a rare condition in patients with multiple sclerosis (MS). We report two patients with a long history of MS who presented with severe acute hypothermia with associated thrombocytopenia and elevated transaminase levels. Several cases of hypothermia or hyperthermia in patients with MS have been reported in the literature. They could be linked with hypothalamic lesions, in particular in the pre-optic area. However, other anatomical locations seem to be involved in thermoregulation and can be affected by MS. Besides, some cases of syndrome of inappropriate antidiuretic hormone secretion have been reported in patients with MS. Finally, some sleep disorders, particularly hypersomnia or narcolepsy, could be related to hypothalamic lesions, through the fall in hypocretin-1 in the cerebrospinal fluid. Hypocretin-1 is a neuropeptide that is secreted by some hypothalamic cells. It plays a role in the sleep-awake rhythm. We report one patient with narcolepsy and cataplexy before the first symptoms of MS appeared. Hypothalamic signs are rare in MS. However, several series of autopsies have shown a high frequency of demyelinating lesions in the hypothalamic area. Among these lesions, the proportion of active lesions seems elevated. Yet only few of them have a clinical or biological translation such as thermoregulation dysfunction, sleep disorders or natremia abnormalities. Thus, it seems unlikely that inflammatory hypothalamic lesions alone, even when bilateral, could be the explanation of these signs. A sufficient number of inflammatory demyelinating lesions, which we can observe in patients with a long history of MS and an already severe disability, is probably necessary to develop such a rare symptomatology. Hypothalamic signs might be a factor of poor prognosis for the disease course and progression of the disability.

  16. Disturbances of the hypothalamic thermoregulation.

    PubMed

    Clar, H E

    1985-01-01

    Although compression of the hypothalamus in cases of suprasellar tumour is common, spontaneous dysregulation of body temperature is extremely rare. Bilateral localization of the hypothalamic nuclei and a high grade of compensatory value of temperature regulation may be the reason for this phenomenon. In the postoperative period temperature dysregulation is observed more often. In order to analyse the influence of diencephalic regulation in these patients classification of the degree of hypothalamic compression is necessary. The problem was studied under experimental and clinical conditions. Experimental studies in rabbits after acute hypothalamic compression and decompression showed a reversible disturbances of temperature regulation. Hypothalamic compression in dogs resulted in reversible hypothalamic endocrine dysfunction. Clinical observations of body temperature in the period after operation of suprasellar tumors showed similar results. The temperature study was extended on patients with cerebral trauma and intracranial haemorrhage to differentiate the degree of hypothalamic lesion. Morphological examinations confirmed alterations localized in the anterior and posterior region of the hypothalamus. The analysis proved the fact that temperature regulation seems to be a highly sensitive parameter of diencephalic function.

  17. Hypoxia-inducible factor directs POMC gene to mediate hypothalamic glucose sensing and energy balance regulation.

    PubMed

    Zhang, Hai; Zhang, Guo; Gonzalez, Frank J; Park, Sung-Min; Cai, Dongsheng

    2011-07-01

    Hypoxia-inducible factor (HIF) is a nuclear transcription factor that responds to environmental and pathological hypoxia to induce metabolic adaptation, vascular growth, and cell survival. Here we found that HIF subunits and HIF2α in particular were normally expressed in the mediobasal hypothalamus of mice. Hypothalamic HIF was up-regulated by glucose to mediate the feeding control of hypothalamic glucose sensing. Two underlying molecular pathways were identified, including suppression of PHDs by glucose metabolites to prevent HIF2α degradation and the recruitment of AMPK and mTOR/S6K to regulate HIF2α protein synthesis. HIF activation was found to directly control the transcription of POMC gene. Genetic approach was then employed to develop conditional knockout mice with HIF inhibition in POMC neurons, revealing that HIF loss-of-function in POMC neurons impaired hypothalamic glucose sensing and caused energy imbalance to promote obesity development. The metabolic effects of HIF in hypothalamic POMC neurons were independent of leptin signaling or pituitary ACTH pathway. Hypothalamic gene delivery of HIF counteracted overeating and obesity under conditions of nutritional excess. In conclusion, HIF controls hypothalamic POMC gene to direct the central nutrient sensing in regulation of energy and body weight balance.

  18. [Functional hypothalamic amenorrhea].

    PubMed

    Stárka, Luboslav; Dušková, Michaela

    2015-10-01

    Functional hypothalamic amenorrhea (FHA) besides pregnancy and syndrome of polycystic ovary is one of the most common causes of secondary amenorrhea. FHA results from the aberrations in pulsatile gonadotropin-releasing hormone (GnRH) secretion, which in turn causes impairment of the gonadotropins (follicle-stimulating hormone and luteinizing hormone). FHA is a form of the defence of organism in situations where life functions are more important than reproductive function. FHA is reversible; it can be normalized after ceasing the stress situation. There are three types of FHA: weight loss related, stress-related, and exercise-related amenorrhea. The final consequences are complex hormonal changes manifested by profound hypoestrogenism. Additionally, these patients present mild hypercortisolemia, low serum insulin levels, low insulin-like growth factor 1 (IGF-1) and low total triiodothyronine. Women health in this disorder is disturbed in several aspects including the skeletal system, cardiovascular system, and mental problems. Patients manifest a decrease in bone mass density, which is related to an increase in fracture risk. Therefore, osteopenia and osteoporosis are the main long-term complications of FHA. Cardiovascular complications include endothelial dysfunction and abnormal changes in the lipid profile. FHA patients present significantly higher depression and anxiety and also sexual problems compared to healthy subjects.

  19. Paraventricular Hypothalamic Mechanisms of Chronic Stress Adaptation

    PubMed Central

    Herman, James P.; Tasker, Jeffrey G.

    2016-01-01

    The hypothalamic paraventricular nucleus (PVN) is the primary driver of hypothalamo–pituitary–adrenocortical (HPA) responses. At least part of the role of the PVN is managing the demands of chronic stress exposure. With repeated exposure to stress, hypophysiotrophic corticotropin-releasing hormone (CRH) neurons of the PVN display a remarkable cellular, synaptic, and connectional plasticity that serves to maximize the ability of the HPA axis to maintain response vigor and flexibility. At the cellular level, chronic stress enhances the production of CRH and its co-secretagogue arginine vasopressin and rearranges neurotransmitter receptor expression so as to maximize cellular excitability. There is also evidence to suggest that efficacy of local glucocorticoid feedback is reduced following chronic stress. At the level of the synapse, chronic stress enhances cellular excitability and reduces inhibitory tone. Finally, chronic stress causes a structural enhancement of excitatory innervation, increasing the density of glutamate and noradrenergic/adrenergic terminals on CRH neuronal cell somata and dendrites. Together, these neuroplastic changes favor the ability of the HPA axis to retain responsiveness even under conditions of considerable adversity. Thus, chronic stress appears able to drive PVN neurons via a number of convergent mechanisms, processes that may play a major role in HPA axis dysfunction seen in variety of stress-linked disease states. PMID:27843437

  20. Growth factors and steroid hormones: a complex interplay in the hypothalamic control of reproductive functions.

    PubMed

    Melcangi, Roberto C; Martini, Luciano; Galbiati, Mariarita

    2002-08-01

    The mechanisms through which LHRH-secreting neurons are controlled still represent a crucial and debated field of research in the neuroendocrine control of reproduction. In the present review, we have specifically considered two potential signals reaching these hypothalamic neurons: steroid hormones and growth factors. Examples of the relevant physiological role of the interactions between these two families of biologically acting molecules have been provided. In many cases, these interactions occur at the level of hypothalamic astrocytes, which are presently accepted as functional partners of the LHRH-secreting neurons. On the basis of the observations here summarized, we have formulated the hypothesis that a functional co-operation of steroid hormones and growth factors occurring in the hypothalamic astrocytic compartment represents a key factor in the neuroendocrine control of reproductive functions.

  1. Hypothalamic Inflammation and Energy Balance Disruptions: Spotlight on Chemokines.

    PubMed

    Le Thuc, Ophélia; Stobbe, Katharina; Cansell, Céline; Nahon, Jean-Louis; Blondeau, Nicolas; Rovère, Carole

    2017-01-01

    The hypothalamus is a key brain region in the regulation of energy balance as it controls food intake and both energy storage and expenditure through integration of humoral, neural, and nutrient-related signals and cues. Many years of research have focused on the regulation of energy balance by hypothalamic neurons, but the most recent findings suggest that neurons and glial cells, such as microglia and astrocytes, in the hypothalamus actually orchestrate together several metabolic functions. Because glial cells have been described as mediators of inflammatory processes in the brain, the existence of a causal link between hypothalamic inflammation and the deregulations of feeding behavior, leading to involuntary weight loss or obesity for example, has been suggested. Several inflammatory pathways that could impair the hypothalamic control of energy balance have been studied over the years such as, among others, toll-like receptors and canonical cytokines. Yet, less studied so far, chemokines also represent interesting candidates that could link the aforementioned pathways and the activity of hypothalamic neurons. Indeed, chemokines, in addition to their role in attracting immune cells to the inflamed site, have been suggested to be capable of neuromodulation. Thus, they could disrupt cellular activity together with synthesis and/or secretion of multiple neurotransmitters/mediators involved in the maintenance of energy balance. This review discusses the different inflammatory pathways that have been identified so far in the hypothalamus in the context of feeding behavior and body weight control impairments, with a particular focus on chemokines signaling that opens a new avenue in the understanding of the major role played by inflammation in obesity.

  2. Age-Dependent Neurochemical Remodeling of Hypothalamic Astrocytes.

    PubMed

    Santos, Camila Leite; Roppa, Paola Haack Amaral; Truccolo, Pedro; Fontella, Fernanda Urruth; Souza, Diogo Onofre; Bobermin, Larissa Daniele; Quincozes-Santos, André

    2017-10-04

    The hypothalamus is a crucial integrative center in the central nervous system, responsible for the regulation of homeostatic activities, including systemic energy balance. Increasing evidence has highlighted a critical role of astrocytes in orchestrating hypothalamic functions; they participate in the modulation of synaptic transmission, metabolic and trophic support to neurons, immune defense, and nutrient sensing. In this context, disturbance of systemic energy homeostasis, which is a common feature of obesity and the aging process, involves inflammatory responses. This may be related to dysfunction of hypothalamic astrocytes. In this regard, the aim of this study was to evaluate the neurochemical properties of hypothalamic astrocyte cultures from newborn, adult, and aged Wistar rats. Age-dependent changes in the regulation of glutamatergic homeostasis, glutathione biosynthesis, amino acid profile, glucose metabolism, trophic support, and inflammatory response were observed. Additionally, signaling pathways including nuclear factor erythroid-derived 2-like 2/heme oxygenase-1 p38 mitogen-activated protein kinase, nuclear factor kappa B, phosphatidylinositide 3-kinase/Akt, and leptin receptor expression may represent putative mechanisms associated with the cellular alterations. In summary, our findings indicate that as age increases, hypothalamic astrocytes remodel and exhibit changes in their neurochemical properties. This process may play a role in the onset and/or progression of metabolic disorders.

  3. The hypothalamic GnRH pulse generator: multiple regulatory mechanisms.

    PubMed

    Krsmanovic, Lazar Z; Hu, Lian; Leung, Po-Ki; Feng, Hao; Catt, Kevin J

    2009-10-01

    Pulsatile secretion of gonadotropin-releasing hormone (GnRH) release is an intrinsic property of hypothalamic GnRH neurons. Pulse generation has been attributed to multiple specific mechanisms, including spontaneous electrical activity of GnRH neurons, calcium and cAMP signaling, a GnRH receptor autocrine regulatory component, a GnRH concentration-dependent switch in GnRH receptor (GnRH-R) coupling to specific G proteins, the expression of G protein-coupled receptors (GPCRs) and steroid receptors, and homologous and heterologous interactions between cell membrane receptors expressed in GnRH neurons. The coexistence of multiple regulatory mechanisms for pulsatile GnRH secretion provides a high degree of redundancy in maintaining this crucial component of the mammalian reproductive process. These studies provide insights into the basic cellular and molecular mechanisms involved in GnRH neuronal function.

  4. [Cortico-hypothalamic interneuronal correlation during learning in cats].

    PubMed

    Merzhanova, G Kh; Berg, A I

    1988-01-01

    Spatial-temporal organization of neuronal activity in the motor cortex and hypothalamus lateral nucleus (inter- and intrastructural neuronal interactions) in cats with elaborated conditioned alimentary instrumental reflexes were studied by means of recording the multineuronal activity of structures under investigation and with the use of cross-correlation method of analysis. An increase was shown of the number of cortico-hypothalamic neurones pairs acting in interconnection after elaboration of conditioned reflexes, and a decrease of their number at extinction due to interaction with temporal delays (up to 30 ms). Local (intrastructural) connections of the motor cortex and lateral hypothalamus had opposite dynamics at extinction of the conditioned reflexes: the number of the first increased and the number of the second decreased. The character of the interconnected activity of neurones pairs of interstructural interaction is discussed.

  5. Neuronal expression of glucosylceramide synthase in central nervous system regulates body weight and energy homeostasis.

    PubMed

    Nordström, Viola; Willershäuser, Monja; Herzer, Silke; Rozman, Jan; von Bohlen Und Halbach, Oliver; Meldner, Sascha; Rothermel, Ulrike; Kaden, Sylvia; Roth, Fabian C; Waldeck, Clemens; Gretz, Norbert; de Angelis, Martin Hrabě; Draguhn, Andreas; Klingenspor, Martin; Gröne, Hermann-Josef; Jennemann, Richard

    2013-01-01

    Hypothalamic neurons are main regulators of energy homeostasis. Neuronal function essentially depends on plasma membrane-located gangliosides. The present work demonstrates that hypothalamic integration of metabolic signals requires neuronal expression of glucosylceramide synthase (GCS; UDP-glucose:ceramide glucosyltransferase). As a major mechanism of central nervous system (CNS) metabolic control, we demonstrate that GCS-derived gangliosides interacting with leptin receptors (ObR) in the neuronal membrane modulate leptin-stimulated formation of signaling metabolites in hypothalamic neurons. Furthermore, ganglioside-depleted hypothalamic neurons fail to adapt their activity (c-Fos) in response to alterations in peripheral energy signals. Consequently, mice with inducible forebrain neuron-specific deletion of the UDP-glucose:ceramide glucosyltransferase gene (Ugcg) display obesity, hypothermia, and lower sympathetic activity. Recombinant adeno-associated virus (rAAV)-mediated Ugcg delivery to the arcuate nucleus (Arc) significantly ameliorated obesity, specifying gangliosides as seminal components for hypothalamic regulation of body energy homeostasis.

