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Sample records for ghrelin induces fos

  1. Activation of c-fos expression in the rat inferior olivary nucleus by ghrelin.

    PubMed

    Zhang, Weizhen; Lin, Theodore R; Hu, Yuexian; Fan, Yongyi; Zhao, Lili; Mulholland, Michael W

    2003-12-26

    Ghrelin, a novel 28-amino-acid hormone secreted by gastric oxyntic glands, stimulates food intake and induces adiposity. We examined whether ghrelin activates the inferior olivary nucleus. Systemic administration of ghrelin (37 nmol/kg) induced the expression of c-fos immunoreactivity in inferior olive neurons (n=6 rats). The number of neurons containing c-fos staining was significantly increased in the ghrelin-treated rats (65+/-14 vs.11+/-6 positive neurons, n=5). No significant difference in c-fos-positive neurons was observed between left (32+/-5) and right (33+/-6) inferior olivary nuclei. The number of c-fos-positive neurons in rats with bilateral vagotomy was not significantly different from those with intact vagal nerves. The present study demonstrates that ghrelin induces c-fos expression in inferior olivary nucleus via a central mechanism.

  2. Anti-ghrelin Spiegelmer inhibits exogenous ghrelin-induced increases in food intake, hoarding, and neural activation, but not food deprivation-induced increases

    PubMed Central

    Teubner, Brett J. W.

    2013-01-01

    Circulating concentrations of the stomach-derived “hunger-peptide” ghrelin increase in direct proportion to the time since the last meal. Exogenous ghrelin also increases food intake in rodents and humans, suggesting ghrelin may increase post-fast ingestive behaviors. Food intake after food deprivation is increased by laboratory rats and mice, but not by humans (despite dogma to the contrary) or by Siberian hamsters; instead, humans and Siberian hamsters increase food hoarding, suggesting the latter as a model of fasting-induced changes in human ingestive behavior. Exogenous ghrelin markedly increases food hoarding by ad libitum-fed Siberian hamsters similarly to that after food deprivation, indicating sufficiency. Here, we tested the necessity of ghrelin to increase food foraging, food hoarding, and food intake, and neural activation [c-Fos immunoreactivity (c-Fos-ir)] using anti-ghrelin Spiegelmer NOX-B11–2 (SPM), an l-oligonucleotide that specifically binds active ghrelin, inhibiting peptide-receptor interaction. SPM blocked exogenous ghrelin-induced increases in food hoarding the first 2 days after injection, and foraging and food intake at 1–2 h and 2–4 h, respectively, and inhibited hypothalamic c-Fos-ir. SPM given every 24 h across 48-h food deprivation inconsistently inhibited food hoarding after refeeding and c-Fos-ir, similarly to inabilities to do so in laboratory rats and mice. These results suggest that ghrelin may not be necessary for food deprivation-induced foraging and hoarding and neural activation. A possible compensatory response, however, may underlie these findings because SPM treatment led to marked increases in circulating ghrelin concentrations. Collectively, these results show that SPM can block exogenous ghrelin-induced ingestive behaviors, but the necessity of ghrelin for food deprivation-induced ingestive behaviors remains unclear. PMID:23804279

  3. Anti-ghrelin Spiegelmer inhibits exogenous ghrelin-induced increases in food intake, hoarding, and neural activation, but not food deprivation-induced increases.

    PubMed

    Teubner, Brett J W; Bartness, Timothy J

    2013-08-15

    Circulating concentrations of the stomach-derived "hunger-peptide" ghrelin increase in direct proportion to the time since the last meal. Exogenous ghrelin also increases food intake in rodents and humans, suggesting ghrelin may increase post-fast ingestive behaviors. Food intake after food deprivation is increased by laboratory rats and mice, but not by humans (despite dogma to the contrary) or by Siberian hamsters; instead, humans and Siberian hamsters increase food hoarding, suggesting the latter as a model of fasting-induced changes in human ingestive behavior. Exogenous ghrelin markedly increases food hoarding by ad libitum-fed Siberian hamsters similarly to that after food deprivation, indicating sufficiency. Here, we tested the necessity of ghrelin to increase food foraging, food hoarding, and food intake, and neural activation [c-Fos immunoreactivity (c-Fos-ir)] using anti-ghrelin Spiegelmer NOX-B11-2 (SPM), an l-oligonucleotide that specifically binds active ghrelin, inhibiting peptide-receptor interaction. SPM blocked exogenous ghrelin-induced increases in food hoarding the first 2 days after injection, and foraging and food intake at 1-2 h and 2-4 h, respectively, and inhibited hypothalamic c-Fos-ir. SPM given every 24 h across 48-h food deprivation inconsistently inhibited food hoarding after refeeding and c-Fos-ir, similarly to inabilities to do so in laboratory rats and mice. These results suggest that ghrelin may not be necessary for food deprivation-induced foraging and hoarding and neural activation. A possible compensatory response, however, may underlie these findings because SPM treatment led to marked increases in circulating ghrelin concentrations. Collectively, these results show that SPM can block exogenous ghrelin-induced ingestive behaviors, but the necessity of ghrelin for food deprivation-induced ingestive behaviors remains unclear.

  4. Actions of Agonists and Antagonists of the ghrelin/GHS-R Pathway on GH Secretion, Appetite, and cFos Activity.

    PubMed

    Hassouna, Rim; Labarthe, Alexandra; Zizzari, Philippe; Videau, Catherine; Culler, Michael; Epelbaum, Jacques; Tolle, Virginie

    2013-01-01

    The stimulatory effects of ghrelin, a 28-AA acylated peptide originally isolated from stomach, on growth hormone (GH) secretion and feeding are exclusively mediated through the growth hormone secretagogue 1a receptor (GHS-R1a), the only ghrelin receptor described so far. Several GHS-R1a agonists and antagonists have been developed to treat metabolic or nutritional disorders but their mechanisms of action in the central nervous system remain poorly understood. In the present study, we compared the activity of BIM-28163, a GHS-R1a antagonist, and of several agonists, including native ghrelin and the potent synthetic agonist, BIM-28131, to modulate food intake, GH secretion, and cFos activity in arcuate nucleus (ArcN), nucleus tractus solitarius (NTS), and area postrema (AP) in wild-type and NPY-GFP mice. BIM-28131 was as effective as ghrelin in stimulating GH secretion, but more active than ghrelin in inducing feeding. It stimulated cFos activity similarly to ghrelin in the NTS and AP but was more powerful in the ArcN, suggesting that the super-agonist activity of BIM-28131 is mostly mediated in the ArcN. BIM-28163 antagonized ghrelin-induced GH secretion but not ghrelin-induced food consumption and cFos activation, rather it stimulated food intake and cFos activity without affecting GH secretion. The level of cFos activation was dependent on the region considered: BIM-28163 was as active as ghrelin in the NTS, but less active in the ArcN and AP. All compounds also induced cFos immunoreactivity in ArcN NPY neurons but BIM-28131 was the most active. In conclusion, these data demonstrate that two peptide analogs of ghrelin, BIM-28163, and BIM-28131, are powerful stimulators of appetite in mice, acting through pathways and key brain regions involved in the control of appetite that are only partially superimposable from those activated by ghrelin. A better understanding of the molecular pathways activated by these compounds could be useful in devising future therapeutic

  5. Actions of Agonists and Antagonists of the ghrelin/GHS-R Pathway on GH Secretion, Appetite, and cFos Activity

    PubMed Central

    Hassouna, Rim; Labarthe, Alexandra; Zizzari, Philippe; Videau, Catherine; Culler, Michael; Epelbaum, Jacques; Tolle, Virginie

    2012-01-01

    The stimulatory effects of ghrelin, a 28-AA acylated peptide originally isolated from stomach, on growth hormone (GH) secretion and feeding are exclusively mediated through the growth hormone secretagogue 1a receptor (GHS-R1a), the only ghrelin receptor described so far. Several GHS-R1a agonists and antagonists have been developed to treat metabolic or nutritional disorders but their mechanisms of action in the central nervous system remain poorly understood. In the present study, we compared the activity of BIM-28163, a GHS-R1a antagonist, and of several agonists, including native ghrelin and the potent synthetic agonist, BIM-28131, to modulate food intake, GH secretion, and cFos activity in arcuate nucleus (ArcN), nucleus tractus solitarius (NTS), and area postrema (AP) in wild-type and NPY-GFP mice. BIM-28131 was as effective as ghrelin in stimulating GH secretion, but more active than ghrelin in inducing feeding. It stimulated cFos activity similarly to ghrelin in the NTS and AP but was more powerful in the ArcN, suggesting that the super-agonist activity of BIM-28131 is mostly mediated in the ArcN. BIM-28163 antagonized ghrelin-induced GH secretion but not ghrelin-induced food consumption and cFos activation, rather it stimulated food intake and cFos activity without affecting GH secretion. The level of cFos activation was dependent on the region considered: BIM-28163 was as active as ghrelin in the NTS, but less active in the ArcN and AP. All compounds also induced cFos immunoreactivity in ArcN NPY neurons but BIM-28131 was the most active. In conclusion, these data demonstrate that two peptide analogs of ghrelin, BIM-28163, and BIM-28131, are powerful stimulators of appetite in mice, acting through pathways and key brain regions involved in the control of appetite that are only partially superimposable from those activated by ghrelin. A better understanding of the molecular pathways activated by these compounds could be useful in devising future therapeutic

  6. Ghrelin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The gut hormone ghrelin was discovered in 1999. In the last 15 years, ample data have been generated on ghrelin. Bedsides its hallmark function as an appetite stimulator, ghrelin also has many other important functions. In this review, we discussed ghrelin's functions in learning and memory, gut mov...

  7. Cisplatin-induced anorexia and ghrelin.

    PubMed

    Hattori, Tomohisa; Yakabi, Koji; Takeda, Hiroshi

    2013-01-01

    Cisplatin, a formidable anticancer treatment, is used for several varieties of cancer. There are, however, many cases in which treatment must be abandoned due to a decrease in the patient's quality of life from loss of appetite associated with vomiting and nausea. There is a moderate degree of improvement in prevention of cisplatin-induced nausea and vomiting when serotonin (5-HT) 3 receptor antagonists, neurokinin 1 receptor antagonists, and steroids-either alone or in combination-are administered. The mechanism of action for anorexia, which continues during or after treatment, is, however, still unclear. This anorexia is, similar to the onset of vomiting and nausea, caused by the action of large amounts of 5-HT released as a result of cisplatin administration on tissue 5-HT receptors. Among the 5-HT receptors, the activation of 5-HT2b and 5-HT2c receptors, in particular, seems to play a major role in cisplatin-induced anorexia. Following activation of these two receptors, there is reduced gastric and hypothalamic secretion of the appetite-stimulating hormone ghrelin. There is ample evidence of the usefulness of exogenous ghrelin, synthetic ghrelin agonists, and the endogenous ghrelin signal-enhancer rikkunshito, which are expected to play significant roles in the clinical treatment and prevention of anorexia in future.

  8. Divergent neuronal circuitries underlying acute orexigenic effects of peripheral or central ghrelin: critical role of brain accessibility.

    PubMed

    Cabral, A; Valdivia, S; Fernandez, G; Reynaldo, M; Perello, M

    2014-08-01

    Ghrelin is an octanoylated peptide hormone that potently and rapidly increases food intake. The orexigenic action of ghrelin involves the hypothalamic arcuate nucleus (ARC), which is accessible to plasma ghrelin and expresses high levels of the ghrelin receptor. Local administration of ghrelin in a variety of other brain nuclei also increases food intake. It is currently unclear, however, whether these non-ARC ghrelin brain targets are impacted by physiological increases of plasma ghrelin. Thus, the present study aimed to clarify which ghrelin brain targets participate in the short-term orexigenic actions of ghrelin. First, c-Fos induction into mouse brains centrally or peripherally treated with ghrelin was analysed. It was confirmed that peripherally administered ghrelin dose-dependently increases food intake and mainly activates c-Fos in ARC neurones. By contrast, centrally administered ghrelin activates c-Fos in a larger number of brain nuclei. To determine which nuclei are directly accessible to ghrelin, mice were centrally or peripherally injected with a fluorescent ghrelin tracer. It was found that peripherally injected tracer mainly accesses the ARC, whereas centrally injected tracer reaches most brain areas known to express ghrelin receptors. Subsequently, the effects of ghrelin were tested in ARC-ablated mice and it was found that these mice failed to increase food intake in response to peripherally administered ghrelin but fully responded to centrally administered ghrelin. ARC-ablated mice showed patterns of ghrelin-induced c-Fos expression similar to those seen in control mice with the exception of the ARC, where no c-Fos was found. Thus, peripheral ghrelin mainly accesses the ARC, which is required for the orexigenic effects of the hormone. Central ghrelin accesses a variety of nuclei, which can mediate the orexigenic effects of the hormone, even in the absence of an intact ARC.

  9. Des-acyl ghrelin attenuates pilocarpine-induced limbic seizures via the ghrelin receptor and not the orexin pathway.

    PubMed

    Portelli, Jeanelle; Coppens, Jessica; Demuyser, Thomas; Smolders, Ilse

    2015-06-01

    Des-acyl ghrelin, widely accepted to work independently of the ghrelin receptor, is increasingly being implicated in a number of biological functions. The involvement of des-acyl ghrelin in epilepsy has only been recently reported. In this study, apart from unravelling the effect of des-acyl ghrelin on seizure thresholds and seizure severity in two models of pilocarpine-induced seizures, we mainly attempted to unravel its anticonvulsant mechanism of action. Since it was found that des-acyl ghrelin administration affected food intake via the orexin pathway, we first determined whether this pathway was responsible for des-acyl ghrelin's seizure-attenuating properties using the dual orexin receptor antagonist almorexant. We noted that, while des-acyl ghrelin showed dose-dependent anticonvulsant effects against focal pilocarpine-evoked seizures in rats, almorexant did not affect seizure severity and did not reverse des-acyl ghrelin's anticonvulsant effect. Subsequently, to investigate whether the ghrelin receptor was implicated in des-acyl ghrelin's anticonvulsant properties, we tested this peptide in ghrelin receptor deficient mice and wild type mice, all infused with pilocarpine intravenously. Unexpectedly, we found that des-acyl ghrelin significantly elevated seizure thresholds in C57Bl/6 and wild type mice but not in ghrelin receptor knock-out mice. Taken together, our results indicate the involvement of the ghrelin receptor in the anticonvulsant effects of des-acyl ghrelin on pilocarpine-induced seizures. We also show for the first time that dual antagonism of hippocampal orexin receptors does not affect seizure severity.

  10. Ghrelin

    PubMed Central

    Müller, T.D.; Nogueiras, R.; Andermann, M.L.; Andrews, Z.B.; Anker, S.D.; Argente, J.; Batterham, R.L.; Benoit, S.C.; Bowers, C.Y.; Broglio, F.; Casanueva, F.F.; D'Alessio, D.; Depoortere, I.; Geliebter, A.; Ghigo, E.; Cole, P.A.; Cowley, M.; Cummings, D.E.; Dagher, A.; Diano, S.; Dickson, S.L.; Diéguez, C.; Granata, R.; Grill, H.J.; Grove, K.; Habegger, K.M.; Heppner, K.; Heiman, M.L.; Holsen, L.; Holst, B.; Inui, A.; Jansson, J.O.; Kirchner, H.; Korbonits, M.; Laferrère, B.; LeRoux, C.W.; Lopez, M.; Morin, S.; Nakazato, M.; Nass, R.; Perez-Tilve, D.; Pfluger, P.T.; Schwartz, T.W.; Seeley, R.J.; Sleeman, M.; Sun, Y.; Sussel, L.; Tong, J.; Thorner, M.O.; van der Lely, A.J.; van der Ploeg, L.H.T.; Zigman, J.M.; Kojima, M.; Kangawa, K.; Smith, R.G.; Horvath, T.; Tschöp, M.H.

    2015-01-01

    Background The gastrointestinal peptide hormone ghrelin was discovered in 1999 as the endogenous ligand of the growth hormone secretagogue receptor. Increasing evidence supports more complicated and nuanced roles for the hormone, which go beyond the regulation of systemic energy metabolism. Scope of review In this review, we discuss the diverse biological functions of ghrelin, the regulation of its secretion, and address questions that still remain 15 years after its discovery. Major conclusions In recent years, ghrelin has been found to have a plethora of central and peripheral actions in distinct areas including learning and memory, gut motility and gastric acid secretion, sleep/wake rhythm, reward seeking behavior, taste sensation and glucose metabolism. PMID:26042199

  11. GOAT induced ghrelin acylation regulates hedonic feeding.

    PubMed

    Davis, J F; Perello, M; Choi, D L; Magrisso, I J; Kirchner, H; Pfluger, P T; Tschoep, M; Zigman, J M; Benoit, S C

    2012-11-01

    Ghrelin is an orexigenic hormone that regulates homeostatic and reward-related feeding behavior. Recent evidence indicates that acylation of ghrelin by the gut enzyme ghrelin O-acyl transferase (GOAT) is necessary to render ghrelin maximally active within its target tissues. Here we tested the hypothesis that GOAT activity modulates food motivation and food hedonics using behavioral pharmacology and mutant mice deficient for GOAT and the ghrelin receptor (GHSR). We evaluated operant responding following pharmacological administration of acyl-ghrelin and assessed the necessity of endogenous GOAT activity for operant responding in GOAT and GHSR-null mice. Hedonic-based feeding behavior also was examined in GOAT-KO and GHSR-null mice using a "Dessert Effect" protocol in which the intake of a palatable high fat diet "dessert" was assessed in calorically-sated mice. Pharmacological administration of acyl-ghrelin augmented operant responding; notably, this effect was dependent on intact GHSR signaling. GOAT-KO mice displayed attenuated operant responding and decreased hedonic feeding relative to controls. These behavioral results correlated with decreased expression of the orexin-1 receptor in reward-related brain regions in GOAT-KO mice. In summary, the ability of ghrelin to stimulate food motivation is dependent on intact GHSR signaling and modified by endogenous GOAT activity. Furthermore, GOAT activity is required for hedonic feeding behavior, an effect potentially mediated by forebrain orexin signaling. These data highlight the significance of the GOAT-ghrelin system for the mediation of food motivation and hedonic feeding.

  12. Ghrelin knockout mice show decreased voluntary alcohol consumption and reduced ethanol-induced conditioned place preference.

    PubMed

    Bahi, Amine; Tolle, Virginie; Fehrentz, Jean-Alain; Brunel, Luc; Martinez, Jean; Tomasetto, Catherine-Laure; Karam, Sherif M

    2013-05-01

    Recent work suggests that stomach-derived hormone ghrelin receptor (GHS-R1A) antagonism may reduce motivational aspects of ethanol intake. In the current study we hypothesized that the endogenous GHS-R1A agonist ghrelin modulates alcohol reward mechanisms. For this purpose ethanol-induced conditioned place preference (CPP), ethanol-induced locomotor stimulation and voluntary ethanol consumption in a two-bottle choice drinking paradigm were examined under conditions where ghrelin and its receptor were blocked, either using ghrelin knockout (KO) mice or the specific ghrelin receptor (GHS-R1A) antagonist "JMV2959". We showed that ghrelin KO mice displayed lower ethanol-induced CPP than their wild-type (WT) littermates. Consistently, when injected during CPP-acquisition, JMV2959 reduced CPP-expression in C57BL/6 mice. In addition, ethanol-induced locomotor stimulation was lower in ghrelin KO mice. Moreover, GHS-R1A blockade, using JMV2959, reduced alcohol-stimulated locomotion only in WT but not in ghrelin KO mice. When alcohol consumption and preference were assessed using the two-bottle choice test, both genetic deletion of ghrelin and pharmacological antagonism of the GHS-R1A (JMV2959) reduced voluntary alcohol consumption and preference. Finally, JMV2959-induced reduction of alcohol intake was only observed in WT but not in ghrelin KO mice. Taken together, these results suggest that ghrelin neurotransmission is necessary for the stimulatory effect of ethanol to occur, whereas lack of ghrelin leads to changes that reduce the voluntary intake as well as conditioned reward by ethanol. Our findings reveal a major, novel role for ghrelin in mediating ethanol behavior, and add to growing evidence that ghrelin is a key mediator of the effects of multiple abused drugs. PMID:23428971

  13. Ghrelin knockout mice show decreased voluntary alcohol consumption and reduced ethanol-induced conditioned place preference.

    PubMed

    Bahi, Amine; Tolle, Virginie; Fehrentz, Jean-Alain; Brunel, Luc; Martinez, Jean; Tomasetto, Catherine-Laure; Karam, Sherif M

    2013-05-01

    Recent work suggests that stomach-derived hormone ghrelin receptor (GHS-R1A) antagonism may reduce motivational aspects of ethanol intake. In the current study we hypothesized that the endogenous GHS-R1A agonist ghrelin modulates alcohol reward mechanisms. For this purpose ethanol-induced conditioned place preference (CPP), ethanol-induced locomotor stimulation and voluntary ethanol consumption in a two-bottle choice drinking paradigm were examined under conditions where ghrelin and its receptor were blocked, either using ghrelin knockout (KO) mice or the specific ghrelin receptor (GHS-R1A) antagonist "JMV2959". We showed that ghrelin KO mice displayed lower ethanol-induced CPP than their wild-type (WT) littermates. Consistently, when injected during CPP-acquisition, JMV2959 reduced CPP-expression in C57BL/6 mice. In addition, ethanol-induced locomotor stimulation was lower in ghrelin KO mice. Moreover, GHS-R1A blockade, using JMV2959, reduced alcohol-stimulated locomotion only in WT but not in ghrelin KO mice. When alcohol consumption and preference were assessed using the two-bottle choice test, both genetic deletion of ghrelin and pharmacological antagonism of the GHS-R1A (JMV2959) reduced voluntary alcohol consumption and preference. Finally, JMV2959-induced reduction of alcohol intake was only observed in WT but not in ghrelin KO mice. Taken together, these results suggest that ghrelin neurotransmission is necessary for the stimulatory effect of ethanol to occur, whereas lack of ghrelin leads to changes that reduce the voluntary intake as well as conditioned reward by ethanol. Our findings reveal a major, novel role for ghrelin in mediating ethanol behavior, and add to growing evidence that ghrelin is a key mediator of the effects of multiple abused drugs.

  14. Anti‐ghrelin Spiegelmer NOX‐B11 inhibits neurostimulatory and orexigenic effects of peripheral ghrelin in rats

    PubMed Central

    Kobelt, P; Helmling, S; Stengel, A; Wlotzka, B; Andresen, V; Klapp, B F; Wiedenmann, B; Klussmann, S; Mönnikes, H

    2006-01-01

    Background and aims Ghrelin, the natural ligand of the growth hormone secretagogue receptor 1a, is the most powerful peripherally active orexigenic agent known. In rodents, ghrelin administration stimulates growth hormone release, food intake, and adiposity. Because of these effects, blocking of ghrelin has been widely discussed as a potential treatment for obesity. Spiegelmer NOX‐B11 is a synthetic l‐oligonucleotide, which was previously shown to bind ghrelin. We examined the effects of NOX‐B11 on ghrelin induced neuronal activation and food intake in non‐fasted rats. Methods Animals received various doses of NOX‐B11, inactive control Spiegelmer, or vehicle intravenously. Ghrelin or vehicle was administered intraperitoneally 12 hours later and food intake was measured over four hours. Neuronal activation was assessed as c‐Fos‐like immunoreactivity in the arcuate nucleus. Results Treatment with NOX‐B11 30 nmol suppressed ghrelin induced c‐Fos‐like immunoreactivity in the arcuate nucleus and blocked the ghrelin induced increase in food intake within the first half hour after ghrelin injection (mean 1.13 (SEM 0.59) g/kg body weight; 4.94 (0.63) g/kg body weight versus 0.58 (0.58) g/kg body weight; p<0.0001). Treatment with NOX‐B11 1 nmol or control Spiegelmer had no effect whereas treatment with NOX‐B11 10 nmol showed an intermediate effect on ghrelin induced food intake. Conclusions Spiegelmer NOX‐B11 suppresses ghrelin induced food intake and c‐Fos induction in the arcuate nucleus in rats. The use of an anti‐ghrelin Spiegelmer could be an innovative new approach to inhibit the biological action of circulating ghrelin. This may be of particular relevance to conditions associated with elevated plasma ghrelin, such as the Prader‐Willi syndrome. PMID:15994217

  15. Sexual reward induces Fos in the cerebellum of female rats.

    PubMed

    Paredes-Ramos, Pedro; Pfaus, James G; Miquel, Marta; Manzo, Jorge; Coria-Avila, Genaro A

    2011-02-01

    The cerebellum is generally considered a neural structure specialized in motor control and recent imaging data suggest its role in sexual behavior. Herein, we analyzed the pattern of Fos immunoreactivity (Fos-IR) in the cerebellum of female rats allowed to pace copulation as a model of sexual reward in rodents. Ovariectomized, hormone-primed, sexually naïve females formed three groups: Pacing, Nonpacing and Control. Pacing occurred in arenas bisected by a middle divider that allowed only females to control sexual interaction with stud males. For nonpaced copulation the divider was removed, and control females were allowed to pace in chambers without a male. Fos-IR was analyzed in granule and Purkinje layers of the 10 cerebellar lobules, and in the fastigial deep nucleus (FDN). Results indicated that Pacing females expressed more Fos-IR in the granule layer compared to Nonpacing and Controls, and more Fos-IR in Purkinje compared to Nonpacing. No differences were observed in FDN. Such response cannot be explained with motor activity because Pacing females moved less in general. We discuss the role of the cerebellum and its connections in the sexual reward induced by pacing. PMID:21059365

  16. Reduced ghrelin production induced anorexia after rat gastric ischemia and reperfusion.

    PubMed

    Mogami, Sachiko; Suzuki, Hidekazu; Fukuhara, Seiichiro; Matsuzaki, Juntaro; Kangawa, Kenji; Hibi, Toshifumi

    2012-02-01

    The gastrointestinal (GI) tract is one of the most susceptible organs to ischemia. We previously reported altered gastric motility after gastric ischemia and reperfusion (I/R). However, there have also been few reports of alterations in the eating behavior after gastric I/R. Ghrelin is a GI peptide that stimulates food intake and GI motility. Although ghrelin itself has been demonstrated to attenuate the mucosal injuries induced by gastric I/R, the endogenous ghrelin dynamics after I/R has not yet been elucidated. The present study was designed to investigate the relationship between food intake and the ghrelin dynamics after gastric I/R. Wistar rats were exposed to 80-min gastric ischemia, followed by 12-h or 48-h reperfusion. The food intake, plasma ghrelin levels, gastric preproghrelin mRNA expression levels, and the histological localization of ghrelin-immunoreactive cells were evaluated. The effect of exogenous ghrelin on the food intake after I/R was also examined. Food intake, the plasma ghrelin levels, the count of ghrelin-immunoreactive cells corrected by the percentage areas of the remaining mucosa, and the expression levels of preproghrelin mRNA in the stomach were significantly reduced at 12 h and 48 h after I/R compared with the levels in the sham-operated rats. Intraperitoneal administration of ghrelin significantly reversed the decrease of food intake after I/R. These data show that gastric I/R evoked anorexia with decreased plasma ghrelin levels and ghrelin production, which appears to be attributable to the I/R-induced gastric mucosal injuries. The decrease in the plasma ghrelin levels may have been responsible for the decreased food intake after gastric I/R. PMID:22114115

  17. Insulin suppresses ghrelin-induced calcium signaling in neuropeptide Y neurons of the hypothalamic arcuate nucleus

    PubMed Central

    Maejima, Yuko; Kohno, Daisuke; Iwasaki, Yusaku; Yada, Toshihiko

    2011-01-01

    Neuropeptide Y (NPY) neurons in the hypothalamic arcuate nucleus (ARC) play an important role in feeding regulation. Plasma levels of ghrelin and insulin show reciprocal dynamics before and after meals. We hypothesized that ghrelin and insulin also exert reciprocal effects on ARC NPY neurons. Cytosolic Ca2+ concentration ([Ca2+]i) was measured by fura-2 microfluorometry in single neurons isolated from ARC of adult rats, followed by immunocytochemical identification of NPY neurons. Ghrelin at 10−10 M increased [Ca2+]i in isolated ARC neurons, and co-administration of insulin concentration-dependently suppressed the ghrelin-induced [Ca2+]i increases. Insulin at 10−16 M, 10−14 M, 10−12 M and 10−10 M counteracted ghrelin action in 26%, 41%, 61% and 53% of ghrelin-responsive neurons, respectively, showing a maximal effect at 10−12 M, the estimated postprandial concentration of insulin in the brain. The majority (>70%) of the ghrelin-activated insulin-inhibited neurons were shown to contain NPY. Double-immunohistochemistry revealed that 85% of NPY neurons in ARC express insulin receptors. These data demonstrate that insulin directly interacts with ARC NPY neurons and counteracts ghrelin action. Our results suggest that postprandial increase in plasma insulin/ghrelin ratio and insulin inhibition of ghrelin action on ARC NPY neurons cooperate to effectively inhibit the neuron activity and terminate feeding. PMID:22081645

  18. Central but not systemic administration of ghrelin induces wakefulness in mice.

    PubMed

    Szentirmai, Éva

    2012-01-01

    Ghrelin is a brain-gut peptide hormone widely known for its orexigenic and growth hormone-releasing activities. Findings from our and other laboratories indicate a role of ghrelin in sleep regulation. The effects of exogenous ghrelin on sleep-wake activity in mice are, however, unknown. The aim of the present study was to determine the sleep-modulating effects of ghrelin after central and systemic administrations in mice. Sleep-wake activity after intracerebroventricular (i.c.v.) administration of 0.2, 1 and 5 µg ghrelin and intraperitoneal injections of 40, 100, and 400 µg/kg ghrelin prior to light onset were determined in C57BL/6 mice. In addition, body temperature, motor activity and 1-hour food intake was measured after the systemic injections. Sleep effects of systemic ghrelin (40 and 400 µg/kg) injected before dark onset were also determined. I.c.v. injection of ghrelin increased wakefulness and suppressed non-rapid-eye-movement sleep and electroencephalographic slow-wave activity in the first hour after injections. Rapid-eye-movement sleep was decreased for 2-4 hours after each dose of ghrelin. Sytemic administration of ghrelin did not induce changes in sleep-wake activity in mice at dark or light onset. Motor activity and body temperature remained unaltered and food intake was significantly increased after systemic injections of ghrelin given prior the light period. These findings indicate that the activation of central, but not peripheral, ghrelin-sensitive mechanisms elicits arousal in mice. The results are consistent with the hypothesis that the activation of the hypothalamic neuronal circuit formed by ghrelin, orexin, and neuropeptide Y neurons triggers behavioral sequence characterized by increased wakefulness, motor activity and feeding in nocturnal rodents.

  19. The Anti-apoptotic Effect of Ghrelin on Restraint Stress-Induced Thymus Atrophy in Mice.

    PubMed

    Lee, Jun Ho; Kim, Tae-Jin; Kim, Jie Wan; Yoon, Jeong Seon; Kim, Hyuk Soon; Lee, Kyung-Mi

    2016-08-01

    Thymic atrophy is a complication that results from exposure to many environmental stressors, disease treatments, and microbial challenges. Such acute stress-associated thymic loss can have a dramatic impact on the host's ability to replenish the necessary naïve T cell output to reconstitute the peripheral T cell numbers and repertoire to respond to new antigenic challenges. We have previously reported that treatment with the orexigenic hormone ghrelin results in an increase in the number and proliferation of thymocytes after dexamethasone challenge, suggesting a role for ghrelin in restraint stress-induced thymic involution and cell apoptosis and its potential use as a thymostimulatory agent. In an effort to understand how ghrelin suppresses thymic T cell apoptosis, we have examined the various signaling pathways induced by receptor-specific ghrelin stimulation using a restraint stress mouse model. In this model, stress-induced apoptosis in thymocytes was effectively blocked by ghrelin. Western blot analysis demonstrated that ghrelin prevents the cleavage of pro-apoptotic proteins such as Bim, Caspase-3, and PARP. In addition, ghrelin stimulation activates the Akt and Mitogen-activated protein kinases (MAPK) signaling pathways in a time/dose-dependent manner. Moreover, we also revealed the involvement of the FoxO3a pathway in the phosphorylation of Akt and ERK1/2. Together, these findings suggest that ghrelin inhibits apoptosis by modulating the stress-induced apoptotic signal pathway in the restraint-induced thymic apoptosis. PMID:27574503

  20. The Anti-apoptotic Effect of Ghrelin on Restraint Stress-Induced Thymus Atrophy in Mice

    PubMed Central

    Kim, Tae-Jin; Kim, Jie Wan; Yoon, Jeong Seon; Kim, Hyuk Soon

    2016-01-01

    Thymic atrophy is a complication that results from exposure to many environmental stressors, disease treatments, and microbial challenges. Such acute stress-associated thymic loss can have a dramatic impact on the host's ability to replenish the necessary naïve T cell output to reconstitute the peripheral T cell numbers and repertoire to respond to new antigenic challenges. We have previously reported that treatment with the orexigenic hormone ghrelin results in an increase in the number and proliferation of thymocytes after dexamethasone challenge, suggesting a role for ghrelin in restraint stress-induced thymic involution and cell apoptosis and its potential use as a thymostimulatory agent. In an effort to understand how ghrelin suppresses thymic T cell apoptosis, we have examined the various signaling pathways induced by receptor-specific ghrelin stimulation using a restraint stress mouse model. In this model, stress-induced apoptosis in thymocytes was effectively blocked by ghrelin. Western blot analysis demonstrated that ghrelin prevents the cleavage of pro-apoptotic proteins such as Bim, Caspase-3, and PARP. In addition, ghrelin stimulation activates the Akt and Mitogen-activated protein kinases (MAPK) signaling pathways in a time/dose-dependent manner. Moreover, we also revealed the involvement of the FoxO3a pathway in the phosphorylation of Akt and ERK1/2. Together, these findings suggest that ghrelin inhibits apoptosis by modulating the stress-induced apoptotic signal pathway in the restraint-induced thymic apoptosis. PMID:27574503

  1. Protective effects of ghrelin on cisplatin-induced nephrotoxicity in mice.

    PubMed

    Nojiri, Takashi; Hosoda, Hiroshi; Kimura, Toru; Tokudome, Takeshi; Miura, Koichi; Takabatake, Hiroyuki; Miyazato, Mikiya; Okumura, Meinoshin; Kangawa, Kenji

    2016-08-01

    Cisplatin is a potent chemotherapeutic agent that has activity against malignant tumors. However, cisplatin causes various adverse effects, such as nephrotoxicity, which are associated with high morbidity and mortality. Recent studies have revealed that the mechanism of cisplatin nephrotoxicity includes a robust inflammatory response. Since ghrelin has been shown to have anti-inflammatory properties, we hypothesized that ghrelin might have protective effects against cisplatin nephrotoxicity. Mice were randomly divided into three groups: control, cisplatin with vehicle, and cisplatin with ghrelin. Ghrelin (0.8μg/kg/min via osmotic-pump, subcutaneously) or vehicle administration was started one day before cisplatin injection. At 72h after cisplatin administration (20mg/kg, intraperitoneally), we measured serum blood urea nitrogen and creatinine, urine albumin/creatinine, renal mRNA levels of monocyte chemoattractant protein-1, interleukin-6, tumor necrosis factor-α, interleukin-1β, kidney injury molecule-1, and neutrophil gelatinase-associated lipocalin by real-time polymerase chain reaction, and histological changes. Ghrelin significantly attenuated the increase in serum blood urea nitrogen and creatinine induced by cisplatin. Ghrelin tended to attenuate the increase in urine albumin/creatinine, although not significantly. Cisplatin-induced renal tubular injury and apoptosis were significantly attenuated by ghrelin pretreatment. Consequently, ghrelin significantly attenuated renal mRNA levels of monocyte chemoattractant protein-1, interleukin-6, kidney injury molecule-1, and neutrophil gelatinase-associated lipocalin. In conclusion, ghrelin produces protective effects in cisplatin-induced nephrotoxicity through inhibition of inflammatory reactions. Pretreatment with ghrelin may become a new prophylactic candidate for cisplatin-induced nephrotoxicity. PMID:27298204

  2. Calorie-restricted weight loss reverses high-fat diet-induced ghrelin resistance, which contributes to rebound weight gain in a ghrelin-dependent manner.

    PubMed

    Briggs, Dana I; Lockie, Sarah H; Wu, Qunli; Lemus, Moyra B; Stark, Romana; Andrews, Zane B

    2013-02-01

    Twelve weeks of high-fat diet feeding causes ghrelin resistance in arcuate neuropeptide Y (NPY)/agouti-related protein (AgRP) neurons. In the current study, we investigated whether diet-induced weight loss could restore NPY/AgRP neuronal responsiveness to ghrelin and whether ghrelin mediates rebound weight gain after calorie-restricted (CR) weight loss. Diet-induced obese (DIO) mice were allocated to one of two dietary interventions until they reached the weight of age-matched lean controls. DIO mice received chow diet ad libitum or chow diet with 40% CR. Chow-fed and high-fat-fed mice served as controls. Both dietary interventions normalized body weight, glucose tolerance, and plasma insulin. We show that diet-induced weight loss with CR increases total plasma ghrelin, restores ghrelin sensitivity, and increases hypothalamic NPY and AgRP mRNA expression. We propose that long-term DIO creates a higher body weight set-point and that weight loss induced by CR, as seen in the high-fat CR group, provokes the brain to protect the new higher set-point. This adaptation to weight loss likely contributes to rebound weight gain by increasing peripheral ghrelin concentrations and restoring the function of ghrelin-responsive neuronal populations in the hypothalamic arcuate nucleus. Indeed, we also show that DIO ghrelin-knockout mice exhibit reduced body weight regain after CR weight loss compared with ghrelin wild-type mice, suggesting ghrelin mediates rebound weight gain after CR weight loss.

  3. MTII attenuates ghrelin- and food deprivation-induced increases in food hoarding and food intake.

    PubMed

    Keen-Rhinehart, Erin; Bartness, Timothy J

    2007-12-01

    Food deprivation triggers a constellation of physiological and behavioral changes including increases in peripherally-produced ghrelin and centrally-produced agouti-related protein (AgRP). Upon refeeding, food intake is increased in most species, however hamsters primarily increase food hoarding. Food deprivation-induced increases in food hoarding by Siberian hamsters are mimicked by peripheral ghrelin and central AgRP injections. Because food deprivation stimulates ghrelin as well as AgRP synthesis/release, food deprivation-induced increases in hoarding may be mediated by melanocortin 3 or 4 receptor (MC3/4-R) antagonism via AgRP, the MC3/4-R inverse agonist. Therefore, we asked: Can a MC3/4-R agonist block food deprivation- or ghrelin-induced increases in foraging, food hoarding and food intake? This was accomplished by injecting melanotan II (MTII), a synthetic MC3/4-R agonist, into the 3rd ventricle in food deprived, fed or peripheral ghrelin injected hamsters and housed in a running wheel-based food delivery foraging system. Three foraging conditions were used: a) no running wheel access, non-contingent food, b) running wheel access, non-contingent food or c) a foraging requirement for food (10 revolutions/pellet). Food deprivation was a more potent stimulator of foraging and hoarding than ghrelin. Concurrent injections of MTII completely blocked food deprivation- and ghrelin-induced increases in food intake and attenuated, but did not always completely block, food deprivation- and ghrelin-induced increases in food hoarding. Collectively, these data suggest that the MC3/4-R are involved in ghrelin- and food deprivation-induced increases in food intake, but other neurochemical systems, such as previously demonstrated with neuropeptide Y, also are involved in increases in food hoarding as well as foraging.