  6. Neuronal Expression of Glucosylceramide Synthase in Central Nervous System Regulates Body Weight and Energy Homeostasis

    PubMed Central

    Nordström, Viola; Willershäuser, Monja; Herzer, Silke; Rozman, Jan; von Bohlen und Halbach, Oliver; Meldner, Sascha; Rothermel, Ulrike; Kaden, Sylvia; Roth, Fabian C.; Waldeck, Clemens; Gretz, Norbert; de Angelis, Martin Hrabě; Draguhn, Andreas; Klingenspor, Martin

    2013-01-01

    Hypothalamic neurons are main regulators of energy homeostasis. Neuronal function essentially depends on plasma membrane-located gangliosides. The present work demonstrates that hypothalamic integration of metabolic signals requires neuronal expression of glucosylceramide synthase (GCS; UDP-glucose:ceramide glucosyltransferase). As a major mechanism of central nervous system (CNS) metabolic control, we demonstrate that GCS-derived gangliosides interacting with leptin receptors (ObR) in the neuronal membrane modulate leptin-stimulated formation of signaling metabolites in hypothalamic neurons. Furthermore, ganglioside-depleted hypothalamic neurons fail to adapt their activity (c-Fos) in response to alterations in peripheral energy signals. Consequently, mice with inducible forebrain neuron-specific deletion of the UDP-glucose:ceramide glucosyltransferase gene (Ugcg) display obesity, hypothermia, and lower sympathetic activity. Recombinant adeno-associated virus (rAAV)-mediated Ugcg delivery to the arcuate nucleus (Arc) significantly ameliorated obesity, specifying gangliosides as seminal components for hypothalamic regulation of body energy homeostasis. PMID:23554574

  7. Gelastic epilepsy: Beyond hypothalamic hamartomas.

    PubMed

    Uribe-San-Martin, Reinaldo; Ciampi, Ethel; Lawson-Peralta, Balduin; Acevedo-Gallinato, Keryma; Torrealba-Marchant, Gonzalo; Campos-Puebla, Manuel; Godoy-Fernández, Jaime

    2015-01-01

    Gelastic epilepsy or laughing seizures have been historically related to children with hypothalamic hamartomas. We report three adult patients who had gelastic epilepsy, defined as the presence of seizures with a prominent laugh component, including brain imaging, surface/invasive electroencephalography, positron emission tomography, and medical/surgical outcomes. None of the patients had hamartoma or other hypothalamic lesion. Two patients were classified as having refractory epilepsy (one had biopsy-proven neurocysticercosis and the other one hippocampal sclerosis and temporal cortical dysplasia). The third patient had no lesion on MRI and had complete control with carbamazepine. Both lesional patients underwent resective surgery, one with complete seizure control and the other one with poor outcome. Although hypothalamic hamartomas should always be ruled out in patients with gelastic epilepsy, laughing seizures can also arise from frontal and temporal lobe foci, which can be surgically removed. In addition, we present the first case of gelastic epilepsy due to neurocysticercosis.

  8. Torsional nystagmus in hypothalamic hamartoma.

    PubMed

    Shaikh, Aasef G

    2013-12-01

    Torsional nystagmus was noted in a patient with hypothalamic hamartoma. Magnetic resonance imaging revealed an exophytic hypothalamic mass extending into the pre-pontine cistern and abutting ventral mesencephalon. The quickphase of the torsional nystagmus was directed towards the left side, ipsilateral to the side of compression by the hamartoma. Ipsi-lesionally directed pure torsional nystagmus in this case is attributed to the compressive lesion of ocular motor structures responsible for the neural integration of torsional and vertical eye movements, the interstitial nucleus of Cajal. [Published with video sequences].

  9. Specification of select hypothalamic circuits and innate behaviors by the embryonic patterning gene Dbx1

    PubMed Central

    Sokolowski, Katie; Esumi, Shigeyuki; Hirata, Tsutomu; Kamal, Yasman; Tran, Tuyen; Lam, Andrew; Oboti, Livio; Brighthaupt, Sherri-Chanelle; Zaghlula, Manar; Martinez, Jennifer; Ghimbovschi, Svetlana; Knoblach, Susan; Pierani, Alessandra; Tamamaki, Nobuaki; Shah, Nirao M; Jones, Kevin S; Corbin, Joshua G

    2015-01-01

    SUMMARY The hypothalamus integrates information required for the production of a variety of innate behaviors such as feeding, mating, aggression and predator avoidance. Despite an extensive knowledge of hypothalamic function, how embryonic genetic programs specify circuits that regulate these behaviors remains unknown. Here, we find that in the hypothalamus the developmentally regulated homeodomain-containing transcription factor Dbx1 is required for the generation of specific subclasses of neurons within the lateral hypothalamic area/zona incerta (LH) and the arcuate (Arc) nucleus. Consistent with this specific developmental role, Dbx1 hypothalamic-specific conditional-knockout mice display attenuated responses to predator odor and feeding stressors but do not display deficits in other innate behaviors such as mating or conspecific aggression. Thus, activity of a single developmentally regulated gene, Dbx1, is a shared requirement for the specification of hypothalamic nuclei governing a subset of innate behaviors. PMID:25864637

  10. A treasure trove of hypothalamic neurocircuitries governing body weight homeostasis.

    PubMed

    Vianna, Claudia R; Coppari, Roberto

    2011-01-01

    Changes in physical activities and feeding habits have transformed the historically rare disease of obesity into a modern metabolic pandemic. Obesity occurs when energy intake exceeds energy expenditure over time. This energy imbalance significantly increases the risk for cardiovascular disease and type 2 diabetes mellitus and as such represents an enormous socioeconomic burden and health threat. To combat obesity, a better understanding of the molecular mechanisms and neurocircuitries underlying normal body weight homeostasis is required. In the 1940s, pioneering lesion experiments unveiled the importance of medial and lateral hypothalamic structures. In the 1980s and 1990s, several neuropeptides and peripheral hormones critical for appropriate feeding behavior, energy expenditure, and hence body weight homeostasis were identified. In the 2000s, results from metabolic analyses of genetically engineered mice bearing mutations only in selected neuronal groups greatly advanced our knowledge of the peripheral/brain feedback-loop modalities by which central neurons control energy balance. In this review, we will summarize these recent progresses with particular emphasis on the biochemical identities of hypothalamic neurons and molecular components underlying normal appetite, energy expenditure, and body weight homeostasis. We will also parse which of those neurons and molecules are critical components of homeostatic adaptive pathways against obesity induced by hypercaloric feeding.

  11. A Treasure Trove of Hypothalamic Neurocircuitries Governing Body Weight Homeostasis

    PubMed Central

    Vianna, Claudia R.; Coppari, Roberto

    2011-01-01

    Changes in physical activities and feeding habits have transformed the historically rare disease of obesity into a modern metabolic pandemic. Obesity occurs when energy intake exceeds energy expenditure over time. This energy imbalance significantly increases the risk for cardiovascular disease and type 2 diabetes mellitus and as such represents an enormous socioeconomic burden and health threat. To combat obesity, a better understanding of the molecular mechanisms and neurocircuitries underlying normal body weight homeostasis is required. In the 1940s, pioneering lesion experiments unveiled the importance of medial and lateral hypothalamic structures. In the 1980s and 1990s, several neuropeptides and peripheral hormones critical for appropriate feeding behavior, energy expenditure, and hence body weight homeostasis were identified. In the 2000s, results from metabolic analyses of genetically engineered mice bearing mutations only in selected neuronal groups greatly advanced our knowledge of the peripheral/brain feedback-loop modalities by which central neurons control energy balance. In this review, we will summarize these recent progresses with particular emphasis on the biochemical identities of hypothalamic neurons and molecular components underlying normal appetite, energy expenditure, and body weight homeostasis. We will also parse which of those neurons and molecules are critical components of homeostatic adaptive pathways against obesity induced by hypercaloric feeding. PMID:21068159

  12. Hypothalamic involvement in chronic migraine

    PubMed Central

    Peres, M; del Rio, M S.; Seabra, M; Tufik, S; Abucham, J; Cipolla-Neto, J; Silberstein, S; Zukerman, E

    2001-01-01

    OBJECTIVES—Chronic migraine (CM), previously called transformed migraine, is a frequent headache disorder that affects 2%-3% of the general population. Analgesic overuse, insomnia, depression, and anxiety are disorders that are often comorbid with CM. Hypothalamic dysfunction has been implicated in its pathogenesis, but it has never been studied in patients with CM. The aim was to analyze hypothalamic involvement in CM by measurement of melatonin, prolactin, growth hormone, and cortisol nocturnal secretion.
METHODS—A total of 338 blood samples (13/patient) from 17 patients with CM and nine age and sex matched healthy volunteers were taken. Melatonin, prolactin, growth hormone, and cortisol concentrations were determined every hour for 12 hours. The presence of comorbid disorders was also evaluated.
RESULTS—An abnormal pattern of hypothalamic hormonal secretion was found in CM. This included: (1) a decreased nocturnal prolactin peak, (2) increased cortisol concentrations, (3) a delayed nocturnal melatonin peak in patients with CM, and (4) lower melatonin concentrations in patients with CM with insomnia. Growth hormone secretion did not differ from controls.
CONCLUSION—These results support hypothalamic involvement in CM, shown by a chronobiologic dysregulation, and a possible hyperdopaminergic state in patients with CM. Insomnia might be an important variable in the study findings.

 PMID:11723194

  13. Hypothalamic proopiomelanocortin processing and the regulation of energy balance

    PubMed Central

    Wardlaw, Sharon L.

    2011-01-01

    Hypothalamic proopiomelanocortin (POMC) neurons play a key role in regulating energy balance and neuroendocrine function. Much attention has been focused on regulation of POMC gene expression with less emphasis on regulated peptide processing. This is particularly important given the complexity of posttranslational POMC processing which is essential for the generation of biologically active MSH peptides. Mutations that impair POMC sorting and processing are associated with obesity in humans and in animals. Specifically, mutations in the POMC processing enzymes prohormone convertase 1/3 (PCI/3) and in carboxypeptidase E (CPE) and in the α-MSH degrading enzyme, PRCP, are associated with changes in energy balance. There is increasing evidence that POMC processing is regulated with respect to energy balance. Studies have implicated both the leptin and insulin signaling pathways in the regulation of POMC at various steps in the processing pathway. This article will review the role of hypothalamic POMC in regulating energy balance with a focus on POMC processing. PMID:21208604

  14. Hypothalamic ER stress: A bridge between leptin resistance and obesity.

    PubMed

    Ramírez, Sara; Claret, Marc

    2015-06-22

    The prevalence of obesity has increased worldwide at an alarming rate. However, non-invasive pharmacological treatments remain elusive. Leptin resistance is a general feature of obesity, thus strategies aimed at enhancing the sensitivity to this hormone may constitute an excellent therapeutical approach to counteract current obesity epidemics. Nevertheless, the etiology and neuronal basis of leptin resistance remains an enigma. A recent hypothesis gaining substantial experimental support is that hypothalamic endoplasmic reticulum (ER) stress plays a causal role in the development of leptin resistance and obesity. The objective of this review article is to provide an updated view on current evidence connecting hypothalamic ER stress with leptin resistance. We discuss the experimental findings supporting this hypothesis, as well as the potential causes and underlying mechanisms leading to this metabolic disorder. Understanding these mechanisms may provide key insights into the development of novel intervention approaches.

  15. Implications of mitochondrial dynamics on neurodegeneration and on hypothalamic dysfunction

    PubMed Central

    Zorzano, Antonio; Claret, Marc

    2015-01-01

    Mitochondrial dynamics is a term that encompasses the movement of mitochondria along the cytoskeleton, regulation of their architecture, and connectivity mediated by tethering and fusion/fission. The importance of these events in cell physiology and pathology has been partially unraveled with the identification of the genes responsible for the catalysis of mitochondrial fusion and fission. Mutations in two mitochondrial fusion genes (MFN2 and OPA1) cause neurodegenerative diseases, namely Charcot-Marie Tooth type 2A and autosomal dominant optic atrophy (ADOA). Alterations in mitochondrial dynamics may be involved in the pathophysiology of prevalent neurodegenerative conditions. Moreover, impairment of the activity of mitochondrial fusion proteins dysregulates the function of hypothalamic neurons, leading to alterations in food intake and in energy homeostasis. Here we review selected findings in the field of mitochondrial dynamics and their relevance for neurodegeneration and hypothalamic dysfunction. PMID:26113818

  16. The TRPM2 channel is a hypothalamic heat sensor that limits fever and can drive hypothermia.

    PubMed

    Song, Kun; Wang, Hong; Kamm, Gretel B; Pohle, Jörg; Reis, Fernanda de Castro; Heppenstall, Paul; Wende, Hagen; Siemens, Jan

    2016-09-23

    Body temperature homeostasis is critical for survival and requires precise regulation by the nervous system. The hypothalamus serves as the principal thermostat that detects and regulates internal temperature. We demonstrate that the ion channel TRPM2 [of the transient receptor potential (TRP) channel family] is a temperature sensor in a subpopulation of hypothalamic neurons. TRPM2 limits the fever response and may detect increased temperatures to prevent overheating. Furthermore, chemogenetic activation and inhibition of hypothalamic TRPM2-expressing neurons in vivo decreased and increased body temperature, respectively. Such manipulation may allow analysis of the beneficial effects of altered body temperature on diverse disease states. Identification of a functional role for TRP channels in monitoring internal body temperature should promote further analysis of molecular mechanisms governing thermoregulation and foster the genetic dissection of hypothalamic circuits involved with temperature homeostasis.