  4. Exogenous Ghrelin Accelerates the Healing of Acetic Acid-Induced Colitis in Rats

    PubMed Central

    Matuszyk, Aleksandra; Ceranowicz, Piotr; Warzecha, Zygmunt; Cieszkowski, Jakub; Ceranowicz, Dagmara; Gałązka, Krystyna; Bonior, Joanna; Jaworek, Jolanta; Bartuś, Krzysztof; Gil, Krzysztof; Olszanecki, Rafał; Dembiński, Artur

    2016-01-01

    Previous studies have shown that ghrelin reduces colonic inflammation induced by trinitrobenzene sulfonic acid and dextran sodium sulfate. In the present study we determined the effect of treatment with ghrelin on the course of acetic acid-induced colitis in rats. Rectal administration of 3% acetic acid solution led to induction of colitis in all animals. Damage of the colonic wall was accompanied by an increase in mucosal concentration of pro-inflammatory interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), as well mucosal activity of myeloperoxidase. Moreover, induction of colitis led to a reduction in colonic blood flow and DNA synthesis. Administration of ghrelin after induction of colitis led to faster regeneration of the colonic wall and reduction in colonic levels of IL-1β, TNF-α, and myeloperoxidase. In addition, treatment with ghrelin improved mucosal DNA synthesis and blood flow. Our study disclosed that ghrelin exhibits a strong anti-inflammatory and healing effect in acetic acid-induced colitis. Our current observation in association with previous findings that ghrelin exhibits curative effect in trinitrobenzene sulfonic acid- and dextran sodium sulfate-induced colitis suggest that therapeutic effect of ghrelin in the colon is universal and independent of the primary cause of colitis. PMID:27598133

  5. Exogenous Ghrelin Accelerates the Healing of Acetic Acid-Induced Colitis in Rats.

    PubMed

    Matuszyk, Aleksandra; Ceranowicz, Piotr; Warzecha, Zygmunt; Cieszkowski, Jakub; Ceranowicz, Dagmara; Gałązka, Krystyna; Bonior, Joanna; Jaworek, Jolanta; Bartuś, Krzysztof; Gil, Krzysztof; Olszanecki, Rafał; Dembiński, Artur

    2016-01-01

    Previous studies have shown that ghrelin reduces colonic inflammation induced by trinitrobenzene sulfonic acid and dextran sodium sulfate. In the present study we determined the effect of treatment with ghrelin on the course of acetic acid-induced colitis in rats. Rectal administration of 3% acetic acid solution led to induction of colitis in all animals. Damage of the colonic wall was accompanied by an increase in mucosal concentration of pro-inflammatory interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), as well mucosal activity of myeloperoxidase. Moreover, induction of colitis led to a reduction in colonic blood flow and DNA synthesis. Administration of ghrelin after induction of colitis led to faster regeneration of the colonic wall and reduction in colonic levels of IL-1β, TNF-α, and myeloperoxidase. In addition, treatment with ghrelin improved mucosal DNA synthesis and blood flow. Our study disclosed that ghrelin exhibits a strong anti-inflammatory and healing effect in acetic acid-induced colitis. Our current observation in association with previous findings that ghrelin exhibits curative effect in trinitrobenzene sulfonic acid- and dextran sodium sulfate-induced colitis suggest that therapeutic effect of ghrelin in the colon is universal and independent of the primary cause of colitis. PMID:27598133

  6. Low glucose-induced ghrelin secretion is mediated by an ATP-sensitive potassium channel.

    PubMed

    Oya, Manami; Kitaguchi, Tetsuya; Harada, Kazuki; Numano, Rika; Sato, Takahiro; Kojima, Masayasu; Tsuboi, Takashi

    2015-07-01

    Ghrelin is synthesized in X/A-like cells of the gastric mucosa, which plays an important role in the regulation of energy homeostasis. Although ghrelin secretion is known to be induced by neurotransmitters or hormones or by nutrient sensing in the ghrelin-secreting cells themselves, the mechanism of ghrelin secretion is not clearly understood. In the present study, we found that changing the extracellular glucose concentration from elevated (25  mM) to optimal (10 mM) caused an increase in the intracellular Ca2+ concentration ([Ca2+]i) in ghrelin-secreting mouse ghrelinoma 3-1 (MGN3-1) cells (n=32, P<0.01), whereas changing the glucose concentration from elevated to lowered (5 or 1 mM) had little effect on [Ca2+]i increase. Overexpression of a closed form of an ATP-sensitive K+ (KATP) channel mutant suppressed the 10  mM glucose-induced [Ca2+]i increase (n=8, P<0.01) and exocytotic events (n=6, P<0.01). We also found that a low concentration of a KATP channel opener, diazoxide, with 25  mM glucose induced [Ca2+]i increase (n=23, P<0.01) and ghrelin secretion (n≥3, P<0.05). In contrast, the application of a low concentration of a KATP channel blocker, tolbutamide, significantly induced [Ca2+]i increase (n=15, P<0.01) and ghrelin secretion (n≥3, P<0.05) under 5 mM glucose. Furthermore, the application of voltage-dependent Ca2+ channel inhibitors suppressed the 10 mM glucose-induced [Ca2+]i increase (n≥26, P<0.01) and ghrelin secretion (n≥5, P<0.05). These findings suggest that KATP and voltage-dependent Ca2+ channels are involved in glucose-dependent ghrelin secretion in MGN3-1 cells.

  7. Ghrelin inhibits sodium metabisulfite induced oxidative stress and apoptosis in rat gastric mucosa.

    PubMed

    Ercan, Sevim; Basaranlar, Goksun; Gungor, Nazlı Ece; Kencebay, Ceren; Sahin, Pınar; Celik-Ozenci, Ciler; Derin, Narin

    2013-06-01

    This study aimed to investigate the effect of ghrelin administration on sulfite induced oxidative and apoptotic changes in rat gastric mucosa. Forty male albino Wistar rats were randomized into control (C), sodium metabisulfite (Na2S2O5) treated (S), ghrelin treated (G) and, Na2S2O5+ghrelin treated (SG) groups. Sodium metabisulfite (100 mg/kg/day) was given by gastric gavage and, ghrelin (20 μg/kg/day) was given intraperitoneally for 5 weeks. Plasma-S-sulfonate level was increased in S and SG groups. Na2S2O5 administration significantly elevated total oxidant status (TOS) levels while depleting total antioxidant status (TAS) levels in gastric mucosa. Ghrelin significantly decreased gastric TOS levels in the SG group compared with the S group. Additionally, TAS levels were found to be higher in SG group in reference to S group. Na2S2O5 administration also markedly increased the number of apoptotic cells, cleaved caspase-3 and PAR expression (PARP activity indicator) and, decreased Ki67 expression (cell proliferation index) in gastric mucosal cells. Ghrelin treatment decreased the number apoptotic cells, cytochrome C release, PAR and, caspase-3 expressions while increasing Ki67 expression in gastric mucosa exposed to Na2S2O5. In conclusion, we suggest that ghrelin treatment might ameliorate ingested-Na2S2O5 induced gastric mucosal injury stemming from apoptosis and oxidative stress in rats.

  8. Ghrelin-induced hypophagia is mediated by the β2 adrenergic receptor in chicken.

    PubMed

    Zendehdel, Morteza; Hassanpour, Shahin

    2014-09-01

    The purpose of this study was to examine the effects of intracerebroventricular injection of metoprolol (a β1 adrenergic receptor antagonist), ICI 118,551 (a β2 adrenergic receptor antagonist), and SR 59230R (a β3 adrenergic receptor antagonist) on ghrelin-induced food and water intake by 3-h food-deprived (FD3) cockerels. The chickens were randomly allocated to 4 treatment groups with 8 replicates in each group. A cannula was surgically implanted into the lateral ventricle of the brain. In experiment 1, chickens received the β1 adrenergic receptor antagonist (24 nmol) before injection of the ghrelin (0.6 nmol). In experiment 2, chickens received the β2 adrenergic receptor antagonist (5 nmol) before injection of the ghrelin (0.6 nmol). In experiment 3, birds were injected with ghrelin (0.6 nmol) after the β3 adrenergic receptor antagonist (20 nmol). Cumulative food and water intake were recorded 3-h post injection and analyzed by two-way analysis of variance. According to the results, ghrelin injection reduced food and water intake by broiler cockerels (p≤0.05). The effect of ghrelin on food intake was significantly attenuated by pretreatment with the β2 receptor antagonist (p≤0.05). Furthermore, the β2 receptor antagonist had no effect on water intake induced by ghrelin. Also, pretreatment with the β1 and β3 receptors antagonists had no effect on ghrelin-induced food and water intake. These results suggest that the effect of ghrelin on cumulative food intake by cockerels is mediated via β2 adrenergic receptors.

  9. Cage-induced stereotypic behaviour in laboratory mice covaries with nucleus accumbens FosB/ΔFosB expression.

    PubMed

    Phillips, Danielle; Choleris, Elena; Ervin, Kelsy S J; Fureix, Carole; Harper, Laura; Reynolds, Kathryn; Niel, Lee; Mason, Georgia J

    2016-03-15

    Stereotypic behaviour (SB) occurs in certain human disorders (e.g. autism), and animals treated with stimulants or raised in impoverished conditions, including laboratory mice in standard cages. Dysfunctional cortico-basal ganglia pathways have been implicated in these examples, but for cage-induced forms of SB, the relative roles of ventral versus dorsal striatum had not been fully ascertained. Here, we used immunohistochemical staining of FosB and ΔFosB to assess long-term activation within the nucleus accumbens and caudate-putamen of C57BL/6 mice. Housed in typical laboratory cages, these mice spontaneously developed different degrees of route-tracing, bar-mouthing and other forms of SB (spending 0% to over 50% of their active time budgets in this behaviour). The most highly stereotypic mice showed the most elevated FosB/ΔFosB activity in the nucleus accumbens. No such patterns occurred in the caudate-putamen. The cage-induced SB common in standard-housed mice thus involves elevated activity within the ventral striatum, suggesting an aetiology closer to compulsive gambling, eating and drug-seeking than to classic amphetamine stereotypies and other behaviours induced by motor loop over-activation.

  10. INHIBITION OF GHRELIN O-ACYLTRANSFERASE ATTENUATES FOOD DEPRIVATION-INDUCED INCREASES IN INGESTIVE BEHAVIOR1

    PubMed Central

    Teubner, Brett J.W.; Garretson, John T.; Hwang, Yousang; Cole, Philip A.; Bartness, Timothy J.

    2013-01-01

    Ghrelin is an orexigenic hormone produced by the stomach in direct proportion to the time since the last meal and has therefore been called a ‘hunger signal’. The octanoylation of ghrelin is critical for its orexigenic functions and is dependent upon ghrelin O-acyltransferase (GOAT) catalyzation. The GOAT inhibitor, GO-CoA-Tat, decreases the circulating concentrations of octanoylated ghrelin and attenuates weight gain on a high fat diet in mice. Unlike rats and mice, Siberian hamsters and humans do not increase food intake after food deprivation, but increase food hoarding after food deprivation. In Siberian hamsters, exogenous ghrelin increases ingestive behaviors similarly to 48–56 h food deprivation. Therefore, we tested the necessity of increased ghrelin in food-deprived Siberian hamsters to stimulate ingestive behaviors. To do so we used our simulated natural housing system that allows hamsters to forage for and hoard food. Animals were given an injection of GO-CoA-Tat (i.p., 11 μmol/kg) every 6 h because that is the duration of its effective inhibition of octanoylated ghrelin concentrations during a 48 h food deprivation. We found that GO-CoA-Tat attenuated food foraging (0–1 h), food intake (0–1 and 2–4 h), and food hoarding (0–1 h and 2 and 3 d) post-refeeding compared with saline treated animals. This suggests that increased octanoylated ghrelin concentrations play a role in the food deprivation-induced increases in ingestive behavior. Therefore, ghrelin is a critical aspect of the multi-faceted mechanisms that stimulate ingestive behaviors, and might be a critical point for a successful clinical intervention scheme in humans. PMID:23399323

  11. Ghrelin enhances cue-induced bar pressing for high fat food.

    PubMed

    St-Onge, Veronique; Watts, Alexander; Abizaid, Alfonso

    2016-02-01

    Ghrelin is an orexigenic hormone produced by the stomach that acts on growth hormone secretagogue receptors (GHSRs) both peripherally and centrally. The presence of GHSRs in the ventral tegmental area (VTA) suggests that ghrelin signaling at this level may increase the incentive value of palatable foods as well as other natural and artificial rewards. The present investigation sought to determine if ghrelin plays a role in relapse to such foods following a period of abstinence. To achieve this, thirty-six male Long Evans rats were trained to press a lever to obtain a high fat chocolate food reward on a fixed ratio schedule of 1. Following an extinction period during which lever presses were not reinforced, rats were implanted with a cannula connected to a minipump that continuously delivered ghrelin, a GHSR antagonist ([d-Lys-3]-GHRP-6), or saline in the VTA for 14days. One week later, food reward-associated cues, food reward priming, and an overnight fast were used to induce reinstatement of the lever pressing response. Our results indicate that intra-VTA ghrelin enhances cue-induced reinstatement of responses for palatable food pellets. To the extent that the reinstatement paradigm is considered a valid model of relapse in humans, this suggests that ghrelin signaling facilitates relapse to preferred foods in response to food cues through GHSR signaling in the VTA. PMID:26592452

  12. Ghrelin enhances cue-induced bar pressing for high fat food.

    PubMed

    St-Onge, Veronique; Watts, Alexander; Abizaid, Alfonso

    2016-02-01

    Ghrelin is an orexigenic hormone produced by the stomach that acts on growth hormone secretagogue receptors (GHSRs) both peripherally and centrally. The presence of GHSRs in the ventral tegmental area (VTA) suggests that ghrelin signaling at this level may increase the incentive value of palatable foods as well as other natural and artificial rewards. The present investigation sought to determine if ghrelin plays a role in relapse to such foods following a period of abstinence. To achieve this, thirty-six male Long Evans rats were trained to press a lever to obtain a high fat chocolate food reward on a fixed ratio schedule of 1. Following an extinction period during which lever presses were not reinforced, rats were implanted with a cannula connected to a minipump that continuously delivered ghrelin, a GHSR antagonist ([d-Lys-3]-GHRP-6), or saline in the VTA for 14days. One week later, food reward-associated cues, food reward priming, and an overnight fast were used to induce reinstatement of the lever pressing response. Our results indicate that intra-VTA ghrelin enhances cue-induced reinstatement of responses for palatable food pellets. To the extent that the reinstatement paradigm is considered a valid model of relapse in humans, this suggests that ghrelin signaling facilitates relapse to preferred foods in response to food cues through GHSR signaling in the VTA.

  13. FosB regulates stretch-induced expression of extracellular matrix proteins in smooth muscle.

    PubMed

    Ramachandran, Aruna; Gong, Edward M; Pelton, Kristine; Ranpura, Sandeep A; Mulone, Michelle; Seth, Abhishek; Gomez, Pablo; Adam, Rosalyn M

    2011-12-01

    Fibroproliferative remodeling in smooth muscle-rich hollow organs is associated with aberrant extracellular matrix (ECM) production. Although mechanical stimuli regulate ECM protein expression, the transcriptional mediators of this process remain poorly defined. Previously, we implicated AP-1 as a mediator of smooth muscle cell (SMC) mechanotransduction; however, its role in stretch-induced ECM regulation has not been explored. Herein, we identify a novel role for the AP-1 subunit FosB in stretch-induced ECM expression in SMCs. The DNA-binding activity of AP-1 increased after stretch stimulation of SMCs in vitro. In contrast to c-Jun and c-fos, which are also activated by the SMC mitogen platelet-derived growth factor, FosB was only activated by stretch. FosB silencing attenuated the expression of the profibrotic factors tenascin C (TNC) and connective tissue growth factor (CTGF), whereas forced expression of Jun~FosB stimulated TNC and CTGF promoter activity. Chromatin immunoprecipitation revealed enrichment of AP-1 at the TNC and CTGF promoters. Bladder distension in vivo enhanced nuclear localization of c-jun and FosB. Finally, the distension-induced expression of TNC and CTGF in the detrusor smooth muscle of bladders from wild-type mice was significantly attenuated in FosB-null mice. Together, these findings identify FosB as a mechanosensitive regulator of ECM production in smooth muscle. PMID:21996678

  14. Cadmium induces phosphorylation and stabilization of c-Fos in HK-2 renal proximal tubular cells

    SciTech Connect

    Iwatsuki, Mamiko; Inageda, Kiyoshi; Matsuoka, Masato

    2011-03-15

    We examined the effects of cadmium chloride (CdCl{sub 2}) exposure on the expression and phosphorylation status of members of the Fos family, components of the activator protein-1 transcription factor, in HK-2 human renal proximal tubular cells. Following the exposure to CdCl{sub 2}, the expression of c-fos, fosB, fra-1, and fra-2 increased markedly, with different magnitudes and time courses. The levels of Fos family proteins (c-Fos, FosB, Fra-1, and Fra-2) also increased in response to CdCl{sub 2} exposure. Although the elevation of c-fos transcripts was transient, c-Fos protein levels increased progressively with lower electrophoretic mobility, suggesting stabilization of c-Fos through post-translational modifications. Consistently, we observed phosphorylation of c-Fos at Ser362 and Ser374 in HK-2 cells treated with CdCl{sub 2}. Phosphorylated forms of mitogen-activated protein kinases (MAPKs)-including extracellular signal-regulated protein kinase (ERK), c-Jun NH{sub 2}-terminal kinase, and p38-increased after CdCl{sub 2} exposure, whereas treatment with the MAPK/ERK kinase inhibitor U0126 and the p38 inhibitor SB203580 suppressed the accumulation and phosphorylation of c-Fos. We mutated Ser362 to alanine (S362A), Ser374 to alanine (S374A), and both residues to alanines (S362A/S374A) to inhibit potential phosphorylation of c-Fos at these sites. S374A or double S362A/S374A mutations reduced c-Fos level markedly, but S362A mutation did not. On the other hand, S362A/S374A mutations induced a more pronounced reduction in c-Fos DNA-binding activity than S374A mutation. These results suggest that while Ser374 phosphorylation seems to play a role in c-Fos stabilization, phosphorylation at two C-terminal serine residues is required for the transcriptional activation of c-Fos in HK-2 cells treated with CdCl{sub 2}.

  15. Photoperiodic regulation of the orexigenic effects of ghrelin in Siberian hamsters.

    PubMed

    Bradley, Sean P; Pattullo, Lucia M; Patel, Priyesh N; Prendergast, Brian J

    2010-09-01

    Animals living in temperate climates with predictable seasonal changes in food availability may use seasonal information to engage different metabolic strategies. Siberian hamsters decrease costs of thermoregulation during winter by reducing food intake and body mass in response to decreasing or short-day lengths (SD). These experiments examined whether SD reduction in food intake in hamsters is driven, at least in part, by altered behavioral responses to ghrelin, a gut-derived orexigenic peptide which induces food intake via NPY-dependent mechanisms. Relative to hamsters housed in long-day (LD) photoperiods, SD hamsters consumed less food in response to i.p. treatment with ghrelin across a range of doses from 0.03 to 3 mg/kg. To determine whether changes in photoperiod alter behavioral responses to ghrelin-induced activation of NPY neurons, c-Fos and NPY expression were quantified in the arcuate nucleus (ARC) via double-label fluorescent immunocytochemistry following i.p. treatment with 0.3 mg/kg ghrelin or saline. Ghrelin induced c-Fos immunoreactivity (-ir) in a greater proportion of NPY-ir neurons of LD relative to SD hamsters. In addition, following ghrelin treatment, a greater proportion of ARC c-Fos-ir neurons were identifiable as NPY-ir in LD relative to SD hamsters. Changes in day length markedly alter the behavioral response to ghrelin. The data also identify photoperiod-induced changes in the ability of ghrelin to activate ARC NPY neurons as a possible mechanism by which changes in day length alter food intake.

  16. Neuronal Deletion of Ghrelin Receptor Almost Completely Prevents Diet-Induced Obesity.

    PubMed

    Lee, Jong Han; Lin, Ligen; Xu, Pingwen; Saito, Kenji; Wei, Qiong; Meadows, Adelina G; Bongmba, Odelia Y N; Pradhan, Geetali; Zheng, Hui; Xu, Yong; Sun, Yuxiang

    2016-08-01

    Ghrelin signaling has major effects on energy and glucose homeostasis, but it is unknown whether ghrelin's functions are centrally and/or peripherally mediated. The ghrelin receptor, growth hormone secretagogue receptor (GHS-R), is highly expressed in the brain and detectable in some peripheral tissues. To understand the roles of neuronal GHS-R, we generated a mouse line where Ghsr gene is deleted in all neurons using synapsin 1 (Syn1)-Cre driver. Our data showed that neuronal Ghsr deletion abolishes ghrelin-induced spontaneous food intake but has no effect on total energy intake. Remarkably, neuronal Ghsr deletion almost completely prevented diet-induced obesity (DIO) and significantly improved insulin sensitivity. The neuronal Ghsr-deleted mice also showed improved metabolic flexibility, indicative of better adaption to different fuels. In addition, gene expression analysis suggested that hypothalamus and/or midbrain might be the sites that mediate the effects of GHS-R in thermogenesis and physical activity, respectively. Collectively, our results indicate that neuronal GHS-R is a crucial regulator of energy metabolism and a key mediator of DIO. Neuronal Ghsr deletion protects against DIO by regulating energy expenditure, not by energy intake. These novel findings suggest that suppressing central ghrelin signaling may serve as a unique antiobesity strategy. PMID:27207529

  17. The interaction between ghrelin and cannabinoid systems in penicillin-induced epileptiform activity in rats.

    PubMed

    Arslan, Gokhan; Ayyildiz, Mustafa; Agar, Erdal

    2014-12-01

    The majority of experimental and clinical studies show that ghrelin and cannabinoids are potent inhibitors of epileptic activity in various models of epilepsy. A number of studies have attempted to understand the connection between ghrelin and cannabinoid signalling in the regulation of food intake. Since no data show a functional interaction between ghrelin and cannabinoids in epilepsy, we examined the relationship between these systems via penicillin-induced epileptiform activity in rats. Doses of the CB1 receptor agonist arachidonyl-2-chloroethylamide (ACEA) (2.5 and 7.5 µg), the CB1 receptor antagonist N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3 carboxamide (AM-251) (0.25 and 0.5 µg) and ghrelin (0.5 and 1 µg) were administered intracerebroventricularly (i.c.v.) 30 minutes after the intracortical (i.c.) application of penicillin. In the interaction groups, the animals received either an effective dose of ACEA (7.5 µg, i.c.v.) or a non-effective dose of ACEA (2.5 µg, i.c.v.) or effective doses of AM-251 (0.25, 0.5 µg, i.c.v.) 10 minutes after ghrelin application. A 1 µg dose of ghrelin suppressed penicillin-induced epileptiform activity. The administration of a 0.25 µg dose of AM-251 increased the frequency of penicillin-induced epileptiform activity by producing status epilepticus-like activity. A 7.5 µg dose of ACEA decreased the frequency of epileptiform activity, whereas a non-effective dose of ACEA (2.5 µg) did not change it. Effective doses of AM-251 (0.25, 0.5 µg) reversed the ghrelin's anticonvulsant activity. The application of non-effective doses of ACEA (2.5 µg) together with ghrelin (0.5 µg) within 10 minutes caused anticonvulsant activity, which was reversed by the administration of AM-251 (0.25 µg). The electrophysiological evidence from this study suggests a possible interaction between ghrelin and cannabinoid CB1 receptors in the experimental model of epilepsy.

  18. The interaction between ghrelin and cannabinoid systems in penicillin-induced epileptiform activity in rats.

    PubMed

    Arslan, Gokhan; Ayyildiz, Mustafa; Agar, Erdal

    2014-12-01

    The majority of experimental and clinical studies show that ghrelin and cannabinoids are potent inhibitors of epileptic activity in various models of epilepsy. A number of studies have attempted to understand the connection between ghrelin and cannabinoid signalling in the regulation of food intake. Since no data show a functional interaction between ghrelin and cannabinoids in epilepsy, we examined the relationship between these systems via penicillin-induced epileptiform activity in rats. Doses of the CB1 receptor agonist arachidonyl-2-chloroethylamide (ACEA) (2.5 and 7.5 µg), the CB1 receptor antagonist N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3 carboxamide (AM-251) (0.25 and 0.5 µg) and ghrelin (0.5 and 1 µg) were administered intracerebroventricularly (i.c.v.) 30 minutes after the intracortical (i.c.) application of penicillin. In the interaction groups, the animals received either an effective dose of ACEA (7.5 µg, i.c.v.) or a non-effective dose of ACEA (2.5 µg, i.c.v.) or effective doses of AM-251 (0.25, 0.5 µg, i.c.v.) 10 minutes after ghrelin application. A 1 µg dose of ghrelin suppressed penicillin-induced epileptiform activity. The administration of a 0.25 µg dose of AM-251 increased the frequency of penicillin-induced epileptiform activity by producing status epilepticus-like activity. A 7.5 µg dose of ACEA decreased the frequency of epileptiform activity, whereas a non-effective dose of ACEA (2.5 µg) did not change it. Effective doses of AM-251 (0.25, 0.5 µg) reversed the ghrelin's anticonvulsant activity. The application of non-effective doses of ACEA (2.5 µg) together with ghrelin (0.5 µg) within 10 minutes caused anticonvulsant activity, which was reversed by the administration of AM-251 (0.25 µg). The electrophysiological evidence from this study suggests a possible interaction between ghrelin and cannabinoid CB1 receptors in the experimental model of epilepsy. PMID

  19. The influence of pretreatment with ghrelin on the development of acetic-acid-induced colitis in rats.

    PubMed

    Maduzia, D; Matuszyk, A; Ceranowicz, D; Warzecha, Z; Ceranowicz, P; Fyderek, K; Galazka, K; Dembinski, A

    2015-12-01

    Ghrelin has been primarily shown to exhibit protective and therapeutic effect in the gut. Pretreatment with ghrelin inhibits the development of acute pancreatitis and accelerates pancreatic recovery in the course of this disease. In the stomach, ghrelin reduces gastric mucosal damage induced by ethanol, stress or alendronate, as well as accelerates the healing of acetic acid-induced gastric and duodenal ulcer. The aim of present studies was to investigate the effect of pretreatment with ghrelin on the development of acetic acid-induced colitis. Studies have been performed on male Wistar rats. Animals were treated intraperitoneally with saline (control) or ghrelin (4, 8 or 16 nmol/kg/dose). Saline or ghrelin was given twice: 8 and 1 h before induction of colitis. Colitis was induced by a rectal enema with 1 ml of 4% solution of acetic acid and the severity of colitis was assessed 1 or 24 hours after induction of inflammation. Rectal administration of acetic acid induced colitis in all animals. Damage of colonic wall was seen at the macroscopic and microscopic level. This effect was accompanied by a reduction in colonic blood flow and mucosal DNA synthesis. Moreover, induction of colitis significantly increased mucosal concentration of pro-inflammatory interleukin-1β (IL-1β), activity of myeloperoxidase and concentration of malondialdehyde (MDA). Mucosal activity of superoxide dismutase (SOD) was reduced. Pretreatment with ghrelin reduced the area and grade of mucosal damage. This effect was accompanied by an improvement of blood flow, DNA synthesis and SOD activity in colonic mucosa. Moreover, ghrelin administration reduced mucosal concentration of IL-1β and MDA, as well as decreased mucosal activity of myeloperoxidase. Administration of ghrelin protects the large bowel against the development of the acetic acid-induced colitis and this effect seems to be related to the ghrelin-evoked anti-inflammatory and anti-oxidative effects.

  20. The influence of pretreatment with ghrelin on the development of acetic-acid-induced colitis in rats.

    PubMed

    Maduzia, D; Matuszyk, A; Ceranowicz, D; Warzecha, Z; Ceranowicz, P; Fyderek, K; Galazka, K; Dembinski, A

    2015-12-01

    Ghrelin has been primarily shown to exhibit protective and therapeutic effect in the gut. Pretreatment with ghrelin inhibits the development of acute pancreatitis and accelerates pancreatic recovery in the course of this disease. In the stomach, ghrelin reduces gastric mucosal damage induced by ethanol, stress or alendronate, as well as accelerates the healing of acetic acid-induced gastric and duodenal ulcer. The aim of present studies was to investigate the effect of pretreatment with ghrelin on the development of acetic acid-induced colitis. Studies have been performed on male Wistar rats. Animals were treated intraperitoneally with saline (control) or ghrelin (4, 8 or 16 nmol/kg/dose). Saline or ghrelin was given twice: 8 and 1 h before induction of colitis. Colitis was induced by a rectal enema with 1 ml of 4% solution of acetic acid and the severity of colitis was assessed 1 or 24 hours after induction of inflammation. Rectal administration of acetic acid induced colitis in all animals. Damage of colonic wall was seen at the macroscopic and microscopic level. This effect was accompanied by a reduction in colonic blood flow and mucosal DNA synthesis. Moreover, induction of colitis significantly increased mucosal concentration of pro-inflammatory interleukin-1β (IL-1β), activity of myeloperoxidase and concentration of malondialdehyde (MDA). Mucosal activity of superoxide dismutase (SOD) was reduced. Pretreatment with ghrelin reduced the area and grade of mucosal damage. This effect was accompanied by an improvement of blood flow, DNA synthesis and SOD activity in colonic mucosa. Moreover, ghrelin administration reduced mucosal concentration of IL-1β and MDA, as well as decreased mucosal activity of myeloperoxidase. Administration of ghrelin protects the large bowel against the development of the acetic acid-induced colitis and this effect seems to be related to the ghrelin-evoked anti-inflammatory and anti-oxidative effects. PMID:26769837

  1. Ghrelin counteracts salt-induced hypertension via promoting diuresis and renal nitric oxide production in Dahl rats.

    PubMed

    Aoki, Hirotaka; Nakata, Masanori; Dezaki, Katsuya; Lu, Ming; Gantulga, Darambazar; Yamamoto, Keiji; Shimada, Kazuyuki; Kario, Kazuomi; Yada, Toshihiko

    2013-01-01

    Ghrelin is the endogenous ligand for the growth hormone-secretagogue receptor expressed in various tissues including the heart, blood vessels and kidney. This study sought to determine the effects of long-term treatment with ghrelin (10 nmol/kg, twice a day, intraperitoneally) on the hypertension induced by high salt (8.0% NaCl) diet in Dahl salt-sensitive hypertensive (DS) rats. Systolic blood pressure (SBP) was measured by a tail cuff method. During the treatment period for 3 weeks, high salt diet increased blood pressure compared to normal salt (0.3% NaCl) diet, and this hypertension was partly but significantly (P<0.01) attenuated by simultaneous treatment with ghrelin. Ghrelin significantly increased urine volume and tended to increase urine Na⁺ excretion. Furthermore, ghrelin increased urine nitric oxide (NO) excretion and tended to increase renal neuronal nitric oxide synthase (nNOS) mRNA expression. Ghrelin did not alter the plasma angiotensin II level and renin activity, nor urine catecholamine levels. Furthermore, ghrelin prevented the high salt-induced increases in heart thickness and plasma ANP mRNA expression. These results demonstrate that long-term ghrelin treatment counteracts salt-induced hypertension in DS rats primarily through diuretic action associated with increased renal NO production, thereby exerting cardio-protective effects.

  2. Ghrelin inhibits high glucose-induced 16HBE cells apoptosis by regulating Wnt/β-catenin pathway.

    PubMed

    Liu, Xiaoyan; Chen, Dilong; Wu, Zhongjun; Li, Jing; Li, Jianqiang; Zhao, Hui; Liu, Tanzhen

    2016-09-01

    Ghrelin has a protective effect on diabetes and its complications. To expound its probable molecular mechanisms, we investigated the effects of ghrelin on high glucose (HG)-induced cell apoptosis and intracellular signaling pathways in cultured human bronchial epithelial cells (16HBE). In this study, we firstly came to conclusion that HG-induced 16HBE apoptosis was significantly inhibited by co-treatment of ghrelin. The molecular mechanism of ghrelin-induced protective effects for lungs is still not understood. We reported here for the first time that ghrelin can not only eliminate apoptosis of 16HBE, but also regulate the disordered cell cycle caused by HG. We speculated here that ghrelin inhibits the apoptosis of 16HBE by regulating the abnormal cell cycle to some extent. The mechanism may be that ghrelin up-regulates the expression of cyclin D1 via regulating Wnt/β-catenin pathway, which has an intimate relationship with lung diseases. These results suggested the possible role of ghrelin in treating diabetic lung diseases, especially in view of its low toxicity in humans. PMID:27378423

  3. Ghrelin Protects against Dexamethasone-Induced INS-1 Cell Apoptosis via ERK and p38MAPK Signaling

    PubMed Central

    2016-01-01

    Glucocorticoid excess induces apoptosis of islet cells, which may result in diabetes. In this study, we investigated the protective effect of ghrelin on dexamethasone-induced INS-1 cell apoptosis. Our data showed that ghrelin (0.1 μM) inhibited dexamethasone-induced (0.1 μM) apoptosis of INS-1 cells and facilitated cell proliferation. Moreover, ghrelin upregulated Bcl-2 expression, downregulated Bax expression, and decreased caspase-3 activity. The protective effect of ghrelin against dexamethasone-induced INS-1 cell apoptosis was mediated via growth hormone secretagogue receptor 1a. Further studies revealed that ghrelin increased ERK activation and decreased p38MAPK expression after dexamethasone treatment. Ghrelin-mediated protection of dexamethasone-induced apoptosis of INS-1 cells was attenuated using the ERK inhibitor U0126 (10 μM), and cell viability increased using the p38MAPK inhibitor SB203580 (10 μM). In conclusion, ghrelin could protect against dexamethasone-induced INS-1 cell apoptosis, at least partially via GHS-R1a and the signaling pathway of ERK and p38MAPK. PMID:27190513

  4. Intracerebroventricular urocortin 3 counteracts central acyl ghrelin-induced hyperphagic and gastroprokinetic effects via CRF receptor 2 in rats

    PubMed Central

    Yeh, Chun; Ting, Ching-Heng; Doong, Ming-Luen; Chi, Chin-Wen; Lee, Shou-Dong; Chen, Chih-Yen

    2016-01-01

    Purpose Urocortin 3 is a key neuromodulator in the regulation of stress, anxiety, food intake, gut motility, and energy homeostasis, while ghrelin elicits feeding behavior and enhances gastric emptying, adiposity, and positive energy balance. However, the interplays between urocortin 3 and ghrelin on food intake and gastric emptying remain uninvestigated. Methods We examined the differential effects of central O-n-octanoylated ghrelin, des-Gln14-ghrelin, and urocortin 3 on food intake, as well as on charcoal nonnutrient semiliquid gastric emptying in conscious rats that were chronically implanted with intracerebroventricular (ICV) catheters. The functional importance of corticotropin-releasing factor (CRF) receptor 2 in urocortin 3-induced responses was examined by ICV injection of the selective CRF receptor 2 antagonist, astressin2-B. Results ICV infusion of urocortin 3 opposed central acyl ghrelin-elicited hyperphagia via CRF receptor 2 in satiated rats. ICV injection of O-n-octanoylated ghrelin and des-Gln14-ghrelin were equally potent in accelerating gastric emptying in fasted rats, whereas ICV administration of urocortin 3 delayed gastric emptying. In addition, ICV infusion of urocortin 3 counteracted central acyl ghrelin-induced gastroprokinetic effects via CRF receptor 2 pathway. Conclusion ICV-infused urocortin 3 counteracts central acyl ghrelin-induced hyperphagic and gastroprokinetic effects via CRF receptor 2 in rats. Our results clearly showed that enhancing ghrelin and blocking CRF receptor 2 signaling in the brain accelerated gastric emptying, which provided important clues for a new therapeutic avenue in ameliorating anorexia and gastric ileus found in various chronic wasting disorders. PMID:27757017

  5. A Natural Variant of Obestatin, Q90L, Inhibits Ghrelin's Action on Food Intake and GH Secretion and Targets NPY and GHRH Neurons in Mice

    PubMed Central

    Hassouna, Rim; Zizzari, Philippe; Viltart, Odile; Yang, Seung-Kwon; Gardette, Robert; Videau, Catherine; Badoer, Emilio; Epelbaum, Jacques; Tolle, Virginie

    2012-01-01

    Background Ghrelin and obestatin are two gut-derived peptides originating from the same ghrelin/obestatin prepropeptide gene (GHRL). While ghrelin stimulates growth hormone (GH) secretion and food intake and inhibits γ-aminobutyric-acid synaptic transmission onto GHRH (Growth Hormone Releasing Hormone) neurons, obestatin blocks these effects. In Humans, GHRL gene polymorphisms have been associated with pathologies linked to an unbalanced energy homeostasis. We hypothesized that one polymorphism located in the obestatin sequence (Q to L substitution in position 90 of the ghrelin/obestatin prepropeptide, rs4684677) may impact on the function of obestatin. In the present study, we tested the activity of native and Q90L obestatin to modulate ghrelin-induced food intake, GH secretion, cFos activity in GHRH and Neuropeptide Y (NPY) neurons and γ-aminobutyric-acid activity onto GHRH neurons. Methodology/Principal findings Food intake, GH secretion and electrophysiological recordings were assessed in C57BL/6 mice. cFos activity was measured in NPY-Renilla-GFP and GHRH-eGFP mice. Mice received saline, ghrelin or ghrelin combined to native or Q90L obestatin (30 nmol each) in the early light phase. Ghrelin stimulation of food intake and GH secretion varied considerably among individual mice with 59–77% eliciting a robust response. In these high-responders, ghrelin-induced food intake and GH secretion were reduced equally by native and Q90L obestatin. In contrast to in vivo observations, Q90L was slightly more efficient than native obestatin in inhibiting ghrelin-induced cFos activation within the hypothalamic arcuate nucleus and the nucleus tractus solitarius of the brainstem. After ghrelin injection, 26% of NPY neurons in the arcuate nucleus expressed cFos protein and this number was significantly reduced by co-administration of Q90L obestatin. Q90L was also more potent that native obestatin in reducing ghrelin-induced inhibition of γ-aminobutyric-acid synaptic

  6. Ghrelin Is an Essential Factor for Motilin-Induced Gastric Contraction in Suncus murinus.

    PubMed

    Kuroda, Kayuri; Hequing, Huang; Mondal, Anupom; Yoshimura, Makoto; Ito, Kazuma; Mikami, Takashi; Takemi, Shota; Jogahara, Takamichi; Sakata, Ichiro; Sakai, Takafumi

    2015-12-01

    Motilin was discovered in the 1970s as the most important hormone for stimulating strong gastric contractions; however, the mechanisms by which motilin causes gastric contraction are not clearly understood. Here, we determined the coordinated action of motilin and ghrelin on gastric motility during fasted and postprandial contractions by using house musk shrew (Suncus murinus; order: Insectivora, suncus named as the laboratory strain). Motilin-induced gastric contractions at phases I and II of the migrating motor complex were inhibited by pretreatment with (D-Lys(3))-GHRP-6 (6 mg/kg/h), a ghrelin receptor antagonist. Administration of the motilin receptor antagonist MA-2029 (0.1 mg/kg) and/or (D-Lys(3))-GHRP-6 (0.6 mg/kg) at the peak of phase III abolished the spontaneous gastric phase III contractions in vivo. Motilin did not stimulate gastric contractions in the postprandial state. However, in the presence of a low dose of ghrelin, motilin evoked phase III-like gastric contractions even in the postprandial state, and postprandial gastric emptying was accelerated. In addition, pretreatment with (D-Lys(3))-GHRP-6 blocked the motilin-induced gastric contraction in vitro and in vivo, and a γ-aminobutyric acid (GABA) antagonist reversed this block in gastric contraction. These results indicate that blockade of the GABAergic pathway by ghrelin is essential for motilin-induced gastric contraction. PMID:26441238

  7. NPY Y1 receptor is involved in ghrelin- and fasting-induced increases in foraging, food hoarding, and food intake.

    PubMed

    Keen-Rhinehart, Erin; Bartness, Timothy J

    2007-04-01

    Fasting triggers a constellation of physiological and behavioral changes, including increases in peripherally produced ghrelin and centrally produced hypothalamic neuropeptide Y (NPY). Refeeding stimulates food intake in most species; however, hamsters primarily increase foraging and food hoarding with smaller increases in food intake. Fasting-induced increases in foraging and food hoarding in Siberian hamsters are mimicked by peripheral ghrelin, central NPY, and NPY Y1 receptor agonist injections. Because fasting stimulates ghrelin and subsequently NPY synthesis/release, it may be that fasting-induced increased hoarding is mediated by NPY Y1 receptor activation. Therefore, we asked: Can an Y1 receptor antagonist block fasting- or ghrelin-induced increases in foraging, food hoarding, and food intake? This was accomplished by injecting the NPY Y1 receptor antagonist 1229U91 intracerebroventricularly in hamsters fasted, fed, or given peripheral ghrelin injections and housed in a running wheel-based food delivery foraging system coupled with simulated-burrow housing. Three foraging conditions were used: 1) no running wheel access, free food, 2) running wheel access, free food, or 3) foraging requirement (10 revolutions/pellet) for food. Fasting was a more potent stimulator of foraging and food hoarding than ghrelin. Concurrent injections of 1229U91 completely blocked fasting- and ghrelin-induced increased foraging and food intake and attenuated, but did not always completely block, fasting- and ghrelin-induced increases in food hoarding. Collectively, these data suggest that the NPY Y1 receptor is important for the effects of ghrelin- and fasting-induced increases in foraging and food intake, but other NPY receptors and/or other neurochemical systems are involved in increases in food hoarding.