  17. [Hypothalamic inflammation and energy balance deregulations: focus on chemokines.

    PubMed

    Le Thuc, Ophélia; Rovère, Carole

    2016-01-01

    The hypothalamus is a key brain region in the regulation of energy balance. It especially controls food intake and both energy storage and expenditure through integration of humoral, neural and nutrient-related signals and cues. Hypothalamic neurons and glial cells act jointly to orchestrate, both spatially and temporally, regulated metabolic functions of the hypothalamus. Thus, the existence of a causal link between hypothalamic inflammation and deregulations of feeding behavior, such as involuntary weight-loss or obesity, has been suggested. Among the inflammatory mediators that could induce deregulations of hypothalamic control of the energy balance, chemokines represent interesting candidates. Indeed, chemokines, primarily known for their chemoattractant role of immune cells to the inflamed site, have also been suggested capable of neuromodulation. Thus, chemokines could disrupt cellular activity together with synthesis and/or secretion of multiple neurotransmitters/mediators that are involved in the maintenance of energy balance. Here, we relate, on one hand, recent results showing the primary role of the central chemokinergic signaling CCL2/CCR2 for metabolic and behavioral adaptation to high-grade inflammation, especially loss of appetite and weight, through its activity on hypothalamic neurons producing the orexigenic peptide Melanin-Concentrating Hormone (MCH) and, on the other hand, results that suggest that chemokines could also deregulate hypothalamic neuropeptidergic circuits to induce an opposite phenotype and eventually participate in the onset/development of obesity. In more details, we will emphasize a study recently showing, in a model of high-grade acute inflammation of LPS injection in mice, that central CCL2/CCR2 signaling is of primary importance for several aspects explaining weight loss associated with inflammation: after LPS injection, animals lose weight, reduce their food intake, increase their fat oxidation (thus energy consumption from

  18. Fluorescent visualisation of the hypothalamic oxytocin neurones activated by cholecystokinin-8 in rats expressing c-fos-enhanced green fluorescent protein and oxytocin-monomeric red fluorescent protein 1 fusion transgenes.

    PubMed

    Katoh, A; Shoguchi, K; Matsuoka, H; Yoshimura, M; Ohkubo, J-I; Matsuura, T; Maruyama, T; Ishikura, T; Aritomi, T; Fujihara, H; Hashimoto, H; Suzuki, H; Murphy, D; Ueta, Y

    2014-05-01

    The up-regulation of c-fos gene expression is widely used as a marker of neuronal activation elicited by various stimuli. Anatomically precise observation of c-fos gene products can be achieved at the RNA level by in situ hybridisation or at the protein level by immunocytochemistry. Both of these methods are time and labour intensive. We have developed a novel transgenic rat system that enables the trivial visualisation of c-fos expression using an enhanced green fluorescent protein (eGFP) tag. These rats express a transgene consisting of c-fos gene regulatory sequences that drive the expression of a c-fos-eGFP fusion protein. In c-fos-eGFP transgenic rats, robust nuclear eGFP fluorescence was observed in osmosensitive brain regions 90 min after i.p. administration of hypertonic saline. Nuclear eGFP fluorescence was also observed in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) 90 min after i.p. administration of cholecystokinin (CCK)-8, which selectively activates oxytocin (OXT)-secreting neurones in the hypothalamus. In double transgenic rats that express c-fos-eGFP and an OXT-monomeric red fluorescent protein 1 (mRFP1) fusion gene, almost all mRFP1-positive neurones in the SON and PVN expressed nuclear eGFP fluorescence 90 min after i.p. administration of CCK-8. It is possible that not only a plane image, but also three-dimensional reconstruction image may identify cytoplasmic vesicles in an activated neurone at the same time.

  19. Hypothalamic Hormones and Metabolism

    PubMed Central

    Thio, Liu Lin

    2011-01-01

    Summary The ketogenic diet is an effective treatment for medically intractable epilepsy and may have antiepileptogenic, neuroprotective, and antitumor properties. While on a ketogenic diet, the body obtains most of its calories from fat rather than carbohydrates. This dramatic change in caloric composition results in a unique metabolic state. In turn, these changes in caloric composition and metabolism alter some of the neurohormones that participate in the complex neuronal network regulating energy homeostasis. Two observed changes are an increase in serum leptin and a decrease in serum insulin. These opposing changes in leptin and insulin are unique compared to other metabolic stimuli and may modify the activity of several cell signaling cascades including phosphoinositidyl-3 kinase (PI3K), adenosine monophosphate activated protein kinase (AMPK), and mammalian target of rapamycin (mTOR). These cell signaling pathways may mediate the anticonvulsant and other beneficial effects of the diet, though the neurohormonal changes induced by the ketogenic diet and the physiological consequences of these changes remain poorly characterized. PMID:21856125

  20. An indirect action contributes to c-fos induction in paraventricular hypothalamic nucleus by neuropeptide Y

    USDA-ARS?s Scientific Manuscript database

    Neuropeptide Y (NPY) is a well-established orexigenic peptide and hypothalamic paraventricular nucleus (PVH) is one major brain site that mediates the orexigenic action of NPY. NPY induces abundant expression of C-Fos, an indicator for neuronal activation, in the PVH, which has been used extensively...

  1. Hypothalamic S1P/S1PR1 axis controls energy homeostasis.

    PubMed

    Silva, Vagner R R; Micheletti, Thayana O; Pimentel, Gustavo D; Katashima, Carlos K; Lenhare, Luciene; Morari, Joseane; Mendes, Maria Carolina S; Razolli, Daniela S; Rocha, Guilherme Z; de Souza, Claudio T; Ryu, Dongryeol; Prada, Patrícia O; Velloso, Lício A; Carvalheira, José B C; Pauli, José Rodrigo; Cintra, Dennys E; Ropelle, Eduardo R

    2014-09-25

    Sphingosine 1-phosphate receptor 1 (S1PR1) is a G-protein-coupled receptor for sphingosine-1-phosphate (S1P) that has a role in many physiological and pathophysiological processes. Here we show that the S1P/S1PR1 signalling pathway in hypothalamic neurons regulates energy homeostasis in rodents. We demonstrate that S1PR1 protein is highly enriched in hypothalamic POMC neurons of rats. Intracerebroventricular injections of the bioactive lipid, S1P, reduce food consumption and increase rat energy expenditure through persistent activation of STAT3 and the melanocortin system. Similarly, the selective disruption of hypothalamic S1PR1 increases food intake and reduces the respiratory exchange ratio. We further show that STAT3 controls S1PR1 expression in neurons via a positive feedback mechanism. Interestingly, several models of obesity and cancer anorexia display an imbalance of hypothalamic S1P/S1PR1/STAT3 axis, whereas pharmacological intervention ameliorates these phenotypes. Taken together, our data demonstrate that the neuronal S1P/S1PR1/STAT3 signalling axis plays a critical role in the control of energy homeostasis in rats.

  2. SF-1 in the ventral medial hypothalamic nucleus: A key regulator of homeostasis

    USDA-ARS?s Scientific Manuscript database

    The ventral medial hypothalamic nucleus (VMH) regulates food intake and body weight homeostasis. The nuclear receptor NR5A1 (steroidogenic factor 1; SF-1) is a transcription factor whose expression is highly restricted in the VMH and is required for the development of the nucleus. Neurons expressing...

  3. Hypothalamic neurohormones and immune responses

    PubMed Central

    Quintanar, J. Luis; Guzmán-Soto, Irene

    2013-01-01

    The aim of this review is to provide a comprehensive examination of the current literature describing the neural-immune interactions, with emphasis on the most recent findings of the effects of neurohormones on immune system. Particularly, the role of hypothalamic hormones such as Thyrotropin-releasing hormone (TRH), Corticotropin-releasing hormone (CRH) and Gonadotropin-releasing hormone (GnRH). In the past few years, interest has been raised in extrapituitary actions of these neurohormones due to their receptors have been found in many non-pituitary tissues. Also, the receptors are present in immune cells, suggesting an autocrine or paracrine role within the immune system. In general, these neurohormones have been reported to exert immunomodulatory effects on cell proliferation, immune mediators release and cell function. The implications of these findings in understanding the network of hypothalamic neuropeptides and immune system are discussed. PMID:23964208

  4. Hypothalamic neurohormones and immune responses.

    PubMed

    Quintanar, J Luis; Guzmán-Soto, Irene

    2013-01-01

    The aim of this review is to provide a comprehensive examination of the current literature describing the neural-immune interactions, with emphasis on the most recent findings of the effects of neurohormones on immune system. Particularly, the role of hypothalamic hormones such as Thyrotropin-releasing hormone (TRH), Corticotropin-releasing hormone (CRH) and Gonadotropin-releasing hormone (GnRH). In the past few years, interest has been raised in extrapituitary actions of these neurohormones due to their receptors have been found in many non-pituitary tissues. Also, the receptors are present in immune cells, suggesting an autocrine or paracrine role within the immune system. In general, these neurohormones have been reported to exert immunomodulatory effects on cell proliferation, immune mediators release and cell function. The implications of these findings in understanding the network of hypothalamic neuropeptides and immune system are discussed.

  5. Glucose and hypothalamic astrocytes: More than a fueling role?

    PubMed

    Leloup, C; Allard, C; Carneiro, L; Fioramonti, X; Collins, S; Pénicaud, L

    2016-05-26

    Brain plays a central role in energy homeostasis continuously integrating numerous peripheral signals such as circulating nutrients, and in particular blood glucose level, a variable that must be highly regulated. Then, the brain orchestrates adaptive responses to modulate food intake and peripheral organs activity in order to achieve the fine tuning of glycemia. More than fifty years ago, the presence of glucose-sensitive neurons was discovered in the hypothalamus, but what makes them specific and identifiable still remains disconnected from their electrophysiological signature. On the other hand, astrocytes represent the major class of macroglial cells and are now recognized to support an increasing number of neuronal functions. One of these functions consists in the regulation of energy homeostasis through neuronal fueling and nutrient sensing. Twenty years ago, we discovered that the glucose transporter GLUT2, the canonical "glucosensor" of the pancreatic beta-cell together with the glucokinase, was also present in astrocytes and participated in hypothalamic glucose sensing. Since then, many studies have identified other actors and emphasized the astroglial participation in this mechanism. Growing evidence suggest that astrocytes form a complex network and have to be considered as spatially coordinated and regulated metabolic units. In this review we aim to provide an updated view of the molecular and respective cellular pathways involved in hypothalamic glucose sensing, and their relevance in physiological and pathological states.

  6. Clusterin and LRP2 are critical components of the hypothalamic feeding regulatory pathway.

    PubMed

    Gil, So Young; Youn, Byung-Soo; Byun, Kyunghee; Huang, Hu; Namkoong, Churl; Jang, Pil-Geum; Lee, Joo-Yong; Jo, Young-Hwan; Kang, Gil Myoung; Kim, Hyun-Kyong; Shin, Mi-Seon; Pietrzik, Claus U; Lee, Bonghee; Kim, Young-Bum; Kim, Min-Seon

    2013-01-01

    Hypothalamic feeding circuits are essential for the maintenance of energy balance. There have been intensive efforts to discover new biological molecules involved in these pathways. Here we report that central administration of clusterin, also called apolipoprotein J, causes anorexia, weight loss and activation of hypothalamic signal transduction-activated transcript-3 in mice. In contrast, inhibition of hypothalamic clusterin action results in increased food intake and body weight, leading to adiposity. These effects are likely mediated through the mutual actions of the low-density lipoprotein receptor-related protein-2, a potential receptor for clusterin, and the long-form leptin receptor. In response to clusterin, the low-density lipoprotein receptor-related protein-2 binding to long-form leptin receptor is greatly enhanced in cultured neuronal cells. Furthermore, long-form leptin receptor deficiency or hypothalamic low-density lipoprotein receptor-related protein-2 suppression in mice leads to impaired hypothalamic clusterin signalling and actions. Our study identifies the hypothalamic clusterin-low-density lipoprotein receptor-related protein-2 axis as a novel anorexigenic signalling pathway that is tightly coupled with long-form leptin receptor-mediated signalling.

  7. The Recreational Drug Ecstasy Disrupts the Hypothalamic-Pituitary-Gonadal Reproductive Axis in Adult Male Rats

    PubMed Central

    Dickerson, Sarah M.; Walker, Deena M.; Reveron, Maria E.; Duvauchelle, Christine L.; Gore, Andrea C.