  8. Rewarding brain stimulation induces only sparse Fos-like immunoreactivity in dopaminergic neurons.

    PubMed

    Hunt, G E; McGregor, I S

    1998-03-01

    ) and pontine tegmental area (A7) were Fos positive. Overall, the results show that rewarding, brain stimulation induces Fos-like immunoreactivity in many forebrain regions but only sparsely in mesolimbic and mesocortical dopamine neurons. The similar patterns of Fos-like immunoreactivity seen in the self-stimulation and yoked-stimulation groups suggests that the operant responding for brain stimulation causes minimal Fos expression in itself.

  9. Psychostimulant-induced Fos protein expression in the thalamic paraventricular nucleus.

    PubMed

    Deutch, A Y; Bubser, M; Young, C D

    1998-12-15

    Lesions of glutamatergic afferents to the nucleus accumbens have been reported to block psychostimulant-induced behavioral sensitization. However, thalamic glutamatergic projections to the nucleus accumbens have received little attention in the context of psychostimulant actions. We examined the effects of acute amphetamine and cocaine administration on expression of Fos protein in the thalamic paraventricular nucleus (PVT), which provides glutamatergic inputs to the nucleus accumbens and also receives dopaminergic afferents. Immunoblot and immunohistochemical studies revealed that both psychostimulants dose-dependently increased PVT Fos expression. PVT neurons retrogradely labeled from the nucleus accumbens were among the PVT cells that showed a Fos response to amphetamine. D2 family dopamine agonists, including low doses of the D3-preferring agonist 7-OH-DPAT, increased the numbers of Fos-like-immunoreactive neurons in the PVT. Conversely, the effects of cocaine and amphetamine on PVT Fos expression were blocked by pretreatment with the dopamine D2/3 antagonist raclopride. Because PVT neurons express D3 but not other dopamine receptor transcripts, it appears that psychostimulants induce Fos in PVT neurons through a D3 dopamine receptor. We suggest that the PVT may be an important part of an extended circuit subserving both the arousing properties and reinforcing aspects of psychostimulants. PMID:9852603

  10. Mechanically induced c-fos expression is mediated by cAMP in MC3T3-E1 osteoblasts

    NASA Technical Reports Server (NTRS)

    Fitzgerald, J.; Hughes-Fulford, M.

    1999-01-01

    In serum-deprived MC3T3-E1 osteoblasts, mechanical stimulation caused by mild (287 x g) centrifugation induced a 10-fold increase in mRNA levels of the proto-oncogene, c-fos. Induction of c-fos was abolished by the cAMP-dependent protein kinase inhibitor H-89, suggesting that the transient c-fos mRNA increase is mediated by cAMP. Down-regulation of protein kinase C (PKC) activity by chronic TPA treatment failed to significantly reduce c-fos induction, suggesting that TPA-sensitive isoforms of PKC are not responsible for c-fos up-regulation. In addition, 287 x g centrifugation increased intracellular prostaglandin E2 (PGE2) levels 2.8-fold (P<0. 005). Since we have previously shown that prostaglandin E2 (PGE2) can induce c-fos expression via a cAMP-mediated mechanism, we asked whether the increase in c-fos mRNA was due to centrifugation-induced PGE2 release. Pretreatment with the cyclooxygenase inhibitors indomethacin and flurbiprofen did not hinder the early induction of c-fos by mechanical stimulation. We conclude that c-fos expression induced by mild mechanical loading is dependent primarily on cAMP, not PKC, and initial induction of c-fos is not necessarily dependent on the action of newly synthesized PGE2.

  11. Mechanism of Ghrelin-Induced Gastric Contractions in Suncus murinus (House Musk Shrew): Involvement of Intrinsic Primary Afferent Neurons

    PubMed Central

    Mondal, Anupom; Aizawa, Sayaka; Sakata, Ichiro; Goswami, Chayon; Oda, Sen-ichi; Sakai, Takafumi

    2013-01-01

    Here, we have reported that motilin can induce contractions in a dose-dependent manner in isolated Suncus murinus (house musk shrew) stomach. We have also shown that after pretreatment with a low dose of motilin (10−10 M), ghrelin also induces gastric contractions at levels of 10−10 M to 10−7 M. However, the neural mechanism of ghrelin action in the stomach has not been fully revealed. In the present study, we studied the mechanism of ghrelin-induced contraction in vitro using a pharmacological method. The responses to ghrelin in the stomach were almost completely abolished by hexamethonium and were significantly suppressed by the administration of phentolamine, prazosin, ondansetron, and naloxone. Additionally, N-nitro-l-arginine methylester significantly potentiated the contractions. Importantly, the mucosa is essential for ghrelin-induced, but not motilin-induced, gastric contractions. To evaluate the involvement of intrinsic primary afferent neurons (IPANs), which are multiaxonal neurons that pass signals from the mucosa to the myenteric plexus, we examined the effect of the IPAN-related pathway on ghrelin-induced contractions and found that pretreatment with adenosine and tachykinergic receptor 3 antagonists (SR142801) significantly eliminated the contractions and GR113808 (5-hydroxytryptamine receptor 4 antagonist) almost completely eliminated it. The results indicate that ghrelin stimulates and modulates suncus gastric contractions through cholinergic, adrenergic, serotonergic, opioidergic neurons and nitric oxide synthases in the myenteric plexus. The mucosa is also important for ghrelin-induced gastric contractions, and IPANs may be the important interneurons that pass the signal from the mucosa to the myenteric plexus. PMID:23565235

  12. Differentiation-induced skin cancer suppression by FOS, p53, and TACE/ADAM17

    PubMed Central

    Guinea-Viniegra, Juan; Zenz, Rainer; Scheuch, Harald; Jiménez, María; Bakiri, Latifa; Petzelbauer, Peter; Wagner, Erwin F.

    2012-01-01

    Squamous cell carcinomas (SCCs) are heterogeneous and aggressive skin tumors for which innovative, targeted therapies are needed. Here, we identify a p53/TACE pathway that is negatively regulated by FOS and show that the FOS/p53/TACE axis suppresses SCC by inducing differentiation. We found that epidermal Fos deletion in mouse tumor models or pharmacological FOS/AP-1 inhibition in human SCC cell lines induced p53 expression. Epidermal cell differentiation and skin tumor suppression were caused by a p53-dependent transcriptional activation of the metalloprotease TACE/ADAM17 (TNF-α–converting enzyme), a previously unknown p53 target gene that was required for NOTCH1 activation. Although half of cutaneous human SCCs display p53-inactivating mutations, restoring p53/TACE activity in mouse and human skin SCCs induced tumor cell differentiation independently of the p53 status. We propose FOS/AP-1 inhibition or p53/TACE reactivating strategies as differentiation-inducing therapies for SCCs. PMID:22772468

  13. REGION-SPECIFIC MECHANISMS FOR TESTOSTERONE-INDUCED FOS IN HAMSTER BRAIN

    PubMed Central

    Nagypál, Anita; Wood, Ruth I.

    2007-01-01

    Hamsters self-administer androgens. Previously, we determined that testosterone (T) activates select steroid- and opiate-sensitive brain regions. Is T-stimulated neuronal activation androgenic? 35 castrated males with physiologic T replacement (n=7/group) were pre-treated with the androgen antagonist flutamide (15 mg/kg sc) or ethanol (0.25 ml), and infused into the lateral ventricle (ICV) for 4h with 40 μg T (TF and TE, respectively) or 40 μl vehicle (VF and VE). To determine if androgens and opiates activate overlapping brain areas, 7 additional males received 20 μg morphine sulfate ICV following ethanol injection (ME). Immediately after ICV infusion, animals were perfused. 60 μm coronal brain slices were stained for Fos. Fos-positive neurons were counted in a 0.3 mm2 area from 5 regions previously shown to express T-induced Fos: the posteromedial bed nucleus of the stria terminalis (BSTPM), posteromedial amygdala (MeP), lateral habenula (LHb), ventral tegmental area, and lateral pontine nucleus. T induced Fos in all areas reported previously (TE vs. VE, p<0.05), except LHb (p>0.05). Morphine induced Fos in all 5 brain regions (ME vs. VE, p<0.05), indicating that androgens and opiates activate overlapping brain regions. Flutamide alone did not induce Fos (VF vs. VE, p>0.05). Moreover, flutamide treatment blocked T-induced Fos expression only in the steroid-sensitive BSTPM, suggesting that androgens mediate neuronal activation in this area (mean±SEM: TF: 68.4±13.2 vs. TE: 137.9±17.6, p<0.05). The absence of flutamide effects on T-induced Fos in the steroid-sensitive MeP (TE: 210.6±50.0 vs. TF: 215.3±28.2, p>0.05) suggests that distinct mechanisms activate Fos in individual androgen-responsive nuclei. PMID:17276422

  14. Ghrelin mediates stress-induced food-reward behavior in mice.

    PubMed

    Chuang, Jen-Chieh; Perello, Mario; Sakata, Ichiro; Osborne-Lawrence, Sherri; Savitt, Joseph M; Lutter, Michael; Zigman, Jeffrey M

    2011-07-01

    The popular media and personal anecdotes are rich with examples of stress-induced eating of calorically dense "comfort foods." Such behavioral reactions likely contribute to the increased prevalence of obesity in humans experiencing chronic stress or atypical depression. However, the molecular substrates and neurocircuits controlling the complex behaviors responsible for stress-based eating remain mostly unknown, and few animal models have been described for probing the mechanisms orchestrating this response. Here, we describe a system in which food-reward behavior, assessed using a conditioned place preference (CPP) task, is monitored in mice after exposure to chronic social defeat stress (CSDS), a model of prolonged psychosocial stress, featuring aspects of major depression and posttraumatic stress disorder. Under this regime, CSDS increased both CPP for and intake of high-fat diet, and stress-induced food-reward behavior was dependent on signaling by the peptide hormone ghrelin. Also, signaling specifically in catecholaminergic neurons mediated not only ghrelin's orexigenic, antidepressant-like, and food-reward behavioral effects, but also was sufficient to mediate stress-induced food-reward behavior. Thus, this mouse model has allowed us to ascribe a role for ghrelin-engaged catecholaminergic neurons in stress-induced eating. PMID:21701068

  15. Impact of [d-Lys(3)]-GHRP-6 and feeding status on hypothalamic ghrelin-induced stress activation.

    PubMed

    Brockway, Emma T; Krater, Katherine R; Selva, Joaquín A; Wauson, Shelby E R; Currie, Paul J

    2016-05-01

    Ghrelin administration directly into hypothalamic nuclei, including the arcuate nucleus (ArcN) and the paraventricular nucleus (PVN), alters the expression of stress-related behaviors. In the present study we investigated the effect of feeding status on the ability of ghrelin to induce stress and anxiogenesis. Adult male Sprague Dawley rats were implanted with guide cannula targeting either the ArcN or PVN. In the first experiment we confirmed that ArcN and PVN ghrelin treatment produced anxiety-like behavior as measured using the elevated plus maze (EPM) paradigm. Ghrelin was administered during the early dark cycle. Immediately after microinjections rats were placed in the EPM for 5min. Both ArcN and PVN treatment reduced open arm exploration. The effect was attenuated by pretreatment with the ghrelin 1a receptor antagonist [d-Lys(3)]-GHRP-6. In a separate group of animals ghrelin was injected into either nucleus and rats were returned to their home cages for 60min with free access to food. An additional group of rats was returned to home cages with no food access. After 60min with or without food access all rats were tested in the EPM. Results indicated that food consumption just prior to EPM testing reversed the avoidance of the open arms of the EPM. In contrast, rats injected with ghrelin, placed in their home cage for 60min without food, and subsequently tested in the EPM, exhibited an increased avoidance of the open arms, consistent with stress activation. Overall, our findings demonstrate that ghrelin 1a receptor blockade and feeding status appear to impact the ability of ArcN and PVN ghrelin to elicit stress and anxiety-like behaviors. PMID:27020248

  16. d-LSD-induced c-Fos expression occurs in a population of oligodendrocytes in rat prefrontal cortex.

    PubMed

    Reissig, Chad J; Rabin, Richard A; Winter, Jerrold C; Dlugos, Cynthia A

    2008-03-31

    Induction of mRNA or protein for immediate-early genes, such as c-fos, is used to identify brain areas, specific cell types, and neuronal circuits that become activated in response to various stimuli including psychoactive drugs. The objective of the present study was to identify the cell types in the prefrontal cortex in which lysergic acid diethylamide (d-LSD) induces c-Fos expression. Systemic administration of d-LSD resulted in a dose-dependent increase in c-Fos immunoreactivity. Although c-Fos-positive cells were found in all cortical layers, they were most numerous in layers III, IV, and V. d-LSD-induced c-Fos immunoreactivity was found in cells co-labeled with anti-neuron-specific enolase or anti-oligodendrocyte Oligo1. The Oligo1-labeled cells had small, round bodies and nuclear diameters characteristic of oligodendrocytes. Studies using confocal microscopy confirmed colocalization of c-Fos-labeled nuclei in NeuN-labeled neurons. Astrocytes and microglia labeled with glial fibrillary acidic protein antibody and OX-42 antibody, respectively, did not display LSD-induced c-Fos expression. Pyramidal neurons labeled with anti-neurofilament antibody also did not show induction of c-Fos immunoreactivity after systemic d-LSD administration. The present study demonstrates that d-LSD induced expression of c-Fos in the prefrontal cortex occurs in subpopulations of neurons and in oligodendrocytes, but not in pyramidal neurons, astrocytes, and microglia.

  17. Central ghrelin increases food foraging/hoarding that is blocked by GHSR antagonism and attenuates hypothalamic paraventricular nucleus neuronal activation.

    PubMed

    Thomas, Michael A; Ryu, Vitaly; Bartness, Timothy J

    2016-02-01

    The stomach-derived "hunger hormone" ghrelin increases in the circulation in direct response to time since the last meal, increasing preprandially and falling immediately following food consumption. We found previously that peripheral injection of ghrelin potently stimulates food foraging (FF), food hoarding (FH), and food intake (FI) in Siberian hamsters. It remains, however, largely unknown if central ghrelin stimulation is necessary/sufficient to increase these behaviors regardless of peripheral stimulation of the ghrelin receptor [growth hormone secretagogue receptor (GHSR)]. We injected three doses (0.01, 0.1, and 1.0 μg) of ghrelin into the third ventricle (3V) of Siberian hamsters and measured changes in FF, FH, and FI. To test the effects of 3V ghrelin receptor blockade, we used the potent GHSR antagonist JMV2959 to block these behaviors in response to food deprivation or a peripheral ghrelin challenge. Finally, we examined neuronal activation in the arcuate nucleus and paraventricular hypothalamic nucleus in response to peripheral ghrelin administration and 3V GHSR antagonism. Third ventricular ghrelin injection significantly increased FI through 24 h and FH through day 4. Pretreatment with 3V JMV2959 successfully blocked peripheral ghrelin-induced increases in FF, FH, and FI at all time points and food deprivation-induced increases in FF, FH, and FI up to 4 h. c-Fos immunoreactivity was significantly reduced in the paraventricular hypothalamic nucleus, but not in the arcuate nucleus, following pretreatment with intraperitoneal JMV2959 and ghrelin. Collectively, these data suggest that central GHSR activation is both necessary and sufficient to increase appetitive and consummatory behaviors in Siberian hamsters.

  18. Lysergic acid diethylamide-induced Fos expression in rat brain: role of serotonin-2A receptors.

    PubMed

    Gresch, P J; Strickland, L V; Sanders-Bush, E

    2002-01-01

    Lysergic acid diethylamide (LSD) produces altered mood and hallucinations in humans and binds with high affinity to serotonin-2A (5-HT(2A)) receptors. Although LSD interacts with other receptors, the activation of 5-HT(2A) receptors is thought to mediate the hallucinogenic properties of LSD. The goal of this study was to identify the brain sites activated by LSD and to determine the influence of 5-HT(2A) receptors in this activation. Rats were pretreated with the 5-HT(2A) receptor antagonist MDL 100907 (0.3 mg/kg, i.p.) or vehicle 30 min prior to LSD (500 microg/kg, i.p.) administration and killed 3 h later. Brain tissue was examined for Fos protein expression by immunohistochemistry. LSD administration produced a five- to eight-fold increase in Fos-like immunoreactivity in medial prefrontal cortex, anterior cingulate cortex, and central nucleus of amygdala. However, in dorsal striatum and nucleus accumbens no increase in Fos-like immunoreactivity was observed. Pretreatment with MDL 100907 completely blocked LSD-induced Fos-like immunoreactivity in medial prefrontal cortex and anterior cingulate cortex, but only partially blocked LSD-induced Fos-like immunoreactivity in amygdala. Double-labeled immunohistochemistry revealed that LSD did not induce Fos-like immunoreactivity in cortical cells expressing 5-HT(2A) receptors, suggesting an indirect activation of cortical neurons. These results indicate that the LSD activation of medial prefrontal cortex and anterior cingulate cortex is mediated by 5-HT(2A) receptors, whereas in amygdala 5-HT(2A) receptor activation is a component of the response. These findings support the hypothesis that the medial prefrontal cortex, anterior cingulate cortex, and perhaps the amygdala, are important regions involved in the production of hallucinations.

  19. Central neuropeptide Y receptors are involved in 3rd ventricular ghrelin induced alteration of colonic transit time in conscious fed rats

    PubMed Central

    Tebbe, Johannes J; Tebbe, Clemens G; Mronga, Silke; Ritter, Michael; Schäfer, Martin KH

    2005-01-01

    Background Feeding related peptides have been shown to be additionally involved in the central autonomic control of gastrointestinal functions. Recent studies have shown that ghrelin, a stomach-derived orexigenic peptide, is involved in the autonomic regulation of GI function besides feeding behavior. Pharmacological evidence indicates that ghrelin effects on food intake are mediated by neuropeptide Y in the central nervous system. Methods In the present study we examine the role of ghrelin in the central autonomic control of GI motility using intracerobroventricular and IP microinjections in a freely moving conscious rat model. Further the hypothesis that a functional relationship between NPY and ghrelin within the CNS exists was addressed. Results ICV injections of ghrelin (0.03 nmol, 0.3 nmol and 3.0 nmol/5 μl and saline controls) decreased the colonic transit time up to 43%. IP injections of ghrelin (0.3 nmol – 3.0 nmol kg-1 BW and saline controls) decreased colonic transit time dose related. Central administration of the NPY1 receptor antagonist, BIBP-3226, prior to centrally or peripherally administration of ghrelin antagonized the ghrelin induced stimulation of colonic transit. On the contrary ICV-pretreatment with the NPY2 receptor antagonist, BIIE-0246, failed to modulate the ghrelin induced stimulation of colonic motility. Conclusion The results suggest that ghrelin acts in the central nervous system to modulate gastrointestinal motor function utilizing NPY1 receptor dependent mechanisms. PMID:15720710

  20. Overexpression of intraislet ghrelin enhances β-cell proliferation after streptozotocin-induced β-cell injury in mice.

    PubMed

    Bando, Mika; Iwakura, Hiroshi; Ariyasu, Hiroyuki; Koyama, Hiroyuki; Hosoda, Kiminori; Adachi, Souichi; Nakao, Kazuwa; Kangawa, Kenji; Akamizu, Takashi

    2013-07-01

    Previously, we reported that exogenous administration of ghrelin ameliorates glucose metabolism in a neonate streptozotocin (STZ)-induced diabetic rat model through enhancement of β-cell proliferation. However, it was not clear whether the observed β-cell proliferation was a direct or indirect effect (e.g., via orexigenic or growth hormone-stimulated pathways) of ghrelin activity. Here, we aimed to investigate whether ghrelin directly impacts β-cell proliferation after STZ-induced injury in mice. Seven-week-old male rat insulin II promoter-ghrelin internal ribosomal sequence ghrelin O-acyltransferase transgenic (RIP-GG Tg) mice, which have elevated pancreatic ghrelin levels, but only minor changes in plasma ghrelin levels when fed a medium-chain triglyceride-rich diet, were treated with STZ. Then, serum insulin, pancreatic insulin mRNA expression, and islet histology were evaluated. We found that the serum insulin levels, but not blood glucose levels, of RIP-GG Tg mice were significantly ameliorated 14 days post-STZ treatment. Pancreatic insulin mRNA expression was significantly elevated in RIP-GG Tg mice, and β-cell numbers in islets were increased. Furthermore, the number of phospho-histone H3⁺ or Ki67⁺ proliferating β-cells was significantly elevated in RIP-GG Tg mice, whereas the apoptotic indexes within the islets, as determined by TUNEL assay, were not changed. These results indicate that ghrelin can directly stimulate β-cell proliferation in vivo after β-cell injury even without its orexigenic or GH-stimulating activities, although it did not have enough impact to normalize the glucose tolerance in adult mice.

  1. Context-Induced Reinstatement of Methamphetamine Seeking Is Associated with Unique Molecular Alterations in Fos-Expressing Dorsolateral Striatum Neurons

    PubMed Central

    Rubio, F. Javier; Liu, Qing-Rong; Li, Xuan; Cruz, Fabio C.; Leão, Rodrigo M.; Warren, Brandon L.; Kambhampati, Sarita; Babin, Klil R.; McPherson, Kylie B.; Cimbro, Raffaello; Bossert, Jennifer M.; Shaham, Yavin

    2015-01-01

    Context-induced reinstatement of drug seeking is a well established animal model for assessing the neural mechanisms underlying context-induced drug relapse, a major factor in human drug addiction. Neural activity in striatum has previously been shown to contribute to context-induced reinstatement of heroin, cocaine, and alcohol seeking, but not yet for methamphetamine seeking. In this study, we found that context-induced reinstatement of methamphetamine seeking increased expression of the neural activity marker Fos in dorsal but not ventral striatum. Reversible inactivation of neural activity in dorsolateral but not dorsomedial striatum using the GABA agonists muscimol and baclofen decreased context-induced reinstatement. Based on our previous findings that Fos-expressing neurons play a critical role in conditioned drug effects, we assessed whether context-induced reinstatement was associated with molecular alterations selectively induced within context-activated Fos-expressing neurons. We used fluorescence-activated cell sorting to isolate reinstatement-activated Fos-positive neurons from Fos-negative neurons in dorsal striatum and used quantitative PCR to assess gene expression within these two populations of neurons. Context-induced reinstatement was associated with increased expression of the immediate early genes Fos and FosB and the NMDA receptor subunit gene Grin2a in only Fos-positive neurons. RNAscope in situ hybridization confirmed that Grin2a, as well as Grin2b, expression were increased in only Fos-positive neurons from dorsolateral, but not dorsomedial, striatum. Our results demonstrate an important role of dorsolateral striatum in context-induced reinstatement of methamphetamine seeking and that this reinstatement is associated with unique gene alterations in Fos-expressing neurons. PMID:25855177

  2. Ghrelin reverses experimental diabetic neuropathy in mice

    SciTech Connect

    Kyoraku, Itaru; Shiomi, Kazutaka; Kangawa, Kenji; Nakazato, Masamitsu

    2009-11-20

    Ghrelin, an acylated peptide produced in the stomach, increases food intake and growth hormone secretion, suppresses inflammation and oxidative stress, and promotes cell survival and proliferation. We investigated the pharmacological potential of ghrelin in the treatment of polyneuropathy in uncontrolled streptozotocin (STZ)-induced diabetes in mice. Ghrelin or desacyl-ghrelin was administered daily for 4 weeks after STZ-induced diabetic polyneuropathy had developed. Ghrelin administration did not alter food intake, body weight gain, blood glucose levels, or plasma insulin levels when compared with mice given saline or desacyl-ghrelin administration. Ghrelin administration ameliorated reductions in motor and sensory nerve conduction velocities in diabetic mice and normalized their temperature sensation and plasma concentrations of 8-isoprostaglandin {alpha}, an oxidative stress marker. Desacyl-ghrelin failed to have any effect. Ghrelin administration in a mouse model of diabetes ameliorated polyneuropathy. Thus, ghrelin's effects represent a novel therapeutic paradigm for the treatment of this otherwise intractable disorder.

  3. Tail pinch induces fos immunoreactivity within several regions of the male rat brain: effects of age.

    PubMed

    Smith, W J; Stewart, J; Pfaus, J G

    1997-05-01

    Brief, intermittent stressors, such as low-level foot shock or tail pinch, induce a general excitement and autonomic arousal in rats that increases their sensitivity to external incentives. Such stimulation can facilitate a variety of behaviors, including feeding, aggression, sexual activity, parental behavior, and drug taking if the appropriate stimuli exist in the environment. However, the ability of tail pinch to induce general arousal and incentive motivation appears to diminish with age. Here we report on the ability of tail pinch to induce Fos immunoreactivity within several brain regions as a function of age. Young (2-3 months) and middle-aged (12-13 months) male rats were administered either five tail pinches (one every 2 min), one tail pinch, or zero (sham) tail pinches (n = 4 per stimulation condition). Rats were sacrificed 75 min following the onset of stimulation, and their brains were prepared for immunocytochemical detection of Fos protein. Fos immunoreactivity was induced by one and five tail pinches in several brain regions, including the anterior medial preoptic area (mPOA), paraventricular nucleus of the hypothalamus (PVN), paraventricular nucleus of the thalamus (PV-Thal), medial amygdala (MEA), basolateral amygdala (BLA), lateral habenula (LHab), and ventral tegmental area (VTA), of young rats compared with those that received zero tail pinches. In contrast to young rats, middle-aged rats had significantly less Fos induced by one and five tail pinches in the mPOA, PVN, MEA, BLA, and VTA, but an equivalent amount induced in the LHab. Fos immunoreactivity was not found within the medial prefrontal cortex, nucleus accumbens, striatum, lateral septum, or locus coeruleus in either young or old rats. Tail pinch appears to activate regions of the brain known to be involved in behavioral responses to both incentive cues and stressors. The lower level of cellular reactivity to tail pinch in middle-aged rats suggests a diminished neural responsiveness to

  4. Inflammation-mediated skin tumorigenesis induced by epidermal c-Fos

    PubMed Central

    Briso, Eva M.; Guinea-Viniegra, Juan; Bakiri, Latifa; Rogon, Zbigniew; Petzelbauer, Peter; Eils, Roland; Wolf, Ronald; Rincón, Mercedes; Angel, Peter; Wagner, Erwin F.

    2013-01-01

    Skin squamous cell carcinomas (SCCs) are the second most prevalent skin cancers. Chronic skin inflammation has been associated with the development of SCCs, but the contribution of skin inflammation to SCC development remains largely unknown. In this study, we demonstrate that inducible expression of c-fos in the epidermis of adult mice is sufficient to promote inflammation-mediated epidermal hyperplasia, leading to the development of preneoplastic lesions. Interestingly, c-Fos transcriptionally controls mmp10 and s100a7a15 expression in keratinocytes, subsequently leading to CD4 T-cell recruitment to the skin, thereby promoting epidermal hyperplasia that is likely induced by CD4 T-cell-derived IL-22. Combining inducible c-fos expression in the epidermis with a single dose of the carcinogen 7,12-dimethylbenz(a)anthracene (DMBA) leads to the development of highly invasive SCCs, which are prevented by using the anti-inflammatory drug sulindac. Moreover, human SCCs display a correlation between c-FOS expression and elevated levels of MMP10 and S100A15 proteins as well as CD4 T-cell infiltration. Our studies demonstrate a bidirectional cross-talk between premalignant keratinocytes and infiltrating CD4 T cells in SCC development. Therefore, targeting inflammation along with the newly identified targets, such as MMP10 and S100A15, represents promising therapeutic strategies to treat SCCs. PMID:24029918

  5. Parathyroid hormone induces c-fos and c-jun messenger RNA in rat osteoblastic cells

    NASA Technical Reports Server (NTRS)

    Clohisy, J. C.; Scott, D. K.; Brakenhoff, K. D.; Quinn, C. O.; Partridge, N. C.

    1992-01-01

    PTH is a potent regulator of osteoblast gene expression, yet the nuclear events that mediate PTH action are poorly understood. We were interested in identifying immediate early genes which may regulate PTH-altered gene expression in the osteoblast. Therefore, we examined the effects of PTH on c-fos and c-jun gene expression in a rat osteoblastic cell line (UMR 106-01). Under control conditions, c-fos and c-jun mRNAs were present at low basal levels. After PTH treatment, c-fos mRNA abundance dramatically increased, with a maximal and transient response at 30 min. PTH also stimulated an increase in c-jun mRNA, but in a biphasic manner, with maximal levels at 30 min and 2 h. These responses were dose dependent, not altered by cotreatment with the protein synthesis inhibitor cycloheximide, and preceded PTH-induced expression of matrix metallo-proteinase-1 mRNA. Nuclear run-on assays demonstrated an increased rate of c-fos and c-jun transcription after PTH exposure. To determine the signal transduction pathways involved, second messenger analogs were tested for their ability to mimic the effects of PTH. 8-Bromo-cAMP and phorbol 12-myristate 13-acetate (PMA) caused increases in the abundance of c-fos and c-jun transcripts. Ionomycin had no effect on the expression of these genes. Pretreatment of the cells with PMA resulted in a decrease in basal c-jun expression, but did not alter the PTH-mediated increase in c-fos, c-jun, or matrix metalloproteinase-1 mRNAs.(ABSTRACT TRUNCATED AT 250 WORDS).

  6. Identification of the ghrelin-GHSR 1 system and its influence in the modulation of induced ocular hypertension in rabbit and rat eyes.

    PubMed

    Rocha-Sousa, A; Pereira-Silva, P; Tavares-Silva, M; Azevedo-Pinto, S; Rodrigues-Araújo, J; Pinho, S; Avelino, A; Falcão-Reis, F; Leite-Moreira, A

    2014-07-01

    Recent studies evidenced a decrease in ghrelin's aqueous humor levels in patients with glaucoma. The goal of our investigation was to study the effect of the ghrelin-GHSR-1a system in the modulation of intraocular pressure in acute ocular hypertension models and its expression and distribution in ocular tissues. Two animal models of acute ocular hypertension were used to study the effect of the ghrelin-GHSR-1a system in the modulation of intraocular pressure: the rabbit and the rat. Ocular hypertension was induced by an intravitreal injection of 20% NaCl. Ghrelin or des-acyl ghrelin were delivered subconjunctivally and the intraocular pressure was assessed by a rebound tonometer that was calibrated for each species. In addition, we have studied the influence of nitric oxide and prostaglandins on ghrelin's effect in the rabbit animal model. Finally, we determined by immunofluorescence the expression of ghrelin and GHSR-1 in the rat's ocular tissue. Ghrelin decreased the intraocular pressure in both animal models (maximum decrease: 43.8±12.0% in the rabbit and 29.0±7.46% in the rat). In the rabbit, this effect was blunted in the presence of l-NAME and ketorolac. Des-acyl ghrelin only decreased the intraocular pressure in the rat (maximum decrease: 34.9±8.15%). Ghrelin expression was detected in the ciliary processes and GHSR-1 expression was detected in the trabecular meshwork and ciliary body. The ghrelin-GHSR-1 system is expressed in the anterior segment of the eye. Ghrelin and des-acyl ghrelin are responsible for a hypotensive effect in acute ocular hypertension animal models.

  7. Nitric oxide signaling in ghrelin-induced LH release from goldfish pituitary cells.

    PubMed

    Grey, Caleb L; Chang, John P

    2013-03-01

    Among its many known functions, ghrelin has been proposed to participate in the regulation of reproduction; however, its effect on pituitary LH release is controversial, especially in mammals. In the goldfish, ghrelin directly stimulates pituitary LH release via increased entry of calcium through voltage sensitive channels and activation of protein kinase C. Nitric oxide (NO) is an important signaling molecule in many physiological systems including hormone regulation at the level of the pituitary. Goldfish pituitary cells and extracts have previously been reported to express immunoreactivity for inducible and neuronal NO synthase (iNOS and nNOS). In this study, we determined if NO is involved in goldfish ghrelin (gGRLN(19))-induced LH release from primary cultures of dispersed goldfish pituitary cells in column perifusion. Treatment with the NO scavenger PTIO significantly decreased gGRLN(19)-induced LH release and co-treatment with the NO donor SNP and gGRLN(19) did not induce an additive increase in LH release, suggesting that NO is critical to gGRLN(19) stimulation of LH release in goldfish pituitary cells. Further work examined the involvement of the NOS using the NOS isoform-selective inhibitors 1400W, 7-Ni, and AGH. While 1400W (selective for iNOS) and AGH (selective for iNOS and nNOS) abolished gGRLN(19)-induced LH release from goldfish pituitary cells, 7-Ni (selective for nNOS and endothelial NOS) had no significant effect on this stimulation. Our results indicate, for the first time in a teleost species, that gGRLN(19)-induced LH release from pituitary cells is NO-dependent and likely involves iNOS, adding to the understanding of GRLN intracellular signaling in general and specifically to the regulation of LH release from the pituitary.

  8. Intracisternal TRH analog induces Fos expression in gastric myenteric neurons and glia in conscious rats.

    PubMed

    Miampamba, M; Yang, H; Sharkey, K A; Taché, Y

    2001-05-01

    Activation of gastric myenteric cells by intracisternal injection of the stable thyrotropin-releasing hormone (TRH) analog RX-77368, at a dose inducing near maximal vagal cholinergic stimulation of gastric functions, was investigated in conscious rats. Fos immunoreactivity was assessed in gastric longitudinal muscle-myenteric plexus whole mount preparations 90 min after intracisternal injection. Fos-immunoreactive cells were rare in controls (~1 cell/ganglion), whereas intracisternal RX-77368 (50 ng) increased the number to 24.8 +/- 1.8 and 26.8 +/- 2.2 cells/ganglion in the corpus and antrum, respectively. Hexamethonium (20 mg/kg sc) prevented Fos expression by 90%, whereas atropine (2 mg/kg sc) had no effect. The neuronal marker protein gene product 9.5 and the glial markers S-100 and glial fibrillary acidic proteins showed that RX-77368 induced Fos in both myenteric neurons and glia. Vesicular ACh transporter and calretinin were detected around the activated myenteric neurons. These results indicated that central vagal efferent stimulation by intracisternal RX-77368 activates gastric myenteric neurons as well as glial cells mainly through nicotinic ACh receptors in conscious rats.

  9. Non-photic manipulations induce expression of Fos protein in the suprachiasmatic nucleus and intergeniculate leaflet in the rat.

    PubMed

    Edelstein, K; Amir, S

    1995-09-01

    Expression of Fos protein in the suprachiasmatic nucleus (SCN) and intergeniculate leaflet (IGL) is considered a cellular correlate of light-induced phase-shift of circadian rhythms in rodents. Non-photic stimuli also induce phase shifts, but their effects on Fos expression have not been established. We examined induction of Fos protein in SCN and IGL regions, in response to cage change, intraperitoneal saline injection, and restraint stress. Fos immunoreactivity was observed in SCN and IGL regions, with greater expression observed in IGL during the light phase of the light-dark cycle. Results suggest that cells in SCN and IGL respond to several types of non-photic manipulations and that expression of Fos in these regions is not light-specific. PMID:8535846

  10. Fos immunoreactivity in the rat forebrain induced by electrical stimulation of the dorsolateral periaqueductal gray matter.

    PubMed

    Lim, Lee Wei; Temel, Yasin; Visser-Vandewalle, Veerle; Blokland, Arjan; Steinbusch, Harry

    2009-10-01

    Electrical stimulation of the dorsolateral periaqueductal gray (dlPAG) matter induces panic- or fear-like responses with intense emotional distress and severe anxiety. In this study, we evoked panic-like behaviour by dlPAG stimulation and evaluated the effect on neuronal activation in different brain regions. The number of c-Fos immunoreactive (c-Fos-ir) cells was measured semi-quantitatively through series of stained rat brain sections. Our results demonstrate strong neural activation in the medial prefrontal cortex, orbital cortex, anterior olfactory nuclei, secondary motor cortex, and the somatosensory cortex. Moderate increases in the number of c-Fos-ir cells were detected in various regions, including the hypothalamus, amygdala, and striatum. Additionally, there was mild expression of c-Fos-ir cells in the hippocampus, thalamus, and habenula regions. In conclusion, we have shown that deep brain stimulation of the dlPAG produced a distinctive pattern of neuronal activation across forebrain regions as compared to the sham and control animals.

  11. Fos expression in brain stem nuclei of pregnant rats after hydralazine-induced hypotension.

    PubMed

    Curtis, K S; Cunningham, J T; Heesch, C M

    1999-08-01

    Fos and dopamine beta-hydroxylase immunoreactivity were evaluated in the brain stems of 21-day pregnant and virgin female rats injected with either hydralazine (HDZ; 10 mg/kg iv) or vehicle. HDZ produced significant hypotension in both groups, although baseline blood pressure was lower in pregnant rats (96 +/- 2.5 mmHg) than in virgin female rats (121 +/- 2.8 mmHg). There were no differences in Fos immunoreactivity in the brain stems of pregnant and virgin female rats after vehicle treatment. HDZ-induced hypotension significantly increased Fos expression in both groups; however, the magnitude of the increases differed in the caudal ventrolateral medulla (CVL), the area postrema (AP), and the rostral ventrolateral medulla (RVL). Fos expression after HDZ in pregnant rats was augmented in noncatecholaminergic neurons of the CVL but was attenuated in the AP and in noncatecholaminergic neurons in the RVL. These results are consistent with differences in the sympathetic response to hypotension between pregnant and virgin female rats and indicate that the central response to hypotension may be different in pregnant rats.

  12. Ghrelin mediates stress-induced food-reward behavior in mice

    PubMed Central

    Chuang, Jen-Chieh; Perello, Mario; Sakata, Ichiro; Osborne-Lawrence, Sherri; Savitt, Joseph M.; Lutter, Michael; Zigman, Jeffrey M.

    2011-01-01

    The popular media and personal anecdotes are rich with examples of stress-induced eating of calorically dense “comfort foods.” Such behavioral reactions likely contribute to the increased prevalence of obesity in humans experiencing chronic stress or atypical depression. However, the molecular substrates and neurocircuits controlling the complex behaviors responsible for stress-based eating remain mostly unknown, and few animal models have been described for probing the mechanisms orchestrating this response. Here, we describe a system in which food-reward behavior, assessed using a conditioned place preference (CPP) task, is monitored in mice after exposure to chronic social defeat stress (CSDS), a model of prolonged psychosocial stress, featuring aspects of major depression and posttraumatic stress disorder. Under this regime, CSDS increased both CPP for and intake of high-fat diet, and stress-induced food-reward behavior was dependent on signaling by the peptide hormone ghrelin. Also, signaling specifically in catecholaminergic neurons mediated not only ghrelin’s orexigenic, antidepressant-like, and food-reward behavioral effects, but also was sufficient to mediate stress-induced food-reward behavior. Thus, this mouse model has allowed us to ascribe a role for ghrelin-engaged catecholaminergic neurons in stress-induced eating. PMID:21701068

  13. Neuronal deletion of ghrelin receptor almost completely prevents diet-induced obesity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ghrelin signaling has major effects on energy- and glucose-homeostasis, but it is unknown whether ghrelin's functions are centrally and/or peripherally mediated. The ghrelin receptor, Growth Hormone Secretagogue Receptor (GHS-R), is highly expressed in brain and detectable in some peripheral tissues...

  14. 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.