    2009-01-01

    Reproductive function involves an interaction of three regulatory levels: hypothalamus, pituitary, and gonad. The primary drive upon this system comes from hypothalamic gonadotropin-releasing hormone (GnRH) neurosecretory cells, which receive afferent inputs from other neurotransmitter systems in the central nervous system to result in the proper coordination of reproduction and the environment. Here, we hypothesized that the recreational drug ±-3,4-Methylenedioxymethamphetamine (MDMA; “ecstasy”), which acts through several of the neurotransmitter systems that affect GnRH neurons, suppresses the hypothalamic-pituitary-gonadal (HPG) reproductive axis of male rats. Adult male Sprague-Dawley rats self-administered saline or MDMA or saline either once (acute) or for 20 days (chronic), and were euthanized 7 days following last administration. We quantified hypothalamic GnRH mRNA, serum luteinizing hormone (LH) concentrations, and serum testosterone levels, as indices of hypothalamic, pituitary, and gonadal functions, respectively. The results indicate that the hypothalamic and gonadal levels of the HPG axis are significantly altered by MDMA, with GnRH mRNA and serum testosterone levels suppressed in rats administered MDMA compared to saline. Furthermore, our finding that hypothalamic GnRH mRNA levels are suppressed in the context of low testosterone concentrations suggests that the central GnRH neurosecretory system may be a primary target of inhibitory regulation by MDMA usage. PMID:18309234

  8. EJE PRIZE 2017: Hypothalamic AMPK: a golden target against obesity?

    PubMed

    López, Miguel

    2017-05-01

    AMP-activated protein kinase (AMPK) is a cellular gauge that is activated under conditions, such as low energy, increasing energy production and reducing energy waste. Centrally, the AMPK pathway is a canonical route regulating energy homeostasis, by integrating peripheral signals, such as hormones and metabolites, with neuronal networks. Current evidence links hypothalamic AMPK with feeding, brown adipose tissue (BAT) thermogenesis and browning of white adipose tissue (WAT), as well as muscle metabolism, hepatic function and glucose homeostasis. The relevance of these data is interesting from a therapeutic point of view as several agents with potential anti-obesity and/or antidiabetic effects, some currently in clinical use, such as nicotine, metformin and liraglutide are known to act through AMPK, either peripherally or centrally. Furthermore, the orexigenic and weight-gaining effects of the worldwide use of antipsychotic drugs (APDs), such as olanzapine, are also mediated by hypothalamic AMPK. Overall, this evidence makes hypothalamic AMPK signaling an interesting target for the drug development, with its potential for controlling both sides of the energy balance equation, namely feeding and energy expenditure through defined metabolic pathways. © 2017 The authors.

  9. Role of leptin in energy expenditure: the hypothalamic perspective.

    PubMed

    Pandit, R; Beerens, S; Adan, R A H

    2017-06-01

    The adipocyte-derived hormone leptin is a peripheral signal that informs the brain about the metabolic status of an organism. Although traditionally viewed as an appetite-suppressing hormone, studies in the past decade have highlighted the role of leptin in energy expenditure. Leptin has been shown to increase energy expenditure in particular through its effects on the cardiovascular system and brown adipose tissue (BAT) thermogenesis via the hypothalamus. The current review summarizes the role of leptin signaling in various hypothalamic nuclei and its effects on the sympathetic nervous system to influence blood pressure, heart rate, and BAT thermogenesis. Specifically, the role of leptin signaling on three different hypothalamic nuclei, the dorsomedial hypothalamus, the ventromedial hypothalamus, and the arcuate nucleus, is reviewed. It is known that all of these brain regions influence the sympathetic nervous system activity and thereby regulate BAT thermogenesis and the cardiovascular system. Thus the current work focuses on how leptin signaling in specific neuronal populations within these hypothalamic nuclei influences certain aspects of energy expenditure. Copyright © 2017 the American Physiological Society.

  10. EJE PRIZE 2017: Hypothalamic AMPK: a golden target against obesity?

    PubMed Central

    2017-01-01

    AMP-activated protein kinase (AMPK) is a cellular gauge that is activated under conditions, such as low energy, increasing energy production and reducing energy waste. Centrally, the AMPK pathway is a canonical route regulating energy homeostasis, by integrating peripheral signals, such as hormones and metabolites, with neuronal networks. Current evidence links hypothalamic AMPK with feeding, brown adipose tissue (BAT) thermogenesis and browning of white adipose tissue (WAT), as well as muscle metabolism, hepatic function and glucose homeostasis. The relevance of these data is interesting from a therapeutic point of view as several agents with potential anti-obesity and/or antidiabetic effects, some currently in clinical use, such as nicotine, metformin and liraglutide are known to act through AMPK, either peripherally or centrally. Furthermore, the orexigenic and weight-gaining effects of the worldwide use of antipsychotic drugs (APDs), such as olanzapine, are also mediated by hypothalamic AMPK. Overall, this evidence makes hypothalamic AMPK signaling an interesting target for the drug development, with its potential for controlling both sides of the energy balance equation, namely feeding and energy expenditure through defined metabolic pathways. PMID:28232370

  11. Effects of undernourishment on the hypothalamic orexinergic system.

    PubMed

    Pinos, H; Pérez-Izquierdo, M A; Carrillo, B; Collado, P

    2011-01-10

    The present study examined the effects of a severely restricted diet during the pre- and postnatal periods with later nutritional rehabilitation on orexin hypothalamic neurons in male and female Wistar rats. Immunocytochemistry was used to reveal orexin-immunoreactive (orexin-ir) cells in the ventromedial hypothalamus (VMH), dorsomedial hypothalamus (DMH), lateral hypothalamic area (LH) and the perifornical nucleus (PF). Dietary restriction decreased the number of orexin-ir cells in the LH, whereas DMH or PF orexin-ir populations were not affected in either male or female rats. Nutritional rehabilitation resulted in a differential recovery that depended on the period during which rehabilitation occurred and on the sex of the animal. In summary, our study suggests that the hypothalamic nuclei implicated in eating behavior present a differential vulnerability to adverse environmental conditions during development. Specifically, among the studied nuclei only the LH orexin-ir cells were sensitive to severe food deprivation during development in male and female rats. These results suggest that starvation interferes with developmental events that occur during CNS sexual differentiation. 2010 Elsevier Inc. All rights reserved.

  12. Paraventricular hypothalamic nucleus: axonal projections to the brainstem

    PubMed Central

    Geerling, Joel C.; Shin, Jung-Won; Chimenti, Peter C.; Loewy, Arthur D.

    2010-01-01

    The paraventricular hypothalamic nucleus (PVH) contains many neurons that innervate the brainstem, but information regarding their target sites remains incomplete. Here, we labeled neurons in the rat PVH with an anterograde axonal tracer, Phaseolus vulgaris leucoagglutinin (PHAL) and studied their descending projections in reference to specific neuronal subpopulations throughout the brainstem. While many of their target sites were identified previously, numerous new observations were made. Major findings include: (1) In the midbrain, the PVH projects lightly to the ventral tegmental area, Edinger-Westphal nucleus, ventrolateral periaqueductal gray matter, reticular formation, pedunculopontine tegmental nucleus, and dorsal raphe nucleus. (2) In the dorsal pons, the PVH projects heavily to the pre-locus coeruleus, yet very little to the catecholamine neurons in the locus coeruleus, and selectively targets the viscerosensory subregions of the parabrachial nucleus; (3) In the ventral medulla, the superior salivatory nucleus, retrotrapezoid nucleus, compact and external formations of the nucleus ambiguus, A1 and caudal C1 catecholamine neurons, and caudal pressor area receive dense axonal projections, generally exceeding the PVH projection to the rostral C1 region; (4) The medial nucleus of the solitary tract (including A2 noradrenergic and aldosterone-sensitive neurons) receives the most extensive projections of the PVH, substantially more than the dorsal vagal nucleus or area postrema. Our findings suggest that the PVH may modulate a range of homeostatic functions, including cerebral and ocular blood flow, corneal and nasal hydration, ingestive behavior, sodium intake, and glucose metabolism, as well as cardiovascular, gastrointestinal, and respiratory activities. PMID:20187136

  13. Computational Analysis of the Hypothalamic Control of Food Intake

    PubMed Central

    Tabe-Bordbar, Shayan; Anastasio, Thomas J.

    2016-01-01

    Food-intake control is mediated by a heterogeneous network of different neural subtypes, distributed over various hypothalamic nuclei and other brain structures, in which each subtype can release more than one neurotransmitter or neurohormone. The complexity of the interactions of these subtypes poses a challenge to understanding their specific contributions to food-intake control, and apparent consistencies in the dataset can be contradicted by new findings. For example, the growing consensus that arcuate nucleus neurons expressing Agouti-related peptide (AgRP neurons) promote feeding, while those expressing pro-opiomelanocortin (POMC neurons) suppress feeding, is contradicted by findings that low AgRP neuron activity and high POMC neuron activity can be associated with high levels of food intake. Similarly, the growing consensus that GABAergic neurons in the lateral hypothalamus suppress feeding is contradicted by findings suggesting the opposite. Yet the complexity of the food-intake control network admits many different network behaviors. It is possible that anomalous associations between the responses of certain neural subtypes and feeding are actually consistent with known interactions, but their effect on feeding depends on the responses of the other neural subtypes in the network. We explored this possibility through computational analysis. We made a computer model of the interactions between the hypothalamic and other neural subtypes known to be involved in food-intake control, and optimized its parameters so that model behavior matched observed behavior over an extensive test battery. We then used specialized computational techniques to search the entire model state space, where each state represents a different configuration of the responses of the units (model neural subtypes) in the network. We found that the anomalous associations between the responses of certain hypothalamic neural subtypes and feeding are actually consistent with the known structure

  14. Identification of neuron selective androgen receptor inhibitors.

    PubMed

    Otto-Duessel, Maya; Tew, Ben Yi; Vonderfecht, Steven; Moore, Roger; Jones, Jeremy O

    2017-05-26

    To identify neuron-selective androgen receptor (AR) signaling inhibitors, which could be useful in the treatment of spinal and bulbar muscular atrophy (SBMA), or Kennedy's disease, a neuromuscular disorder in which deterioration of motor neurons leads to progressive muscle weakness. Cell lines representing prostate, kidney, neuron, adipose, and muscle tissue were developed that stably expressed the CFP-AR-YFP FRET reporter. We used these cells to screen a library of small molecules for cell type-selective AR inhibitors. Secondary screening in luciferase assays was used to identify the best cell-type specific AR inhibitors. The mechanism of action of a neuron-selective AR inhibitor was examined in vitro using luciferase reporter assays, immunofluorescence microscopy, and immunoprecipitations. Rats were treated with the most potent compound and tissue-selective AR inhibition was examined using RT-qPCR of AR-regulated genes and immunohistochemistry. We identified the thiazole class of antibiotics as compounds able to inhibit AR signaling in a neuronal cell line but not a muscle cell line. One of these antibiotics, thiostrepton is able to inhibit the activity of both wild type and polyglutamine expanded AR in neuronal GT1-7 cells with nanomolar potency. The thiazole antibiotics are known to inhibit FOXM1 activity and accordingly, a novel FOXM1 inhibitor FDI-6 also inhibited AR activity in a neuron-selective fashion. The selective inhibition of AR is likely indirect as the varied structures of these compounds would not suggest that they are competitive antagonists. Indeed, we found that FOXM1 expression correlates with cell-type selectivity, FOXM1 co-localizes with AR in the nucleus, and that shRNA-mediated knock down of FOXM1 reduces AR activity and thiostrepton sensitivity in a neuronal cell line. Thiostrepton treatment reduces FOXM1 levels and the nuclear localization of beta-catenin, a known co-activator of both FOXM1 and AR, and reduces the association between beta

  15. Hypothalamic pituitary adrenal axis and hypothalamic-neurohypophyseal responsiveness in water-deprived rats.

    PubMed

    Grinevich, V; Ma, X M; Verbalis, J; Aguilera, G

    2001-10-01

    The differential effects of osmotic stimulation on magnocellular and parvocellular hypothalamic neurons were studied by analysis of corticotropin-releasing hormone (CRH) and vasopressin (VP) expression in controls and 48-h water-deprived rats subjected to either restraint for 1 h or a single lipopolysaccharide injection (250 microg/100 g). Water deprivation reduced basal CRH mRNA levels but the increments following 4 h of restraint or 6 h lipopolysaccharide (LPS) injection were similar to those in controls. In contrast, water deprivation had no effect on basal VP heteronuclear RNA (hnRNA) and mRNA levels in parvocellular neurons, but responses to restraint or LPS injection were reduced. VP expression in magnocellular paraventricular and supraoptic nuclei, and plasma sodium and vasopressin were higher in water-deprived rats, changes which were unaffected by restraint. LPS injection reduced VP mRNA but not hnRNA levels in magnocellular neurons and increased plasma vasopressin levels only in water-deprived rats independently of changes in plasma sodium. This was accompanied by an increase in vasopressin mRNA content in the posterior pituitary. The data show that the blunted ACTH responses to acute stress during chronic osmotic stimulation are correlated with the inability of parvocellular neurons to increase VP rather than CRH expression. In addition, LPS-induced endotoxemia causes disturbances of the magnocellular vasopressinergic system with an unexpected potentiation of osmotic simulated VP secretion. The lack of increase in VP transcription after LPS and changes in VP mRNA distribution suggest that endotoxemia affect the secretory process at the levels of the neurohypophyseal axon terminal.

  16. Hypothalamic thermosensitivity in capsaicin-desensitized rats.

    PubMed Central

    Cormarèche-Leydier, M; Shimada, S G; Stitt, J T

    1985-01-01

    In rats, we tested the hypothesis that capsaicin desensitization reduces hypothalamic warm thermosensitivity. We locally heated and cooled the hypothalamus using water-perfused thermodes while observing thermoregulatory variables. In untreated rats, a small dose of capsaicin had profound effects on thermoregulation. However, desensitizing rats to capsaicin had no effect on hypothalamic thermosensitivity for metabolic rate or changes in body temperature due to displacements of hypothalamic temperature. Contrary to current opinion, we conclude that capsaicin desensitization does not alter hypothalamic thermosensitivity to warm or cold. PMID:4020699

  17. Hypothalamic carnitine metabolism integrates nutrient and hormonal feedback to regulate energy homeostasis.

    PubMed

    Stark, Romana; Reichenbach, Alex; Andrews, Zane B

    2015-12-15

    The maintenance of energy homeostasis requires the hypothalamic integration of nutrient feedback cues, such as glucose, fatty acids, amino acids, and metabolic hormones such as insulin, leptin and ghrelin. Although hypothalamic neurons are critical to maintain energy homeostasis research efforts have focused on feedback mechanisms in isolation, such as glucose alone, fatty acids alone or single hormones. However this seems rather too simplistic considering the range of nutrient and endocrine changes associated with different metabolic states, such as starvation (negative energy balance) or diet-induced obesity (positive energy balance). In order to understand how neurons integrate multiple nutrient or hormonal signals, we need to identify and examine potential intracellular convergence points or common molecular targets that have the ability to sense glucose, fatty acids, amino acids and hormones. In this review, we focus on the role of carnitine metabolism in neurons regulating energy homeostasis. Hypothalamic carnitine metabolism represents a novel means for neurons to facilitate and control both nutrient and hormonal feedback. In terms of nutrient regulation, carnitine metabolism regulates hypothalamic fatty acid sensing through the actions of CPT1 and has an underappreciated role in glucose sensing since carnitine metabolism also buffers mitochondrial matrix levels of acetyl-CoA, an allosteric inhibitor of pyruvate dehydrogenase and hence glucose metabolism. Studies also show that hypothalamic CPT1 activity also controls hormonal feedback. We hypothesis that hypothalamic carnitine metabolism represents a key molecular target that can concurrently integrate nutrient and hormonal information, which is critical to maintain energy homeostasis. We also suggest this is relevant to broader neuroendocrine research as it predicts that hormonal signaling in the brain varies depending on current nutrient status. Indeed, the metabolic action of ghrelin, leptin or insulin

  18. Neurokinin B Causes Acute GnRH Secretion and Repression of GnRH Transcription in GT1–7 GnRH Neurons

    PubMed Central

    Glidewell-Kenney, Christine A.; Shao, Paul P.; Iyer, Anita K.; Grove, Anna M. H.; Meadows, Jason D.

    2013-01-01

    Genetic studies in human patients with idiopathic hypogonadotropic hypogonadism (IHH) identified mutations in the genes that encode neurokinin B (NKB) and the neurokinin 3 receptor (NK3R). However, determining the mechanism whereby NKB regulates gonadotropin secretion has been difficult because of conflicting results from in vivo studies investigating the luteinizing hormone (LH) response to senktide, a NK3R agonist. NK3R is expressed in a subset of GnRH neurons and in kisspeptin neurons that are known to regulate GnRH secretion. Thus, one potential source of inconsistency is that NKB could produce opposing direct and indirect effects on GnRH secretion. Here, we employ the GT1-7 cell model to elucidate the direct effects of NKB on GnRH neuron function. We find that GT1-7 cells express NK3R and respond to acute senktide treatment with c-Fos induction and increased GnRH secretion. In contrast, long-term senktide treatment decreased GnRH secretion. Next, we focus on the examination of the mechanism underlying the long-term decrease in secretion and determine that senktide treatment represses transcription of GnRH. We further show that this repression of GnRH transcription may involve enhanced c-Fos protein binding at novel activator protein-1 (AP-1) half-sites identified in enhancer 1 and the promoter, as well as chromatin remodeling at the promoter of the GnRH gene. These data indicate that NKB could directly regulate secretion from NK3R-expressing GnRH neurons. Furthermore, whether the response is inhibitory or stimulatory toward GnRH secretion could depend on the history or length of exposure to NKB because of a repressive effect on GnRH transcription. PMID:23393128

  19. Hypothyroidism Compromises Hypothalamic Leptin Signaling in Mice

    PubMed Central

    Groba, Claudia; Mayerl, Steffen; van Mullem, Alies A.; Visser, Theo J.; Darras, Veerle M.; Habenicht, Andreas J.

    2013-01-01

    The impact of thyroid hormone (TH) on metabolism and energy expenditure is well established, but the role of TH in regulating nutritional sensing, particularly in the central nervous system, is only poorly defined. Here, we studied the consequences of hypothyroidism on leptin production as well as leptin sensing in congenital hypothyroid TRH receptor 1 knockout (Trhr1 ko) mice and euthyroid control animals. Hypothyroid mice exhibited decreased circulating leptin levels due to a decrease in fat mass and reduced leptin expression in white adipose tissue. In neurons of the hypothalamic arcuate nucleus, hypothyroid mice showed increased leptin receptor Ob-R expression and decreased suppressor of cytokine signaling 3 transcript levels. In order to monitor putative changes in central leptin sensing, we generated hypothyroid and leptin-deficient animals by crossing hypothyroid Trhr1 ko mice with the leptin-deficient ob/ob mice. Hypothyroid Trhr1/ob double knockout mice showed a blunted response to leptin treatment with respect to body weight and food intake and exhibited a decreased activation of phospho-signal transducer and activator of transcription 3 as well as a up-regulation of suppressor of cytokine signaling 3 upon leptin treatment, particularly in the arcuate nucleus. These data indicate alterations in the intracellular processing of the leptin signal under hypothyroid conditions and thereby unravel a novel mode of action by which TH affects energy metabolism. PMID:23518925

  20. Hypothyroidism compromises hypothalamic leptin signaling in mice.

    PubMed

    Groba, Claudia; Mayerl, Steffen; van Mullem, Alies A; Visser, Theo J; Darras, Veerle M; Habenicht, Andreas J; Heuer, Heike

    2013-04-01

    The impact of thyroid hormone (TH) on metabolism and energy expenditure is well established, but the role of TH in regulating nutritional sensing, particularly in the central nervous system, is only poorly defined. Here, we studied the consequences of hypothyroidism on leptin production as well as leptin sensing in congenital hypothyroid TRH receptor 1 knockout (Trhr1 ko) mice and euthyroid control animals. Hypothyroid mice exhibited decreased circulating leptin levels due to a decrease in fat mass and reduced leptin expression in white adipose tissue. In neurons of the hypothalamic arcuate nucleus, hypothyroid mice showed increased leptin receptor Ob-R expression and decreased suppressor of cytokine signaling 3 transcript levels. In order to monitor putative changes in central leptin sensing, we generated hypothyroid and leptin-deficient animals by crossing hypothyroid Trhr1 ko mice with the leptin-deficient ob/ob mice. Hypothyroid Trhr1/ob double knockout mice showed a blunted response to leptin treatment with respect to body weight and food intake and exhibited a decreased activation of phospho-signal transducer and activator of transcription 3 as well as a up-regulation of suppressor of cytokine signaling 3 upon leptin treatment, particularly in the arcuate nucleus. These data indicate alterations in the intracellular processing of the leptin signal under hypothyroid conditions and thereby unravel a novel mode of action by which TH affects energy metabolism.

  1. Hypothalamic PKA regulates leptin sensitivity and adiposity

    PubMed Central

    Yang, Linghai; McKnight, G. Stanley

    2015-01-01

    Mice lacking the RIIβ regulatory subunit of cyclic AMP-dependent protein kinase A (PKA) display reduced adiposity and resistance to diet-induced obesity. Here we show that RIIβ knockout (KO) mice have enhanced sensitivity to leptin's effects on both feeding and energy metabolism. After administration of a low dose of leptin, the duration of hypothalamic JAK/STAT3 signalling is increased, resulting in enhanced POMC mRNA induction. Consistent with the extended JAK/STAT3 activation, we find that the negative feedback regulator of leptin receptor signalling, Socs3, is inhibited in the hypothalamus of RIIβ KO mice. During fasting, RIIβ–PKA is activated and this correlates with an increase in CREB phosphorylation. The increase in CREB phosphorylation is absent in the fasted RIIβ KO hypothalamus. Selective inhibition of PKA activity in AgRP neurons partially recapitulates the leanness and resistance to diet-induced obesity of RIIβ KO mice. Our findings suggest that RIIβ–PKA modulates the duration of leptin receptor signalling and therefore the magnitude of the catabolic response to leptin. PMID:26381935

  2. Hypothalamic effects of thyroid hormones on metabolism.

    PubMed

    Martínez-Sánchez, Noelia; Alvarez, Clara V; Fernø, Johan; Nogueiras, Rubén; Diéguez, Carlos; López, Miguel

    2014-10-01

    Over the past few decades, obesity and its related metabolic disorders have increased at an epidemic rate in the developed and developing world. New signals and factors involved in the modulation of energy balance and metabolism are continuously being discovered, providing potential novel drug targets for the treatment of metabolic disease. A parallel strategy is to better understand how hormonal signals, with an already established role in energy metabolism, work, and how manipulation of the pathways involved may lead to amelioration of metabolic dysfunction. The thyroid hormones belong to the latter category, with dysregulation of the thyroid axis leading to marked alterations in energy balance. The potential of thyroid hormones in the treatment of obesity has been known for decades, but their therapeutic use has been hampered because of side-effects. Data gleaned over the past few years, however, have uncovered new features at the mechanisms of action involved in thyroid hormones. Sophisticated neurobiological approaches have allowed the identification of specific energy sensors, such as AMP-activated protein kinase and mechanistic target of rapamycin, acting in specific groups of hypothalamic neurons, mediating many of the effects of thyroid hormones on food intake, energy expenditure, glucose, lipid metabolism, and cardiovascular function. More extensive knowledge about these molecular mechanisms will be of great relevance for the treatment of obesity and metabolic syndrome.

  3. Differential Acute and Chronic Effects of Leptin on Hypothalamic Astrocyte Morphology and Synaptic Protein Levels

    PubMed Central

    García-Cáceres, Cristina; Fuente-Martín, Esther; Burgos-Ramos, Emma; Granado, Miriam; Frago, Laura M.; Barrios, Vicente; Horvath, Tamas

    2011-01-01

    Astrocytes participate in neuroendocrine functions partially through modulation of synaptic input density in the hypothalamus. Indeed, glial ensheathing of neurons is modified by specific hormones, thus determining the availability of neuronal membrane space for synaptic inputs, with the loss of this plasticity possibly being involved in pathological processes. Leptin modulates synaptic inputs in the hypothalamus, but whether astrocytes participate in this action is unknown. Here we report that astrocyte structural proteins, such as glial fibrillary acidic protein (GFAP) and vimentin, are induced and astrocyte morphology modified by chronic leptin administration (intracerebroventricular, 2 wk), with these changes being inversely related to modifications in synaptic protein densities. Similar changes in glial structural proteins were observed in adult male rats that had increased body weight and circulating leptin levels due to neonatal overnutrition (overnutrition: four pups/litter vs. control: 12 pups/litter). However, acute leptin treatment reduced hypothalamic GFAP levels and induced synaptic protein levels 1 h after administration, with no effect on vimentin. In primary hypothalamic astrocyte cultures leptin also reduced GFAP levels at 1 h, with an induction at 24 h, indicating a possible direct effect of leptin. Hence, one mechanism by which leptin may affect metabolism is by modifying hypothalamic astrocyte morphology, which in turn could alter synaptic inputs to hypothalamic neurons. Furthermore, the responses to acute and chronic leptin exposure are inverse, raising the possibility that increased glial activation in response to chronic leptin exposure could be involved in central leptin resistance. PMID:21343257

  4. Decreased food anticipatory activity of obese mice relates to hypothalamic c-Fos expression.

    PubMed

    Luna-Illades, C; Morales, T; Miranda-Anaya, M

    2017-10-01

    During daily Food Restriction (FR), obese Neotomodon alstoni mice present decreased Food Anticipatory Activity (FAA) compared to lean mice. Here, we investigated whether FOS expression in hypothalamic nuclei involved in food synchronization and anticipation parallels decreased FAA during daily FR of obese N. alstoni. Locomotor activity of lean and obese mice in ad libitum feeding conditions was monitored for at least two weeks. Then, a gradual restriction of food access was followed to establish a 5h period of daily food access. FR was maintained during at least two weeks before sacrifice of mice at the starting point of the feeding period. Obese mice subjected to FR displayed an overall reduction of FOS-positive (FOS+) hypothalamic neurons, while lean mice in a similar protocol exhibited an increase in FOS+ neurons within the arcuate and dorsomedial hypothalamic nuclei. These results are consistent with decreased FAA displayed by obese mice in comparison to lean mice. Furthermore, limbic system areas of lean mice, such as the cingulate cortex and the hippocampus, showed an increase in FOS during FR, while no responses were observed in obese mice. The daily food intake of obese mice was severely reduced during FR, compared to the ad libitum condition, whereas food intake in lean mice was not affected by FR. Current data suggests that decreased hypothalamic and limbic neuronal activation may contribute to the reduction of FAA in obese N. alstoni mice. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Bariatric Surgery in Hypothalamic Obesity

    PubMed Central

    Bingham, Nathan C.; Rose, Susan R.; Inge, Thomas H.

    2012-01-01

    Craniopharyngiomas (CP) are epithelial neoplasms generally found in the area of the pituitary and hypothalamus. Despite benign histology, these tumors and/or their treatment often result in significant, debilitating disorders of endocrine, neurological, behavioral, and metabolic systems. Severe obesity is observed in a high percentage of patients with CP resulting in significant comorbidities and negatively impacting quality of life. Obesity occurs as a result of hypothalamic damage and disruption of normal homeostatic mechanisms regulating energy balance. Such pathological weight gain, termed hypothalamic obesity (HyOb), is often severe and refractory to therapy. Unfortunately, neither lifestyle intervention nor pharmacotherapy has proven effective in the treatment of HyOb. Given the limited choices and poor results of these treatments, several groups have examined bariatric surgery as a treatment alternative for patients with CP–HyOb. While a large body of evidence exists supporting the use of bariatric surgery in the treatment of exogenous obesity and its comorbidities, its role in the treatment of HyOb has yet to be defined. To date, the existing literature on bariatric surgery in CP–HyOb is largely limited to case reports and series with short term follow-up. Here we review the current reports on the use of bariatric surgery in the treatment of CP–HyOb. We also compare these results to those reported for other populations of HyOb, including Prader–Willi Syndrome, Bardet–Biedl syndrome, and hypothalamic melanocortin signaling defects. While initial reports of bariatric surgery in CP–HyOb are promising, their limited scope makes it difficult to draw any substantial conclusions as to the long term safety and efficacy of bariatric surgery in CP–HyOb. There continues to be a need for more robust, controlled, prospective studies with long term follow-up in order to better define the role of bariatric surgery in the treatment of HyOb. PMID:22649412

  6. Bariatric surgery in hypothalamic obesity.

    PubMed

    Bingham, Nathan C; Rose, Susan R; Inge, Thomas H

    2012-01-01

    Craniopharyngiomas (CP) are epithelial neoplasms generally found in the area of the pituitary and hypothalamus. Despite benign histology, these tumors and/or their treatment often result in significant, debilitating disorders of endocrine, neurological, behavioral, and metabolic systems. Severe obesity is observed in a high percentage of patients with CP resulting in significant comorbidities and negatively impacting quality of life. Obesity occurs as a result of hypothalamic damage and disruption of normal homeostatic mechanisms regulating energy balance. Such pathological weight gain, termed hypothalamic obesity (HyOb), is often severe and refractory to therapy. Unfortunately, neither lifestyle intervention nor pharmacotherapy has proven effective in the treatment of HyOb. Given the limited choices and poor results of these treatments, several groups have examined bariatric surgery as a treatment alternative for patients with CP-HyOb. While a large body of evidence exists supporting the use of bariatric surgery in the treatment of exogenous obesity and its comorbidities, its role in the treatment of HyOb has yet to be defined. To date, the existing literature on bariatric surgery in CP-HyOb is largely limited to case reports and series with short term follow-up. Here we review the current reports on the use of bariatric surgery in the treatment of CP-HyOb. We also compare these results to those reported for other populations of HyOb, including Prader-Willi Syndrome, Bardet-Biedl syndrome, and hypothalamic melanocortin signaling defects. While initial reports of bariatric surgery in CP-HyOb are promising, their limited scope makes it difficult to draw any substantial conclusions as to the long term safety and efficacy of bariatric surgery in CP-HyOb. There continues to be a need for more robust, controlled, prospective studies with long term follow-up in order to better define the role of bariatric surgery in the treatment of HyOb.