  15. Modulation of cue-induced firing of ventral tegmental area dopamine neurons by leptin and ghrelin

    PubMed Central

    van der Plasse, G; van Zessen, R; Luijendijk, M C M; Erkan, H; Stuber, G D; Ramakers, G M J; Adan, R A H

    2015-01-01

    Background/objectives: The rewarding value of palatable foods contributes to overconsumption, even in satiated subjects. Midbrain dopaminergic activity in response to reward-predicting environmental stimuli drives reward-seeking and motivated behavior for food rewards. This mesolimbic dopamine (DA) system is sensitive to changes in energy balance, yet it has thus far not been established whether reward signaling of DA neurons in vivo is under control of hormones that signal appetite and energy balance such as ghrelin and leptin. Subjects/methods: We trained rats (n=11) on an operant task in which they could earn two different food rewards. We then implanted recording electrodes in the ventral tegmental area (VTA), and recorded from DA neurons during behavior. Subsequently, we assessed the effects of mild food restriction and pretreatment with the adipose tissue-derived anorexigenic hormone leptin or the orexigenic hormone ghrelin on VTA DA reward signaling. Results: Animals showed an increase in performance following mild food restriction (P=0.002). Importantly, food-cue induced DA firing increased when animals were food restricted (P=0.02), but was significantly attenuated after leptin pretreatment (P=0.00). While ghrelin did affect baseline DA activity (P=0.025), it did not affect cue-induced firing (P⩾0.353). Conclusions: Metabolic signals, such as leptin, affect food seeking, a process that is dependent on the formation of cue-reward outcomes and involves midbrain DA signaling. These data show that food restriction engages the encoding of food cues by VTA DA neurons at a millisecond level and leptin suppresses this activity. This suggests that leptin is a key in linking metabolic information to reward signaling. PMID:26183405

  16. Effects of peripherally and centrally applied ghrelin in the pathogenesis of ischemia-reperfusion induced injury of the small intestine.

    PubMed

    Pawlik, M W; Obuchowicz, R; Biernat, J; Szczepanski, W; Pajdo, R; Kwiecień, S; Brzozowski, T; Konturek, S J; Pawlik, W W

    2011-08-01

    Ghrelin is an important hormone involved in the control of the human appetite center. Recently, protective properties of this hormone have been recognized in various models of impairment of the gastric mucosa, including stress, ischemia and reperfusion (I/R). Ghrelin is predominantly secreted by the gastric mucosa of stomach, but there are other sources of ghrelin, for example in the hypothalamus and various parts of the central nervous system (CNS) that should be taken into consideration. This hormone exerts biological effects via the activation of growth hormone secretagogue receptor (GHSR), the presence of which was confirmed in different parts of the gastrointestinal (GI) tract and midbrain structures. Although substantial evidence of the divergent biological effects of ghrelin and the mechanism of its action has been emphasized, the precise mechanisms of ghrelin which affords GI protection is still unclear. Particularly, there is a sparse amount of evidence concerning its action on the GI system. The major aim of the present study was to evaluate the importance of peripherally and centrally administered ghrelin at different times of the ischemia and reperfusion (I/R period in the modulation of resistance of the intestinal mucosa to the injury induced by ischemia and subsequent reperfusion. Secondly, we wanted to evaluate the possible mechanism of the action of ghrelin with a particular focus on its influence on the intestinal blood flow. Male Wistar rats were divided into 4 series (A-D) of the experimental groups (n=7). In series A the importance of peripherally administered ghrelin at different time of I/R period was studied. In series B the importance of centrally administered ghrelin at different time of I/R period was evaluated. In series C and D, the mechanisms of peripherally and centrally administered hormone were examined, respectively. Two models of the I/R period were selected: short lasting (30/60 min) and long lasting (60/120 min). The following

  17. Fos-like immunoreactivity in Siberian hamster brain during initiation of torpor-like hypothermia induced by 2DG.

    PubMed

    Park, Jin Ho; Dark, John

    2007-08-01

    Systemic 2-deoxy-d-glucose (2DG) produces pronounced torpor-like hypothermia (not< approximately 15 degrees C) in the Siberian hamster. Siberian hamsters are heterothermic, naturally undergoing photoperiod-dependent torpor during winter-like photoperiods. Fos was used to identify neural structures activated during the initiation of torpor-like hypothermia induced by 2DG treatment. The Fos-like immunoreactivity (Fos-li) in the area postrema and nucleus of the solitary tract that predominantly characterizes other 2DG-induced responses was absent during 2DG-induced torpor in the present experiment. Fos-li was seen in a number of forebrain and hindbrain sites during entry into hypothermia, but the densest Fos-li was found in the parvocellular portion of the paraventricular nucleus. Fos-li in the medial nucleus of the amygdala and the dorsal lateral septum also distinguished 2DG-induced torpor from other 2DG-induced behaviors. The possible involvement of neuropeptide Y pathways during 2DG-induced expression of reversible hypothermia is discussed.

  18. Ghrelin and the cardiovascular system.

    PubMed

    Tokudome, Takeshi; Kishimoto, Ichiro; Miyazato, Mikiya; Kangawa, Kenj

    2014-01-01

    Ghrelin is a peptide that was originally isolated from the stomach. It exerts potent growth hormone (GH)-releasing and orexigenic activities. Several studies have highlighted the therapeutic benefits of ghrelin for the treatment of cardiovascular disease. In animal models of chronic heart failure, the administration of ghrelin improved cardiac function and remodeling; these findings were replicated in human patients with heart failure. Moreover, in an animal study, ghrelin administration effectively reduced pulmonary hypertension induced by chronic hypoxia. In addition, repeated administration of ghrelin to cachectic patients with chronic obstructive pulmonary disease had positive effects on overall body function, including muscle wasting, functional capacity and sympathetic activity. The administration of ghrelin early after myocardial infarction (MI) reduced fatal arrhythmia and related mortality. In ghrelin-deficient mice, both exogenous and endogenous ghrelin were protective against fatal arrhythmia and promoted remodeling after MI. Although the mechanisms underlying the effects of ghrelin on the cardiovascular system remain unclear, there are indications that its beneficial effects are mediated through both direct physiological actions, including increased GH levels, improved energy balance and direct actions on cardiovascular cells, and regulation of autonomic nervous system activity. Therefore, ghrelin is a promising novel therapeutic agent for cardiovascular disease.

  19. Involvement of cyclooxygenase-1 and cyclooxygenase-2 activity in the therapeutic effect of ghrelin in the course of ethanol-induced gastric ulcers in rats.

    PubMed

    Warzecha, Z; Ceranowicz, P; Dembinski, M; Cieszkowski, J; Ginter, G; Ptak-Belowska, A; Dembinski, A

    2014-02-01

    Previous studies have shown that treatment with ghrelin exhibits protective and therapeutic effects in the gut. Aim of our present investigation was to examine the influence of ghrelin administration on the healing of ethanol-induced gastric ulcers and determine the role of cyclooxygenase-1 and cyclooxygenase-2 in this effect. Our studies were performed on male Wistar rats. Gastric ulcers were induced by intragastric administration of 75% ethanol. Ghrelin alone or in combination with cyclooxygenase inhibitors was administered twice, 1 and 13 hours after ethanol application. Cyclooxygenase-1 (COX-1) inhibitor (SC-560, 10 mg/kg/dose) or COX-2 inhibitor (celecoxib, 10 mg/kg/dose) were given 30 min prior to ghrelin. Twelve or 24 hours after administration of ethanol, rats were anesthetized and experiments were terminated. The study revealed that administration of ethanol induced gastric ulcers in all animals and this effect was accompanied by the reduction in gastric blood flow and mucosal DNA synthesis. Moreover induction of gastric ulcer by ethanol significantly increased mucosal expression of mRNA for COX-2, IL-1β and TNF-α. Treatment with ghrelin significantly accelerated gastric ulcer healing. Therapeutic effect of ghrelin was associated with significant reversion of the ulcer-evoked decrease in mucosal blood flow and DNA synthesis. Ghrelin administration also caused the reduction in mucosal expression of mRNA for IL-1β and TNF-α. Addition of SC-560 slightly reduced the therapeutic effect of ghrelin in the healing of ethanol-induced ulcer and the ulcer area in rats treated SC-560 plus ghrelin was significantly smaller than that observed in rats treated with saline or SC-560 alone. Pretreatment with celecoxib, a COX-2 inhibitor, abolished therapeutic effect of ghrelin. We concluded that treatment with ghrelin increases healing rate of gastric ulcers evoked by ethanol and this effect is related to improvement in mucosal blood flow, an increase in mucosal cell

  20. Ghrelin-Induced Orexigenic Effect in Rats Depends on the Metabolic Status and Is Counteracted by Peripheral CB1 Receptor Antagonism

    PubMed Central

    Alen, Francisco; Crespo, Inmaculada; Ramírez-López, María Teresa; Jagerovic, Nadine; Goya, Pilar; de Fonseca, Fernando Rodríguez; de Heras, Raquel Gómez; Orio, Laura

    2013-01-01

    Ghrelin is an endogenous regulator of energy homeostasis synthesized by the stomach to stimulate appetite and positive energy balance. Similarly, the endocannabinoid system is part of our internal machinery controlling food intake and energy expenditure. Both peripheral and central mechanisms regulate CB1-mediated control of food intake and a functional relationship between hypothalamic ghrelin and cannabinoid CB1 receptor has been proposed. First of all, we investigated brain ghrelin actions on food intake in rats with different metabolic status (negative or equilibrate energy balance). Secondly, we tested a sub-anxiogenic ultra-low dose of the CB1 antagonist SR141716A (Rimonabant) and the peripheral-acting CB1 antagonist LH-21 on ghrelin orexigenic actions. We found that: 1) central administration of ghrelin promotes food intake in free feeding animals but not in 24 h food-deprived or chronically food-restricted animals; 2) an ultra-low dose of SR141716A (a subthreshold dose 75 folds lower than the EC50 for induction of anxiety) completely counteracts the orexigenic actions of central ghrelin in free feeding animals; 3) the peripheral-restricted CB1 antagonist LH-21 blocks ghrelin-induced hyperphagia in free feeding animals. Our study highlights the importance of the animaĺs metabolic status for the effectiveness of ghrelin in promoting feeding, and suggests that the peripheral endocannabinoid system may interact with ghrelińs signal in the control of food intake under equilibrate energy balance conditions. PMID:23565287

  1. c-fos expression in brainstem premotor interneurons during cholinergically induced active sleep in the cat.

    PubMed

    Morales, F R; Sampogna, S; Yamuy, J; Chase, M H

    1999-11-01

    The present study was undertaken to identify trigeminal premotor interneurons that become activated during carbachol-induced active sleep (c-AS). Their identification is a critical step in determining the neural circuits responsible for the atonia of active sleep. Accordingly, the retrograde tracer cholera toxin subunit B (CTb) was injected into the trigeminal motor nuclei complex to label trigeminal interneurons. To identify retrograde-labeled activated neurons, immunocytochemical techniques, designed to label the Fos protein, were used. Double-labeled (i.e., CTb(+), Fos(+)) neurons were found exclusively in the ventral portion of the medullary reticular formation, medial to the facial motor nucleus and lateral to the inferior olive. This region, which encompasses the ventral portion of the nucleus reticularis gigantocellularis and the nucleus magnocellularis, corresponds to the rostral portion of the classic inhibitory region of. This region contained a mean of 606 +/- 41.5 ipsilateral and 90 +/- 32.0 contralateral, CTb-labeled neurons. These cells were of medium-size with an average soma diameter of 20-35 micrometer. Approximately 55% of the retrogradely labeled cells expressed c-fos during a prolonged episode of c-AS. We propose that these neurons are the interneurons responsible for the nonreciprocal postsynaptic inhibition of trigeminal motoneurons that occurs during active sleep. PMID:10531453

  2. Blockade of ENaCs by amiloride induces c-Fos activation of the area postrema.

    PubMed

    Miller, Rebecca L; Denny, George O; Knuepfer, Mark M; Kleyman, Thomas R; Jackson, Edwin K; Salkoff, Lawrence B; Loewy, Arthur D

    2015-03-19

    Epithelial sodium channels (ENaCs) are strongly expressed in the circumventricular organs (CVOs), and these structures may play an important role in sensing plasma sodium levels. Here, the potent ENaC blocker amiloride was injected intraperitoneally in rats and 2h later, the c-Fos activation pattern in the CVOs was studied. Amiloride elicited dose-related activation in the area postrema (AP) but only ~10% of the rats showed c-Fos activity in the organum vasculosum of the lamina terminalis (OVLT) and subfornical organ (SFO). Tyrosine hydroxylase-immunoreactive (catecholamine) AP neurons were activated, but tryptophan hydroxylase-immunoreactive (serotonin) neurons were unaffected. The AP projects to FoxP2-expressing neurons in the dorsolateral pons which include the pre-locus coeruleus nucleus and external lateral part of the parabrachial nucleus; both cell groups were c-Fos activated following systemic injections of amiloride. In contrast, another AP projection target--the aldosterone-sensitive neurons of the nucleus tractus solitarius which express the enzyme 11-β-hydroxysteriod dehydrogenase type 2 (HSD2) were not activated. As shown here, plasma concentrations of amiloride used in these experiments were near or below the IC50 level for ENaCs. Amiloride did not induce changes in blood pressure, heart rate, or regional vascular resistance, so sensory feedback from the cardiovascular system was probably not a causal factor for the c-Fos activity seen in the CVOs. In summary, amiloride may have a dual effect on sodium homeostasis causing a loss of sodium via the kidney and inhibiting sodium appetite by activating the central satiety pathway arising from the AP. PMID:25557402

  3. Localization of tachykinin receptors and Fos-like immunoreactivity induced by substance P in guinea-pig brain.

    PubMed

    Yip, J; Chahl, L A

    2000-11-01

    1. In the present study, a comparison was made between the distribution of tachykinin NK1 and NK3 receptor immunoreactivity and the distribution of Fos-like immunoreactivity induced by the tachykinin agonist substance P (SP) in the guinea-pig brain. 2. In agreement with results from previous studies in rat brain, NK1 receptor-immunoreactive neurons were found to be widely distributed throughout the brain in the striatum and in diencephalic and mesencephalic structures, while NK3 receptor-immunoreactive neurons were mainly in telencephalic structures. Considerable overlap was observed between NK1 and NK3 receptor distributions. 3. Substance P induced Fos-like immunoreactivity (Fos-LI) in extensive areas of the guinea-pig brain. The induction of Fos-LI was markedly inhibited in many areas by pretreatment with the NK1 receptor antagonist SR 140333. The NK3 receptor antagonist SR 142801 reduced Fos-LI staining in fewer areas, although a reduction was observed in the cortex, striatum and hypothalamus. 4. In general, tachykinin receptors were located at sites corresponding to areas of functional activation by SP, as shown by Fos-LI. These results extend previous studies by adding a functional dimension to tachykinin receptor localization studies.

  4. Overexpression of DeltaFosB is associated with attenuated cocaine-induced suppression of saccharin intake in mice.

    PubMed

    Freet, Christopher S; Steffen, Cathy; Nestler, Eric J; Grigson, Patricia S

    2009-04-01

    Rodents suppress intake of saccharin when it is paired with a drug of abuse (Goudie, Dickins, & Thornton, 1978; Risinger & Boyce, 2002). By the authors' account, this phenomenon, referred to as reward comparison, is thought to be mediated by anticipation of the rewarding properties of the drug (P. S. Grigson, 1997; P. S. Grigson & C. S. Freet, 2000). Although a great deal has yet to be discovered regarding the neural basis of reward and addiction, it is known that overexpression of DeltaFosB is associated with an increase in drug sensitization and incentive. Given this, the authors reasoned that overexpression of DeltaFosB should also support greater drug-induced devaluation of a natural reward. To test this hypothesis, NSE-tTA x TetOp-DeltaFosB mice (Chen et al., 1998) with normal or overexpressed DeltaFosB in the striatum were given access to a saccharin cue and then injected with saline, 10 mg/kg cocaine, or 20 mg/kg cocaine. Contrary to the original prediction, overexpression of DeltaFosB was associated with attenuated cocaine-induced suppression of saccharin intake. It is hypothesized that elevation of DeltaFosB not only increases the reward value of drug, but the reward value of the saccharin cue as well.

  5. The Expression Patterns of c-Fos and c-Jun Induced by Different Frequencies of Electroacupuncture in the Brain

    PubMed Central

    Qiu, Zheng-Ying; Ding, Yi; Cui, Lu-ying; Hu, Man-Li; Ding, Ming-Xing

    2015-01-01

    To investigate patterns of c-Fos and c-Jun expression induced by different frequencies of electroacupuncture (EA) in the brain, goats were stimulated by EA of 0, 2, 60, or 100 Hz at a set of “Baihui, Santai, Ergen, and Sanyangluo” points for 30 min. The pain threshold was measured using the potassium iontophoresis method. The levels of c-Fos and c-Jun were determined with Streptavidin-Biotin Complex immunohistochemistry. The results showed that the pain threshold induced by 60 Hz was 82.2% higher (P < 0.01) than that by 0, 2, or 100 Hz (6.5%, 35.2%, or 40.9%). EA induced increased c-Fos and c-Jun expression in most analgesia-related nuclei and areas in the brain. Sixty Hz EA increased more c-Fos or c-Jun expression than 2 Hz or 100 Hz EA in all the measured nuclei and areas except for the nucleus accumbens, the area septalis lateralis, the caudate nucleus, the nucleus amygdala basalis, and the locus coeruleus, in which c-Fos or c-Jun expressions induced by 60 Hz EA did not differ from those by 2 Hz or 100 Hz EA. It was suggested that 60 Hz EA activated more extensive neural circuits in goats, which may contribute to optimal analgesic effects. PMID:26491460

  6. Ghrelin-induced growth hormone release from goldfish pituitary cells is nitric oxide dependent.

    PubMed

    Grey, Caleb L; Chang, John P

    2012-11-01

    Ghrelin (GRLN) is an important neuroendocrine regulator of growth hormone (GH) release in vertebrates. Previous studies show goldfish (g)GRLN(19)-induced GH from the goldfish pituitary involves voltage sensitive Ca(2+) channels, increases in intracellular Ca(2+) and the PKC signalling pathway. We set out to examine the role of the nitric oxide (NO) pathway in gGLRN(19)-induced GH release from primary cultures of goldfish pituitary cells using pharmacological regulators in cell column perifusion systems. The NO scavenger PTIO abolished gGRLN(19)-induced GH release and co-treatment with the NO donor SNP and GRLN did not produce additive GH release responses. Nitric oxide synthase (NOS) inhibitors 1400 W and 7-Ni abolished GRLN-induced GH release while treatment with another NOS inhibitor, AGH, had no significant effect. Taken together, these results demonstrate that the NOS/NO is an integral component of gGRLN(19)-induced signalling within the goldfish pituitary cells, and given the relative specificity of AGH for inducible NOS and endothelial NOS isoforms, suggests that neuronal NOS is the likely NOS isoform utilized in goldfish somatotropes by this physiological regulator.

  7. Striatal dopamine and glutamate receptors modulate methamphetamine-induced cortical Fos expression.

    PubMed

    Gross, N B; Marshall, J F

    2009-07-21

    Methamphetamine (mAMPH) is a psychostimulant drug that increases extracellular levels of monoamines throughout the brain. It has previously been observed that a single injection of mAMPH increases immediate early gene (IEG) expression in both the striatum and cerebral cortex. Moreover, this effect is modulated by dopamine and glutamate receptors since systemic administration of dopamine or glutamate antagonists has been found to alter mAMPH-induced striatal and cortical IEG expression. However, because dopamine and glutamate receptors are found in extra-striatal as well as striatal brain regions, studies employing systemic injection of dopamine or glutamate antagonists fail to localize the effects of mAMPH-induced activation. In the present experiments, the roles of striatal dopamine and glutamate receptors in mAMPH-induced gene expression in the striatum and cerebral cortex were examined. The nuclear expression of Fos, the protein product of the IEG c-fos, was quantified in both the striatum and the cortex of animals receiving intrastriatal dopamine or glutamate antagonist administration. Intrastriatal infusion of dopamine (D1 or D2) or glutamate [N-methyl-D-aspartic acid (NMDA) or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)] antagonists affected not only mAMPH-induced striatal, but also cortical, Fos expression. Overall, the effects of the antagonists occurred dose-dependently, in both the infused and non-infused hemispheres, with greater influences occurring in the infused hemisphere. Finally, unilateral intrastriatal infusion of dopamine or glutamate antagonists changed the behavior of the rats from characteristic mAMPH-induced stereotypy to rotation ipsilateral to the infusion. These results demonstrate that mAMPH's actions on striatal dopamine and glutamate receptors modulate the widespread cortical activation induced by mAMPH. It is hypothesized that dopamine release from nigrostriatal terminals modulates activity within striatal efferent

  8. C-fos expression in the pons and medulla of the cat during carbachol-induced active sleep.

    PubMed

    Yamuy, J; Mancillas, J R; Morales, F R; Chase, M H

    1993-06-01

    Microinjection of carbachol into the rostral pontine tegmentum of the cat induces a state that is comparable to naturally occurring active (REM, rapid eye movement) sleep. We sought to determine, during this pharmacologically induced behavioral state, which we refer to as active sleep-carbachol, the distribution of activated neuron within the pons and medulla using c-fos immunocytochemistry as a functional marker. Compared with control cats, which were injected with saline, active sleep-carbachol cats exhibited higher numbers of c-fos-expressing neurons in (1) the medial and portions of the lateral reticular formation of the pons and medulla, (2) nuclei in the dorsolateral rostral pons, (3) various raphe nuclei, including the dorsal, central superior, magnus, pallidus, and obscurus, (4) the medial and lateral vestibular, prepositus hypoglossi, and intercalatus nuclei, and (5) the abducens nuclei. On the other hand, the mean number of c-fos-expressing neurons found in the masseter, facial, and hypoglossal nuclei was lower in carbachol-injected than in control cats. The data indicate that c-fos expression can be employed as a marker of state-dependent neuronal activity. The specific sites in which there were greater numbers of c-fos-expressing neurons during active sleep-carbachol are discussed in relation to the state of active sleep, as well as the functional role that these sites play in generating the various physiological patterns of activity that occur during this state. PMID:8501533

  9. Exercise protects against obesity induced semen abnormalities via downregulating stem cell factor, upregulating Ghrelin and normalizing oxidative stress

    PubMed Central

    Alhashem, Fahaid; Alkhateeb, Mahmoud; Sakr, Hussein; Alshahrani, Mesfer; Alsunaidi, Mohammad; Elrefaey, Hesham; Alessa, Riyad; Sarhan, Mohammad; Eleawa, Samy M; Khalil, Mohammad A.

    2014-01-01

    Increased oxidative stress and hormonal imbalance have been hypothesized to underlie infertility in obese animals. However, recent evidence suggests that Ghrelin and Stem Cell Factor (SCF) play an important role in fertility, in lean individuals. Therefore, this study aimed at investigating whether changes in the levels of Ghrelin and SCF in rat testes underlie semen abnormal parameters observed in obese rats, and secondly, whether endurance exercise or Orlistat can protect against changes in Ghrelin, SCF, and/or semen parameters in diet induced obese rats. Obesity was modelled in male Wistar rats using High Fat Diet (HFD) 12-week protocol. Eight week-old rats (n=40) were divided into four groups, namely, Group I: fed with a standard diet (12 % of calories as fat); Group II: fed HFD (40 % of calories as fat); Group III: fed the HFD with a concomitant dose of Orlistat (200 mg/kg); and Group IV: fed the HFD and underwent 30 min daily swimming exercise. The model was validated by measuring the levels of testosterone, FSH, LH, estradiol, leptin, triglycerides, total, HDL, and LDL cholesterol, and final change in body weight. Levels were consistent with published obesity models (see Results). As predicted, the HFD group had a 76.8 % decrease in sperm count, 44.72 % decrease in sperm motility, as well as 47.09 % increase in abnormal sperm morphology. Unlike the control group, in the HFD group (i.e. obese rats) Ghrelin mRNA and protein were elevated, while SCF mRNA and protein were diminished in the testes. Furthermore, in the HFD group, SOD and GPx activities were significantly reduced, 48.5±5.8 % (P=0.0012) and 45.6±4.6 % (P=0.0019), respectively, while TBARS levels were significantly increased (112.7±8.9 %, P=0.0001). Finally, endurance exercise training and Orlistat administration individually and differentially protected semen parameters in obese rats. The mechanism includes, but is not limited to, normalizing the levels of Ghrelin, SCF, SOD, GPx and TBARS. In rat

  10. Exercise protects against obesity induced semen abnormalities via downregulating stem cell factor, upregulating Ghrelin and normalizing oxidative stress.

    PubMed

    Alhashem, Fahaid; Alkhateeb, Mahmoud; Sakr, Hussein; Alshahrani, Mesfer; Alsunaidi, Mohammad; Elrefaey, Hesham; Alessa, Riyad; Sarhan, Mohammad; Eleawa, Samy M; Khalil, Mohammad A

    2014-01-01

    Increased oxidative stress and hormonal imbalance have been hypothesized to underlie infertility in obese animals. However, recent evidence suggests that Ghrelin and Stem Cell Factor (SCF) play an important role in fertility, in lean individuals. Therefore, this study aimed at investigating whether changes in the levels of Ghrelin and SCF in rat testes underlie semen abnormal parameters observed in obese rats, and secondly, whether endurance exercise or Orlistat can protect against changes in Ghrelin, SCF, and/or semen parameters in diet induced obese rats. Obesity was modelled in male Wistar rats using High Fat Diet (HFD) 12-week protocol. Eight week-old rats (n=40) were divided into four groups, namely, Group I: fed with a standard diet (12 % of calories as fat); Group II: fed HFD (40 % of calories as fat); Group III: fed the HFD with a concomitant dose of Orlistat (200 mg/kg); and Group IV: fed the HFD and underwent 30 min daily swimming exercise. The model was validated by measuring the levels of testosterone, FSH, LH, estradiol, leptin, triglycerides, total, HDL, and LDL cholesterol, and final change in body weight. Levels were consistent with published obesity models (see Results). As predicted, the HFD group had a 76.8 % decrease in sperm count, 44.72 % decrease in sperm motility, as well as 47.09 % increase in abnormal sperm morphology. Unlike the control group, in the HFD group (i.e. obese rats) Ghrelin mRNA and protein were elevated, while SCF mRNA and protein were diminished in the testes. Furthermore, in the HFD group, SOD and GPx activities were significantly reduced, 48.5±5.8 % (P=0.0012) and 45.6±4.6 % (P=0.0019), respectively, while TBARS levels were significantly increased (112.7±8.9 %, P=0.0001). Finally, endurance exercise training and Orlistat administration individually and differentially protected semen parameters in obese rats. The mechanism includes, but is not limited to, normalizing the levels of Ghrelin, SCF, SOD, GPx and TBARS. In rat

  11. Constitutive nitric oxide synthase-mediated caspase-3 S-nitrosylation in ghrelin protection against Porphyromonas gingivalis-induced salivary gland acinar cell apoptosis.

    PubMed

    Slomiany, B L; Slomiany, A

    2010-06-01

    Recent advances in identifying the salivary constituents capable of influencing the oral mucosal inflammatory responses have brought to focus the importance of a peptide hormone, ghrelin. Here, we report on the involvement of ghrelin in controlling the apoptotic processes induced in sublingual salivary gland acinar cells by the lipopolysaccharide (LPS) of a periodontopathic bacterium, Porphyromonas gingivalis. We show that the countering effect of ghrelin on the LPS-induced acinar cell apoptosis was associated with the increase in constitutive nitric oxide synthase (cNOS) activity, and the reduction in caspase-3 and inducible nitric oxide synthase (iNOS). The loss in countering effect of ghrelin on the LPS-induced changes in apoptosis and caspase-3 activity was attained with Src kinase inhibitor, PP2, as well as Akt inhibitor, SH-5, and cNOS inhibitor, L-NAME, but not the iNOS inhibitor, 1400W. The effect of ghrelin on the LPS-induced changes in cNOS activity, moreover, was reflected in the increased cNOS phosphorylation that was sensitive to PP2 as well as SH-5. Furthermore, the ghrelin-induced up-regulation in cNOS activity was associated with the increase in caspase-3 S-nitrosylation that was susceptible to the blockage by SH-5 and L-NAME. The findings point to the involvement of ghrelin in Src/Akt kinase-mediated cNOS activation and the apoptogenic signal inhibition through the NO-induced caspase-3 S-nitrosylation.

  12. Area postrema lesions attenuate LiCl-induced c-Fos expression correlated with conditioned taste aversion learning

    PubMed Central

    Spencer, Corinne M.; Eckel, Lisa A.; Nardos, Rahel; Houpt, Thomas A.

    2011-01-01

    Lesions of the area postrema (AP) block many of the behavioral and physiological effects of lithium chloride (LiCl) in rats, including formation of conditioned taste aversions (CTAs). Systemic administration of LiCl induces c-Fos immunoreactivity in several brain regions, including the AP, nucleus of the solitary tract (NTS), lateral parabrachial nucleus (latPBN), supraoptic nucleus (SON), paraventricular nucleus (PVN), and central nucleus of the amygdala (CeA). To determine which of these brain regions may be activated in parallel with the acquisition of LiCl-induced CTAs, we disrupted CTA learning in rats by ablating the AP and then quantified c-Fos-positive cells in these brain regions in sham- and AP-lesioned rats 1 h following LiCl or saline injection. Significant c-Fos induction after LiCl was observed in the CeA and SON of AP-lesioned rats, demonstrating activation independent of an intact AP. LiCl-induced c-Fos was significantly attenuated in the NTS, latPBN, PVN and CeA of AP-lesioned rats, suggesting that these regions are dependent on AP activation. Almost all of the lesioned rats showed some damage to the subpostremal NTS, and some rats also had damage to the dorsal motor nucleus of the vagus; this collateral damage in the brainstem may have contributed to the deficits in c-Fos response. Because c-Fos induction in several regions was correlated with magnitude of CTA acquisition, these regions are implicated in the central mediation of lithium effects during CTA learning. PMID:21889521

  13. The atypical antipsychotic, olanzapine, potentiates ghrelin-induced receptor signaling: An in vitro study with cells expressing cloned human growth hormone secretagogue receptor.

    PubMed

    Tagami, Keita; Kashiwase, Yohei; Yokoyama, Akinobu; Nishimura, Hitomi; Miyano, Kanako; Suzuki, Masami; Shiraishi, Seiji; Matoba, Motohiro; Ohe, Yuichiro; Uezono, Yasuhito

    2016-08-01

    The growth hormone secretagogue receptor (GHS-R) belongs to Gαq-coupled G protein-coupled receptor (GPCR) that mediates growth hormone release, food intake, appetite, glucose metabolism and body composition. Ghrelin has been identified as an endogenous ligand for GHS-R, and it is the only orexigenic peptide found in the peripheral organs. Olanzapine, an atypical antipsychotic agent that binds to and inhibits the activation of GPCR for several neurotransmitters, has metabolic side effects such as excessive appetite and weight gain. Recently, studies have revealed that the orexigenic mechanism of olanzapine is mediated via GHS-R signaling, although the precise mechanisms have not been clarified. In this study, we investigated the effect of olanzapine on ghrelin-mediated GHS-R signaling by using an electrical impedance-based receptor biosensor assay system (CellKey™). Olanzapine at concentrations of 10(-7) and 10(-6)mol/L enhanced ghrelin-induced (10(-10)-10(-8)mol/L) GHS-R activation. A Ca(2+) imaging assay revealed that olanzapine (10(-7) and 10(-6)mol/L) enhanced ghrelin (10(-7) M)-induced GHS-R activity. In contrast, haloperidol (an antipsychotic agent) failed to enhance this ghrelin-mediated GHS-R activation, as demonstrated by both the CellKey™ and Ca(2+) imaging assays. Together, these results suggest that olanzapine, but not haloperidol, promotes appetite by enhancing ghrelin-mediated GHS-R signaling. PMID:26775231

  14. Environmental enrichment and gut inflammation modify stress-induced c-Fos expression in the mouse corticolimbic system.

    PubMed

    Reichmann, Florian; Painsipp, Evelin; Holzer, Peter

    2013-01-01

    Environmental enrichment (EE) has a beneficial effect on rodent behaviour, neuronal plasticity and brain function. Although it may also improve stress coping, it is not known whether EE influences the brain response to an external (psychological) stressor such as water avoidance stress (WAS) or an internal (systemic) stressor such as gastrointestinal inflammation. This study hence explored whether EE modifies WAS-induced activation of the mouse corticolimbic system and whether this stress response is altered by gastritis or colitis. Male C67BL/6N mice were housed under standard or enriched environment for 9 weeks, after which they were subjected to a 1-week treatment with oral iodoacetamide to induce gastritis or oral dextran sulfate sodium to induce colitis. Following exposure to WAS the expression of c-Fos, a marker of neuronal activation, was measured by immunocytochemistry. EE aggravated experimentally induced colitis, but not gastritis, as shown by an increase in the disease activity score and the colonic myeloperoxidase content. In the brain, EE enhanced the WAS-induced activation of the dentate gyrus and unmasked an inhibitory effect of gastritis and colitis on WAS-evoked c-Fos expression within this part of the hippocampus. Conversely, EE inhibited the WAS-evoked activation of the central amygdala and prevented the inhibitory effect of gastritis and colitis on WAS-evoked c-Fos expression in this region. EE, in addition, blunted the WAS-induced activation of the infralimbic cortex and attenuated the inhibitory effect of gastritis and colitis on WAS-evoked c-Fos expression in this area. These data reveal that EE has a region-specific effect on stress-induced c-Fos expression in the corticolimbic system, which is likely to improve stress resilience. The response of the prefrontal cortex - amygdala - hippocampus circuitry to psychological stress is also modified by the systemic stress of gut inflammation, and this interaction between external and internal

  15. GABAergic neurons of the cat dorsal raphe nucleus express c-fos during carbachol-induced active sleep.

    PubMed

    Torterolo, P; Yamuy, J; Sampogna, S; Morales, F R; Chase, M H

    2000-11-24

    Serotonergic neurons of the dorsal raphe nucleus (DRN) cease firing during active sleep (AS, also called rapid-eye-movement sleep). This cessation of electrical activity is believed to play a 'permissive' role in the generation of AS. In the present study we explored the possibility that GABAergic cells in the DRN are involved in the suppression of serotonergic activity during AS. Accordingly, we examined whether immunocytochemically identified GABAergic neurons in the DRN were activated, as indicated by their expression of c-fos, during carbachol-induced AS (AS-carbachol). Three chronically-prepared cats were euthanized after prolonged episodes of AS that was induced by microinjections of carbachol into the nucleus pontis oralis. Another four cats (controls) were maintained 2 h in quiet wakefulness before being euthanized. Thereafter, immunocytochemical studies were performed on brainstem sections utilizing antibodies against Fos, GABA and serotonin. When compared with identically prepared tissue from awake cats, the number of Fos+ neurons was larger in the DRN during AS-carbachol (35.9+/-5.6 vs. 13.9+/-4.4, P<0.05). Furthermore, a larger number of GABA+ Fos+ neurons were observed during AS-carbachol than during wakefulness (24.8+/-3.3 vs. 4.0+/-1.0, P<0.001). These GABA+ Fos+ neurons were distributed asymmetrically with a larger number located ipsilaterally to the site of injection. There was no significant difference between control and experimental animals in the number of non-GABAergic neurons that expressed c-fos in the DRN. We therefore suggest that activated GABAergic neurons of the DRN are responsible for the inhibition of serotonergic neurons that occurs during natural AS. PMID:11082488

  16. Prenatal ethanol exposure alters ethanol-induced Fos immunoreactivity and dopaminergic activity in the mesocorticolimbic pathway of the adolescent brain.

    PubMed

    Fabio, M C; Vivas, L M; Pautassi, R M

    2015-08-20

    Prenatal ethanol exposure (PEE) promotes alcohol intake during adolescence, as shown in clinical and pre-clinical animal models. The mechanisms underlying this effect of prenatal ethanol exposure on postnatal ethanol intake remain, however, mostly unknown. Few studies assessed the effects of moderate doses of prenatal ethanol on spontaneous and ethanol-induced brain activity on adolescence. This study measured, in adolescent (female) Wistar rats prenatally exposed to ethanol (0.0 or 2.0g/kg/day, gestational days 17-20) or non-manipulated (NM group) throughout pregnancy, baseline and ethanol-induced cathecolaminergic activity (i.e., colocalization of c-Fos and tyrosine hydroxylase) in ventral tegmental area (VTA), and baseline and ethanol-induced Fos immunoreactivity (ir) in nucleus accumbens shell and core (AcbSh and AcbC, respectively) and prelimbic (PrL) and infralimbic (IL) prefrontal cortex. The rats were challenged with ethanol (dose: 0.0, 1.25, 2.5 or 3.25g/kg, i.p.) at postnatal day 37. Rats exposed to vehicle prenatally (VE group) exhibited reduced baseline dopaminergic tone in VTA; an effect that was inhibited by prenatal ethanol exposure (PEE group). Dopaminergic activity in VTA after the postnatal ethanol challenge was greater in PEE than in VE or NM animals. Ethanol-induced Fos-ir at AcbSh was found after 1.25g/kg and 2.5g/kg ethanol, in VE and PEE rats, respectively. PEE did not alter ethanol-induced Fos-ir at IL but reduced ethanol-induced Fos-ir at PrL. These results suggest that prenatal ethanol exposure heightens dopaminergic activity in the VTA and alters the response of the mesocorticolimbic pathway to postnatal ethanol exposure. These effects may underlie the enhanced vulnerability to develop alcohol-use disorders of adolescents with a history of in utero ethanol exposure.

  17. Chronic wheel running affects cocaine-induced c-Fos expression in brain reward areas in rats.

    PubMed

    Zlebnik, Natalie E; Hedges, Valerie L; Carroll, Marilyn E; Meisel, Robert L

    2014-03-15

    Emerging evidence from human and animal studies suggests that exercise is a highly effective treatment for drug addiction. However, most work has been done in behavioral models, and the effects of exercise on the neurobiological substrates of addiction have not been identified. Specifically, it is unknown whether prior exercise exposure alters neuronal activation of brain reward circuitry in response to drugs of abuse. To investigate this hypothesis, rats were given 21 days of daily access to voluntary wheel running in a locked or unlocked running wheel. Subsequently, they were challenged with a saline or cocaine (15 mg/kg, i.p.) injection and sacrificed for c-Fos immunohistochemistry. The c-Fos transcription factor is a measure of cellular activity and was used to quantify cocaine-induced activation of reward-processing areas of the brain: nucleus accumbens (NAc), caudate putamen (CPu), medial prefrontal cortex (mPFC), and orbitofrontal cortex (OFC). The mean fold change in cocaine-induced c-Fos cell counts relative to saline-induced c-Fos cell counts was significantly higher in exercising compared to control rats in the NAc core, dorsomedial and dorsolateral CPu, the prelimbic area, and the OFC, indicating differential cocaine-specific cellular activation of brain reward circuitry between exercising and control animals. These results suggest neurobiological mechanisms by which voluntary wheel running attenuates cocaine-motivated behaviors and provide support for exercise as a novel treatment for drug addiction. PMID:24342748

  18. Chronic wheel running affects cocaine-induced c-Fos expression in brain reward areas in rats

    PubMed Central

    Zlebnik, Natalie E.; Hedges, Valerie L.; Carroll, Marilyn E.; Meisel, Robert L.

    2014-01-01

    Emerging evidence from human and animal studies suggests that exercise is a highly effective treatment for drug addiction. However, most work has been done in behavioral models, and the effects of exercise on the neurobiological substrates of addiction have not been identified. Specifically, it is unknown whether prior exercise exposure alters neuronal activation of brain reward circuitry in response to drugs of abuse. To investigate this hypothesis, rats were given 21 days of daily access to voluntary wheel running in a locked or unlocked running wheel. Subsequently, they were challenged with a saline or cocaine (15 mg/kg, ip) injection and sacrificed for c-Fos immunohistochemistry. The c-Fos transcription factor is a measure of cellular activity and was used to quantify cocaine-induced activation of reward-processing areas of the brain: nucleus accumbens (NAc), caudate putamen (CPu), medial prefrontal cortex (mPFC), and orbitofrontal cortex (OFC). The mean fold change in cocaine-induced c-Fos cell counts relative to saline-induced c-Fos cell counts was significantly higher in exercising compared to control rats in the NAc core, dorsomedial and dorsolateral CPu, the prelimbic area, and the OFC, indicating differential cocaine-specific cellular activation of brain reward circuitry between exercising and control animals. These results suggest neurobiological mechanisms by which voluntary wheel running attenuates cocaine-motivated behaviors and provide support for exercise as a novel treatment for drug addiction. PMID:24342748

  19. Diet-Induced Obesity and Ghrelin Effects on Pituitary Gonadotrophs: Immunohistomorphometric Study in Male Rats

    PubMed Central

    Ristic, Natasa; Stevanovic, Darko; Nesic, Dejan; Ajdzanovic, Vladimir; Rakocevic, Rastko; Jaric, Ivana; Milosevic, Verica

    2016-01-01

    Objective The close relationship between energy metabolism, nutritional state, and reproductive physiology suggests that nutritional and metabolic disorders can disrupt normal reproductive function and fertility. Considering the importance of leptin and ghrelin effects in regulation of the hypothalamic-pituitary-gonadal axis, the objective of this study was to investigate the influence of obesity and centrally applied ghrelin on immunohistochemical appearance and quantitative morphology of the pituitary follicle-stimulating hormone (FSH) and luteinizing hormone (LH) producing cells in adult male rats. Materials and Methods In this experimental study, animals were given two differ- ent diets: normal-fat (NF) and high-fat (HF), for 4 weeks, corresponding to normal and positive energy balance (n=2×14), respectively. Each group was subsequently divided into two subgroups (n=7) receiving intracerebroventricular (ICV) injections of either ghrelin [G, 1 µg/5 µL phosphate buffered saline (PBS)] or vehicle (5 µL PBS, control group) every 24 hours for five consecutive days. Results Morphometric analyses showed that in HF control group, the percentage of FSH cells per unit volume of total pituitary gland tissue (in μm3), i.e. volume density (Vvc), was increased (P<0.05) by 9.1% in comparison with the NF controls. After ICV treatment with ghrelin, volume (Vc) and volume density (Vvc) of FSH cells in ghrelin+NF (GNF) and ghrelin+HF (GHF) groups remained unchanged in comparison with NF and HF controls. Volume of LH cells in HF control group was increased by 17% (P<0.05), but their Vvc was decreased by 8.3% (P<0.05) in comparison with NF controls. In GNF group, the volume of LH cells increased by 7% (P<0.05), in comparison with the NF controls, but in GHF group, the same parameter remained unchanged when compared with HF controls. The central application of ghrelin de- creased the Vvc of LH cells only in GNF group by 38.9% (P<0.05) in comparison with the NF control animals

  20. Expression pattern of FOS in orexin neurons during sleep induced by an adenosine A2A receptor agonist.

    PubMed

    Satoh, Shinsuke; Matsumura, Hitoshi; Kanbayashi, Takashi; Yoshida, Yasushi; Urakami, Takahito; Nakajima, Tomoko; Kimura, Nobuko; Nishino, Seiji; Yoneda, Hiroshi

    2006-06-30

    The present study examined the expression pattern of FOS in the hypothalamic peptide neurons during the sleep-dominant state induced by an adenosine A2A receptor agonist. The control rats, those that received the microdialysis-perfusion of their ventral striatum with artificial cerebrospinal fluid in the dark-active phase, spent 24% of the 90-min period prior to sacrifice in non-rapid eye movement (non-REM) sleep and 2.3% of that in REM sleep. These rats exhibited FOS, a transcription factor, in 21% of their orexin neurons and in 1.0% of their melanin-concentrating hormone (MCH) neurons in the perifornical/lateral hypothalamic areas. However, the rats perfused with 50 microM CGS21680, an adenosine A2A receptor agonist, spent 60% of the 90-min period prior to sacrifice in non-REM sleep and 11% of that in REM sleep. These rats exhibited FOS in 1.7% of their orexin neurons and FOS in 0.5% of their MCH neurons. When the sleep-dominant state was disturbed by mild stimulation and the rats were kept in the sleepy state by treatment with a sleep-inducing dose of CGS21680, the rats exhibited FOS in 13.3% of their orexin neurons, which percentage was about half of that for the control rats. These results suggest that the sleep-promoting process induced by this adenosine A2A receptor agonist was associated with a decline in the activity of orexin neurons. MCH neurons are not likely to change their activities during this sleep-promoting process.

  1. Leptin levels are reduced by intravenous ghrelin administration and correlated with cue-induced alcohol craving.

    PubMed

    Haass-Koffler, C L; Aoun, E G; Swift, R M; de la Monte, S M; Kenna, G A; Leggio, L

    2015-01-01

    Increasing evidence supports the role of appetite-regulating pathways, including ghrelin and leptin, in alcoholism. This study tested the hypothesis that intravenous exogenous ghrelin administration acutely decreases endogenous serum leptin levels, and that changes in leptin levels negatively correlate with alcohol craving. This was a double-blind, placebo-controlled human laboratory study. Non-treatment-seeking, alcohol-dependent, heavy drinkers (n=45) were randomized to receive intravenous ghrelin or placebo, followed by a cue-reactivity procedure, during which participants were exposed to neutral (juice) and alcohol trial cues. There was a main effect for intravenous ghrelin administration, compared with placebo, in reducing serum leptin levels (P<0.01). Post hoc analysis showed significant differences in serum leptin levels at the alcohol trial (P<0.05) that persisted at the end of the experiment (P<0.05). By contrast, there were no significant differences in serum leptin levels at the juice trial (P=not significant (NS)). The change of serum leptin level at the alcohol trial correlated with the increase in alcohol urge (P<0.05), whereas urge to drink juice was not correlated with the leptin change at the juice trial (P=NS). These findings provide preliminary evidence of ghrelin-leptin cross-talk in alcoholic individuals and suggest that their relationship may have a role in alcohol craving.

  2. Water deprivation-induced sodium appetite and differential expression of encephalic c-Fos immunoreactivity in the spontaneously hypertensive rat.

    PubMed

    Pereira-Derderian, Daniela T B; Vendramini, Regina C; Menani, José V; De Luca, Laurival A

    2010-05-01

    The spontaneously hypertensive rat (SHR) has an intense consumption of NaCl solution. Water deprivation (WD) followed by water intake to satiety induces partial rehydration (PR)-the WD-PR protocol-and sodium appetite. In the present work, WD produced similar water intake and no alterations in arterial pressure among spontaneously hypertensive rat (SHR), Wistar-Kyoto, and Holtzman strains. It also increased the number of cells with positive c-Fos immunoreactivity (Fos-IR) in the lamina terminalis and in the hypothalamic supraoptic (SON) and paraventricular (parvocellular, PVNp) nucleus in these strains. The WD and WD-PR produced similar alterations in all strains in serum osmolality and protein, plasma renin activity, and sodium balance. The SHR ingested about 10 times more 0.3 M NaCl than normotensives strains in the sodium appetite test that follows WD-PR. After WD-PR, the Fos-IR persisted, elevated in the lamina terminalis of all strains but notably in the subfornical organ of the SHR. The WD-PR reversed Fos-IR in the SON of all strains and in the PVNp of SHR. It induced Fos-IR in the area postrema and in the nucleus of the solitary tract (NTS), dorsal raphe, parabrachial (PBN), pre-locus coeruleus (pre-LC), suprachiasmatic, and central amygdalar nucleus of all strains. This effect was bigger in the caudal-NTS, pre-LC, and medial-PBN of SHRs. The results indicate that WD-PR increases cell activity in the forebrain and hindbrain areas that control sodium appetite in the rat. They also suggest that increased cell activity in facilitatory brain areas precedes the intense 0.3 M NaCl intake of the SHR in the sodium appetite test.

  3. Fos Expression in Rat Brain During Depletion-Induced Thirst and Salt Appetite

    NASA Technical Reports Server (NTRS)

    Thunhorst, R. L.; Xu, Z.; Cicha, M. Z.; Zardetto-Smith, A. M.; Johnson, A. K.

    1998-01-01

    The expression of Fos protein (Fos immunoreactivity, Fos-ir) was mapped in the brain of rats subjected to an angiotensin-dependent model of thirst and salt appetite. The physiological state associated with water and sodium ingestion was produced by the concurrent subcutaneous administration of the diuretic furosemide (10 mg/kg) and a low dose of the angiotensin-converting enzyme (ACE) inhibitor captopril (5 mg/kg; Furo/Cap treatment). The animals were killed 2 h posttreatment, and the brains were processed for Fos-ir to assess neural activation. Furo/Cap treatment significantly increased Fos-ir density above baseline levels both in structures of the lamina terminalis and hypothalamus known to mediate the actions of ANG 2 and in hindbrain regions associated with blood volume and pressure regulation. Furo/Cap treatment also typically increased Fos-ir density in these structures above levels observed after administration of furosemide or captopril separately. Fos-ir was reduced to a greater extent in forebrain than in hindbrain areas by a dose of captopril (100 mg/kg sc) known to block the actions of ACE in the brain. The present work provides further evidence that areas of lamina terminalis subserve angiotensin-dependent thirst and salt appetite.

  4. Dentin bonding agents induce c-fos and c-jun protooncogenes expression in human gingival fibroblasts.

    PubMed

    Huang, Fu-Mei; Chou, Ming-Yung; Chang, Yu-Chao

    2003-01-01

    An important requirement for a dentin bonding agent is biologic compatibility; the bonding agent usually remains in close contact with living dental tissues over a long period of time. Information on the genotoxicity/mutagenicity and cacinogenicity potentials of dentin bonding agents is rare. It has been shown that c-fos and c-jun are induced rapidly by a variety of chemical and physical stimuli. Little is known about the induction of cellular signaling events and specific gene expression after cell exposure to dentin bonding agents. Therefore, we used primary human gingival fibroblasts to examine the effect of six dentin bonding agents on the expression of c-fos and c-jun protooncogenes to evaluate the genotoxicity/mutagenicity and cacinogenicity potential of the dentin bonding agents. The levels of mRNA were measured by the quantitative RT-PCR analysis. c-fos and c-jun mRNA expression in dentin bonding agents-treated cells revealed a rapid accumulation of the transcript, a significant signal first was detectable after 1h of exposure. Persistent induction of c-jun and c-fos protooncogenes by dentine bonding agents may distribute systemically to cause some unexpected adverse effects on human beings. It would be necessary to identify the severely toxic compounds and replace these substances by better biocompatible components. Otherwise, leaching of those genotoxicity/mutagenicity and cacinogenicity components must be minimized or prevented.

  5. The distribution of cannabinoid-induced Fos expression in rat brain: differences between the Lewis and Wistar strain.

    PubMed

    Arnold, J C; Topple, A N; Mallet, P E; Hunt, G E; McGregor, I S

    2001-12-01

    Previous studies have suggested that cannabis-like drugs produce mainly aversive and anxiogenic effects in Wistar strain rats, but rewarding effects in Lewis strain rats. In the present study we compared Fos expression, body temperature effects and behavioral effects elicited by the cannabinoid CB(1) receptor agonist CP 55,940 in Lewis and Wistar rats. Both a moderate (50 microg/kg) and a high (250 microg/kg) dose level were used. The 250 microg/kg dose caused locomotor suppression, hypothermia and catalepsy in both strains, but with a significantly greater effect in Wistar rats. The 50 microg/kg dose provoked moderate hypothermia and locomotor suppression but in Wistar rats only. CP 55,940 caused significant Fos immunoreactivity in 24 out of 33 brain regions examined. The most dense expression was seen in the paraventricular nucleus of the hypothalamus, the islands of Calleja, the lateral septum (ventral), the central nucleus of the amygdala, the bed nucleus of the stria terminalis (lateral division) and the ventrolateral periaqueductal gray. Despite having a similar distribution of CP 55,940-induced Fos expression, Lewis rats showed less overall Fos expression than Wistars in nearly every brain region counted. This held equally true for anxiety-related brain structures (e.g. central nucleus of the amygdala, periaqueductal gray and the paraventricular nucleus of the hypothalamus) and reward-related sites (nucleus accumbens and pedunculopontine tegmental nucleus). In a further experiment, Wistar rats and Lewis rats did not differ in the amount of Fos immunoreactivity produced by cocaine (15 mg/kg). These results indicate that Lewis rats are less sensitive to the behavioral, physiological and neural effects of cannabinoids. The exact mechanism underlying this subsensitivity requires further investigation.

  6. Oral ‘hydrogen water' induces neuroprotective ghrelin secretion in mice

    PubMed Central

    Matsumoto, Akio; Yamafuji, Megumi; Tachibana, Tomoko; Nakabeppu, Yusaku; Noda, Mami; Nakaya, Haruaki

    2013-01-01

    The therapeutic potential of molecular hydrogen (H2) is emerging in a number of human diseases and in their animal models, including in particular Parkinson's disease (PD). H2 supplementation of drinking water has been shown to exert disease-modifying effects in PD patients and neuroprotective effects in experimental PD model mice. However, H2 supplementation does not result in detectable changes in striatal H2 levels, indicating an indirect effect. Here we show that H2 supplementation increases gastric expression of mRNA encoding ghrelin, a growth hormone secretagogue, and ghrelin secretion, which are antagonized by the β1-adrenoceptor blocker, atenolol. Strikingly, the neuroprotective effect of H2 water was abolished by either administration of the ghrelin receptor-antagonist, D-Lys3 GHRP-6, or atenolol. Thus, the neuroprotective effect of H2 in PD is mediated by enhanced production of ghrelin. Our findings point to potential, novel strategies for ameliorating pathophysiology in which a protective effect of H2 supplementation has been demonstrated. PMID:24253616

  7. Papillomavirus-Associated Tumor Formation Critically Depends on c-Fos Expression Induced by Viral Protein E2 and Bromodomain Protein Brd4

    PubMed Central

    Schneider, Markus; Schuetz, Johanna; Leiprecht, Natalie; Hudjetz, Benjamin; Brodbeck, Stephan; Corall, Silke; Dreer, Marcel; Schwab, Roxana Michaela; Grimm, Martin; Wu, Shwu-Yuan; Stubenrauch, Frank; Chiang, Cheng-Ming; Iftner, Thomas

    2016-01-01

    We investigated the mechanism of how the papillomavirus E2 transcription factor can activate promoters through activator protein (AP)1 binding sites. Using an unbiased approach with an inducible cell line expressing the viral transcription factor E2 and transcriptome analysis, we found that E2 induces the expression of the two AP1 components c-Fos and FosB in a Brd4-dependent manner. In vitro RNA interference confirmed that c-Fos is one of the AP1 members driving the expression of viral oncogenes E6/E7. Mutation analysis and in vivo RNA interference identified an essential role for c-Fos/AP1 and also for the bromodomain protein Brd4 for papillomavirus-induced tumorigenesis. Lastly, chromatin immunoprecipitation analysis demonstrated that E2 binds together with Brd4 to a canonical E2 binding site (E2BS) in the promoter of c-Fos, thus activating c-Fos expression. Thus, we identified a novel way how E2 activates the viral oncogene promoter and show that E2 may act as a viral oncogene by direct activation of c-Fos involved in skin tumorigenesis. PMID:26727473

  8. Papillomavirus-Associated Tumor Formation Critically Depends on c-Fos Expression Induced by Viral Protein E2 and Bromodomain Protein Brd4.

    PubMed

    Delcuratolo, Maria; Fertey, Jasmin; Schneider, Markus; Schuetz, Johanna; Leiprecht, Natalie; Hudjetz, Benjamin; Brodbeck, Stephan; Corall, Silke; Dreer, Marcel; Schwab, Roxana Michaela; Grimm, Martin; Wu, Shwu-Yuan; Stubenrauch, Frank; Chiang, Cheng-Ming; Iftner, Thomas

    2016-01-01

    We investigated the mechanism of how the papillomavirus E2 transcription factor can activate promoters through activator protein (AP)1 binding sites. Using an unbiased approach with an inducible cell line expressing the viral transcription factor E2 and transcriptome analysis, we found that E2 induces the expression of the two AP1 components c-Fos and FosB in a Brd4-dependent manner. In vitro RNA interference confirmed that c-Fos is one of the AP1 members driving the expression of viral oncogenes E6/E7. Mutation analysis and in vivo RNA interference identified an essential role for c-Fos/AP1 and also for the bromodomain protein Brd4 for papillomavirus-induced tumorigenesis. Lastly, chromatin immunoprecipitation analysis demonstrated that E2 binds together with Brd4 to a canonical E2 binding site (E2BS) in the promoter of c-Fos, thus activating c-Fos expression. Thus, we identified a novel way how E2 activates the viral oncogene promoter and show that E2 may act as a viral oncogene by direct activation of c-Fos involved in skin tumorigenesis. PMID:26727473

  9. Inhibition of carcinogen induced c-Ha-ras and c-fos proto-oncogenes expression by dietary curcumin

    PubMed Central

    Limtrakul, Porn-ngarm; Anuchapreeda, Songyot; Lipigorngoson, Suwiwek; Dunn, Floyd W

    2001-01-01

    Background We investigated the chemopreventive action of dietary curcumin on 7,12-dimethylbenz(a)anthracene (DMBA)-initiated and 12,0-tetradecanoylphorbol-13-acetate (TPA)-promoted skin tumor formation in Swiss albino mice. Curcumin, a yellow coloring matter isolated from roots of Curcuma longa Linn, is a phenolic compound possessing antioxidant, free radical scavenger, and antiinflammatory properties. It has been shown by previously reported work that TPA-induced skin tumors were inhibited by topical application of curcumin, and curcumin has been shown to inhibit a variety of biological activities of TPA. Topical application of curcumin was reported to inhibit TPA-induced c-fos, c-jun and c-myc gene expression in mouse skin. This paper reports the effects of orally administered curcumin, which was consumed as a dietary component at concentrations of 0.2 % or 1 %, in ad libitum feeding. Results Animals in which tumors had been initiated with DMBA and promoted with TPA experienced significantly fewer tumors and less tumor volume if they ingested either 0.2% or 1% curcumin diets. Also, the dietary consumption of curcumin resulted in a significantly decreased expression of ras and fos proto-oncogenes in the tumorous skin, as measured by enhanced chemiluminesence Western blotting detection system (Amersham). Conclusions Whereas earlier work demonstrated that topical application of curcumin to mouse skin inhibited TPA-induced expression of c-fos, c-jun and c-myc oncogenes, our results are the first to show that orally consumed curcumin significantly inhibited DMBA- and TPA-induced ras and fos gene expression in mouse skin. PMID:11231886

  10. Spatiotemporal differences in the c-fos pathway between C57BL/6J and DBA/2J mice following flurothyl-induced seizures: a dissociation of hippocampal Fos from seizure activity

    PubMed Central

    Kadiyala, Sridhar B.; Papandrea, Dominick; Tuz, Karina; Anderson, Tara M.; Jayakumar, Sachidhanand; Herron, Bruce J.; Ferland, Russell J.

    2014-01-01

    Significant differences in seizure characteristics between inbred mouse strains highlight the importance of genetic predisposition to epilepsy. Here, we examined the genetic differences between the seizure-resistant C57BL/6J (B6) mouse strain and the seizure-susceptible DBA/2J (D2) strain in the phospho-Erk and Fos pathways to examine seizure-induced neuronal activity to uncover potential mechanistic correlates to these disparate seizure responsivities. Expression of neural activity markers was examined following 1, 5, or 8 seizures, or after 8 seizures, a 28 day rest period, and a final flurothyl rechallenge. Two brain regions, the hippocampus and ventromedial nucleus of the hypothalamus (VMH), had significantly different Fos expression profiles following seizures. Fos expression was highly robust in B6 hippocampus following one seizure and remained elevated following multiple seizures. Conversely, there was an absence of Fos (and phospho-Erk) expression in D2 hippocampus following one generalized seizure that increased with multiple seizures. This lack of Fos expression occurred despite intracranial electroencephalographic recordings indicating that the D2 hippocampus propagated ictal discharge during the first flurothyl seizure suggesting a dissociation of seizure discharge from Fos and phospho-Erk expression. Global transcriptional analysis confirmed a dysregulation of the c-fos pathway in D2 mice following 1 seizure. Moreover, global analysis of RNA expression differences between B6 and D2 hippocampus revealed a unique pattern of transcripts that were co-regulated with Fos in D2 hippocampus following 1 seizure. These expression differences could, in part, account for D2’s seizure susceptibility phenotype. Following 8 seizures, a 28 day rest period, and a final flurothyl rechallenge, ~85% of B6 mice develop a more complex seizure phenotype consisting of a clonic-forebrain seizure that uninterruptedly progresses into a brainstem seizure. This seizure phenotype

  11. AP-1 Transcription Factors c-FOS and c-JUN Mediate GnRH-Induced Cadherin-11 Expression and Trophoblast Cell Invasion.

    PubMed

    Peng, Bo; Zhu, Hua; Ma, Liyang; Wang, Yan-Ling; Klausen, Christian; Leung, Peter C K

    2015-06-01

    GnRH is expressed in first-trimester human placenta and increases cell invasion in extravillous cytotrophoblasts (EVTs). Invasive phenotypes have been reported to be regulated by transcription factor activator protein 1 (AP-1) and mesenchymal cadherin-11. The aim of our study was to investigate the roles of AP-1 components (c-FOS/c-JUN) and cadherin-11 in GnRH-induced cell invasion in human EVT cells. Phosphorylated c-FOS and phosphorylated c-JUN were detected in the cell column regions of human first-trimester placental villi by immunohistochemistry. GnRH treatment increased c-FOS, c-JUN, and cadherin-11 mRNA and protein levels in immortalized EVT (HTR-8/SVneo) cells. Moreover, GnRH treatment induced c-FOS and c-JUN protein phosphorylation and nuclear accumulation. Pretreatment with antide, a GnRH antagonist, attenuated GnRH-induced cadherin-11 expression. Importantly, basal and GnRH-induced cadherin-11 expression and cell invasion were reduced by small interfering RNA-mediated knockdown of c-FOS, c-JUN, and cadherin-11 in HTR-8/SVneo cells. Our results suggest that GnRH induces the expression and phosphorylation of the AP-1 transcription factors c-FOS and c-JUN in trophoblast cells, which contributes to GnRH-induced elevation of cadherin-11 expression and cell invasion. PMID:25794160

  12. Neuronal NOS inhibitor and conventional antidepressant drugs attenuate stress-induced fos expression in overlapping brain regions.

    PubMed

    Silva, Michelle; Aguiar, Daniele C; Diniz, Cassiano R A; Guimarães, Francisco Silveira; Joca, Sâmia R L

    2012-04-01

    Recent evidence indicates that the administration of inhibitors of neuronal nitric oxide synthase (nNOS) induces antidepressant-like effects in animal models such as the forced swimming test (FST). However, the neural circuits involved in these effects are not yet known. Therefore, this study investigated the expression of Fos protein, a marker of neuronal activity, in the brain of rats submitted to FST and treated with the preferential nNOS inhibitor, 7-nitroindazole (7-NI), or with classical antidepressant drugs (Venlafaxine and Fluoxetine). Male Wistar rats were submitted to a forced swimming pretest (PT) and, immediately after, started receiving a sequence of three ip injections (0, 5, and 23 h after PT) of Fluoxetine (10 mg/kg), Venlafaxine (10 mg/kg), 7-NI (30 mg/kg) or respective vehicles. One hour after the last drug injection the animals were submitted to the test session, when immobility time was recorded. After the FST they were sacrificed and had their brains removed and processed for Fos immunohistochemistry. Independent group of non-stressed animals received the same drug treatments, or no treatment (naïve). 7-NI, Venlafaxine or Fluoxetine reduced immobility time in the FST, an antidepressant-like effect. None of the treatments induce significant changes in Fos expression per se. However, swimming stress induced significant increases in Fos expression in the following brain regions: medial prefrontal cortex, nucleus accumbens, locus coeruleus, raphe nuclei, striatum, hypothalamic nucleus, periaqueductal grey, amygdala, habenula, paraventricular nucleus of hypothalamus, and bed nucleus of stria terminalis. This effect was attenuated by 7-NI, Venlafaxine or Fluoxetine. These results show that 7-NI produces similar behavioral and neuronal activation effects to those of typical antidepressants, suggesting that these drugs share common neurobiological substrates.

  13. Fos and serotonin immunoreactivity in the raphe nuclei of the cat during carbachol-induced active sleep: a double-labeling study.

    PubMed

    Yamuy, J; Sampogna, S; López-Rodríguez, F; Luppi, P H; Morales, F R; Chase, M H

    1995-07-01

    The microinjection of carbachol into the nucleus pontis oralis produces a state which is polygraphically and behaviorally similar to active sleep (rapid eye movement sleep). In the present study, using double-labeling techniques for serotonin and the protein product of c-fos (Fos), we sought to examine whether immunocytochemically identified serotonergic neurons of the raphe nuclei of the cat were activated, as indicated by their expression of c-fos, during this pharmacologically-induced behavioral state (active sleep-carbachol). Compared with control cats, which were injected with saline, active sleep-carbachol cats exhibited a significantly greater number of c-fos-expressing neurons in the raphe dorsalis, magnus and pallidus. Whereas most of the c-fos-expressing neurons in the raphe dorsalis were small, those in the raphe magnus were medium-sized and in the raphe pallidus they were small and medium-sized. The mean number of serotonergic neurons that expressed c-fos (i.e. double-labeled cells) was similar in control and active sleep-carbachol cats. These data indicate that there is an increased number of non-serotonergic, c-fos-expressing neurons in the raphe dorsalis, magnus and pallidus during the carbachol-induced state.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7477901

  14. Ghrelin Prevents Cisplatin-Induced Testicular Damage by Facilitating Repair of DNA Double Strand Breaks Through Activation of p53 in Mice.

    PubMed

    Garcia, Jose M; Chen, Ji-an; Guillory, Bobby; Donehower, Lawrence A; Smith, Roy G; Lamb, Dolores J

    2015-07-01

    Cisplatin administration induces DNA damage resulting in germ cell apoptosis and subsequent testicular atrophy. Although 50 percent of male cancer patients receiving cisplatin-based chemotherapy develop long-term secondary infertility, medical treatment to prevent spermatogenic failure after chemotherapy is not available. Under normal conditions, testicular p53 promotes cell cycle arrest, which allows time for DNA repair and reshuffling during meiosis. However, its role in the setting of cisplatin-induced infertility has not been studied. Ghrelin administration ameliorates the spermatogenic failure that follows cisplatin administration in mice, but the mechanisms mediating these effects have not been well established. The aim of the current study was to characterize the mechanisms of ghrelin and p53 action in the testis after cisplatin-induced testicular damage. Here we show that cisplatin induces germ cell damage through inhibition of p53-dependent DNA repair mechanisms involving gamma-H2AX and ataxia telangiectasia mutated protein kinase. As a result, testicular weight and sperm count and motility were decreased with an associated increase in sperm DNA damage. Ghrelin administration prevented these sequelae by restoring the normal expression of gamma-H2AX, ataxia telangiectasia mutated, and p53, which in turn allows repair of DNA double stranded breaks. In conclusion, these findings indicate that ghrelin has the potential to prevent or diminish infertility caused by cisplatin and other chemotherapeutic agents by restoring p53-dependent DNA repair mechanisms. PMID:26019260

  15. Effects of ghrelin and des-acyl ghrelin on neurogenesis of the rat fetal spinal cord

    SciTech Connect

    Sato, Miho; Nakahara, Keiko; Goto, Shintaro; Kaiya, Hiroyuki; Miyazato, Mikiya . E-mail: a0d201u@cc.miyazaki-u.ac.jp; Date, Yukari; Nakazato, Masamitsu; Kangawa, Kenji; Murakami, Noboru

    2006-11-24

    Expressions of the growth hormone secretagogue receptor (GHS-R) mRNA and its protein were confirmed in rat fetal spinal cord tissues by RT-PCR and immunohistochemistry. In vitro, over 3 nM ghrelin and des-acyl ghrelin induced significant proliferation of primary cultured cells from the fetal spinal cord. The proliferating cells were then double-stained using antibodies against the neuronal precursor marker, nestin, and the cell proliferation marker, 5-bromo-2'-deoxyuridine (BrdU), and the nestin-positive cells were also found to be co-stained with antibody against GHS-R. Furthermore, binding studies using [{sup 125}I]des-acyl ghrelin indicated the presence of a specific binding site for des-acyl ghrelin, and confirmed that the binding was displaced with unlabeled des-acyl ghrelin or ghrelin. These results indicate that ghrelin and des-acyl ghrelin induce proliferation of neuronal precursor cells that is both dependent and independent of GHS-R, suggesting that both ghrelin and des-acyl ghrelin are involved in neurogenesis of the fetal spinal cord.

  16. Ghrelin inhibits sympathetic nervous activity in sepsis.

    PubMed

    Wu, Rongqian; Zhou, Mian; Das, Padmalaya; Dong, Weifeng; Ji, Youxin; Yang, Derek; Miksa, Michael; Zhang, Fangming; Ravikumar, Thanjavur S; Wang, Ping

    2007-12-01

    Our previous studies have shown that norepinephrine (NE) upregulates proinflammatory cytokines by activating alpha(2)-adrenoceptor. Therefore, modulation of the sympathetic nervous system represents a novel treatment for sepsis. We have also shown that a novel stomach-derived peptide, ghrelin, is downregulated in sepsis and that its intravenous administration decreases proinflammatory cytokines and mitigates organ injury. However, it remains unknown whether ghrelin inhibits sympathetic activity through central ghrelin receptors [i.e., growth hormone secretagogue receptor 1a (GHSR-la)] in sepsis. To study this, sepsis was induced in male rats by cecal ligation and puncture (CLP). Ghrelin was administered through intravenous or intracerebroventricular injection 30 min before CLP. Our results showed that intravenous administration of ghrelin significantly reduced the elevated NE and TNF-alpha levels at 2 h after CLP. NE administration partially blocked the inhibitory effect of ghrelin on TNF-alpha in sepsis. GHSR-la inhibition by the administration of a GHSR-la antagonist, [d-Arg(1),d-Phe(5), d-Trp(7,9),Leu(11)]substance P, significantly increased both NE and TNF-alpha levels even in normal animals. Markedly elevated circulating levels of NE 2 h after CLP were also significantly decreased by intracerebroventricular administration of ghrelin. Ghrelin's inhibitory effect on NE release was completely blocked by intracerebroventricular injection of the GHSR-1a antagonist or a neuropeptide Y (NPY)/Y(1) receptor antagonist. However, ghrelin's downregulatory effect on TNF-alpha release was only partially diminished by these agents. Thus ghrelin has sympathoinhibitory properties that are mediated by central ghrelin receptors involving a NPY/Y1 receptor-dependent pathway. Ghrelin's inhibitory effect on TNF-alpha production in sepsis is partially because of its modulation of the overstimulated sympathetic nerve activation.

  17. Ghrelin protects against depleted uranium-induced apoptosis of MC3T3-E1 cells through oxidative stress-mediated p38-mitogen-activated protein kinase pathway.

    PubMed

    Hao, Yuhui; Liu, Cong; Huang, Jiawei; Gu, Ying; Li, Hong; Yang, Zhangyou; Liu, Jing; Wang, Weidong; Li, Rong

    2016-01-01

    Depleted uranium (DU) mainly accumulates in the bone over the long term. Osteoblast cells are responsible for the formation of bone, and they are sensitive to DU damage. However, studies investigating methods of reducing DU damage in osteoblasts are rarely reported. Ghrelin is a stomach hormone that stimulates growth hormones released from the hypothalamic-pituitary axis, and it is believed to play an important physiological role in bone metabolism. This study evaluates the impact of ghrelin on DU-induced apoptosis of the osteoblast MC3T3-E1 and investigates its underlying mechanisms. The results show that ghrelin relieved the intracellular oxidative stress induced by DU, eliminated reactive oxygen species (ROS) and reduced lipid peroxidation by increasing intracellular GSH levels; in addition, ghrelin effectively suppressed apoptosis, enhanced mitochondrial membrane potential, and inhibited cytochrome c release and caspase-3 activation after DU exposure. Moreover, ghrelin significantly reduced the expression of DU-induced phosphorylated p38-mitogen-activated protein kinase (MAPK). A specific inhibitor (SB203580) or specific siRNA of p38-MAPK could significantly suppress DU-induced apoptosis and related signals, whereas ROS production was not affected. In addition, ghrelin receptor inhibition could reduce the anti-apoptosis effect of ghrelin on DU and reverse the effect of ghrelin on intracellular ROS and p38-MAPK after DU exposure. These results suggest that ghrelin can suppress DU-induced apoptosis of MC3T3-E1 cells, reduce DU-induced oxidative stress by interacting with its receptor, and inhibit downstream p38-MAPK activation, thereby suppressing the mitochondrial-dependent apoptosis pathway.

  18. Changes in CREB and deltaFosB are associated with the behavioural sensitization induced by methylenedioxypyrovalerone.

    PubMed

    Buenrostro-Jáuregui, Mario; Ciudad-Roberts, Andres; Moreno, Josep; Muñoz-Villegas, Patricia; López-Arnau, Raúl; Pubill, David; Escubedo, Elena; Camarasa, Jorge

    2016-07-01

    Methylenedioxypyrovalerone (MDPV) is a synthetic cathinone which has recently emerged as a designer drug of abuse. The objective of this study was to investigate the locomotor sensitization induced by MDPV in adolescent mice, and associated neuroplastic changes in the nucleus accumbens and striatum through deltaFosB and CREB expression. Behavioural testing consisted of three phases: Phase I: conditioning regimen with MDPV (0.3 mg/kg/day for five days) or saline; Phase II: resting (11 days); Phase III: challenged with MDPV (0.3 mg/kg), cocaine (10 mg/kg) or saline on day 16 for both groups. Mice repeatedly exposed to MDPV increased locomotor activity by 165-200% following acute MDPV or cocaine administration after an 11-day resting period, showing a MDPV-induced sensitization to itself and to cocaine. An explanation for this phenomenon could be the common mechanism of action between these two psychostimulants. Furthermore, the MDPV challenge resulted in higher levels of phospho-CREB in MDPV-conditioned mice compared with MDPV-naive mice, probably due to an up-regulation of the cAMP pathway. Likewise, MDPV exposure induced a persistent increase in the striatal expression of deltaFosB; the priming dose of MDPV also produced a significant increase in the accumbal expression of this transcription factor. This study constitutes the first evidence that an exposure to a low dose of MDPV during adolescence induces behavioural sensitization and provides a neurobiological basis for a relationship between MDPV and cocaine. We hypothesize that, similar to cocaine, both CREB and deltaFosB play a role in the induction of this behavioural sensitization. PMID:27147595

  19. SUMOylation of the inducible (c-Fos:c-Jun)/AP-1 transcription complex occurs on target promoters to limit transcriptional activation.

    PubMed

    Tempé, D; Vives, E; Brockly, F; Brooks, H; De Rossi, S; Piechaczyk, M; Bossis, G

    2014-02-13

    The inducible proto-oncogenic (c-Fos:c-Jun)/AP-1 transcription complex binds 12-O-tetradecanoylphorbol 13-acetate (TPA)-responsive elements (TRE) in its target genes. It is tightly controlled at multiple levels to avoid the deleterious effects of its inappropriate activation. In particular, SUMOylation represses its transactivation capacity in transient reporter assays using constitutively expressed proteins. This led to the presumption that (c-Fos:c-Jun)/AP-1 SUMOylation would be required to turn-off transcription of its target genes, as proposed for various transcription factors. Instead, thanks to the generation of an antibody specific for SUMO-modified c-Fos, we provide here direct evidence that SUMOylated c-Fos is present on a stably integrated reporter TPA-inducible promoter at the onset of transcriptional activation and colocalizes with RNA polymerase II within chromatin. Interestingly, (c-Fos:c-Jun)/AP-1 SUMOylation limits reporter gene induction, as well as the appearance of active transcription-specific histone marks on its promoter. Moreover, non-SUMOylatable mutant (c-Fos:c-Jun)/AP-1 dimers accumulate to higher levels on their target promoter, suggesting that SUMOylation might facilitate the release of (c-Fos:c-Jun)/AP-1 from promoters. Finally, activation of GADD153, an AP-1 target gene, is also associated with a rapid increase in SUMOylation at the level of its TRE and c-Fos SUMOylation dampens its induction by TPA. Taken together, our data suggest that SUMOylation could serve to buffer transcriptional activation of AP-1 target genes.

  20. Comprehensive Profiling of GPCR Expression in Ghrelin-Producing Cells.

    PubMed

    Koyama, Hiroyuki; Iwakura, Hiroshi; Dote, Katsuko; Bando, Mika; Hosoda, Hiroshi; Ariyasu, Hiroyuki; Kusakabe, Toru; Son, Choel; Hosoda, Kiminori; Akamizu, Takashi; Kangawa, Kenji; Nakao, Kazuwa

    2016-02-01

    To determine the comprehensive G protein-coupled receptor (GPCR) expression profile in ghrelin-producing cells and to elucidate the role of GPCR-mediated signaling in the regulation of ghrelin secretion, we determined GPCR expression profiles by RNA sequencing in the ghrelin-producing cell line MGN3-1 and analyzed the effects of ligands for highly expressed receptors on intracellular signaling and ghrelin secretion. Expression of selected GPCRs was confirmed in fluorescence-activated cell-sorted fluorescently tagged ghrelin-producing cells from ghrelin-promoter CreERT2/Rosa-CAG-LSL-ZsGreen1 mice. Expression levels of GPCRs previously suggested to regulate ghrelin secretion including adrenergic-β1 receptor, GPR81, oxytocin receptor, GPR120, and somatostatin receptor 2 were high in MGN3-1 cells. Consistent with previous reports, isoproterenol and oxytocin stimulated the Gs and Gq pathways, respectively, whereas lactate, palmitate, and somatostatin stimulated the Gi pathway, confirming the reliability of current assays. Among other highly expressed GPCRs, prostaglandin E receptor 4 agonist prostaglandin E2 significantly stimulated the Gs pathway and ghrelin secretion. Muscarine, the canonical agonist of cholinergic receptor muscarinic 4, stimulated both the Gq and Gi pathways. Although muscarine treatment alone did not affect ghrelin secretion, it did suppress forskolin-induced ghrelin secretion, suggesting that the cholinergic pathway may play a role in counterbalancing the stimulation of ghrelin by Gs (eg, by adrenaline). In addition, GPR142 ligand tryptophan stimulated ghrelin secretion. In conclusion, we determined the comprehensive expression profile of GPCRs in ghrelin-producing cells and identified two novel ghrelin regulators, prostaglandin E2 and tryptophan. These results will lead to a greater understanding of the physiology of ghrelin and facilitate the development of ghrelin-modulating drugs.

  1. Anorexia in rats caused by a valine-deficient diet is not ameliorated by systemic ghrelin treatment.

    PubMed

    Goto, S; Nagao, K; Bannai, M; Takahashi, M; Nakahara, K; Kangawa, K; Murakami, N

    2010-03-10

    Rodents exhibit aversive behavior toward a diet that lacks at least one of the essential amino acids. We sought to determine whether the particular form of anorexia caused by such diets could be ameliorated by the administration of orexigenic peptides while simultaneously analyzing the neural mechanisms underlying anorexia. Rats were fed a valine-deficient diet, which induced severe anorexia (reducing food consumption by 80%). The severe anorexia was associated with a significant decrease in the cerebrospinal fluid valine concentration and hyper-ghrelinemia. Between 6 and 12 days after initiation of the valine-deficient diet, we injected rats twice daily with valine and/or an orexigenic peptide (ghrelin, neuropeptide Y, or agouti-related protein) either i.p. or i.c.v.. We then measured dietary intake. An i.c.v. valine injection allowed earlier food intake compared with an i.p valine injection and increased the density of c-Fos-positive ependymal cells lining the third ventricle. Whereas an i.c.v. injection of ghrelin or neuropeptide Y increased consumption of the valine-deficient diet, i.p injection of ghrelin or i.c.v. injection of agouti-related protein did not. Following i.c.v. administration of either valine or ghrelin, we did not observe complete recovery of consumption of the valine-deficient diet. This may be due to the ineffectiveness of peripheral ghrelin and central agouti-related protein and/or to conditioned aversion to the valine-deficient diet. Since ghrelin is known to be involved in food anticipatory activities, whether the hyper-ghrelinemia observed in valine-deficient rats play role in foraging behavior other than food intake is the future study to be investigated.