  7. Alterations in the hypothalamic melanocortin pathway in amyotrophic lateral sclerosis.

    PubMed

    Vercruysse, Pauline; Sinniger, Jérôme; El Oussini, Hajer; Scekic-Zahirovic, Jelena; Dieterlé, Stéphane; Dengler, Reinhard; Meyer, Thomas; Zierz, Stephan; Kassubek, Jan; Fischer, Wilhelm; Dreyhaupt, Jens; Grehl, Torsten; Hermann, Andreas; Grosskreutz, Julian; Witting, Anke; Van Den Bosch, Ludo; Spreux-Varoquaux, Odile; Ludolph, Albert C; Dupuis, Luc

    2016-04-01

    Amyotrophic lateral sclerosis, the most common adult-onset motor neuron disease, leads to death within 3 to 5 years after onset. Beyond progressive motor impairment, patients with amyotrophic lateral sclerosis suffer from major defects in energy metabolism, such as weight loss, which are well correlated with survival. Indeed, nutritional intervention targeting weight loss might improve survival of patients. However, the neural mechanisms underlying metabolic impairment in patients with amyotrophic lateral sclerosis remain elusive, in particular due to the lack of longitudinal studies. Here we took advantage of samples collected during the clinical trial of pioglitazone (GERP-ALS), and characterized longitudinally energy metabolism of patients with amyotrophic lateral sclerosis in response to pioglitazone, a drug with well-characterized metabolic effects. As expected, pioglitazone decreased glycaemia, decreased liver enzymes and increased circulating adiponectin in patients with amyotrophic lateral sclerosis, showing its efficacy in the periphery. However, pioglitazone did not increase body weight of patients with amyotrophic lateral sclerosis independently of bulbar involvement. As pioglitazone increases body weight through a direct inhibition of the hypothalamic melanocortin system, we studied hypothalamic neurons producing proopiomelanocortin (POMC) and the endogenous melanocortin inhibitor agouti-related peptide (AGRP), in mice expressing amyotrophic lateral sclerosis-linked mutant SOD1(G86R). We observed lower Pomc but higher Agrp mRNA levels in the hypothalamus of presymptomatic SOD1(G86R) mice. Consistently, numbers of POMC-positive neurons were decreased, whereas AGRP fibre density was elevated in the hypothalamic arcuate nucleus of SOD1(G86R) mice. Consistent with a defect in the hypothalamic melanocortin system, food intake after short term fasting was increased in SOD1(G86R) mice. Importantly, these findings were replicated in two other amyotrophic

  8. Ghrelin Regulates Glucose and Glutamate Transporters in Hypothalamic Astrocytes.

    PubMed

    Fuente-Martín, Esther; García-Cáceres, Cristina; Argente-Arizón, Pilar; Díaz, Francisca; Granado, Miriam; Freire-Regatillo, Alejandra; Castro-González, David; Ceballos, María L; Frago, Laura M; Dickson, Suzanne L; Argente, Jesús; Chowen, Julie A

    2016-03-30

    Hypothalamic astrocytes can respond to metabolic signals, such as leptin and insulin, to modulate adjacent neuronal circuits and systemic metabolism. Ghrelin regulates appetite, adiposity and glucose metabolism, but little is known regarding the response of astrocytes to this orexigenic hormone. We have used both in vivo and in vitro approaches to demonstrate that acylated ghrelin (acyl-ghrelin) rapidly stimulates glutamate transporter expression and glutamate uptake by astrocytes. Moreover, acyl-ghrelin rapidly reduces glucose transporter (GLUT) 2 levels and glucose uptake by these glial cells. Glutamine synthetase and lactate dehydrogenase decrease, while glycogen phosphorylase and lactate transporters increase in response to acyl-ghrelin, suggesting a change in glutamate and glucose metabolism, as well as glycogen storage by astrocytes. These effects are partially mediated through ghrelin receptor 1A (GHSR-1A) as astrocytes do not respond equally to desacyl-ghrelin, an isoform that does not activate GHSR-1A. Moreover, primary astrocyte cultures from GHSR-1A knock-out mice do not change glutamate transporter or GLUT2 levels in response to acyl-ghrelin. Our results indicate that acyl-ghrelin may mediate part of its metabolic actions through modulation of hypothalamic astrocytes and that this effect could involve astrocyte mediated changes in local glucose and glutamate metabolism that alter the signals/nutrients reaching neighboring neurons.

  9. Ghrelin Regulates Glucose and Glutamate Transporters in Hypothalamic Astrocytes

    PubMed Central

    Fuente-Martín, Esther; García-Cáceres, Cristina; Argente-Arizón, Pilar; Díaz, Francisca; Granado, Miriam; Freire-Regatillo, Alejandra; Castro-González, David; Ceballos, María L.; Frago, Laura M.; Dickson, Suzanne L.; Argente, Jesús; Chowen, Julie A.

    2016-01-01

    Hypothalamic astrocytes can respond to metabolic signals, such as leptin and insulin, to modulate adjacent neuronal circuits and systemic metabolism. Ghrelin regulates appetite, adiposity and glucose metabolism, but little is known regarding the response of astrocytes to this orexigenic hormone. We have used both in vivo and in vitro approaches to demonstrate that acylated ghrelin (acyl-ghrelin) rapidly stimulates glutamate transporter expression and glutamate uptake by astrocytes. Moreover, acyl-ghrelin rapidly reduces glucose transporter (GLUT) 2 levels and glucose uptake by these glial cells. Glutamine synthetase and lactate dehydrogenase decrease, while glycogen phosphorylase and lactate transporters increase in response to acyl-ghrelin, suggesting a change in glutamate and glucose metabolism, as well as glycogen storage by astrocytes. These effects are partially mediated through ghrelin receptor 1A (GHSR-1A) as astrocytes do not respond equally to desacyl-ghrelin, an isoform that does not activate GHSR-1A. Moreover, primary astrocyte cultures from GHSR-1A knock-out mice do not change glutamate transporter or GLUT2 levels in response to acyl-ghrelin. Our results indicate that acyl-ghrelin may mediate part of its metabolic actions through modulation of hypothalamic astrocytes and that this effect could involve astrocyte mediated changes in local glucose and glutamate metabolism that alter the signals/nutrients reaching neighboring neurons. PMID:27026049

  10. Oestrogen Modulates Hypothalamic Control of Energy Homeostasis Through Multiple Mechanisms

    PubMed Central

    Roepke, Troy A.

    2009-01-01

    The control of energy homeostasis in women is correlated with the anorectic effects of oestrogen, which can attenuate body weight gain and reduce food intake in rodent models. This review will investigate the multiple signalling pathways and cellular targets that oestrogen utilises to control energy homeostasis in the hypothalamus. Oestrogen affects all of the hypothalamic nuclei that control energy homeostasis. Oestrogen controls the activity of hypothalamic neurones through gene regulation and neuronal excitability. Oestrogen’s primary cellular pathway is the control of gene transcription through the classical ERs (ERα and ERβ) with ERα having the primary role in energy homeostasis. Oestrogen also controls energy homeostasis through membrane-mediated events via membrane-associated ERs or a novel, putative membrane ER that is coupled to G-proteins. Therefore, oestrogen has at least two receptors with multiple signalling and transcriptional pathways to activate during immediate and long-term anorectic effects. Ultimately, it is the interactions of all the receptor-mediated processes in hypothalamus and other areas of the CNS that will determine the anorectic effects of oestrogen and its control of energy homeostasis. PMID:19076267

  11. Neurokinin B and the Hypothalamic Regulation of Reproduction

    PubMed Central

    Rance, Naomi E.; Krajewski, Sally J.; Smith, Melinda A.; Cholanian, Marina; Dacks, Penny A.

    2010-01-01

    Loss of function mutations in the genes encoding either neurokinin B (NKB) or its receptor, NK3 (NK3R), result in hypogonadotropic hypogonadism, characterized by an absence of pubertal development and low circulating levels of LH and gonadal steroids. These studies implicate NKB and NK3R as essential elements of the human reproductive axis. Studies over the last two decades provide evidence that a group of neurons in the hypothalamic infundibular/arcuate nucleus form an important component of this regulatory circuit. These neurons are steroid-responsive and coexpress NKB, kisspeptin, dynorphin, NK3R and estrogen receptor α (ERα) in a variety of mammalian species. Compelling evidence in the human indicates these neurons function in the hypothalamic circuitry regulating estrogen negative feedback on gonadotropin-releasing hormone (GnRH) secretion. Moreover, in the rat, they form a bilateral, interconnected network that projects to NK3R-expressing GnRH terminals in the median eminence. This network provides an anatomical framework to explain how coordination among NKB/kisspeptin/dynorphin/NK3R/ERα neurons could mediate feedback information from the gonads to modulate pulsatile GnRH secretion. There is substantial (but indirect) evidence that this network may be part of the neural circuitry known as the “GnRH pulse generator”, with NK3R signaling as an important component. This theory provides a compelling explanation for the occurrence of hypogonadotropic hypogonadism in patients with inactivating mutations in the TAC3 orTACR3 genes. Future studies will be needed to determine whether NKB signaling plays a permissive role in the onset of puberty or is part of the driving force initiating the maturation of reproductive function. PMID:20800582

  12. Regulation of the hypothalamic-pituitary-adrenocortical stress response

    PubMed Central

    Herman, James P.; McKlveen, Jessica M.; Ghosal, Sriparna; Kopp, Brittany; Wulsin, Aynara; Makinson, Ryan; Scheimann, Jessie; Myers, Brent

    2016-01-01

    The hypothalamo-pituitary-adrenocortical (HPA axis) is required for stress adaptation. Activation of the HPA axis causes secretion of glucocorticoids, which act on multiple organ systems to redirect energy resources to meet real or anticipated demand. The HPA stress response is driven primarily by neural mechanisms, invoking corticotrophin releasing hormone (CRH) release from hypothalamic paraventricular nucleus (PVN) neurons. Pathways activating CRH release are stressor dependent: reactive responses to homeostatic disruption frequently involve direct noradrenergic or peptidergic drive of PVN neurons by sensory relays, whereas anticipatory responses use oligosynaptic pathways originating in upstream limbic structures. Anticipatory responses are driven largely by disinhibition, mediated by trans-synaptic silencing of tonic PVN inhibition via GABAergic neurons in the amygdala. Stress responses are inhibited by negative feedback mechanisms, whereby glucocorticoids act to diminish drive (brainstem), promote trans-synaptic inhibition by limbic structures (e.g, hippocampus). Glucocorticoids also act at the PVN to rapidly inhibit CRH neuronal activity via membrane glucocorticoid receptors. Chronic stress-induced activation of the HPA axis takes many forms (chronic basal hypersecretion, sensitized stress responses, even adrenal exhaustion), with manifestation dependent upon factors such as stressor chronicity, intensity, frequency and modality. Neural mechanisms driving chronic stress responses can be distinct from those controlling acute reactions, including recruitment of novel limbic, hypothalamic and brainstem circuits. Importantly, an individual’s response to acute or chronic stress is determined by numerous factors, including genetics, early life experience, environmental conditions, sex and age. The context in which stressors occur will determine whether an individual’s acute or chronic stress responses are adaptive or maladaptive (pathological). PMID:27065163

  13. The histone acetyltransferase MOF activates hypothalamic polysialylation to prevent diet-induced obesity in mice

    PubMed Central

    Brenachot, Xavier; Rigault, Caroline; Nédélec, Emmanuelle; Laderrière, Amélie; Khanam, Tasneem; Gouazé, Alexandra; Chaudy, Sylvie; Lemoine, Aleth; Datiche, Frédérique; Gascuel, Jean; Pénicaud, Luc; Benani, Alexandre

    2014-01-01

    Overfeeding causes rapid synaptic remodeling in hypothalamus feeding circuits. Polysialylation of cell surface molecules is a key step in this neuronal rewiring and allows normalization of food intake. Here we examined the role of hypothalamic polysialylation in the long-term maintenance of body weight, and deciphered the molecular sequence underlying its nutritional regulation. We found that upon high fat diet (HFD), reduced hypothalamic polysialylation exacerbated the diet-induced obese phenotype in mice. Upon HFD, the histone acetyltransferase MOF was rapidly recruited on the St8sia4 polysialyltransferase-encoding gene. Mof silencing in the mediobasal hypothalamus of adult mice prevented activation of the St8sia4 gene transcription, reduced polysialylation, altered the acute homeostatic feeding response to HFD and increased the body weight gain. These findings indicate that impaired hypothalamic polysialylation contribute to the development of obesity, and establish a role for MOF in the brain control of energy balance. PMID:25161885

  14. Hypothalamic KLF4 mediates leptin's effects on food intake via AgRP

    PubMed Central

    Imbernon, Monica; Sanchez-Rebordelo, Estrella; Gallego, Rosalia; Gandara, Marina; Lear, Pamela; Lopez, Miguel; Dieguez, Carlos; Nogueiras, Ruben

    2014-01-01

    Krüppel-like factor 4 (KLF4) is a zinc-finger-type transcription factor expressed in a range of tissues that plays multiple functions. We report that hypothalamic KLF4 represents a new transcription factor specifically modulating agouti-related protein (AgRP) expression in vivo. Hypothalamic KLF4 colocalizes with AgRP neurons and is modulated by nutritional status and leptin. Over-expression of KLF4 in the hypothalamic arcuate nucleus (ARC) induces food intake and increases body weight through the specific stimulation of AgRP, as well as blunting leptin sensitivity in lean rats independent of forkhead box protein 01 (FoxO1). Down-regulation of KLF4 in the ARC inhibits fasting-induced food intake in both lean and diet-induced obese (DIO) rats. Silencing KLF4, however, does not, on its own, enhance peripheral leptin sensitivity in DIO rats. PMID:24944903

  15. Hypothalamic KLF4 mediates leptin's effects on food intake via AgRP.

    PubMed

    Imbernon, Monica; Sanchez-Rebordelo, Estrella; Gallego, Rosalia; Gandara, Marina; Lear, Pamela; Lopez, Miguel; Dieguez, Carlos; Nogueiras, Ruben

    2014-07-01

    Krüppel-like factor 4 (KLF4) is a zinc-finger-type transcription factor expressed in a range of tissues that plays multiple functions. We report that hypothalamic KLF4 represents a new transcription factor specifically modulating agouti-related protein (AgRP) expression in vivo. Hypothalamic KLF4 colocalizes with AgRP neurons and is modulated by nutritional status and leptin. Over-expression of KLF4 in the hypothalamic arcuate nucleus (ARC) induces food intake and increases body weight through the specific stimulation of AgRP, as well as blunting leptin sensitivity in lean rats independent of forkhead box protein 01 (FoxO1). Down-regulation of KLF4 in the ARC inhibits fasting-induced food intake in both lean and diet-induced obese (DIO) rats. Silencing KLF4, however, does not, on its own, enhance peripheral leptin sensitivity in DIO rats.

  16. Suppression of the HPA Axis During Cholestasis Can Be Attributed to Hypothalamic Bile Acid Signaling.

    PubMed

    McMillin, Matthew; Frampton, Gabriel; Quinn, Matthew; Divan, Ali; Grant, Stephanie; Patel, Nisha; Newell-Rogers, Karen; DeMorrow, Sharon

    2015-12-01

    Suppression of the hypothalamic-pituitary-adrenal (HPA) axis has been shown to occur during cholestatic liver injury. Furthermore, we have demonstrated that in a model of cholestasis, serum bile acids gain entry into the brain via a leaky blood brain barrier and that hypothalamic bile acid content is increased. Therefore, the aim of the current study was to determine the effects of bile acid signaling on the HPA axis. The data presented show that HPA axis suppression during cholestatic liver injury, specifically circulating corticosterone levels and hypothalamic corticotropin releasing hormone (CRH) expression, can be attenuated by administration of the bile acid sequestrant cholestyramine. Secondly, treatment of hypothalamic neurons with various bile acids suppressed CRH expression and secretion in vitro. However, in vivo HPA axis suppression was only evident after the central injection of the bile acids taurocholic acid or glycochenodeoxycholic acid but not the other bile acids studied. Furthermore, we demonstrate that taurocholic acid and glycochenodeoxycholic acid are exerting their effects on hypothalamic CRH expression after their uptake through the apical sodium-dependent bile acid transporter and subsequent activation of the glucocorticoid receptor. Taken together with previous studies, our data support the hypothesis that during cholestatic liver injury, bile acids gain entry into the brain, are transported into neurons through the apical sodium-dependent bile acid transporter and can activate the glucocorticoid receptor to suppress the HPA axis. These data also lend themselves to the broader hypothesis that bile acids may act as central modulators of hypothalamic peptides that may be altered during liver disease.

  17. Suppression of the HPA Axis During Cholestasis Can Be Attributed to Hypothalamic Bile Acid Signaling

    PubMed Central

    McMillin, Matthew; Frampton, Gabriel; Quinn, Matthew; Divan, Ali; Grant, Stephanie; Patel, Nisha; Newell-Rogers, Karen

    2015-01-01

    Suppression of the hypothalamic-pituitary-adrenal (HPA) axis has been shown to occur during cholestatic liver injury. Furthermore, we have demonstrated that in a model of cholestasis, serum bile acids gain entry into the brain via a leaky blood brain barrier and that hypothalamic bile acid content is increased. Therefore, the aim of the current study was to determine the effects of bile acid signaling on the HPA axis. The data presented show that HPA axis suppression during cholestatic liver injury, specifically circulating corticosterone levels and hypothalamic corticotropin releasing hormone (CRH) expression, can be attenuated by administration of the bile acid sequestrant cholestyramine. Secondly, treatment of hypothalamic neurons with various bile acids suppressed CRH expression and secretion in vitro. However, in vivo HPA axis suppression was only evident after the central injection of the bile acids taurocholic acid or glycochenodeoxycholic acid but not the other bile acids studied. Furthermore, we demonstrate that taurocholic acid and glycochenodeoxycholic acid are exerting their effects on hypothalamic CRH expression after their uptake through the apical sodium-dependent bile acid transporter and subsequent activation of the glucocorticoid receptor. Taken together with previous studies, our data support the hypothesis that during cholestatic liver injury, bile acids gain entry into the brain, are transported into neurons through the apical sodium-dependent bile acid transporter and can activate the glucocorticoid receptor to suppress the HPA axis. These data also lend themselves to the broader hypothesis that bile acids may act as central modulators of hypothalamic peptides that may be altered during liver disease. PMID:26431088

  18. Regulation of hypothalamic corticotropin-releasing hormone transcription by elevated glucocorticoids.

    PubMed

    Evans, Andrew N; Liu, Ying; Macgregor, Robert; Huang, Victoria; Aguilera, Greti

    2013-11-01

    Negative glucocorticoid feedback is essential for preventing the deleterious effects of excessive hypothalamic pituitary adrenal axis axis activation, with an important target being CRH transcription in the hypothalamic paraventricular nucleus. The aim of these studies was to determine whether glucocorticoids repress CRH transcription directly in CRH neurons, by examining glucocorticoid effects on glucocorticoid receptor (GR)-CRH promoter interaction and the activation of proteins required for CRH transcription. Immunoprecipitation of hypothalamic chromatin from intact or adrenalectomized rats subjected to either stress or corticosterone injections showed minor association of the proximal CRH promoter with the GR compared with that with phospho-CREB (pCREB). In contrast, the Period-1 (Per1, a glucocorticoid-responsive gene) promoter markedly recruited GR. Stress increased pCREB recruitment by the CRH but not the Per1 promoter, irrespective of circulating glucocorticoids. In vitro, corticosterone pretreatment (30 minutes or 18 hours) only slightly inhibited basal and forskolin-stimulated CRH heteronuclear RNA in primary hypothalamic neuronal cultures and CRH promoter activity in hypothalamic 4B cells. In 4B cells, 30 minutes or 18 hours of corticosterone exposure had no effect on forskolin-induced nuclear accumulation of the recognized CRH transcriptional regulators, pCREB and transducer of regulated CREB activity 2. The data show that inhibition of CRH transcription by physiological glucocorticoids in vitro is minor and that direct interaction of GR with DNA in the proximal CRH promoter may not be a major mechanism of CRH gene repression. Although GR interaction with distal promoter elements may have a role, the data suggest that transcriptional repression of CRH by glucocorticoids involves protein-protein interactions and/or modulation of afferent inputs to the hypothalamic paraventricular nucleus.

  19. Hypothalamic and Brainstem Sources of Pituitary Adenylate Cyclase-Activating Polypeptide Nerve Fibers Innervating the Hypothalamic Paraventricular Nucleus in the Rat

    PubMed Central

    DAS, MAHASWETA; VIHLEN, CHRISTOPHER S.; LEGRADI, GABOR

    2007-01-01

    The hypothalamic paraventricular nucleus (PVN) coordinates major neuroendocrine and behavioral mechanisms, particularly responses to homeostatic challenges. Parvocellular and magnocellular PVN neurons are richly innervated by pituitary adenylate cyclase-activating polypeptide (PACAP) axons. Our recent functional observations have also suggested that PACAP may be an excitatory neuropeptide at the level of the PVN. Nevertheless, the exact localization of PACAP-producing neurons that project to the PVN is not understood. The present study examined the specific contribution of various brain areas sending PACAP innervation to the rat PVN by using iontophoretic microinjections of the retrograde neuroanatomical tracer cholera toxin B subunit (CTb). Retrograde transport was evaluated from hypothalamic and brainstem sections by using multiple labeling immunofluorescence for CTb and PACAP. PACAP-containing cell groups were found to be retrogradely labeled from the PVN in the median preoptic nucleus; preoptic and lateral hypothalamic areas; arcuate, dorsomedial, ventromedial, and supramammillary nuclei; ventrolateral midbrain periaqueductal gray; rostral and midlevel ventrolateral medulla, including the C1 catecholamine cell group; nucleus of the solitary tract; and dorsal motor nucleus of vagus. Minor PACAP projections with scattered double-labeled neurons originated from the parabrachial nucleus, pericoeruleus area, and caudal regions of the nucleus of the solitary tract and ventrolateral medulla. These observations indicate a multisite origin of PACAP innervation to the PVN and provide a strong chemical neuroanatomical foundation for interaction between PACAP and its potential target neurons in the PVN, such as parvocellular CRH neurons, controlling physiologic responses to stressful challenges and other neuroendocrine or preautonomic PVN neurons. PMID:17154257

  20. The role of insulin receptor substrate 2 in hypothalamic and β cell function

    PubMed Central

    Choudhury, Agharul I.; Heffron, Helen; Smith, Mark A.; Al-Qassab, Hind; Xu, Allison W.; Selman, Colin; Simmgen, Marcus; Clements, Melanie; Claret, Marc; MacColl, Gavin; Bedford, David C.; Hisadome, Kazunari; Diakonov, Ivan; Moosajee, Vazira; Bell, Jimmy D.; Speakman, John R.; Batterham, Rachel L.; Barsh, Gregory S.; Ashford, Michael L.J.; Withers, Dominic J.

    2005-01-01

    Insulin receptor substrate 2 (Irs2) plays complex roles in energy homeostasis. We generated mice lacking Irs2 in β cells and a population of hypothalamic neurons (RIPCreIrs2KO), in all neurons (NesCreIrs2KO), and in proopiomelanocortin neurons (POMCCreIrs2KO) to determine the role of Irs2 in the CNS and β cell. RIPCreIrs2KO mice displayed impaired glucose tolerance and reduced β cell mass. Overt diabetes did not ensue, because β cells escaping Cre-mediated recombination progressively populated islets. RIPCreIrs2KO and NesCreIrs2KO mice displayed hyperphagia, obesity, and increased body length, which suggests altered melanocortin action. POMCCreIrs2KO mice did not display this phenotype. RIPCreIrs2KO and NesCreIrs2KO mice retained leptin sensitivity, which suggests that CNS Irs2 pathways are not required for leptin action. NesCreIrs2KO and POMCCreIrs2KO mice did not display reduced β cell mass, but NesCreIrs2KO mice displayed mild abnormalities of glucose homeostasis. RIPCre neurons did not express POMC or neuropeptide Y. Insulin and a melanocortin agonist depolarized RIPCre neurons, whereas leptin was ineffective. Insulin hyperpolarized and leptin depolarized POMC neurons. Our findings demonstrate a critical role for IRS2 in β cell and hypothalamic function and provide insights into the role of RIPCre neurons, a distinct hypothalamic neuronal population, in growth and energy homeostasis. PMID:15841180

  1. Defective regulation of POMC precedes hypothalamic inflammation in diet-induced obesity

    PubMed Central

    Souza, Gabriela F. P.; Solon, Carina; Nascimento, Lucas F.; De-Lima-Junior, Jose C.; Nogueira, Guilherme; Moura, Rodrigo; Rocha, Guilherme Z.; Fioravante, Milena; Bobbo, Vanessa; Morari, Joseane; Razolli, Daniela; Araujo, Eliana P.; Velloso, Licio A.

    2016-01-01

    Obesity is the result of a long-term positive energy balance in which caloric intake overrides energy expenditure. This anabolic state results from the defective activity of hypothalamic neurons involved in the sensing and response to adiposity. However, it is currently unknown what the earliest obesity-linked hypothalamic defect is and how it orchestrates the energy imbalance present in obesity. Using an outbred model of diet-induced obesity we show that defective regulation of hypothalamic POMC is the earliest marker distinguishing obesity-prone from obesity-resistant mice. The early inhibition of hypothalamic POMC was sufficient to transform obesity-resistant in obesity-prone mice. In addition, the post-prandial change in the blood level of β-endorphin, a POMC-derived peptide, correlates with body mass gain in rodents and humans. Taken together, these results suggest that defective regulation of POMC expression, which leads to a change of β-endorphin levels, is the earliest hypothalamic defect leading to obesity. PMID:27373214

  2. Nutrient-sensing hypothalamic TXNIP links nutrient excess to energy imbalance in mice.

    PubMed

    Blouet, Clémence; Schwartz, Gary J

    2011-04-20

    Nutrient excess in obesity and diabetes is emerging as a common putative cause for multiple deleterious effects across diverse cell types, responsible for a variety of metabolic dysfunctions. The hypothalamus is acknowledged as an important regulator of whole-body energy homeostasis, through both detection of nutrient availability and coordination of effectors that determine nutrient intake and utilization, thus preventing cellular and whole-body nutrient excess. However, the mechanisms underlying hypothalamic nutrient detection and its impact on peripheral nutrient utilization remain poorly understood. Recent data suggest a role for thioredoxin-interacting protein (TXNIP) as a molecular nutrient sensor important in the regulation of energy metabolism, but the role of hypothalamic TXNIP in the regulation of energy balance has not been evaluated. Here we show in mice that TXNIP is expressed in nutrient-sensing neurons of the mediobasal hypothalamus, responds to hormonal and nutrient signals, and regulates adipose tissue metabolism, fuel partitioning, and glucose homeostasis. Hypothalamic expression of TXNIP is induced by acute nutrient excess and in mouse models of obesity and diabetes, and downregulation of mediobasal hypothalamic TXNIP expression prevents diet-induced obesity and insulin resistance. Thus, mediobasal hypothalamic TXNIP plays a critical role in nutrient sensing and the regulation of fuel utilization.