  2. Ghrelin and ghrelin receptor modulation of psychostimulant action

    PubMed Central

    Wellman, Paul J.; Clifford, P. Shane; Rodriguez, Juan A.

    2013-01-01

    Ghrelin (GHR) is an orexigenic gut peptide that modulates multiple homeostatic functions including gastric emptying, anxiety, stress, memory, feeding, and reinforcement. GHR is known to bind and activate growth-hormone secretagogue receptors (termed GHR-Rs). Of interest to our laboratory has been the assessment of the impact of GHR modulation of the locomotor activation and reward/reinforcement properties of psychostimulants such as cocaine and nicotine. Systemic GHR infusions augment cocaine stimulated locomotion and conditioned place preference (CPP) in rats, as does food restriction (FR) which elevates plasma ghrelin levels. Ghrelin enhancement of psychostimulant function may occur owing to a direct action on mesolimbic dopamine function or may reflect an indirect action of ghrelin on glucocorticoid pathways. Genomic or pharmacological ablation of GHR-Rs attenuates the acute locomotor-enhancing effects of nicotine, cocaine, amphetamine and alcohol and blunts the CPP induced by food, alcohol, amphetamine and cocaine in mice. The stimulant nicotine can induce CPP and like amphetamine and cocaine, repeated administration of nicotine induces locomotor sensitization in rats. Inactivation of ghrelin circuit function in rats by injection of a ghrelin receptor antagonist (e.g., JMV 2959) diminishes the development of nicotine-induced locomotor sensitization. These results suggest a key permissive role for GHR-R activity for the induction of locomotor sensitization to nicotine. Our finding that GHR-R null rats exhibit diminished patterns of responding for intracranial self-stimulation complements an emerging literature implicating central GHR circuits in drug reward/reinforcement. Finally, antagonism of GHR-Rs may represent a smoking cessation modality that not only blocks nicotine-induced reward but that also may limit weight gain after smoking cessation. PMID:24093007

  3. DNA binding of Jun and Fos bZip domains: homodimers and heterodimers induce a DNA conformational change in solution.

    PubMed Central

    John, M; Leppik, R; Busch, S J; Granger-Schnarr, M; Schnarr, M

    1996-01-01

    We constructed plasmids encoding the sequences for the bZip modules of c-Jun and c-Fos which could then be expressed as soluble proteins in Escherichia coli. The purified bZip modules were tested for their binding capacities of synthetic oligonucleotides containing either TRE or CRE recognition sites in electrophoretic mobility shift assays and circular dichroism (CD). Electrophoretic mobility shift assays showed that bZip Jun homodimers and bZip Jun/Fos heterodimers bind a collagenase-like TRE (CTGACTCAT) with dissociation constants of respectively 1.4 x 10(-7) M and 5 x 10(-8) M. As reported earlier [Patel et al. (1990) Nature 347, 572-575], DNA binding induces a marked change of the protein structure. However, we found that the DNA also undergoes a conformational change. This is most clearly seen with small oligonucleotides of 13 or 14 bp harboring respectively a TRE (TGACTCA) or a CRE (TGACGTCA) sequence. In this case, the positive DNA CD signal at 280 nm increases almost two-fold with a concomitant blue-shift of 3-4 nm. Within experimental error the same spectral changes are observed for TRE and CRE containing DNA fragments. The spectral changes observed with a non-specific DNA fragment are weaker and the signal of free DNA is recovered upon addition of much smaller salt concentrations than required for a specific DNA fragment. Surprisingly the spectral changes induced by Jun/Jun homodimers are not identical to those induced by Jun/Fos heterodimers. However, in both cases the increase of the positive CD band and the concomitant blue shift would be compatible with a B to A-transition of part of the binding site or a DNA conformation intermediate between the canonical A and B structures. PMID:8948639

  4. Fos activation of selective afferents to ventral tegmental area during cue-induced reinstatement of cocaine seeking in rats.

    PubMed

    Mahler, Stephen V; Aston-Jones, Gary S

    2012-09-19

    Ventral tegmental area (VTA) dopamine neurons are crucial for appetitive responses to Pavlovian cues, including cue-induced reinstatement of drug seeking. However, it is unknown which VTA inputs help activate these neurons, transducing stimuli into salient cues that drive drug-seeking behavior. Here we examined 56 VTA afferents from forebrain and midbrain that are Fos activated during cue-induced reinstatement. We injected the retrograde tracer cholera toxin β subunit (CTb) unilaterally into rostral or caudal VTA of male rats. All animals were trained to self-administer cocaine, then extinguished of this behavior. On a final test day, animals were exposed to response-contingent cocaine-associated cues, extinction conditions, a non-cocaine-predictive CS-, or a novel environment, and brains were processed to visualize CTb and Fos immunoreactivity to identify VTA afferents activated in relation to behaviors. VTA-projecting neurons in subregions of medial accumbens shell, ventral pallidum, elements of extended amygdala, and lateral septum (but not prefrontal cortex) were activated specifically during cue-induced cocaine seeking, and some of these were also activated proportionately to the degree of cocaine seeking. Surprisingly, though efferents from the lateral hypothalamic orexin field were also Fos activated during reinstatement, these were largely non-orexinergic. Also, VTA afferents from the rostromedial tegmental nucleus and lateral habenula were specifically activated during extinction and CS- tests, when cocaine was not expected. These findings point to a select set of subcortical nuclei which provide reinstatement-related inputs to VTA, translating conditioned stimuli into cocaine-seeking behavior.

  5. N-acetylcysteine treatment blocks the development of ethanol-induced behavioural sensitization and related ΔFosB alterations.

    PubMed

    Morais-Silva, Gessynger; Alves, Gabrielle Cunha; Marin, Marcelo T

    2016-11-01

    Ethanol addiction is a serious public health problem that still needs more effective pharmacological treatment. A key factor in the development and maintenance of this disease is the advent of neuroadaptations in the mesocorticolimbic brain pathway upon chronic ethanol abuse. In general, these neuroadaptations are maladaptive and affect numerous neurotransmitter systems and intracellular molecules. One of these molecules is ΔFosB, a transcription factor that is altered after chronic drug use. Behavioural sensitization is a useful model for the study of the neuroadaptations related to addiction. Recent works have shown a role for the imbalance of glutamatergic neurotransmission in the symptoms found in addicted people. In this sense, the treatment with N-acetylcysteine, a l-cysteine prodrug that acts by restoring extrasynaptic concentrations of glutamate through the activation of cystine-glutamate antiporter, has shown promising results in the treatment of addiction. Thus, an animal model of behavioural sensitization was used to evaluate the effects of N-acetylcysteine treatment in the behavioural and molecular alterations induced by chronic ethanol administration. Swiss mice were subject to 13 days of daily ethanol administration to induce behavioural sensitization. Two hours before each ethanol administration and locomotor activity evaluation, the animals received intraperitoneally N-acetylcysteine injections. Immediately after the last test session, their brains were removed for ΔFosB and cystine-glutamate antiporter quantification. It was found that N-acetylcysteine treatment blocked ethanol-induced behavioural sensitization, the increase of ΔFosB content in the prefrontal cortex, and its reduction in the nucleus accumbens. The results suggest a possible use of N-acetylcysteine in ethanol-related disorders. PMID:27401790

  6. Inducibility of c-Fos protein in visuo-motor system and limbic structures after acute and repeated administration of nicotine in the rat.

    PubMed

    Mathieu-Kia, A M; Pages, C; Besson, M J

    1998-08-01

    To identify neuroanatomical substrates affected by nicotine, we have studied its effects after acute and repeated administration through the c-Fos protein inducibility in various brain structures. Ninety minutes after acute nicotine (0.35 mg/kg, s.c.) the number of c-Fos-like immunoreactive nuclei was consistently increased in visuo-motor structures such as the superior colliculus, the medial terminal nucleus of accessory optic tract, and the nucleus of the optic tract. The anteroventral and lateroposterior thalamic nuclei, connected with the retina and involved in limbic processing, showed a c-Fos induction. c-Fos was preferentially induced in terminal fields of neurons of the ventral tegmental area such as the nucleus accumbens, the central amygdala, the lateral habenula, the lateral septum, as well as the cingulate, medial prefrontal, orbital and piriform cortices. In chronically treated rats (0.35 mg/kg s.c., 3 x day for 14 days), the last nicotine injection given on the 15th day was still able to induce 90 minutes later c-Fos protein in visuo-motor, retino-limbic, subcortical, and cortical limbic structures. Moreover, this chronic treatment produced an additional recruitment of c-Fos-positive nuclei in the cingulate cortex, the core and the ventral shell of the nucleus accumbens. c-Fos induction after nicotine differs from that reported after other addictive drugs in terms of pattern and chronic inducibility, indicating that different mechanisms are involved for maintaining this transcription factor. In addition to a preferential sensitivity of mesolimbic dopaminergic neurons to nicotine, activation of visuo-limbic and limbic regions could be relevant for understanding some context-dependent and addictive behaviors produced by nicotine.

  7. Receptor-Selective Agonists Induce Emesis and Fos Expression in the Brain and Enteric Nervous System of the Least Shrew (Cryptotis parva)

    PubMed Central

    Ray, Andrew P.; Chebolu, Seetha; Darmani, Nissar A.

    2009-01-01

    Research on the mechanisms of emesis has implicated multiple neurotransmitters via both central (dorsal vagal complex) and peripheral (enteric neurons and enterochromaffin cells) anatomical substrates. Taking advantage of advances in receptor-specific agonists, and utilizing Fos expression as a functional activity marker, this study demonstrates a strong, but incomplete, overlap in anatomical substrates for a variety of emetogens. We used cisplatin and specific agonists to 5-HT3 serotonergic, D2/D3 dopaminergic, and NK1 tachykininergic receptors to induce vomiting in the least shrew (Cryptotis parva), and quantified the resulting Fos expression. The least shrew is a small mammal whose responses to emetic challenges are very similar to its human counterparts. In all cases, the enteric nervous system, nucleus of the solitary tract, and dorsal motor nucleus of the vagus demonstrated significantly increased Fos immunoreactivity (Fos-IR). However, Fos-IR induction was notably absent from the area postrema following the dopaminergic and NK1 receptor-specific agents. Two brain nuclei not usually discussed regarding emesis, the dorsal raphe nucleus and paraventricular thalamic nucleus, also demonstrated increased emesis-related Fos-IR. Taken together, these data suggest the dorsal vagal complex is part of a common pathway for a variety of distinct emetogens, but there are central emetic substrates, both medullary and diencephalic, that can be accessed without directly stimulating the area postrema. PMID:19699757

  8. c-fos Expression in mesopontine noradrenergic and cholinergic neurons of the cat during carbachol-induced active sleep: a double-labeling study.

    PubMed

    Yamuy, J; Sampogna, S; Morales, F R; Chase, M H

    1998-01-01

    The interaction of cholinergic and catecholaminergic mechanisms in the mesopontine region has been hypothesized as being critical for the generation and maintenance of active (REM) sleep. To further examine this hypothesis, we sought to determine the pattern of neuronal activation (via c-fos expression) of catecholaminergic and cholinergic neurons in this region during active sleep induced by the pontine microapplication of carbachol (designated as active sleep-carbachol). Accordingly, we used two sets of double-labeling techniques; the first to identify tyrosine hydroxylase-containing neurons (putative catecholaminergic cells) which also express the c-fos protein product Fos, and the second to reveal choline acetyltransferase-containing neurons (putative cholinergic cells) which also express Fos. Compared to control cats, active sleep-carbachol cats exhibited a significantly greater number of Fos-expressing neurons in the dorsolateral region of the pons, which encompasses the locus coeruleus, the lateral pontine reticular formation, the peribrachial nuclei and the latero-dorsal and pedunculo-pontine tegmental nuclei. However, both control and active sleep-carbachol cats exhibited a similar number of catecholaminergic and cholinergic neurons in those regions that expressed Fos (i.e., double-labeled cells). A large number of c-fos-expressing neurons in the active sleep-carbachol cats whose neurotransmitter phenotype was not identified suggests that non-catecholaminergic, non-cholinergic neuronal populations in mesopontine regions are involved in the generation and maintenance of active sleep. The lack of increased c-fos expression in catecholaminergic neurons during active sleep-carbachol confirms and extends previous data that indicate that these cells are silent during active sleep-carbachol and naturally-occurring active sleep. The finding that cholinergic neurons of the dorsolateral pons were not activated either during wakefulness or active sleep

  9. c-fos Expression in mesopontine noradrenergic and cholinergic neurons of the cat during carbachol-induced active sleep: a double-labeling study.

    PubMed

    Yamuy, J; Sampogna, S; Morales, F R; Chase, M H

    1998-01-01

    The interaction of cholinergic and catecholaminergic mechanisms in the mesopontine region has been hypothesized as being critical for the generation and maintenance of active (REM) sleep. To further examine this hypothesis, we sought to determine the pattern of neuronal activation (via c-fos expression) of catecholaminergic and cholinergic neurons in this region during active sleep induced by the pontine microapplication of carbachol (designated as active sleep-carbachol). Accordingly, we used two sets of double-labeling techniques; the first to identify tyrosine hydroxylase-containing neurons (putative catecholaminergic cells) which also express the c-fos protein product Fos, and the second to reveal choline acetyltransferase-containing neurons (putative cholinergic cells) which also express Fos. Compared to control cats, active sleep-carbachol cats exhibited a significantly greater number of Fos-expressing neurons in the dorsolateral region of the pons, which encompasses the locus coeruleus, the lateral pontine reticular formation, the peribrachial nuclei and the latero-dorsal and pedunculo-pontine tegmental nuclei. However, both control and active sleep-carbachol cats exhibited a similar number of catecholaminergic and cholinergic neurons in those regions that expressed Fos (i.e., double-labeled cells). A large number of c-fos-expressing neurons in the active sleep-carbachol cats whose neurotransmitter phenotype was not identified suggests that non-catecholaminergic, non-cholinergic neuronal populations in mesopontine regions are involved in the generation and maintenance of active sleep. The lack of increased c-fos expression in catecholaminergic neurons during active sleep-carbachol confirms and extends previous data that indicate that these cells are silent during active sleep-carbachol and naturally-occurring active sleep. The finding that cholinergic neurons of the dorsolateral pons were not activated either during wakefulness or active sleep

  10. Effect of blonanserin on methamphetamine-induced disruption of latent inhibition and c-Fos expression in rats.

    PubMed

    Kuramashi, Aki; Abe, Hiroshi; Koganemaru, Go; Matsuo, Hisae; Ikeda, Tetsuya; Ebihara, Kosuke; Funahashi, Hideki; Takeda, Ryuichiro; Nishimori, Toshikazu; Ishida, Yasushi

    2013-08-01

    To clarify the psychopharmacological profile of blonanserin, a novel antipsychotic, we examined its effect on the methamphetamine-induced disruption of latent inhibition (LI) and the neural activation related to this effect in rats. To evaluate the LI, we used a conditioned emotional response in which a tone (conditioned stimulus) was paired with a mild foot shock (unconditioned stimulus). This paradigm was presented to rats licking water. Methamphetamine-induced (1.0mg/kg, i.p.) disruption of LI was significantly improved by the administration of a higher dose (3.0mg/kg, i.p.) of blonanserin and tended to be improved by 1.0-mg/kg blonanserin and 0.2-mg/kg haloperidol but not by a lower dose (0.3mg/kg) of blonanserin. Immunohistochemical examination showed blonanserin (3.0mg/kg, i.p.) increased c-Fos expression in the shell area but not in the core area of the nucleus accumbens while methamphetamine (3.0mg/kg, i.p.) produced the opposite expression pattern. Blonanserin also increased the number of c-Fos expressions in the central amygdala nucleus but not in the basolateral amygdala nucleus or the prefrontal cortex. Blonanserin ameliorates the methamphetamine-induced disruption of LI, as other antipsychotics do, and a neuronal activation and/or modulation of neurotransmission in the nucleus accumbens is related to the disruption of LI by methamphetamine and to its amelioration by blonanserin.

  11. Modulatory effect of environmental context and drug history on heroin-induced psychomotor activity and fos protein expression in the rat brain.

    PubMed

    Paolone, Giovanna; Conversi, David; Caprioli, Daniele; Bianco, Paola Del; Nencini, Paolo; Cabib, Simona; Badiani, Aldo

    2007-12-01

    The goal of the present study was to investigate the role of environmental context and drug history in modulating the effects of heroin on locomotor activity and Fos protein expression in the neocortex and striatal complex of the rat. It was found that (1) repeated i.p. administrations of a relatively low dose of heroin (1 mg/kg, i.p.) induced psychomotor sensitization only when the treatment was administered in a relatively 'novel' environment (ie, a unique test environment distinct from the home cage) but not when the same treatment was administered in the home cage; (2) environmental novelty facilitated heroin-induced Fos expression in the caudate, particularly in its most caudal regions; (3) environmental context also modulated heroin-induced Fos expression in the nucleus accumbens and in the neocortex; (4) repeated exposures to heroin dramatically altered its effects on Fos expression in the caudate and in the neocortex; and (5) Fos protein levels in the postero-dorsal caudate, in the shell of the nucleus accumbens, and in the barrel field cortex predicted most of the variance in heroin-induced activity scores, as shown by multiple regression analysis. The present report demonstrates that environment and drug history powerfully interact in shaping the neurobehavioral response to heroin, as previously shown for amphetamine and cocaine. Thus, a full understanding of the mechanisms responsible for the neurobehavioral adaptations produced by addictive drugs will also require taking into due consideration the environment in which drugs are experienced.

  12. Neural Correlates of Birth: Labor Contractions Induce C-Fos Expression In Newborn Rat Brain

    NASA Technical Reports Server (NTRS)

    Ronca, A. E.; Daly, M. E.; Baer, L. A.; Hills, E. M.; Conway, G.; Dalton, Bonnie (Technical Monitor)

    2002-01-01

    At birth, the newborn mammal must make rapid adaptations to the extrauterine environment to survive. We have previously shown that labor contractions augment the appearance of adaptive responses at birth, viz., postpartum breathing and the onset of suckling. Since neuronal activity has been shown to upregulate the activity of immediate early genes (IEGs) in the brain, we analyzed the neural distribution of c-Fos protein expression in newborn rats using immunohistochemistry. Previous studies have reported a burst of c-Fos mRNA expression in mouse and rat brain at birth however relationships to labor and delivery have not been examined. In the present study, we exposed near-term rat fetuses to elements of the vaginal birth process: 1) Simulated labor contractions. 2) Postpartum cooling (22 deg C). 3) Umbilical cord occlusion. and 4) Stroking to mimic postpartum licking by the dam. Cardinally delivered newborns (VG) were compared with those delivered by cesarean section following either prenatal exposure to compressions (C) [simulated labor contractions], or no compressions (NC) [no labor contractions]. Similar patterns of c-fos activation were observed throughout hypothalamic and thalamic nuclei, hippocampus and cerebral cortex in VG and C newborns that were not apparent in NC newborns. Our results indicate that labor contractions play a role in the induction of widespread neural activation in the newborn brain.

  13. Attenuation by butalbital of capsaicin-induced c-fos-like immunoreactivity in trigeminal nucleus caudalis.

    PubMed

    Cutrer, F M; Mitsikostas, D D; Ayata, G; Sanchez del Rio, M

    1999-01-01

    We examined the effects of butalbital (30, 100, and 1000 micrograms/kg) on the number of cells expressing c-fos-like immunoreactivity (c-fos-LI), a marker of neuronal activation, within lamina I, IIo of the trigeminal nucleus caudalis and the nucleus of the solitary tract 2 hours after the intracisternal injection of capsaicin (0.1 mL; 15.25 mg/mL) or vehicle in urethane-anesthetized guinea pigs (N = 45). Robust c-fos-LI was observed within nuclei of cells in the trigeminal nucleus caudalis after capsaicin (329 +/- 35). Butalbital dose-dependently reduced the number of labeled cells to a maximum of 66% (1000 micrograms/kg intraperitoneally [i.p.], P < .01) in lamina I, IIo but not within area postrema, medial reticular nucleus, or the nucleus of the solitary tract. Pretreatment with bicuculline (30 micrograms/kg i.p.) blocked the effect of butalbital, thereby suggesting the importance of the GABAA receptor to activation involved in the transmission of nociceptive information. Our studies suggest the possibility that GABAA receptors might provide an important therapeutic target in migraine and related headache disorders.

  14. Antifibrotic Activity of Acylated and Unacylated Ghrelin

    PubMed Central

    Angelino, Elia; Reano, Simone; Ferrara, Michele; Agosti, Emanuela; Graziani, Andrea; Filigheddu, Nicoletta

    2015-01-01

    Fibrosis can affect almost all tissues and organs, it often represents the terminal stage of chronic diseases, and it is regarded as a major health issue for which efficient therapies are needed. Tissue injury, by inducing necrosis/apoptosis, triggers inflammatory response that, in turn, promotes fibroblast activation and pathological deposition of extracellular matrix. Acylated and unacylated ghrelin are the main products of the ghrelin gene. The acylated form, through its receptor GHSR-1a, stimulates appetite and growth hormone (GH) release. Although unacylated ghrelin does not bind or activate GHSR-1a, it shares with the acylated form several biological activities. Ghrelin peptides exhibit anti-inflammatory, antioxidative, and antiapoptotic activities, suggesting that they might represent an efficient approach to prevent or reduce fibrosis. The aim of this review is to summarize the available evidence regarding the effects of acylated and unacylated ghrelin on different pathologies and experimental models in which fibrosis is a predominant characteristic. PMID:25960743

  15. Effect of simvastatin on mitochondrial enzyme activities, ghrelin, hypoxia-inducible factor 1α in hepatic tissue during early phase of sepsis.

    PubMed

    Yorulmaz, Hatice; Ozkok, Elif; Erguven, Mine; Ates, Gulten; Aydın, Irfan; Tamer, Sule

    2015-01-01

    We aimed to investigate the effects of prior treatment of simvastatin on mitochondrial enzyme, ghrelin, and hypoxia-inducible factor 1 α (HIF-1 α) on hepatic tissue in rats treated with Lipopolysaccharides (LPS) during the early phase of sepsis. Rats were divided into four groups: control, LPS (20 mg/kg, i.p.), Simvastatin (20 mg/kg, p.o.), and LPS + Simvastatin group. We measured citrate synthase, complex I, II, I-III, II-III enzymes activities, serum and tissue levels of TNF-α, IL-10 using ELISA. Liver sections underwent histopathologic examination and TNF-α, IL-10, HIF-1α and ghrelin immunoreactivity were examined using immunohistochemistry methods. There were no differences in all groups for mitochondrial enzyme activities. In terms of both ELISA and immunohistochemistry findings; the levels of serum and tissue TNF-α and IL-10 were higher in the experimental groups than controls (P < 0.05). In the LPS group, the hepatocyte cell membrane and sinusoid structure were damaged. In the Simvastatin +LPS group, hepatocytes and sinusoidal cord structure were partially improved. For HIF-1α, in all experimental groups immunoreactivity was increased (P < 0.05). In the Simvastatin group, Ghrelin levels were increased in comparison with the other groups (P < 0.01). Ghrelin levels were greatly decreased in LPS (P < 0.05). We observed that the degree of hepatocellular degeneration was partially reduced depending on the dosage and duration of prior simvastatin treatment with LPS, probably due to alterations of Ghrelin and HIF-1α levels. PMID:26064259

  16. Suppression by Ghrelin of Porphyromonas gingivalis-Induced Constitutive Nitric Oxide Synthase S-Nitrosylation and Apoptosis in Salivary Gland Acinar Cells.

    PubMed

    Slomiany, Bronislaw L; Slomiany, Amalia

    2010-01-01

    Oral mucosal inflammatory responses to periodontopathic bacterium, P. gingivalis, and its key virulence factor, LPS, are characterized by a massive rise in epithelial cell apoptosis and the disturbances in NO signaling pathways. Here, we report that the LPS-induced enhancement in rat sublingual salivary gland acinar cell apoptosis and NO generation was associated with the suppression in constitutive nitric oxide synthase (cNOS) activity and a marked increase in the activity of inducible nitric oxide synthase (iNOS). We demonstrate that the detrimental effect of the LPS on cNOS was manifested by the enzyme protein S-nitrosylation, that was susceptible to inhibition by iNOS inhibitor, 1400 W. Further, we show that a peptide hormone, ghrelin, countered the LPS-induced changes in apoptosis and cNOS activity. This effect of ghrelin was reflected in the decrease in cNOS S-nitrosylation and the increase in phosphorylation. Our findings imply that P. gingivalis-induced disturbances in the acinar cell NO signaling pathways result from upregulation in iNOS-derived NO that causes cNOS S-nitrosylation that interferes with its activation through phosphorylation. We also show that ghrelin protection against P. gingivalis-induced disturbances involves cNOS activation associated with a decrease in its S-nitrosylation and the increase in phosphorylation.

  17. Obesity Impairs the Action of the Neuroendocrine Ghrelin System

    PubMed Central

    Zigman, Jeffrey M.; Bouret, Sebastien G.; Andrews, Zane B.

    2016-01-01

    Ghrelin is a metabolic hormone that promotes energy conservation by regulating appetite and energy expenditure. Although some studies suggest that antagonizing ghrelin function attenuates body weight gain and glucose intolerance on a high calorie diet, there is little information about the metabolic actions of ghrelin in the obese state. In this review, we discuss the novel concept of obesity-induced central ghrelin resistance in neural circuits regulating behavior, and impaired ghrelin secretion from the stomach. Interestingly, weight loss restores ghrelin secretion and function, and we hypothesize that ghrelin resistance is a mechanism designed to protect a higher body weight set-point established during times of food availability, to maximize energy reserves during a time of food scarcity. PMID:26542050

  18. Peripheral injection of bombesin induces c-Fos in NUCB2/nesfatin-1 neurons.

    PubMed

    Engster, Kim-Marie; Kroczek, Arthur L; Rose, Matthias; Stengel, Andreas; Kobelt, Peter

    2016-10-01

    As anorexigenic hormones bombesin and nucleobindin2 (NUCB2)/nesfatin-1 decrease food intake in rodents. Both hormones have been described in brain nuclei that play a role in the modulation of hunger and satiety, like the paraventricular nucleus of the hypothalamus (PVN) and the nucleus of the solitary tract (NTS). However, the direct interaction of the two hormones is unknown so far. The aim of study was to elucidate whether bombesin directly interacts with NUCB2/nesfatin-1 neurons in the PVN and NTS. Therefore, we injected bombesin intraperitoneally (ip) at two doses (26 and 32nmol/kg body weight) and assessed c-Fos activation in the PVN, arcuate nucleus (ARC) and NTS compared to vehicle treated rats (0.15M NaCl). We also performed co-localization studies with oxytocin or tyrosine hydroxylase. Bombesin at both doses increased the number of c-Fos positive neurons in the PVN (p<0.05) and NTS (p<0.05) compared to vehicle, while in the ARC no modulation was observed (p>0.05). In the PVN and NTS the number of c-Fos positive neurons colocalized with NUCB2/nesfatin-1 increased after bombesin injection compared to vehicle treatment (p<0.05). Moreover, an increase of activated NUCB2/nesfatin-1 immunoreactive neurons that co-expressed oxytocin in the PVN (p<0.05) or tyrosine hydroxylase in the NTS (p<0.05) was observed compared to vehicle. Our results show that peripherally injected bombesin activates NUCB2/nesfatin-1 neurons in the PVN and NTS giving rise to a possible interaction between bombesin and NUCB2/nesfatin-1 in the modulation of food intake. PMID:27396908

  19. Peripheral injection of bombesin induces c-Fos in NUCB2/nesfatin-1 neurons.

    PubMed

    Engster, Kim-Marie; Kroczek, Arthur L; Rose, Matthias; Stengel, Andreas; Kobelt, Peter

    2016-10-01

    As anorexigenic hormones bombesin and nucleobindin2 (NUCB2)/nesfatin-1 decrease food intake in rodents. Both hormones have been described in brain nuclei that play a role in the modulation of hunger and satiety, like the paraventricular nucleus of the hypothalamus (PVN) and the nucleus of the solitary tract (NTS). However, the direct interaction of the two hormones is unknown so far. The aim of study was to elucidate whether bombesin directly interacts with NUCB2/nesfatin-1 neurons in the PVN and NTS. Therefore, we injected bombesin intraperitoneally (ip) at two doses (26 and 32nmol/kg body weight) and assessed c-Fos activation in the PVN, arcuate nucleus (ARC) and NTS compared to vehicle treated rats (0.15M NaCl). We also performed co-localization studies with oxytocin or tyrosine hydroxylase. Bombesin at both doses increased the number of c-Fos positive neurons in the PVN (p<0.05) and NTS (p<0.05) compared to vehicle, while in the ARC no modulation was observed (p>0.05). In the PVN and NTS the number of c-Fos positive neurons colocalized with NUCB2/nesfatin-1 increased after bombesin injection compared to vehicle treatment (p<0.05). Moreover, an increase of activated NUCB2/nesfatin-1 immunoreactive neurons that co-expressed oxytocin in the PVN (p<0.05) or tyrosine hydroxylase in the NTS (p<0.05) was observed compared to vehicle. Our results show that peripherally injected bombesin activates NUCB2/nesfatin-1 neurons in the PVN and NTS giving rise to a possible interaction between bombesin and NUCB2/nesfatin-1 in the modulation of food intake.

  20. The hallucinogen d-lysergic acid diethylamide (d-LSD) induces the immediate-early gene c-Fos in rat forebrain.

    PubMed

    Frankel, Paul S; Cunningham, Kathryn A

    2002-12-27

    The hallucinogen d-lysergic acid diethylamide (d-LSD) evokes dramatic somatic and psychological effects. In order to analyze the neural activation induced by this unique psychoactive drug, we tested the hypothesis that expression of the immediate-early gene product c-Fos is induced in specific regions of the rat forebrain by a relatively low, behaviorally active, dose of d-LSD (0.16 mg/kg, i.p.); c-Fos protein expression was assessed at 30 min, and 1, 2 and 4 h following d-LSD injection. A time- and region-dependent expression of c-Fos was observed with a significant increase (P<0.05) in the number of c-Fos-positive cells detected in the anterior cingulate cortex at 1 h, the shell of the nucleus accumbens at 1 and 2 h, the bed nucleus of stria terminalis lateral at 2 h and the paraventricular hypothalamic nucleus at 1, 2 and 4 h following systemic d-LSD administration. These data demonstrate a unique pattern of c-Fos expression in the rat forebrain following a relatively low dose of d-LSD and suggest that activation of these forebrain regions contributes to the unique behavioral effects of d-LSD.

  1. Antidepressant treatment reduces Fos-like immunoreactivity induced by swim stress in different columns of the periaqueductal gray matter.

    PubMed

    Lino-de-Oliveira, Cilene; de Oliveira, Rúbia M W; Pádua Carobrez, Antonio; de Lima, Thereza C M; del Bel, Elaine Aparecida; Guimarães, Francisco Silveira

    2006-10-16

    Antidepressant treatment attenuates behavioral changes induced by uncontrollable stress. The periaqueductal gray matter (PAG) is proposed to be a brain site involved in the behavioral responses to uncontrollable stress and antidepressant effects. The main goal of the present study was to investigate the effect of antidepressant treatment on the pattern of neural activation of the PAG along its mediolateral and rostrocaudal subregions after a forced swim stress episode. Male Wistar rats were sub-acutely treated with desipramine (a selective noradrenaline re-uptake blocker, three injections of 10 mg/kg in 24 h) or clomipramine (a non-selective serotonin and noradrenaline re-uptake blocker, three injections of 10 mg/kg in 24 h) and submitted to the forced swimming test (FST). Two hours after the test their brain were removed for Fos immunohistochemistry. Fos-like immunoreactivity (FLI) in rostral, intermediate and caudal portions of dorsomedial (dmPAG), dorsolateral (dlPAG), lateral (lPAG) and ventrolateral (vlPAG) PAG were quantified by a computerized system. The FST session increased FLI in most parts of the PAG. Previous treatment with desipramine or clomipramine reduced FLI in all columns of the PAG. FLI in the PAG correlated positively with to the immobility time and negatively with to climbing behavior scored during the test. These results indicate that neurons in the PAG are activated by uncontrollable stress. Moreover, inhibitory action of antidepressants on this activity may be associated with the anti-immobility effects of these drugs in the FST.

  2. Cocaine-induced c-Fos expression in rats selectively bred for high or low saccharin intake and in rats selected for high or low impulsivity.

    PubMed

    Regier, Paul S; Carroll, Marilyn E; Meisel, Robert L

    2012-08-01

    Sweet preference and impulsivity are predictors of cocaine self-administration; however, no research has been conducted to investigate neuronal activation in key brain reward areas after first time exposure to cocaine in rats that differ in their propensity for cocaine-seeking and -taking behavior. In this study we used rats that had been selectively bred for high vs. low saccharin intake and rats selected for high vs. low impulsivity for food. The goal of this study was to investigate whether there are differences of c-Fos reactivity between high and low phenotypes and determine whether these differences are similar between the two animal models. A group of rats was bred for high or low saccharin intake. Another group of rats was selected as high or low impulsive based on performance in a delay-discounting task. Subsequently, rats were given an acute injection of cocaine or saline and then c-Fos expression was observed and analyzed in several brain regions. The low reward-seeking phenotypes showed higher cocaine-induced c-Fos expression in several of these regions. Low saccharin preferring rats showed higher cocaine-induced c-Fos expression in the nucleus accumbens shell, and low impulsive rats showed higher cocaine-induced c-Fos expression in the orbitofrontal cortex and cingulate gyrus 1 area. In addition, both low impulsive and low saccharin rats had higher cocaine-induced c-Fos in the dorsal medial and dorsal lateral caudate putamen. The results indicate that individual differences in neuronal reactivity exist prior to chronic exposure to drugs of abuse. Furthermore, similar differences between the two animal models may be indicative of a common mechanism underlying vulnerability to drugs of abuse.

  3. GABAergic neurons of the laterodorsal and pedunculopontine tegmental nuclei of the cat express c-fos during carbachol-induced active sleep.

    PubMed

    Torterolo, P; Yamuy, J; Sampogna, S; Morales, F R; Chase, M H

    2001-02-23

    The laterodorsal and pedunculopontine tegmental nuclei (LDT-PPT) are involved in the generation of active sleep (AS; also called REM or rapid eye movement sleep). Although the LDT-PPT are composed principally of cholinergic neurons that participate in the control of sleep and waking states, the function of the large number of GABAergic neurons that are also located in the LDT-PPT is unknown. Consequently, we sought to determine if these neurons are activated (as indicated by their c-fos expression) during active sleep induced by the microinjection of carbachol into the rostro-dorsal pons (AS-carbachol). Accordingly, immunocytochemical double-labeling techniques were used to identify GABA and Fos protein, as well as choline acetyltransferase (ChAT), in histological sections of the LDT-PPT. Compared to control awake cats, there was a larger number of GABAergic neurons that expressed c-fos during AS-carbachol (31.5+/-6.1 vs. 112+/-15.2, P<0.005). This increase in the number of GABA+Fos+ neurons occurred on the ipsilateral side relative to the injection site; there was a small decrease in GABA+Fos+ cells in the contralateral LDT-PPT. However, the LDT-PPT neurons that exhibited the largest increase in c-fos expression during AS-carbachol were neither GABA+ nor ChAT+ (47+/-22.5 vs. 228.7+/-14.0, P<0.0005). The number of cholinergic neurons that expressed c-fos during AS-carbachol was not significantly different compared to wakefulness. These data demonstrate that, during AS-carbachol, GABAergic as well as an unidentified population of neurons are activated in the LDT-PPT. We propose that these non-cholinergic LDT-PPT neurons may participate in the regulation of active sleep. PMID:11172778

  4. Brain regional differences in social encounter-induced Fos expression in male and female rats after post-weaning social isolation.

    PubMed

    Ahern, Megan; Goodell, Dayton J; Adams, Jessica; Bland, Sondra T

    2016-01-01

    Early life adversity has been related to a number of psychological disorders including mood and other disorders that can manifest as inappropriate or aggressive responses to social challenges. The present study used post-weaning social isolation (PSI) in rats, a model of early life adversity, to examine its effects on Fos protein expression produced by exposure to a novel social encounter. We have previously reported that the social encounter-induced increase in Fos expression in the medial prefrontal cortex observed in group-housed controls (GRP) was attenuated in rats that had experienced PSI. Here we assessed Fos expression in other brain regions thought to be involved in emotion regulation and social behavior. Male and female rats were housed in same-sex groups or in isolation (ISO) for 4 weeks beginning on postnatal day (P) 21 and were exposed to a single 15 min social encounter with a novel same-sex conspecific on P49. Fos positive cells were assessed using immunohistochemistry in 16 regions within the forebrain. Exposure to a novel conspecific increased Fos expression in the forebrain of GRP rats in a region- and sex-specific fashion. This increase was blunted or absent in ISO rats within many regions including cortical regions, thalamus, habenula, dentate gyrus, lateral septum, and basolateral amygdala. In several regions, the increase in Fos was greater in male than in female group housed rats. Negative relationships were observed between social interactions and Fos in some regions. Forebrain hypofunction produced by early-life adversity may be involved in socially inappropriate behavior.

  5. Brain regional differences in social encounter-induced Fos expression in male and female rats after post-weaning social isolation.

    PubMed

    Ahern, Megan; Goodell, Dayton J; Adams, Jessica; Bland, Sondra T

    2016-01-01

    Early life adversity has been related to a number of psychological disorders including mood and other disorders that can manifest as inappropriate or aggressive responses to social challenges. The present study used post-weaning social isolation (PSI) in rats, a model of early life adversity, to examine its effects on Fos protein expression produced by exposure to a novel social encounter. We have previously reported that the social encounter-induced increase in Fos expression in the medial prefrontal cortex observed in group-housed controls (GRP) was attenuated in rats that had experienced PSI. Here we assessed Fos expression in other brain regions thought to be involved in emotion regulation and social behavior. Male and female rats were housed in same-sex groups or in isolation (ISO) for 4 weeks beginning on postnatal day (P) 21 and were exposed to a single 15 min social encounter with a novel same-sex conspecific on P49. Fos positive cells were assessed using immunohistochemistry in 16 regions within the forebrain. Exposure to a novel conspecific increased Fos expression in the forebrain of GRP rats in a region- and sex-specific fashion. This increase was blunted or absent in ISO rats within many regions including cortical regions, thalamus, habenula, dentate gyrus, lateral septum, and basolateral amygdala. In several regions, the increase in Fos was greater in male than in female group housed rats. Negative relationships were observed between social interactions and Fos in some regions. Forebrain hypofunction produced by early-life adversity may be involved in socially inappropriate behavior. PMID:26562664

  6. Hypoxia and electrical stimulation of the carotid sinus nerve induce Fos-like immunoreactivity within catecholaminergic and serotoninergic neurons of the rat brainstem.

    PubMed

    Erickson, J T; Millhorn, D E

    1994-10-01

    A complete understanding of the neural mechanisms responsible for the chemoreceptor and baroreceptor reflexes requires precise knowledge of the locations and chemical phenotypes of higher-order neurons within these reflex pathways. In the present study, the protein product (Fos) of the c-fos protooncogene was used as a metabolic marker to trace central neural pathways following activation of carotid sinus nerve afferent fibers. In addition, immunohistochemical double-labeling techniques were used to define the chemical phenotypes of activated neurons. Both electrical stimulation of the carotid sinus nerve and physiological stimulation of the carotid bodies by hypoxia induced Fos-like immunoreactivity in catecholaminergic neurons containing tyrosine hydroxylase or phenylethanolamine-N-methyltransferase in the ventrolateral medulla oblongata and, to a lesser degree, in the dorsal vagal complex. Tyrosine hydroxylase/Fos colocalization was also observed in the locus coeruleus and the A5 noradrenergic cell group in pons. Many serotoninergic neurons in nucleus raphe pallidus, nucleus raphe magnus, and along the ventral medullary surface contained Fos-like immunoreactivity. In pons and midbrain, Fos-like immunoreactivity was observed in the lateral parabrachial and Kölliker-Fuse nuclei, the inferior colliculus, the cuneiform nucleus, and in the vicinity of the Edinger-Westphal nucleus, but no catecholaminergic or serotoninergic colocalization was observed in these regions. Although Fos-labeled cells were observed within and lateral to the dorsal raphe nucleus, few were catecholaminergic or serotoninergic. This study further defines a potential central neuroanatomical substrate for the chemoreceptor and/or baroreceptor reflexes. PMID:7814687

  7. GABAergic neurons of the laterodorsal and pedunculopontine tegmental nuclei of the cat express c-fos during carbachol-induced active sleep.

    PubMed

    Torterolo, P; Yamuy, J; Sampogna, S; Morales, F R; Chase, M H

    2001-02-23

    The laterodorsal and pedunculopontine tegmental nuclei (LDT-PPT) are involved in the generation of active sleep (AS; also called REM or rapid eye movement sleep). Although the LDT-PPT are composed principally of cholinergic neurons that participate in the control of sleep and waking states, the function of the large number of GABAergic neurons that are also located in the LDT-PPT is unknown. Consequently, we sought to determine if these neurons are activated (as indicated by their c-fos expression) during active sleep induced by the microinjection of carbachol into the rostro-dorsal pons (AS-carbachol). Accordingly, immunocytochemical double-labeling techniques were used to identify GABA and Fos protein, as well as choline acetyltransferase (ChAT), in histological sections of the LDT-PPT. Compared to control awake cats, there was a larger number of GABAergic neurons that expressed c-fos during AS-carbachol (31.5+/-6.1 vs. 112+/-15.2, P<0.005). This increase in the number of GABA+Fos+ neurons occurred on the ipsilateral side relative to the injection site; there was a small decrease in GABA+Fos+ cells in the contralateral LDT-PPT. However, the LDT-PPT neurons that exhibited the largest increase in c-fos expression during AS-carbachol were neither GABA+ nor ChAT+ (47+/-22.5 vs. 228.7+/-14.0, P<0.0005). The number of cholinergic neurons that expressed c-fos during AS-carbachol was not significantly different compared to wakefulness. These data demonstrate that, during AS-carbachol, GABAergic as well as an unidentified population of neurons are activated in the LDT-PPT. We propose that these non-cholinergic LDT-PPT neurons may participate in the regulation of active sleep.

  8. Hyperglycemia abolishes meal-induced satiety by a dysregulation of ghrelin and peptide YY3-36 in healthy overweight/obese humans.

    PubMed

    Knudsen, Sine H; Karstoft, Kristian; Solomon, Thomas P J

    2014-01-15

    Satiety and satiety-regulating gut hormone levels are abnormal in hyperglycemic individuals. We aimed to determine whether these abnormalities are secondary to hyperglycemia. Ten healthy overweight/obese subjects (age: 56 ± 3 yr; BMI: 30.3 ± 1.2 kg/m(2)) received three equicaloric meals at t = 0, 4, and 8 h in the absence (control trial) and presence of experimental hyperglycemia (hyperglycemia trial; 5.4 mM above basal). Circulating levels of glucose, insulin, ghrelin, and peptide YY (PYY)3-36 and visual analog scale ratings of satiety were measured throughout each trial. In the control trial, glucose, insulin, PYY3-36, and the feeling of fullness were increased in the postprandial periods, whereas ghrelin was decreased. In the hyperglycemia trial, in which plasma glucose was increased to 11.2 ± 0.1 mmol/l, postprandial meal responses (AUC: 0-2, 4-6, and 8-10 h) of PYY3-36 were lower (meal 1, P < 0.0001; meal 2, P < 0.001; meal 3, P < 0.05), whereas insulin (meal 1, P < 0.01; meal 2, P < 0.001; meal 3, P < 0.05) and ghrelin (meal 1, P < 0.05; meal 2, P > 0.05; meal 3, P > 0.05) were higher compared with the control trial. Furthermore, the incremental (Δ0-0.5, 4-4.5, and 8-8.5 h) ghrelin response to the first and third meals was higher in the hyperglycemia trial in contrast to control (Δ: 2.3 ± 8.0, P = 0.05; Δ: 14.4 ± 2.5, P < 0.05). Also, meal-induced fullness was prevented (meal 1, P = 0.06; meal 2, P = 0.01; meal 3, P = 0.08) by experimental hyperglycemia. Furthermore, trends in ghrelin, PYY3-36, and fullness were described by different polynomial functions between the trials. In conclusion, hyperglycemia abolishes meal-induced satiety and dysregulates postprandial responses of the gut hormones PYY3-36 and ghrelin in overweight/obese healthy humans.

  9. Prostaglandin E2-induced up-regulation of c-fos messenger ribonucleic acid is primarily mediated by 3',5'-cyclic adenosine monophosphate in MC3T3-E1 osteoblasts

    NASA Technical Reports Server (NTRS)

    Fitzgerald, J.; Dietz, T. J.; Hughes-Fulford, M.

    2000-01-01

    The mechanism by which the proto-oncogene, c-fos, is up-regulated in response to PGE2 in the mouse osteoblastic (MC3T3-E1) cell line was investigated using RT-PCR. c-fos messenger RNA up-regulation by dmPGE2 is rapid, starting 10 min post stimulation, and transient. The specific protein kinase A (PKA) inhibitor, H89, inhibited c-fos induction. Moreover, down-regulation of protein kinase C (PKC) activity by chronic TPA treatment had no effect on the induction of c-fos by dmPGE2. We conclude that up-regulation of c-fos by dmPGE2 is primarily dependent on PKA in MC3T3-E1 osteoblasts. In S49 lymphoma wild-type but not S49 cyc- cells, which are deficient in cAMP signaling, dmPGE2 up-regulates c-fos and increases cell growth compared with unstimulated cells. Thus in S49 lymphoma cells, c-fos induction by PGE2 is also dependent on cAMP signaling. The minimal c-fos promoter region required for dmPGE2-induced expression was identified by transfecting c-fos promoter deletion constructs coupled to the chloramphenicol acetyltransferase (CAT) reporter gene into Vero cells. Transfection of a plasmid containing 99 bp c-fos proximal promoter was sufficient to direct c-fos/CAT expression following stimulation with dmPGE2. Because induction of c-fos is mediated by cAMP, these data are consistent with activation of c-fos via the CRE/ATF cis element.

  10. A novel human ghrelin variant (In1-ghrelin) and ghrelin-O-acyltransferase are overexpressed in breast cancer: potential pathophysiological relevance.

    PubMed

    Gahete, Manuel D; Córdoba-Chacón, José; Hergueta-Redondo, Marta; Martínez-Fuentes, Antonio J; Kineman, Rhonda D; Moreno-Bueno, Gema; Luque, Raúl M; Castaño, Justo P

    2011-01-01

    The human ghrelin gene, which encodes the ghrelin and obestatin peptides, contains 5 exons (Ex), with Ex1-Ex4 encoding a 117 amino-acid (aa) preproprotein that is known to be processed to yield a 28-aa (ghrelin) and/or a 23-aa (obestatin) mature peptides, which possess biological activities in multiple tissues. However, the ghrelin gene also encodes additional peptides through alternative splicing or post-translational modifications. Indeed, we previously identified a spliced mRNA ghrelin variant in mouse (In2-ghrelin-variant), which is regulated in a tissue-dependent manner by metabolic status and may thus be of biological relevance. Here, we have characterized a new human ghrelin variant that contains Ex0-1, intron (In) 1, and Ex2 and lacks Ex3-4. This human In1-ghrelin variant would encode a new prepropeptide that conserves the first 12aa of native-ghrelin (including the Ser3-potential octanoylation site) but has a different C-terminal tail. Expression of In1-variant was detected in 22 human tissues and its levels were positively correlated with those of ghrelin-O-acyltransferase (GOAT; p = 0.0001) but not with native-ghrelin expression, suggesting that In1-ghrelin could be a primary substrate for GOAT in human tissues. Interestingly, levels of In1-ghrelin variant expression in breast cancer samples were 8-times higher than those of normal mammary tissue, and showed a strong correlation in breast tumors with GOAT (p = 0.0001), ghrelin receptor-type 1b (GHSR1b; p = 0.049) and cyclin-D3 (a cell-cycle inducer/proliferation marker; p = 0.009), but not with native-ghrelin or GHSR1a expression. Interestingly, In1-ghrelin variant overexpression increased basal proliferation of MDA-MB-231 breast cancer cells. Taken together, our results provide evidence that In1-ghrelin is a novel element of the ghrelin family with a potential pathophysiological role in breast cancer.

  11. Stress-Induced Locomotor Sensitization to Amphetamine in Adult, but not in Adolescent Rats, Is Associated with Increased Expression of ΔFosB in the Nucleus Accumbens.

    PubMed

    Carneiro de Oliveira, Paulo E; Leão, Rodrigo M; Bianchi, Paula C; Marin, Marcelo T; Planeta, Cleopatra da Silva; Cruz, Fábio C

    2016-01-01

    While clinical and pre-clinical evidence suggests that adolescence is a risk period for the development of addiction, the underlying neural mechanisms are largely unknown. Stress during adolescence has a huge influence on drug addiction. However, little is known about the mechanisms related to the interaction among stress, adolescence and addiction. Studies point to ΔFosB as a possible target for this phenomenon. In the present study, adolescent and adult rats (postnatal day 28 and 60, respectively) were restrained for 2 h once a day for 7 days. Three days after their last exposure to stress, the animals were challenged with saline or amphetamine (1.0 mg/kg i.p.) and amphetamine-induced locomotion was recorded. Immediately after the behavioral tests, rats were decapitated and the nucleus accumbens was dissected to measure ΔFosB protein levels. We found that repeated restraint stress increased amphetamine-induced locomotion in both the adult and adolescent rats. Furthermore, in adult rats, stress-induced locomotor sensitization was associated with increased expression of ΔFosB in the nucleus accumbens. Our data suggest that ΔFosB may be involved in some of the neuronal plasticity changes associated with stress induced-cross sensitization with amphetamine in adult rats. PMID:27672362

  12. Stress-Induced Locomotor Sensitization to Amphetamine in Adult, but not in Adolescent Rats, Is Associated with Increased Expression of ΔFosB in the Nucleus Accumbens

    PubMed Central

    Carneiro de Oliveira, Paulo E.; Leão, Rodrigo M.; Bianchi, Paula C.; Marin, Marcelo T.; Planeta, Cleopatra da Silva; Cruz, Fábio C.

    2016-01-01

    While clinical and pre-clinical evidence suggests that adolescence is a risk period for the development of addiction, the underlying neural mechanisms are largely unknown. Stress during adolescence has a huge influence on drug addiction. However, little is known about the mechanisms related to the interaction among stress, adolescence and addiction. Studies point to ΔFosB as a possible target for this phenomenon. In the present study, adolescent and adult rats (postnatal day 28 and 60, respectively) were restrained for 2 h once a day for 7 days. Three days after their last exposure to stress, the animals were challenged with saline or amphetamine (1.0 mg/kg i.p.) and amphetamine-induced locomotion was recorded. Immediately after the behavioral tests, rats were decapitated and the nucleus accumbens was dissected to measure ΔFosB protein levels. We found that repeated restraint stress increased amphetamine-induced locomotion in both the adult and adolescent rats. Furthermore, in adult rats, stress-induced locomotor sensitization was associated with increased expression of ΔFosB in the nucleus accumbens. Our data suggest that ΔFosB may be involved in some of the neuronal plasticity changes associated with stress induced-cross sensitization with amphetamine in adult rats.

  13. Stress-Induced Locomotor Sensitization to Amphetamine in Adult, but not in Adolescent Rats, Is Associated with Increased Expression of ΔFosB in the Nucleus Accumbens

    PubMed Central

    Carneiro de Oliveira, Paulo E.; Leão, Rodrigo M.; Bianchi, Paula C.; Marin, Marcelo T.; Planeta, Cleopatra da Silva; Cruz, Fábio C.

    2016-01-01

    While clinical and pre-clinical evidence suggests that adolescence is a risk period for the development of addiction, the underlying neural mechanisms are largely unknown. Stress during adolescence has a huge influence on drug addiction. However, little is known about the mechanisms related to the interaction among stress, adolescence and addiction. Studies point to ΔFosB as a possible target for this phenomenon. In the present study, adolescent and adult rats (postnatal day 28 and 60, respectively) were restrained for 2 h once a day for 7 days. Three days after their last exposure to stress, the animals were challenged with saline or amphetamine (1.0 mg/kg i.p.) and amphetamine-induced locomotion was recorded. Immediately after the behavioral tests, rats were decapitated and the nucleus accumbens was dissected to measure ΔFosB protein levels. We found that repeated restraint stress increased amphetamine-induced locomotion in both the adult and adolescent rats. Furthermore, in adult rats, stress-induced locomotor sensitization was associated with increased expression of ΔFosB in the nucleus accumbens. Our data suggest that ΔFosB may be involved in some of the neuronal plasticity changes associated with stress induced-cross sensitization with amphetamine in adult rats. PMID:27672362

  14. Cathinone increases body temperature, enhances locomotor activity, and induces striatal c-fos expression in the Siberian hamster.

    PubMed

    Jones, S; Fileccia, E L; Murphy, M; Fowler, M J; King, M V; Shortall, S E; Wigmore, P M; Green, A R; Fone, K C F; Ebling, F J P

    2014-01-24

    Cathinone is a β-keto alkaloid that is the major active constituent of khat, the leaf of the Catha edulis plant that is chewed recreationally in East Africa and the Middle East. Related compounds, such as methcathinone and mephedrone have been increasing in popularity as recreational drugs, resulting in the recent proposal to classify khat as a Class C drug in the UK. There is still limited knowledge of the pharmacological effects of cathinone. This study examined the acute effects of cathinone on core body temperature, locomotor and other behaviors, and neuronal activity in Siberian hamsters. Adult male hamsters, previously implanted with radio telemetry devices, were treated with cathinone (2 or 5mg/kg i.p.), the behavioral profile scored and core body temperature and locomotor activity recorded by radio telemetry. At the end of the study, hamsters received vehicle or cathinone (5mg/kg) and neuronal activation in the brain was determined using immunohistochemical evaluation of c-fos expression. Cathinone dose-dependently induced significant (p<0.0001) increases in both temperature and locomotor activity lasting 60-90min. Cathinone (2mg/kg) increased rearing (p<0.02), and 5mg/kg increased both rearing (p<0.001) and lateral head twitches (p<0.02). Both cathinone doses decreased the time spent at rest (p<0.001). The number of c-fos immunopositive cells were significantly increased in the striatum (p<0.0001) and suprachiasmatic nucleus (p<0.05) following cathinone, indicating increased neuronal activity. There was no effect of cathinone on food intake or body weight. It is concluded that systemic administration of cathinone induces significant behavioral changes and CNS activation in the hamster.

  15. Activation of the neu tyrosine kinase induces the fos/jun transcription factor complex, the glucose transporter and ornithine decarboxylase

    PubMed Central

    1989-01-01

    We have studied the ability of the neu tyrosine kinase to induce a signal for the activation of cell growth-regulated genes. Serum-starved NIH 3T3 cells expressing an epidermal growth factor receptor (EGF- R)/neu construct encoding a hybrid receptor protein were stimulated with EGF and the activation of the neu tyrosine kinase and stimulation of growth factor inducible genes were followed at the mRNA, protein, and activity levels, and compared to the corresponding responses in the neu proto-oncogene and oncogene expressing cells. Induction of the expression of jun mRNAs was an immediate early effect of EGF stimulation, followed by a marked increase in the biosynthesis of the fos/jun transcription factor complex and an increased transcription factor activity as measured by a recombinant transcription unit using chloramphenicol acetyltransferase assays. In distinction, elevated AP- 1/PEA-1 activity in the absence of a significant increase in jun and fos expression was characteristic of the neu oncogene-expressing cells. The glucose transporter mRNA increased at 2 h of EGF stimulation and was associated with enhanced glucose transport of the EGF-treated cells. An increase of ornithine decarboxylase (ODC) mRNA and activity followed these changes. In contrast, serum-starved, EGF-treated neu proto-oncogene- and oncogene-expressing cells showed constitutively low and high glucose transporter and ODC activities, respectively. These findings demonstrate that the chimeric EGF-R/neu receptor is capable of activating the expression of both immediate early genes and biochemical activities associated with cell growth stimulation. PMID:2572601

  16. The antagonism of aluminum against fluoride-induced oxidative stress and c-Fos overexpression in rat testes.

    PubMed

    Wang, Junling; Zhang, Haojun; Xu, Feixue; Xu, Feihua; Zhang, Ke; Zhang, Yingmei

    2014-02-01

    Sodium fluoride (NaF) has been found to interfere with the reproductive system of animals. However, the cellular mechanisms underlying the reproductive toxicity of fluoride are unclear. The present study aims to define a possible mechanism of NaF-induced reproductive toxicity with respect to mineral, oxidative stress and c-Fos expression and the role of aluminum (Al) in intervening the toxic effect of NaF on rat testes. Fifty-six male Wistar rats were treated with normal saline, 1.0, 2.0, and 3.0 mg NaF/kg body weight (bw)/day, and each NaF concentration plus Al ion (0.1 mg Al(3+)/kg bw/day). After 90 days, no significant changes in the contents of Fe and Cu were observed in any of the NaF-treated groups compared with those of the control group. There were, however, significant decreases in the contents of Ca in the 1.0 mg NaF group, Zn in all NaF-treated groups and Mg in the 3.0 mg NaF group. The levels of malondialdehyde (MDA) in the 1.0 mg NaF group and hydrogen peroxide (H2O2) in the 2.0 mg NaF group significantly increased, whereas the activity of nitric oxide synthase (NOS) significantly decreased in the 1.0 mg NaF group. Meanwhile, the protein expression of c-Fos increased significantly in the 1.0 and 2.0 mg NaF groups compared with the control group. Conversely, these changes were partially attenuated in rats simultaneously administered Al. The present study suggested that NaF could decrease the contents of Ca, Fe and Mg and enhance oxidative stress leading to c-Fos overexpression, and some deleterious effects were more prominent at lower NaF intake. Furthermore, Al within the research concentration could minimize reproductive toxicity caused by fluoride.

  17. Food restriction, ghrelin, its antagonist and obestatin control expression of ghrelin and its receptor in chicken hypothalamus and ovary.

    PubMed

    Sirotkin, Alexander V; Pavlova, Silvia; Tena-Sempere, Manuel; Grossmann, Roland; Jiménez, Magdalena Romero; Rodriguez, Juan Manuel Castellano; Valenzuela, Francisco

    2013-01-01

    The purpose of the present study was to identify the role of age, nutritional state and some metabolic hormones in control of avian hypothalamic and ovarian ghrelin/ghrelin receptor system. We examined the effect of food restriction, administration of ghrelin 1-18, ghrelin antagonistic analogue (D-Lys-3)-GHRP-6, obestatin and combinations of them on the expression of ghrelin and ghrelin receptor (GHS-R1a) in hypothalamus and ovary of old (23months of age) and young (7months of age) chickens. Expression of mRNAs for ghrelin and GHS-R1a in both hypothalamus and largest ovarian follicle was measured by RT-PCR. It was observed that food restriction could promote the expression of ghrelin and GHS-R1a in hypothalamus and ovary of the old chickens, but in the young chickens it reduced expression of ghrelin and did not affect expression of GHS-R1a in the ovary. Administration of ghrelin 1-18 did not affect hypothalamic or ovarian ghrelin mRNA, but significantly increased the expression of GHS-R1a in hypothalamus, but not in ovary. (D-Lys-3)-GHRP-6, significantly stimulated accumulation of ghrelin, but not GHS-R1a mRNA in hypothalamus or ghrelin or GHS-R1a in the ovary. Ghrelin 1-18 and (D-Lys-3)-GHRP-6, when given together, were able either to prevent or to induce effect of these hormones. Obestatin administration increased expression of ghrelin gene in the hypothalamus, but not expression of hypothalamic GHS-R1a, ovarian ghrelin and GHS-R1a. Furthermore, obestatin was able to modify effect of both ghrelin and fasting on hypothalamic and ovarian mRNA for ghrelin GHS-R1a. Our results (1) confirm the existence of ghrelin and its functional receptors GHS-R1a in the chicken hypothalamus and ovary (2) confirm the age-dependent control of ovarian ghrelin by feeding, (3) demonstrate, that nutritional status can influence the expression of both ghrelin and GHS-R1a in hypothalamus and in the ovary (3) demonstrates for the first time, that ghrelin can promote generation of its

  18. From synapse to gene product: Prolonged expression of c-fos induced by a single microinjection of carbachol in the pontomesencephalic tegmentum

    PubMed Central

    Quattrochi, James J.; Bazalakova, Mihaela; Hobson, J. Allan

    2006-01-01

    It is not known how the brain modifies its regulatory systems in response to the application of a drug, especially over the long term of weeks and months. We have developed a model system approach to this question by manipulating cholinergic cell groups of the laterodorsal and pedunculopontine tegmental (LDT/PPT) nuclei in the pontomesencephalic tegmentum (PMT), which are known to be actively involved in the timing and quantity of rapid eye movement (REM) sleep. In a freely moving feline model, a single microinjection of the cholinergic agonist carbachol conjugated to a latex nanosphere delivery system into the caudolateral PMT elicits a long-term enhancement of one distinguishing phasic event of REM sleep, ponto-geniculo-occipital (PGO) waves, lasting 5 days but without any significant change in REM sleep or other behavioral state. Here, we test the hypothesis that cholinergic activation within the caudolateral PMT alters the postsynaptic excitability of the PGO network, stimulating the prolonged expression of c-fos that underlies this long-term PGO enhancement (LTPE) effect. Using quantitative Fos immunohistochemistry, we found that the number of Fos-immunoreactive (Fos-IR) neurons surrounding the caudolateral PMT injection site decreased sharply by postcarbachol day 03, while the number of Fos-IR neurons in the more rostral LDT/PPT increased >30-fold and remained at a high level following the course of LTPE. These results demonstrate a sustained c-fos expression in response to pharmacological stimulation of the brain and suggest that carbachol's acute effects induce LTPE via cholinergic receptors, with subsequent transsynaptic activation of the LDT/PPT maintaining the LTPE effect. PMID:15893601

  19. From synapse to gene product: prolonged expression of c-fos induced by a single microinjection of carbachol in the pontomesencephalic tegmentum.

    PubMed

    Quattrochi, James J; Bazalakova, Mihaela; Hobson, J Allan

    2005-05-20

    It is not known how the brain modifies its regulatory systems in response to the application of a drug, especially over the long term of weeks and months. We have developed a model system approach to this question by manipulating cholinergic cell groups of the laterodorsal and pedunculopontine tegmental (LDT/PPT) nuclei in the pontomesencephalic tegmentum (PMT), which are known to be actively involved in the timing and quantity of rapid eye movement (REM) sleep. In a freely moving feline model, a single microinjection of the cholinergic agonist carbachol conjugated to a latex nanosphere delivery system into the caudolateral PMT elicits a long-term enhancement of one distinguishing phasic event of REM sleep, ponto-geniculo-occipital (PGO) waves, lasting 5 days but without any significant change in REM sleep or other behavioral state. Here, we test the hypothesis that cholinergic activation within the caudolateral PMT alters the postsynaptic excitability of the PGO network, stimulating the prolonged expression of c-fos that underlies this long-term PGO enhancement (LTPE) effect. Using quantitative Fos immunohistochemistry, we found that the number of Fos-immunoreactive (Fos-IR) neurons surrounding the caudolateral PMT injection site decreased sharply by postcarbachol day 03, while the number of Fos-IR neurons in the more rostral LDT/PPT increased >30-fold and remained at a high level following the course of LTPE. These results demonstrate a sustained c-fos expression in response to pharmacological stimulation of the brain and suggest that carbachol's acute effects induce LTPE via cholinergic receptors, with subsequent transsynaptic activation of the LDT/PPT maintaining the LTPE effect.

  20. Differential modulation of ghrelin-induced GH and LH release by PACAP and dopamine in goldfish pituitary cells.

    PubMed

    Grey, Caleb L; Chang, John P

    2013-09-15

    Ghrelin (GRLN) participates in multiple physiological processes, including the regulation of growth hormone (GH) and luteinizing hormone (LH) release. In the goldfish, neuroendocrine control of GH and LH release are multifactorial. In this system, pituitary adenylate cyclase-activating polypeptide (PACAP)-stimulated GH and LH secretion, as well as dopamine (DA)-induced GH release, are mediated by protein kinase A (PKA)-dependent, but protein kinase C (PKC)-independent, mechanisms. In addition, DA inhibits LH secretion by actions at sites along both PKA and PKC signaling pathways. Recently, goldfish GRLN (gGRLN19) has been shown to induce GH release via PKC, and LH secretion via both PKC and PKA. To further understand the neuroendocrine regulation of goldfish GH and LH release, we examined the effects of DA and PACAP on gGRLN19 actions in primary cultures of goldfish pituitary cells in perifusion and in Ca(2+)-imaging experiments. Consistent with their known intracellular signaling mechanisms in gonadotrophs, DA inhibited gGRLN19-induced LH release while cotreatment of PACAP and gGRLN19 did not produce additive LH responses. When applied prior to gGRLN19, PACAP potentiated gGRLN19-induced GH release and Ca(2+) signals within somatotrophs. In contrast, neither prior treatment with DA followed by gGRLN19 nor pretreatment with gGRLN19 prior to PACAP produced an enhanced GH release response. These observations suggest that PKA activators positively modulate gGRLN19 actions on goldfish somatotrophs in a ligand- and treatment order-specific manner. Results add to our understanding of the complexity of neuroendocrine control of GH and LH release at the pituitary cell level, and our understanding of GRLN action.

  1. Ghrelin treatment prevents development of activity based anorexia in mice.

    PubMed

    Legrand, Romain; Lucas, Nicolas; Breton, Jonathan; Azhar, Saïda; do Rego, Jean-Claude; Déchelotte, Pierre; Coëffier, Moïse; Fetissov, Sergueï O

    2016-06-01

    Stimulation of feeding is necessary for treatment of pathological conditions of chronic malnutrition due to anorexia. Ghrelin, a hunger hormone, is one of the candidate for pharmacological treatments of anorexia, but because of its instability in plasma has limited efficacy. We previously showed that plasmatic IgG protect ghrelin from degradation and that IgG from obese subjects and mice may increase ghrelin׳s orexigenic effect. In this study we tested if ghrelin alone or combined with IgG may improve feeding in chronically food-restricted mice with or without physical activity-based anorexia (ABA) induced by free access to a running wheel. Mice received a single daily intraperitoneal injection of ghrelin (1nM) together or not with total IgG (1nM) from obese ob/ob or lean mice before access to food during 8 days of 3h/day feeding time. We found that both ghrelin and ghrelin combined with IgG from obese, but not lean mice, prevented ABA, however, they were not able to diminish body weight loss. Physical activity was lower during the feeding period and was increased shortly after feeding in mice receiving ghrelin together with IgG from obese mice. In food-restricted mice without ABA, ghrelin treatments did not have significant effects on food intake. Thus, this study supports pharmacological use of ghrelin or ghrelin combined with IgG from obese animals for treatment of anorexia accompanied by elevated physical activity. The utility of combining ghrelin with protective IgG should be further determined in animal models of anorexia with unrestricted access to food.

  2. Peripheral therapeutic ultrasound stimulation alters the distribution of spinal C-fos immunoreactivity induced by early or late phase of inflammation.

    PubMed

    Hsieh, Yueh-Ling

    2008-03-01

    The purpose of this investigation was to examine the central modulated effects of therapeutic ultrasound (US) on neuronal activity in the spinal cord on early and late phases of inflammation. In this study, induction of c-Fos protein, which reflects neuronal activation (particularly inflammatory nociception), was investigated in the lumbar spinal cord with immunohistochemistry. Inflammatory monoarthritis was induced in 20 male Wistar rats (weighing 250-300 g) via intra-articular injection of complete Freund's adjuvant (CFA) into the tibiotarsal joint. Two phases of arthritis, early phase (18 h after adjuvant injection) and late phase (7 d after adjuvant injection), were studied in the rats. Pulsed-mode US (1 MHz, the spatial average temporal average intensity [I(SATA)] = 0.5 W/cm(2), 50% duty cycle) was applied for 5 min. The effects of US and sham treatments against these phases of arthritis were demonstrated by spinal c-Fos-like immunoreactivity (c-Fos-LI). All data were evaluated statistically with the paired t-test or analysis of variance with Bonferroni corrections. c-Fos-LI neurons were abundant (average 264.2 +/- 11.9) in the L3 and L4 neurons of the spinal cord in areas ipsilateral to the CFA-induced arthritic leg in the early phase, but few were present (average 40.4 +/- 4.5) in the late phase in sham-treated animals. Bonferroni corrections to the alpha level were used to check the group differences in spinal c-Fos expression, and significance was reached when p < 0.025. In the early inflammatory phase, US treatment significantly suppressed the increased number of c-Fos-LI neurons associated with CFA-induced arthritis in superficial laminae, nucleus proprius, deep laminae and ventral horn of the spinal cord. However, during the late inflammatory phase, US significantly triggered c-Fos expression in most laminae, particularly in the nucleus proprius, deep laminae and ventral horn of the spinal cord. The results of our study suggest that administration of US

  3. Centrally and peripherally administered ghrelin potently inhibits water intake in rats.

    PubMed

    Hashimoto, Hirofumi; Fujihara, Hiroaki; Kawasaki, Makoto; Saito, Takeshi; Shibata, Minori; Otsubo, Hiroki; Takei, Yoshio; Ueta, Yoichi

    2007-04-01

    Ghrelin is known as a potent orexigenic hormone through its action on the brain. In this study, we examined the effects of intracerebroventricular (icv) and iv injection of ghrelin on water intake, food intake, and urine volume in rats deprived of water for 24 h. Water intake that occurred after water deprivation was significantly inhibited by icv injection of ghrelin (0.1, 1, and 10 nmol/rat) in a dose-related manner, although food intake was stimulated by the hormone. The antidipsogenic effect was as potent as the orexigenic effect. Similarly, water intake was inhibited, whereas food intake was stimulated dose dependently after iv injection of ghrelin (0.1, 1, and 10 nmol/kg). The inhibition of drinking was comparable with, or even more potent than, atrial natriuretic peptide (ANP), an established antidipsogenic hormone, when administered icv, although the antidipsogenic effect lasted longer. ANP had no effect on food intake. Urine volume decreased dose relatedly after icv injection of ghrelin but not by ANP. Intravenous injection of ghrelin had no effect on urine volume. Because drinking usually occurs with feeding, food was withdrawn to remove the prandial drinking. Then the antidipsogenic effect of ghrelin became more potent than that of ANP and continued longer than when food was available. Expression of Fos was increased in the area postrema and the nucleus of the tractus solitarius by using immunohistochemistry after icv and iv injection of ghrelin. The present study convincingly showed that ghrelin is a potent antidisogenic peptide in rats.

  4. Cocaine-induced Fos expression is detectable in the frontal cortex and striatum of rats under isoflurane but not α-chloralose anesthesia: implications for FMRI

    PubMed Central

    Kufahl, Peter R.; Pentkowski, Nathan S.; Heintzelman, Krista; Neisewander, Janet L.

    2009-01-01

    The ability of intravenous cocaine to induce Fos protein expression in anesthetized rats was tested. Two anesthetic regimens commonly used for in vivo FMRI of animals, i.v. α-chloralose and gaseous isoflurane, were studied in separate cohorts. The first experiment included three groups that received the following treatments: saline i.v. and no anesthetic; 2 mg/kg cocaine i.v. and no anesthetic; and 2 mg/kg cocaine i.v. under 36 mg/kg/h α-chloralose anesthesia. The second experiment had a factorial design of four groups that were either nonanesthetized or isoflurane-treated and were either given saline or cocaine (2 mg/kg, i.v.). Anesthetized rats were maintained for 2 h under 2.5–3.5% isoflurane anesthesia, while nonanesthetized rats were kept in an alternative environment for the same time period. Rats were given 2 mg/kg cocaine or saline i.v., 30 min into the test session. Rats were perfused and their brains were processed for Fos immunohistochemistry 90 min after the i.v. treatment. In both experiments, the frontal cortex and striatum of the cocaine-treated nonanesthetized rats expressed Fos in greater amounts than the saline-treated nonanesthetized rats, as expected. The α-chloralose treatment prevented cocaine-induced Fos expression across all eight subregions of the striatum and frontal cortex that were examined. In contrast, isoflurane only partially attenuated Fos expression in the orbital and Cg2 subregions of frontal cortex. These results suggest a strong advantage for using isoflurane, as opposed to α-chloralose, when studying anesthetized rats for in vivo effects of psychostimulants. PMID:19467261

  5. Ghrelin and reproductive disorders.

    PubMed

    Repaci, Andrea; Gambineri, Alessandra; Pagotto, Uberto; Pasquali, Renato

    2011-06-20

    Ghrelin is an important factor involved in most of the metabolic and hormonal signals which adapt the reproductive functions in conditions of altered energy balance. Moreover, the coordinated role of leptin and ghrelin appears in fact to have a specific role in the regulation of puberty. Systemic action of ghrelin on the reproductive axis involves the control of the hypothalamic-pituitary-gondal axis. In addition, it has been shown that ghrelin may directly act at a gonadal level in both females and males. Available data also demonstrate that sex steroid hormones and gonadotropins may in turn regulate the gonadal effect of ghrelin, as documented by studies performed in females with the polycystic ovary syndrome and in hypogonadal men. Notably, recent studies also confirm a potentially important role for ghrelin in fetal and neonatal energy balance, and specifically in allowing fetal adaptation to an adverse intrauterine environment.

  6. Phytoestrogens directly inhibit TNF-α-induced bone resorption in RAW264.7 cells by suppressing c-fos-induced NFATc1 expression.

    PubMed

    Karieb, Sahar; Fox, Simon W

    2011-02-01

    TNF-α-induced osteoclastogenesis is central to post-menopausal and inflammatory bone loss, however, the effect of phytoestrogens on TNF-α-induced bone resorption has not been studied. The phytoestrogens genistein, daidzein, and coumestrol directly suppressed TNF-α-induced osteoclastogenesis and bone resorption. TRAP positive osteoclast formation and resorption area were significantly reduced by genistein (10(-7)  M), daidzein (10(-5)  M), and coumestrol (10(-7)  M), which was prevented by the estrogen antagonist ICI 182,780. TRAP expression in mature TNF-α-induced osteoclasts was also significantly reduced by these phytoestrogen concentrations. In addition, in the presence of ICI 182,780 genistein and coumestrol (10(-5) -10(-6)  M) augmented TNF-α-induced osteoclast formation and resorption. However, this effect was not observed in the absence of estrogen antagonist indicating that genistein's and coumestrol's ER-dependent anti-osteoclastic action normally negates this pro-osteoclastic effect. To determine the mechanism mediating the anti-osteoclastic action we examined the effect of genistein, coumestrol, and daidzein on caspase 3/7 activity, cell viability and expression of key genes regulating osteoclast differentiation and fusion. While anti-osteoclastic phytoestrogen concentrations had no effect on caspase 3/7 activity or cell viability they did significantly reduce TNF-α-induced c-fos and NFATc1 expression in an ER dependent manner and also inhibited NFATc1 nuclear translocation. Significant decreases in NFκB and DC-STAMP levels were also noted. Interestingly, constitutive c-fos expression prevented the anti-osteoclastic action of phytoestrogens on differentiation, resorption and NFATc1. This suggests that phytoestrogens suppress TNF-α-induced osteoclastogenesis via inhibition of c-fos-dependent NFATc1 expression. Our data provides further evidence that phytoestrogens have a potential role in the treatment of post-menopausal and inflammatory

  7. Ghrelin inhibits oxLDL-induced inflammation in RAW264.7 mouse macrophages through down-regulation of LOX-1 expression via NF-κB signaling pathway.

    PubMed

    Sun, N; Wang, H; Wang, L

    2016-01-01

    Oxidized low-density lipoprotein (oxLDL) is one of the many causes of the initiation and progression of atherosclerosis, which can subsequently promote the uptake of oxLDL by macrophages and lead to inflammation in the blood vessels. In the present study, we evaluated the protective effects of ghrelin on oxLDL-induced RAW264.7 mouse macrophages. Ghrelin was able to inhibit the release of several pro-inflammatory cytokines including tumor necrosis factor (TNF)-α and interleukin (IL)-6. In addition, ghrelin also inhibited the expression of Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in oxLDL treated macrophages. Furthermore, we demonstrated that ghrelin could inhibit the expression of p-IκBα, and the inhibitory effects could be blocked by BAY 117082. Taken together, ghrelin possesses anti-inflammatory effects on oxLDL-induced inflammation in macrophages, suggesting that it can prevent or treat atherosclerosis, and deserves to be further studied and developed to be potent drug for treating atherosclerosis. PMID:26950452

  8. The role of the vagus nerve in the migrating motor complex and ghrelin- and motilin-induced gastric contraction in suncus.

    PubMed

    Miyano, Yuki; Sakata, Ichiro; Kuroda, Kayuri; Aizawa, Sayaka; Tanaka, Toru; Jogahara, Takamichi; Kurotani, Reiko; Sakai, Takafumi

    2013-01-01

    The upper gastrointestinal (GI) tract undergoes a temporally coordinated cyclic motor pattern known as the migrating motor complex (MMC) in both dogs and humans during the fasted state. Feeding results in replacement of the MMC by a pattern of noncyclic, intermittent contractile activity termed as postprandial contractions. Although the MMC is known to be stimulated by motilin, recent studies have shown that ghrelin, which is from the same peptide family as motilin, is also involved in the regulation of the MMC. In the present study, we investigated the role of the vagus nerve on gastric motility using conscious suncus-a motilin- and ghrelin-producing small animal. During the fasted state, cyclic MMC comprising phases I, II, and III was observed in both sham-operated and vagotomized suncus; however, the duration and motility index (MI) of phase II was significantly decreased in vagotomized animals. Motilin infusion (50 ng·kg(-1)·min(-1) for 10 min) during phase I had induced phase III-like contractions in both sham-operated and vagotomized animals. Ghrelin infusion (0.1, 0.3, 1, 3, or 10 µg·kg(-1)·min(-1) for 10 min) enhanced the amplitude of phase II MMC in sham-operated animals, but not in vagotomized animals. After feeding, phase I was replaced by postprandial contractions, and motilin infusion (50 ng·kg(-1)·min(-1) for 10 min) did not induce phase III-like contractions in sham-operated suncus. However, in vagotomized suncus, feeding did not evoke postprandial contractions, but exogenous motilin injection strongly induced phase III-like contractions, as noted during the phase I period. Thus, the results indicate that ghrelin stimulates phase II of the MMC via the vagus nerve in suncus. Furthermore, the vagus nerve is essential for initiating postprandial contractions, and inhibition of the phase III-like contractions induced by motilin is highly dependent on the vagus nerve. PMID:23724093

  9. Chronic light deprivation inhibits appetitive associative learning induced by ethanol and its respective c-Fos and pCREB expression.

    PubMed

    Varela, Patrícia; Escosteguy-Neto, João Carlos; Coelho, Carolina Tesone; Mello, Luiz Eugênio; da Silveira, Dartiu Xavier; Santos-Junior, Jair Guilherme

    2014-11-01

    To address the role of mixed anxiety/mood disorder on appetitive associative learning, we verify whether previous chronic light deprivation changes ethanol-induced conditioned place preference and its respective expression of c-Fos and pCREB, markers of neuronal activity and plasticity. The experimental group was maintained in light deprivation for 24 h for a period of 4 wk. Subsequently, it was adapted to a standard light-dark cycle for 1 wk. As a control, some mice were maintained in standard cycle for a period of 4 wk (Naïve group). Then, all animals were submitted to behavioral tests to assess emotionality: elevated plus maze; open field; and forced swim. After that, they were submitted to ethanol-induced conditioned place preference. Ninety minutes after the place preference test, they were perfused, and their brains processed for c-Fos and pCREB immunohistochemistry. Light deprivation induced anxiety-like trait (elevated plus maze), despair (forced swim), and hyperlocomotion (open field), common features seen in other animal models of depression. Ethanol-induced conditioned place preference was accompanied by increases on c-Fos and pCREB in the hippocampus, prefrontal cortex and striatum. Interestingly, mice previously submitted to light deprivation did not develop either acquisition and/or expression of ethanol-induced conditioned place preference or increases in c-Fos and pCREB. Therefore, chronic light deprivation mimics several behavioral aspects of other animal models of depression. Furthermore, it could be useful to study the neurochemical mechanisms involved in the dual diagnosis. However, given its likely deleterious effects on appetitive associative memory, it should be used with caution to investigate the cognitive aspects related to the dual diagnosis. PMID:24905237

  10. RB101(S), a dual inhibitor of enkephalinases does not induce antinociceptive tolerance, or cross-tolerance with morphine: a c-Fos study at the spinal level.