  3. Hypothalamic astroglial connexins are required for brain glucose sensing-induced insulin secretion.

    PubMed

    Allard, Camille; Carneiro, Lionel; Grall, Sylvie; Cline, Brandon H; Fioramonti, Xavier; Chrétien, Chloé; Baba-Aissa, Fawzia; Giaume, Christian; Pénicaud, Luc; Leloup, Corinne

    2014-02-01

    Hypothalamic glucose detection participates in maintaining glycemic balance, food intake, and thermogenesis. Although hypothalamic neurons are the executive cells involved in these responses, there is increasing evidence that astrocytes participate in glucose sensing (GS); however, it is unknown whether astroglial networking is required for glucose sensitivity. Astroglial connexins 30 and 43 (Cx30 and Cx43) form hexameric channels, which are apposed in gap junctions, allowing for the intercellular transfer of small molecules such as glucose throughout the astroglial networks. Here, we hypothesized that hypothalamic glucose sensitivity requires these connexins. First, we showed that both Cxs are enriched in the rat hypothalamus, with highly concentrated Cx43 expression around blood vessels of the mediobasal hypothalamus (MBH). Both fasting and high glycemic levels rapidly altered the protein levels of MBH astroglial connexins, suggesting cross talk within the MBH between glycemic status and the connexins' ability to dispatch glucose. Finally, the inhibition of MBH Cx43 (by transient RNA interference) attenuated hypothalamic glucose sensitivity in rats, which was demonstrated by a pronounced decreased insulin secretion in response to a brain glucose challenge. These results illustrate that astroglial connexins contribute to hypothalamic GS.

  4. Gene array analysis of embryonic- versus adult-derived hypothalamic NPY-expressing cell lines.

    PubMed

    Dhillon, Sandeep S; Gingerich, Sarah; Virtanen, Carl; Belsham, Denise D

    2012-07-06

    Few studies have utilized microarray analysis to understand the genome wide changes involved in the development of the hypothalamus despite its overall importance to basic physiology. Gene expression profiling of immortalized, clonal hypothalamic neurons, embryonic-derived mHypoE-46 and adult-derived mHypoA-2/12, reveals that the expression of 1225 probes was significantly changed between the two neuronal models. Further comparison of the gene expression profiles identified two categories of genes that were confirmed with qRT-PCR: (i) genes implicated in the Wnt signaling pathway; and (ii) transcription factors previously implicated in the development of the central nervous system. Yet, functional analysis of the two cell lines, including hormonal responses and secretion, indicate that they are comparable despite their developmental origin. This study provides a comprehensive analysis of embryonic- and adult-derived hypothalamic neuronal cell models that both express neuropeptide Y, and identifies novel genes as candidates for mediating the development of specific hypothalamic neurons. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  5. Inhibition of hypothalamic MCT1 expression increases food intake and alters orexigenic and anorexigenic neuropeptide expression

    PubMed Central

    Elizondo-Vega, Roberto; Cortés-Campos, Christian; Barahona, María José; Carril, Claudio; Ordenes, Patricio; Salgado, Magdiel; Oyarce, Karina; García-Robles, María de los Angeles

    2016-01-01

    Hypothalamic glucosensing, which involves the detection of glucose concentration changes by brain cells and subsequent release of orexigenic or anorexigenic neuropeptides, is a crucial process that regulates feeding behavior. Arcuate nucleus (AN) neurons are classically thought to be responsible for hypothalamic glucosensing through a direct sensing mechanism; however, recent data has shown a metabolic interaction between tanycytes and AN neurons through lactate that may also be contributing to this process. Monocarboxylate transporter 1 (MCT1) is the main isoform expressed by tanycytes, which could facilitate lactate release to hypothalamic AN neurons. We hypothesize that MCT1 inhibition could alter the metabolic coupling between tanycytes and AN neurons, altering feeding behavior. To test this, we inhibited MCT1 expression using adenovirus-mediated transfection of a shRNA into the third ventricle, transducing ependymal wall cells and tanycytes. Neuropeptide expression and feeding behavior were measured in MCT1-inhibited animals after intracerebroventricular glucose administration following a fasting period. Results showed a loss in glucose regulation of orexigenic neuropeptides and an abnormal expression of anorexigenic neuropeptides in response to fasting. This was accompanied by an increase in food intake and in body weight gain. Taken together, these results indicate that MCT1 expression in tanycytes plays a role in feeding behavior regulation. PMID:27677351

  6. Hypothalamic control of bone metabolism.

    PubMed

    Sharan, Kunal; Yadav, Vijay K

    2014-10-01

    Bones are structures in vertebrates that provide support to organs, protect soft organs, and give them shape and defined features, functions that are essential for their survival. To perform these functions, bones are constantly renewed throughout life. The process through which bones are renewed is known as bone remodeling, an energy demanding process sensitive to changes in energy homeostasis of the organism. A close interplay takes place between the diversity of nutritional cues and metabolic signals with different elements of the hypothalamic circuits to co-ordinate energy metabolism with the regulation of bone mass. In this review, we focus on how mouse and human genetics have elucidated the roles of hormonal signals and neural circuits that originate in, or impinge on, the hypothalamus in the regulation of bone mass. This will help to understand the mechanisms whereby regulation of bone is gated and dynamically regulated by the hypothalamus.

  7. Molecular Approach to Hypothalamic Rhythms

    DTIC Science & Technology

    1994-03-14

    in vitro to Targeted Cloning Strategy for reset or phase shift circadian rhythms of neuronal G Protein-Coupled Receptors activity in the SCN (Prosser...Kozak, M. (1984). Compilation and analysis of sequences up- nabe, S. (1992). Phase - resetting effect of 8-OH-DPAT, a seroto- Neuron 458 ninA receptor...JR, Lohse MJ, Kobilka BK. Caron MJ and Medanic M and Gillette MU (1992) Serotonin regulates the Lefkowitz. RJ (1988) The genomic clone G-21 which phase

  8. Nutritional programming affects hypothalamic organization and early response to leptin.

    PubMed

    Coupé, Bérengère; Amarger, Valérie; Grit, Isabelle; Benani, Alexandre; Parnet, Patricia

    2010-02-01

    Nutritional programming, taking place in utero or early after birth, is closely linked with metabolic and appetite disorders in adulthood. Following the hypothesis that nutritional programming impacts hypothalamic neuronal organization, we report on discrepancies of multiple molecular and cellular early events that take place in the hypothalamus of rats submitted to intrauterine growth restriction (IUGR). Expression screening performed on hypothalami from IUGR rats at birth and at postnatal d 12 identified changes in gene expression of neurodevelopmental process (cell differentiation and cytoskeleton organization). Additionally, a slight reduction of agouti-related protein and a strong reduction of alpha-MSH-immunoreactive efferent fibers were demonstrated in the paraventricular nucleus of IUGR rats. Rapid catch-up growth of IUGR rats, 5 d after birth, had a positive effect on neurodevelopmental factors and on neuronal projections emanating from the arcuate nucleus. The molecular and cellular anomalies detected in IUGR rats can be related to the reduced and delayed plasma leptin surge from d 0-16 when compared with control and IUGR rats with catch-up growth. However, the ability of leptin to activate intracellular signaling in arcuate nucleus neurons was not reduced in IUGR rats. Other mechanism such as epigenetic regulation of the major appetite-regulating neuropeptides genes was analyzed in parallel with their mRNA expression during postnatal development. This study reveals the importance of an early catch-up growth that reduces abnormal organization of hypothalamic pathways involved in energy homeostasis, whereas protein restriction, maintained during postnatal development leads to an important immaturity of the hypothalamus.

  9. The hypothalamic peptidergic system, hypocretin/orexin and vigilance control.

    PubMed

    Nishino, Seiji

    2007-06-01

    Using forward and reverse genetics, the genes (hypocretin/orexin ligand and its receptor) involved in the pathogenesis of the sleep disorder, narcolepsy, in animals, have been identified. Mutations in hypocretin related-genes are extremely rare in humans, but hypocretin-ligand deficiency is found in most narcolepsy-cataplexy cases. Hypocretin deficiency in humans can be clinically detected by CSF hypocretin-1 measures, and undetectably low CSF hypocretin-1 is now included in the revised international diagnostic criteria of narcolepsy. Since hypocretin-ligand deficiency is the major pathophysiology in human narcolepsy, hypocretin replacements (using hypocretin agonists or gene therapy) are promising future therapeutic options. New insights into the roles of hypocretin system on sleep physiology have also rapidly increased. Hypocretins are involved in various fundamental hypothalamic functions such as feeding, energy homeostasis and neuroendocrine regulation. Hypocretin neurons project to most ascending arousal systems (including monoaminergic and cholinergic systems), and generally exhibit excitatory inputs. Together with the recent finding of the sleep promoting system in the hypothalamus (especially in the GABA/galanin ventrolateral preoptic area which exhibits inhibitory inputs to these ascending systems), the hypothalamus is now recognized as the most important brain site for the sleep switch, and other peptidergic systems may also participate in this regulation. Meanwhile, narcolepsy now appears to be a more complex condition than previously thought. The pathophysiology of the disease is involved in the abnormalities of sleep and various hypothalamic functions due to hypocretin deficiency, such as the changes in energy homeostasis, stress reactions and rewarding. Narcolepsy is therefore, an important model to study the link between sleep regulation and other fundamental hypothalamic functions.

  10. Hypothalamic neuropeptide systems and anticipatory weight change in Siberian hamsters.

    PubMed

    Adam, C L; Mercer, J G

    2001-01-01

    Seasonal animals are able both to programme changes in body weight in response to annual changes in photoperiod (anticipatory regulation) and to correct changes in body weight caused by imposed energetic demand (compensatory regulation). Experimental evidence from the Siberian hamster suggests that seasonally appropriate body weight is continually reset according to photoperiodic history, even when actual body weight is driven away from this target weight by manipulation of energy intake. These characteristics constitute the "sliding set point" of seasonal body weight regulation. To define the mechanisms and molecules underlying anticipatory body weight regulation, we are investigating the involvement of hypothalamic systems with an established role in the compensatory defence of body weight. Weight loss or restricted growth induced by short days (SD) results in low circulating leptin compared with long day (LD) controls. However, this chronic low leptin signal is read differently from acute low leptin resulting from food deprivation; leptin receptor gene expression in the hypothalamic arcuate nucleus (ARC) is lower in SD, whereas food deprivation increases expression levels, suggesting changes in sensitivity to leptin feedback. SD alterations in mRNA levels for a number of hypothalamic neuropeptide and receptor genes appear counter-intuitive for a SD body weight trajectory. However, early increases in ARC cocaine-and amphetamine-regulated transcript (CART) gene expression in SDs could be involved in driving body weight loss or growth restriction. The sites of photoperiod interaction with energy balance neuronal circuitry and the neurochemical encoding of body weight set point require full characterisation. Study of anticipatory regulation in seasonal animals offers new insight into body weight regulation across mammalian species, including man.

  11. Projections from the Subfornical Region of the Lateral Hypothalamic Area

    PubMed Central

    GOTO, MARINA; CANTERAS, NEWTON S.; BURNS, GULLY; SWANSON, LARRY W.

    2010-01-01

    The L-shaped anterior zone of the lateral hypothalamic area’s subfornical region (LHAsfa) is delineated by a pontine nucleus incertus input. Function evidence suggests the subfornical region and nucleus incertus modulate foraging and defensive behaviors, although subfornical region connections are poorly understood. A high resolution Phaseolus vulgaris-leucoagglutinin (PHAL) structural analysis is presented here of the LHAsfa neuron population’s overall axonal projection pattern. The strongest LHAsfa targets are in the interbrain and cerebral hemisphere. The former include inputs to anterior hypothalamic nucleus, dorsomedial part of the ventromedial nucleus, and ventral region of the dorsal premammillary nucleus (defensive behavior control system components), and to lateral habenula and dorsal region of the dorsal premammillary nucleus (foraging behavior control system components). The latter include massive inputs to lateral and medial septal nuclei (septo-hippocampal system components), and inputs to bed nuclei of the stria terminalis posterior division related to the defensive behavior system, intercalated amygdalar nucleus (projecting to central amygdalar nucleus), and posterior part of the basomedial amygdalar nucleus. LHAsfa vertical and horizontal limb basic projection patterns are similar, although each preferentially innervates certain terminal fields. Lateral hypothalamic area regions immediately medial, lateral, and caudal to the LHAsfa each generate quite distinct projection patterns. Combined with previous evidence that major sources LHAsfa neural inputs include the parabrachial nucleus (nociceptive information), defensive and foraging behavior system components, and the septo-hippocampal system, the present results suggest that the LHAsfa helps match adaptive behavioral responses (either defensive or foraging) to current internal motivational status and external environmental conditions. PMID:16261534

  12. Lateral Hypothalamic Control of the Ventral Tegmental Area: Reward Evaluation and the Driving of Motivated Behavior.