    PubMed

    Le Guen, Stéphanie; Noble, Florence; Fournié-Zaluski, Marie-Claude; Roques, Bernard Pierre; Besson, Jean-Marie; Buritova, Jaroslava

    2002-04-26

    In behavioural tests, RB101 (N-[(S)-2-benzyl-3[(S)(2-amino-4-methyl-thio)butyldithio]-1-oxopropyl]-L-phenylalanine benzyl ester), a mixed inhibitor of enkephalin-degrading enzymes, induces antinociceptive effects without producing tolerance, or cross-tolerance with morphine. In the present experiments, the acute or chronic effects of enantiomer RB101(S) were examined on the response of spinal cord neurons to nociceptive inflammatory stimulation (intraplantar injection of carrageenin) using c-Fos studies in awake rats. The number of c-Fos immunoreactive nuclei was evaluated in the lumbar spinal cord 90 min after carrageenin. c-Fos-immunoreactive nuclei were preferentially located in the superficial (I-II) and deep (V-VI) laminae of segments L4-L5 (areas containing numerous neurones responding exclusively, or not, to nociceptive stimuli). In the first experimental series, acute RB101(S) (30 mg/kg, i.v.), morphine (3 mg/kg, i.v.), or respective vehicles were injected in rats chronically treated with RB101(S) (160 mg/kg/day for 4 days, s.c.). In chronically treated RB101(S) rats, both acute RB101(S) and morphine reduced the total number of carrageenin-evoked c-Fos-immunoreactive nuclei. In the second experimental series, acute RB101(S) (30 mg/kg, i.v.) reduced the total number of carrageenin-evoked c-Fos-immunoreactive nuclei with similar magnitude in naive and in morphine-tolerant (100 mg/kg/day for 3 days, s.c.) rats. These data provide further evidence that different cellular mechanisms occurred after chronic stimulation of opioid receptors by morphine or endogenous enkephalins.

  11. IP{sub 3}-dependent intracellular Ca{sup 2+} release is required for cAMP-induced c-fos expression in hippocampal neurons

    SciTech Connect

    Zhang, Wenting; Tingare, Asmita; Ng, David Chi-Heng; Johnson, Hong W.; Schell, Michael J.; Lord, Rebecca L.; Chawla, Sangeeta

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer cAMP-induced c-fos expression in hippocampal neurons requires a submembraneous Ca{sup 2+} pool. Black-Right-Pointing-Pointer The submembraneous Ca{sup 2+} pool derives from intracellular ER stores. Black-Right-Pointing-Pointer Expression of IP{sub 3}-metabolizing enzymes inhibits cAMP-induced c-fos expression. Black-Right-Pointing-Pointer SRE-mediated and CRE-mediated gene expression is sensitive to IP{sub 3}-metabolizing enzymes. Black-Right-Pointing-Pointer Intracellular Ca{sup 2+} release is required for cAMP-induced nuclear translocation of TORC1. -- Abstract: Ca{sup 2+} and cAMP are widely used in concert by neurons to relay signals from the synapse to the nucleus, where synaptic activity modulates gene expression required for synaptic plasticity. Neurons utilize different transcriptional regulators to integrate information encoded in the spatiotemporal dynamics and magnitude of Ca{sup 2+} and cAMP signals, including some that are Ca{sup 2+}-responsive, some that are cAMP-responsive and some that detect coincident Ca{sup 2+} and cAMP signals. Because Ca{sup 2+} and cAMP can influence each other's amplitude and spatiotemporal characteristics, we investigated how cAMP acts to regulate gene expression when increases in intracellular Ca{sup 2+} are buffered. We show here that cAMP-mobilizing stimuli are unable to induce expression of the immediate early gene c-fos in hippocampal neurons in the presence of the intracellular Ca{sup 2+} buffer BAPTA-AM. Expression of enzymes that attenuate intracellular IP{sub 3} levels also inhibited cAMP-dependent c-fos induction. Synaptic activity induces c-fos transcription through two cis regulatory DNA elements - the CRE and the SRE. We show here that in response to cAMP both CRE-mediated and SRE-mediated induction of a luciferase reporter gene is attenuated by IP{sub 3} metabolizing enzymes. Furthermore, cAMP-induced nuclear translocation of the CREB coactivator TORC1 was inhibited by

  12. Methyl Supplementation Attenuates Cocaine-Seeking Behaviors and Cocaine-Induced c-Fos Activation in a DNA Methylation-Dependent Manner

    PubMed Central

    Wright, Katherine N.; Hollis, Fiona; Duclot, Florian; Dossat, Amanda M.; Strong, Caroline E.; Francis, T. Chase; Mercer, Roger; Feng, Jian; Dietz, David M.; Lobo, Mary Kay; Nestler, Eric J.

    2015-01-01

    Epigenetic mechanisms, such as histone modifications, regulate responsiveness to drugs of abuse, such as cocaine, but relatively little is known about the regulation of addictive-like behaviors by DNA methylation. To investigate the influence of DNA methylation on the locomotor-activating effects of cocaine and on drug-seeking behavior, rats receiving methyl supplementation via chronic l-methionine (MET) underwent either a sensitization regimen of intermittent cocaine injections or intravenous self-administration of cocaine, followed by cue-induced and drug-primed reinstatement. MET blocked sensitization to the locomotor-activating effects of cocaine and attenuated drug-primed reinstatement, with no effect on cue-induced reinstatement or sucrose self-administration and reinstatement. Furthermore, upregulation of DNA methyltransferase 3a and 3b and global DNA hypomethylation were observed in the nucleus accumbens core (NAc), but not in the medial prefrontal cortex (mPFC), of cocaine-pretreated rats. Glutamatergic projections from the mPFC to the NAc are critically involved in the regulation of cocaine-primed reinstatement, and activation of both brain regions is seen in human addicts when reexposed to the drug. When compared with vehicle-pretreated rats, the immediate early gene c-Fos (a marker of neuronal activation) was upregulated in the NAc and mPFC of cocaine-pretreated rats after cocaine-primed reinstatement, and chronic MET treatment blocked its induction in both regions. Cocaine-induced c-Fos expression in the NAc was associated with reduced methylation at CpG dinucleotides in the c-Fos gene promoter, effects reversed by MET treatment. Overall, these data suggest that drug-seeking behaviors are, in part, attributable to a DNA methylation-dependent process, likely occurring at specific gene loci (e.g., c-Fos) in the reward pathway. PMID:26063926

  13. Methyl supplementation attenuates cocaine-seeking behaviors and cocaine-induced c-Fos activation in a DNA methylation-dependent manner.

    PubMed

    Wright, Katherine N; Hollis, Fiona; Duclot, Florian; Dossat, Amanda M; Strong, Caroline E; Francis, T Chase; Mercer, Roger; Feng, Jian; Dietz, David M; Lobo, Mary Kay; Nestler, Eric J; Kabbaj, Mohamed

    2015-06-10

    Epigenetic mechanisms, such as histone modifications, regulate responsiveness to drugs of abuse, such as cocaine, but relatively little is known about the regulation of addictive-like behaviors by DNA methylation. To investigate the influence of DNA methylation on the locomotor-activating effects of cocaine and on drug-seeking behavior, rats receiving methyl supplementation via chronic l-methionine (MET) underwent either a sensitization regimen of intermittent cocaine injections or intravenous self-administration of cocaine, followed by cue-induced and drug-primed reinstatement. MET blocked sensitization to the locomotor-activating effects of cocaine and attenuated drug-primed reinstatement, with no effect on cue-induced reinstatement or sucrose self-administration and reinstatement. Furthermore, upregulation of DNA methyltransferase 3a and 3b and global DNA hypomethylation were observed in the nucleus accumbens core (NAc), but not in the medial prefrontal cortex (mPFC), of cocaine-pretreated rats. Glutamatergic projections from the mPFC to the NAc are critically involved in the regulation of cocaine-primed reinstatement, and activation of both brain regions is seen in human addicts when reexposed to the drug. When compared with vehicle-pretreated rats, the immediate early gene c-Fos (a marker of neuronal activation) was upregulated in the NAc and mPFC of cocaine-pretreated rats after cocaine-primed reinstatement, and chronic MET treatment blocked its induction in both regions. Cocaine-induced c-Fos expression in the NAc was associated with reduced methylation at CpG dinucleotides in the c-Fos gene promoter, effects reversed by MET treatment. Overall, these data suggest that drug-seeking behaviors are, in part, attributable to a DNA methylation-dependent process, likely occurring at specific gene loci (e.g., c-Fos) in the reward pathway.

  14. Do Lactation-Induced Changes in Ghrelin, Glucagon-Like Peptide-1, and Peptide YY Influence Appetite and Body Weight Regulation during the First Postpartum Year?

    PubMed Central

    Larson-Meyer, D. Enette; Schueler, Jessica; Kyle, Erin; Austin, Kathleen J.; Hart, Ann Marie; Alexander, Brenda M.

    2016-01-01

    To determine whether fasting and meal-induced appetite-regulating hormones are altered during lactation and associated with body weight retention after childbearing, we studied 24 exclusively breastfeeding women (BMI = 25.2 ± 3.6 kg/m2) at 4-5 weeks postpartum and 20 never-pregnant controls (BMI = 24.0 ± 3.1 kg/m2). Ghrelin, PYY, GLP-1, and appetite ratings were measured before/and 150 minutes after a standardized breakfast and 60 minutes after an ad libitum lunch. Body weight/composition were measured at 6 and 12 months. Fasting and area under-the-curve responses for appetite-regulating hormones did not differ between lactating and control groups; ghrelinacyl, however, tended to track higher after the standardized breakfast in lactating women and was higher (p < 0.05) after the ad libitum lunch despite a 24% higher energy intake (p < 0.05). By 12 months, lactating women lost 5.3 ± 2.2 kg (n = 18), whereas control women (n = 15) remained weight stable (p = 0.019); fifteen of the lactating women returned to within ±2.0 kg of prepregnancy weight but three retained >6.0 kg. The retainers had greater (p < 0.05) postmeal ghrelin rebound responses following breakfast. Overall these studies do not support the hypothesis that appetite-regulating hormones are altered during lactation and associated with postpartum weight retention. Altered ghrelin responses, however, deserve further exploration. PMID:27313876

  15. Cannabidiol attenuates haloperidol-induced catalepsy and c-Fos protein expression in the dorsolateral striatum via 5-HT1A receptors in mice.

    PubMed

    Sonego, Andreza B; Gomes, Felipe V; Del Bel, Elaine A; Guimaraes, Francisco S

    2016-08-01

    Cannabidiol (CBD) is a major non-psychoactive compound from Cannabis sativa plant. Given that CBD reduces psychotic symptoms without inducing extrapyramidal motor side-effects in animal models and schizophrenia patients, it has been proposed to act as an atypical antipsychotic. In addition, CBD reduced catalepsy induced by drugs with distinct pharmacological mechanisms, including the typical antipsychotic haloperidol. To further investigate this latter effect, we tested whether CBD (15-60mg/kg) would attenuate the catalepsy and c-Fos protein expression in the dorsal striatum induced by haloperidol (0.6mg/kg). We also evaluated if these effects occur through the facilitation of 5-HT1A receptor-mediated neurotransmission. For this, male Swiss mice were treated with CBD and haloperidol systemically and then subjected to the catalepsy test. Independent groups of animals were also treated with the 5-HT1A receptor antagonist WAY100635 (0.1mg/kg). As expected, haloperidol induced catalepsy throughout the experiments, an effect that was prevented by systemic CBD treatment 30min before haloperidol administration. Also, CBD, administered 2.5h after haloperidol, reversed haloperidol-induced catalepsy. Haloperidol also increased c-Fos protein expression in the dorsolateral striatum, an effect attenuated by previous CBD administration. CBD effects on catalepsy and c-Fos protein expression induced by haloperidol were blocked by the 5-HT1A receptor antagonist. We also evaluated the effects of CBD (60nmol) injection into the dorsal striatum on haloperidol-induced catalepsy. Similar to systemic administration, this treatment reduced catalepsy induced by haloperidol. Altogether, these results suggest that CBD acts in the dorsal striatum to improve haloperidol-induced catalepsy via postsynaptic 5-HT1A receptors. PMID:27131780

  16. Lesion-induced increase in nerve growth factor mRNA is mediated by c-fos

    SciTech Connect

    Hengerer, B.; Lindholm, D.; Heumann, R.; Thoenen, H. ); Ruether, U. ); Wagner, E.F. )

    1990-05-01

    Lesion of the sciatic nerve caused a rapid increase in c-fos and c-jun mRNA that was followed about 2 hr later by an increase in nerve growth factor (NGF) mRNA. To evaluate whether the initial increase in c-fos mRNA is casually related to the subsequent increase in NGF mRNA, the authors performed experiments with fibroblasts of transgenic mice carrying an exogenous c-fos gene under the control of a metallothionein promoter. In primary cultures of these fibroblasts, CdCl{sub 2} evoked a rapid increase in exogenous c-fos mRNA, followed immediately by an increase in endogenous c-jun mRNA and with a slight delay by an increase in NGF mRNA. In fibroblasts of C3H control mice, CdCl{sub 2} had no effect on the mRNA levels of the protooncogenes c-fos and c-jun or of NGF. Additional evidence for a casual relationship between c-fos induction and the subsequent increase in NGF mRNA was obtained in cotransfection experiments. DNase I footprint experiments demonstrated that a binding site for transcription factor AP-1 in the first intron of the NGF gene was protected following c-fos induction. That this protected AP-1 site indeed was functional in the regulation of NGF expression was verified by deletion experiments and by a point mutation in the corresponding AP-1 binding region in the NGF promoter-chloramphenicol acetyltransferase reporter construct.

  17. Expression and colocalization of NMDA receptor and FosB/ΔFosB in sensitive brain regions in rats after chronic morphine exposure.

    PubMed

    Zhang, Qiang; Liu, Qi; Li, Tongzhou; Liu, You; Wang, Lei; Zhang, Zhonghai; Liu, Hongzhi; Hu, Min; Qiao, Yuehua; Niu, Haichen

    2016-02-12

    Research in the last decade demonstrated that the NMDA receptor (NMDAR) has an important role in opiate-induced neural and behavioral plasticity. In addition, increased levels of FosB-like proteins (FosB/ΔFosB) were found to be related to morphine withdrawal behaviors. However, the relationship between NMDAR and FosB/ΔFosB in sensitive brain regions during morphine withdrawal is largely unknown. In this study, we aimed to investigate NMDAR dynamics and FosB/ΔFosB levels in multiple brain regions and whether they are related in sensitive brain regions during morphine abstinence. Quantitative immunohistochemistry was adopted to test NMDAR and FosB/ΔfosB levels during morphine withdrawal in rats. Increased NMDAR and FosB/ΔFosB levels were found in the nucleus accumbens core (AcbC), nucleus accumbens shell (AcbSh), central amygdaloid nucleuscapsular part (CeC), ventral tegmental area (VTA) and cingulate cortex (Cg). Double-immunofluorescence labeling indicated that NMDAR colocalized with Fos/ΔFosB in these five regions. These results suggest that multiple phenotypic regions are mediated by NMDAR and Fos/ΔFosB during morphine withdrawal, such as the motivational (AcbC, AcbSh), limbic (CeC, VTA) and executive (Cg) system pathways, and may be the primary targets of NMDAR and Fos/ΔfosB that impact morphine withdrawal behaviors.

  18. Ghrelin reduces hepatic mitochondrial fatty acid beta oxidation.

    PubMed

    Rigault, C; Le Borgne, F; Georges, B; Demarquoy, J

    2007-04-01

    Ghrelin is a 28-amino-acid peptide secreted during starvation by gastric cells. Ghrelin physiologically induces food intake and seems to alter lipid and glucid metabolism in several tissues such as adipose tissue and liver. Liver has a key position in lipid metabolism as it allows the metabolic orientation of fatty acids between oxidation and esterification. We investigated the effects of peripheral ghrelin administration on 2 crucial parameters of fatty acid oxidation: the levocarnitine (L-carnitine)-dependent entry of the fatty acids in the mitochondria and the mitochondrial fatty acid oxidation. Ghrelin was either given to rats prior to the hepatocyte preparation and culture or used to treat hepatocytes prepared from control animals. Direct incubation of ghrelin to raw hepatocytes did not induce any change in the studied parameters. In hepatocytes prepared from 3 nmol ghrelin-treated rats, a 44% reduction of the mitochondrial fatty acid oxidation while no alteration of the L-carnitine-related parameters were observed. These results suggested (a) that ghrelin has no direct effect on liver, and (b) that when administrated to a whole organism, ghrelin may alter the lipid metabolism and the energy balance through a marked decrease in liver fatty acid oxidation. PMID:17556859

  19. Acylated but not des-acyl ghrelin is neuroprotective in an MPTP mouse model of Parkinson's disease.

    PubMed

    Bayliss, Jacqueline A; Lemus, Moyra; Santos, Vanessa V; Deo, Minh; Elsworth, John D; Andrews, Zane B

    2016-05-01

    The gut hormone ghrelin is widely beneficial in many disease states. However, ghrelin exists in two distinctive isoforms, each with its own metabolic profile. In Parkinson's Disease (PD) acylated ghrelin administration is neuroprotective, however, the role of des-acylated ghrelin remains unknown. In this study, we wanted to identify the relative contribution each isoform plays using the MPTP model of PD. Chronic administration of acylated ghrelin in mice lacking both isoforms of ghrelin (Ghrelin KO) attenuated the MPTP-induced loss on tyrosine hydroxylase (TH) neuronal number and volume and TH protein expression in the nigrostriatal pathway. Moreover, acylated ghrelin reduced the increase in glial fibrillary acidic protein and Ionized calcium binding adaptor molecule 1 microglia in the substantia nigra. However, injection of acylated ghrelin also elevated plasma des-acylated ghrelin, indicating in vivo deacetylation. Next, we chronically administered des-acylated ghrelin to Ghrelin KO mice and observed no neuroprotective effects in terms of TH cell number, TH protein expression, glial fibrillary acidic protein and ionized calcium binding adaptor molecule 1 cell number. The lack of a protective effect was mirrored in ghrelin-O-acyltransferase KO mice, which lack the ability to acylate ghrelin and consequently these mice have chronically increased plasma des-acyl ghrelin. Plasma corticosterone was elevated in ghrelin-O-acyltransferase KO mice and with des-acylated ghrelin administration. Overall, our studies suggest that acylated ghrelin is the isoform responsible for in vivo neuroprotection and that pharmacological approaches preventing plasma conversion from acyl ghrelin to des-acyl ghrelin may have clinical efficacy to help slow or prevent the debilitating effects of PD. Ghrelin exists in the plasma as acyl and des-acyl ghrelin. We determined the form responsible for in vivo neuroprotection in a mouse model of Parkinson's disease. Although exogenous acyl ghrelin

  20. Ghrelin and cancer.

    PubMed

    Chopin, Lisa; Walpole, Carina; Seim, Inge; Cunningham, Peter; Murray, Rachael; Whiteside, Eliza; Josh, Peter; Herington, Adrian

    2011-06-20

    Ghrelin is a peptide hormone that was originally isolated from the stomach as the endogenous ligand for the growth hormone secretagogue receptor (GHSR). Ghrelin has many functions, including the regulation of appetite and gut motility, growth hormone release from the anterior pituitary and roles in the cardiovascular and immune systems. Ghrelin and its receptor are expressed in a number of cancers and cancer cell lines and may play a role in processes associated with cancer progression, including cell proliferation, apoptosis, and cell invasion and migration.

  1. Molecular evolution of GPCRs: Ghrelin/ghrelin receptors.

    PubMed

    Kaiya, Hiroyuki; Kangawa, Kenji; Miyazato, Mikiya

    2014-06-01

    After the discovery in 1996 of the GH secretagogue-receptor type-1a (GHS-R1a) as an orphan G-protein coupled receptor, many research groups attempted to identify the endogenous ligand. Finally, Kojima and colleagues successfully isolated the peptide ligand from rat stomach extracts, determined its structure, and named it ghrelin. The GHS-R1a is now accepted to be the ghrelin receptor. The existence of the ghrelin system has been demonstrated in many animal classes through biochemical and molecular biological strategies as well as through genome projects. Our work, focused on identifying the ghrelin receptor and its ligand ghrelin in laboratory animals, particularly nonmammalian vertebrates, has provided new insights into the molecular evolution of the ghrelin receptor. In mammals, it is assumed that the ghrelin receptor evolution is in line with the plate tectonics theory. In contrast, the evolution of the ghrelin receptor in nonmammalian vertebrates differs from that of mammals: multiplicity of the ghrelin receptor isoforms is observed in nonmammalian vertebrates only. This multiplicity is due to genome duplication and polyploidization events that particularly occurred in Teleostei. Furthermore, it is likely that the evolution of the ghrelin receptor is distinct from that of its ligand, ghrelin, because only one ghrelin isoform has been detected in all species examined so far. In this review, we summarize current knowledge related to the molecular evolution of the ghrelin receptor in mammalian and nonmammalian vertebrates. PMID:24353285

  2. Adipokines and ghrelin in gastric cancer cachexia

    PubMed Central

    Kerem, Mustafa; Ferahkose, Zafer; Yilmaz, Utku Tonguc; Pasaoglu, Hatice; Ofluoglu, Ebru; Bedirli, Abdulkadir; Salman, Bulent; Sahin, Tevfik Tolga; Akin, Murat

    2008-01-01

    AIM: To investigate the roles of the adipocytokines, ghrelin and leptin in gastric cancer cachexia. METHODS: Resistin, ghrelin, leptin, adiponectin, insulin and insulin-like growth factor (IGF-I), were measured in 30 healthy subjects, and 60 gastric cancer patients of which 30 suffered from cancer-induced cachexia and 30 served as a control group. The relationships between hormones, body mass index (BMI) loss ratio, age, gender, and Glasgow Prognostic Score (GPS) were investigated. RESULTS: Cachexia patients had higher tumor stage and GPS when compared with non-cachexia patients (P < 0.05). Ghrelin, resistin, leptin, adiponectin and IGF-I, showed a significant correlation with BMI loss ratio and GPS (P < 0.05). A strong correlation was seen between GPS and BMI loss (R = -0.570, P < 0.0001). Multivariate analysis indicated that BMI loss was significantly independent as a predictor of ghrelin, resistin, leptin and IGF-I (P < 0.05). Existence of an important significant relationship between resistin and insulin resistance was also noted. CONCLUSION: These results showed that serum ghrelin, leptin, adiponectin, and IGF-I play important roles in cachexia-related gastric cancers. No relationship was found between resistin and cancer cachexia. Also, because of the correlation between these parameters and GPS, these parameters might be used as a predictor factor. PMID:18595130

  3. Role of protein kinase D2 phosphorylation on Tyr in modulation by ghrelin of Helicobacter pylori-induced up-regulation in gastric mucosal matrix metalloproteinase-9 (MMP-9) secretion.

    PubMed

    Slomiany, B L; Slomiany, A

    2016-06-01

    Matrix metalloproteinas-9 (MMP-9) is a glycosylated endopeptidase associated with host reaction to microbial endotoxins and also characterizes gastric mucosal inflammatory response to H. pylori infection. Here, we report on the factors involved in gastric mucosal MMP-9 secretion in response to H. pylori LPS, and the effect of hormone, ghrelin. We show that both the LPS-elicited induction in MMP-9 secretion and also the modulatory influence of ghrelin occur at the level of MMP-9 processing between the endoplasmic reticulum (ER) and Golgi. Further, we demonstrate that the LPS effect is associated with up-regulation in the activation of Arf1, a small GTPase of the ADP-ribosylation factor family, and the recruitment and phosphorylation of protein kinase D2 (PKD2), involved in the secretory cargo processing in the Golgi. Moreover, we reveal that the LPS-induced up-regulation in MMP-9 secretion is reflected in a marked increase in PKCδ-mediated PKD2 phosphorylation on Ser, while the modulatory effect of ghrelin is manifested by the SFK-PTKs-dependent phosphorylation of PKD2 on Tyr. Thus, our findings demonstrate the role of Arf1/PKD2 in mediation of H. pylori LPS-induced up-regulation in gastric mucosal MMP-9 secretion and suggest the modulatory mechanism of ghrelin action. PMID:27209313

  4. Impact of bread making on fructan chain integrity and effect of fructan enriched breads on breath hydrogen, satiety, energy intake, PYY and ghrelin.

    PubMed

    Morris, C; Lynn, A; Neveux, C; Hall, A C; Morris, G A

    2015-08-01

    Recently, there has been considerable interest in the satiety inducing properties of inulin type fructans (ITF) as a tool for weight management. As a staple food, breads provide an excellent vehicle for ITF supplementation however the integrity of the ITF chains and properties upon bread making need to be assessed. Breads enriched with 12% fructooligosaccharides (FOS) and 12% inulin were baked and the degree of polymerisation of fructans extracted from the breads were compared to those of pure compounds. An acute feeding study with a single blind cross-over design was conducted with 11 participants to investigate the effect of ITF enriched breads on breath hydrogen, self-reported satiety levels, active ghrelin, total PYY and energy intake. Size exclusion chromatography indicated that little or no depolymerisation of inulin occurred during bread making, however, there was evidence of modest FOS depolymerisation. Additionally, ITF enriched breads resulted in increased concentrations of exhaled hydrogen although statistical significance was reached only for the inulin enriched bread (p = 0.001). There were no significant differences between bread types in reported satiety (p = 0.129), plasma active ghrelin (p = 0.684), plasma PYY (p = 0.793) and energy intake (p = 0.240). These preliminary results indicate that inulin enriched bread may be a suitable staple food to increase ITF intake. Longer intervention trials are required to assess the impact of inulin enriched breads on energy intake and body weight.

  5. Deprivation of anticipated food under scheduled feeding induces c-Fos expression in the caudal part of the arcuate nucleus of hypothalamus through histamine H₁ receptors in rats: potential involvement of E3 subgroup of histaminergic neurons in tuberomammillary nucleus.

    PubMed

    Umehara, Hayato; Mizuguchi, Hiroyuki; Mizukawa, Nami; Matsumoto, Mai; Takeda, Noriaki; Senba, Emiko; Fukui, Hiroyuki

    2011-04-28

    It is well established that histaminergic neurons densely innervate the anterior hypothalamus and regulate several functions through histamine H(1) receptor (H1R). However, functional innervations of histaminergic neurons in the caudal hypothalamus have been poorly investigated. Recently, we have demonstrated that c-Fos, a marker of neuronal activation, was significantly induced by food deprivation under scheduled feeding in H1R-expressing cells in the caudal part of the arcuate nucleus of hypothalamus (cARC) of rats and histaminergic neurons innervating this area. In this study, we have examined the functional involvement of histaminergic neurons in the food deprivation-induced c-Fos expression in the cARC under scheduled feeding. The c-Fos expression in the cARC by food deprivation was significantly suppressed by pretreatment with antihistamines. After food deprivation, the number of c-Fos-histidine decarboxylase (HDC) double-positive neurons was mostly increased in the E3 subdivision of the tuberomammillary nucleus (TM). Under the restricted feeding schedule, significant expressions of c-Fos were detected in the TM and cARC only when rats strongly anticipated feeding, compared with a slight c-Fos induction in both nuclei when they were satiated. These findings suggest that the histaminergic neurons in the E3 subdivision of the TM are selectively activated by deprivation of an anticipated food under scheduled feeding and functionally innervate the H1R-expressing neurons in the cARC.

  6. Anxiolytic activity of the MGLU2/3 receptor agonist LY354740 on the elevated plus maze is associated with the suppression of stress-induced c-Fos in the hippocampus and increases in c-Fos induction in several other stress-sensitive brain regions.

    PubMed

    Linden, A-M; Greene, S J; Bergeron, M; Schoepp, D D

    2004-03-01

    LY354740 is a potent and selective agonist for group II metabotropic glutamate (mGlu) receptors, mGlu2 and mGlu3 receptors, with anxiolytic activity in several animal models of anxiety, including the elevated plus maze (EPM) test. Here, we studied neuronal activation in mouse brain after EPM exposure in saline- and LY354740-treated mice using c-Fos immunoreactivity as a marker. The effect of LY354740 on c-Fos expression was also studied in cage control (no EPM) mice. Pretreatment with LY354740 (20 mg/kg, s.c.) produced robust anxiolytic behavior on the EPM. LY354740 administration decreased EPM-induced increases in c-Fos expression in the CA3 of the hippocampus, while having no significant effects on basal c-Fos expression in the hippocampus. LY354740 administration significantly increased c-Fos expression in specific limbic regions, including the lateral division of the central nucleus of the amygdala (CeL), lateral parabrachial nucleus, locus coeruleus, and Edinger-Westphal nucleus, whether or not animals were exposed to the EPM. Moreover, LY354740 administration per se significantly increased c-Fos expression in regions processing sensory information, including the paraventricular and lateral geniculate nucleus of the thalamus as well as the nucleus of the optic tract and superior colliculus. In particular, the suppression of fear-evoked neuronal activity in the hippocampus and drug-induced increases in neuronal activation in the CeL have been previously linked to the anxiolytic effects of clinically effective drugs such as benzodiazepines, and thus may contribute to anxiolytic actions of LY354740 in animal models and human anxiety patients. PMID:14694349

  7. Autoregulation of fos: the dyad symmetry element as the major target of repression.

    PubMed Central

    König, H; Ponta, H; Rahmsdorf, U; Büscher, M; Schönthal, A; Rahmsdorf, H J; Herrlich, P

    1989-01-01

    Fos and Jun co-operatively repress the fos promoter. Removal of all putative Fos/Jun binding sites from the fos promoter neither obliterates the repression by Fos/Jun in transient cotransfection experiments in NIH3T3 cells nor the turn-off kinetics of serum-induced fos expression in stably transfected NIH3T3 cells. The dyad symmetry element (DSE) suffices to subject a promoter to this type of repression. However, one of the putative Fos/Jun binding sites (-292 to -299 and thus located immediately adjacent to the DSE), determines the very low level of basal expression. Images PMID:2511006

  8. CRF Type 2 Receptors Mediate the Metabolic Effects of Ghrelin in C2C12 cells

    PubMed Central

    Gershon, Eran; Vale, Wylie W

    2014-01-01

    Objective Ghrelin is known to regulate appetite control and cellular metabolism. The Corticotropin-Releasing Factor (CRF) family is also known to regulate energy balance. In this study, we investigated the links between ghrelin and the CRF family in C2C12 cells, a mouse myoblast cell line. Design and methods C2C12 cells were treated with ghrelin in the presence or absence of CRF receptor antagonists and then subjected to different metabolic analyses. Results Ghrelin enhanced glucose uptake by C2C12 cells, induced GLUT4 translocation to the cell surface and decreased RBP4 expression. A CRF-R2 selective antagonist, anti-sauvagine-30, blocked ghrelin-induced glucose uptake, Ghrelin upregulated CRF-R2 but not CRF-R1 levels. Moreover, ghrelin-treated C2C12 cells displayed a cAMP and pERK activation in response to Ucn3, a CRF-R2 specific ligand, but not in response to CRF or stressin, CRF-R1 specific ligands. Ghrelin also induced UCP2 and UCP3 expression, which were blocked by anti-sauvagine-30. Ghrelin did not induce fatty acids uptake by C2C12 cells or ACC expression. Even though C2C12 cells clearly exhibited responses to ghrelin, the known ghrelin receptor, GHSR1a, was not detectable in C2C12 cells. Conclusion Our results suggest that, ghrelin plays a role in regulating muscle glucose and, raise the possibility that suppression of the CRF-R2 pathway might provide benefits in high ghrelin states. PMID:23804489

  9. Rats showing low and high sensitization of frequency-modulated 50-kHz vocalization response to amphetamine differ in amphetamine-induced brain Fos expression.

    PubMed

    Kaniuga, Ewelina; Taracha, Ewa; Stępień, Tomasz; Wierzba-Bobrowicz, Teresa; Płaźnik, Adam; Chrapusta, Stanisław J

    2016-10-01

    Individuals predisposed to addiction constitute a minority of drug users, in both humans and animal models of the disorder, but there are no established characteristics that would allow identifying them beforehand. Our studies demonstrate that sensitization of rat 50-kHz ultrasonic vocalization (USV) response to amphetamine shows marked inter-individual diversity but substantial intra-individual stability. Low sensitization of the response shows relevance to the acquisition of self-administration of this drug and hence might be of predictive value regarding the risk of addiction. We compared amphetamine-induced Fos expression in 16 brain regions considered important for the development of addiction between rats preselected for low and high sensitization of the response and next given nine daily amphetamine doses followed by a 2-week withdrawal and final amphetamine challenge. Ventral tegmental area and nucleus accumbens shell Fos-positive nuclei counts correlated positively with 50-kHz USV response to the challenge in high-sensitized rats. Compared to those in amphetamine-untreated controls, Fos-positive nuclei counts were significantly and markedly (2-6 times) higher in 12 regions in high-sensitized rats, whereas in low-sensitized rats they were significantly higher in the cingulate cortex and dorsomedial striatum only. The difference in the counts between the latter two subsets reached statistical significance in dorsomedial and dorsolateral striatum and three out of four cortical regions studied. The fact that the diversification was most distinct in dorsal striatum that plays a critical role in the transition from controlled to compulsive drug intake suggests that the USV-based categorization may be related to divergent vulnerability of rats to AMPH addiction. PMID:27507424

  10. A pivotal role of FOS-mediated BECN1/Beclin 1 upregulation in dopamine D2 and D3 receptor agonist-induced autophagy activation

    PubMed Central

    Wang, Jian-Da; Cao, Yu-Lan; Li, Qian; Yang, Ya-Ping; Jin, Mengmeng; Chen, Dong; Wang, Fen; Wang, Guang-Hui; Qin, Zheng-Hong; Hu, Li-Fang; Liu, Chun-Feng

    2015-01-01

    Autophagy dysfunction is implicated in the pathogenesis of Parkinson disease (PD). BECN1/Beclin 1 acts as a critical regulator of autophagy and other cellular processes; yet, little is known about the function and regulation of BECN1 in PD. In this study, we report that dopamine D2 and D3 receptor (DRD2 and DRD3) activation by pramipexole and quinpirole could enhance BECN1 transcription and promote autophagy activation in several cell lines, including PC12, MES23.5 and differentiated SH-SY5Y cells, and also in tyrosine hydroxylase positive primary midbrain neurons. Moreover, we identified a novel FOS (FBJ murine osteosarcoma viral oncogene homolog) binding sequence (5′-TGCCTCA-3′) in the rat and human Becn1/BECN1 promoter and uncovered an essential role of FOS binding in the enhancement of Becn1 transcription in PC12 cells in response to the dopamine agonist(s). In addition, we demonstrated a critical role of intracellular Ca2+ elevation, followed by the enhanced phosphorylation of CAMK4 (calcium/calmodulin-dependent protein kinase IV) and CREB (cAMP responsive element binding protein) in the increases of FOS expression and autophagy activity. More importantly, pramipexole treatment ameliorated the SNCA/α-synuclein accumulation in rotenone-treated PC12 cells that overexpress wild-type or A53T mutant SNCA by promoting autophagy flux. This effect was also demonstrated in the substantia nigra and the striatum of SNCAA53T transgenic mice. The inhibition of SNCA accumulation by pramipexole was attenuated by cotreatment with the DRD2 and DRD3 antagonists and Becn1 siRNAs. Thus, our findings suggest that DRD2 and DRD3 agonist(s) may induce autophagy activation via a BECN1-dependent pathway and have the potential to reduce SNCA accumulation in PD. PMID:26649942

  11. Injections of urocortin 1 into the basolateral amygdala induce anxiety-like behavior and c-Fos expression in brainstem serotonergic neurons.

    PubMed

    Spiga, F; Lightman, S L; Shekhar, A; Lowry, C A

    2006-01-01

    The amygdala plays a key role in emotional processing and anxiety-related physiological and behavioral responses. Previous studies have shown that injections of the anxiety-related neuropeptide corticotropin-releasing factor or the related neuropeptide urocortin 1 into the region of the basolateral amygdaloid nucleus induce anxiety-like behavior in several behavioral paradigms. Brainstem serotonergic systems in the dorsal raphe nucleus and median raphe nucleus may be part of a distributed neural system that, together with the basolateral amygdala, regulates acute and chronic anxiety states. We therefore investigated the effect of an acute bilateral injection of urocortin 1 into the basolateral amygdala on behavior in the social interaction test and on c-Fos expression within serotonergic neurons in the dorsal raphe nucleus and median raphe nucleus. Male rats were implanted with bilateral cannulae directed at the region of the basolateral amygdala; 72 h after surgery, rats were injected with urocortin 1 (50 fmol/100 nl) or vehicle (100 nl of 1% bovine serum albumin in distilled water). Thirty minutes after injection, a subgroup of rats from each experimental group was exposed to the social interaction test; remaining animals were left in the home cage. Two hours after injection rats were perfused with paraformaldehyde and brains were removed and processed for immunohistochemistry. Acute injection of urocortin 1 had anxiogenic effects in the social interaction test, reducing total interaction time without affecting locomotor activity or exploratory behavior. These behavioral effects were associated with increases in c-Fos expression within brainstem serotonergic neurons. In home cage rats and rats exposed to the social interaction test, urocortin 1 treatment increased the number of c-Fos-immunoreactive serotonergic neurons within subdivisions of both the dorsal raphe nucleus and median raphe nucleus. These results are consistent with the hypothesis that the

  12. Regional Fos-expression induced by γ-hydroxybutyrate (GHB): comparison with γ-butyrolactone (GBL) and effects of co-administration of the GABAB antagonist SCH 50911 and putative GHB antagonist NCS-382.

    PubMed

    van Nieuwenhuijzen, P S; McGregor, I S; Chebib, M; Hunt, G E

    2014-09-26

    γ-Hydroxybutyrate (GHB) has a complex array of neural actions that include effects on its own high-affinity GHB receptor, the release of neuroactive steroids, and agonist actions at GABAA and GABAB receptors. We previously reported partial overlap in the c-Fos expression patterns produced by GHB and the GABAB agonist, baclofen in rats. The present study extends these earlier findings by examining the extent to which GHB Fos expression and behavioral sedation are prevented by (2S)-(+)-5,5-dimethyl-2-morpholineacetic acid (SCH 50911), a GABAB antagonist, and NCS-382, a putative antagonist at the high-affinity GHB receptor. We also compare Fos expression caused by GHB and its precursor γ-butyrolactone (GBL), which is a pro-drug for GHB but lacks the high sodium content of the parent GHB molecule. Both GHB (1,000 mg/kg) and GBL (600 mg/kg) induced rapid sedation in rats that lasted over 90 min and caused similar Fos expression patterns, albeit with GBL causing greater activation of the nucleus accumbens (core and shell) and dentate gyrus (granular layer). Pretreatment with SCH 50911 (100mg/kg) partly reversed the sedative effects of GHB and significantly reduced GHB-induced Fos expression in only four regions: the tenia tecta, lateral habenula, dorsal raphe and laterodorsal tegmental nucleus. NCS-382 (50mg/kg) had no effect on GHB-induced sedation or Fos expression. When given alone, both NCS-382 and SCH 50911 increased Fos expression in the bed nucleus of the stria terminalis, central amygdala, parasubthalamic nucleus and nucleus of the solitary tract. SCH 50911 alone affected the Islands of Calleja and the medial, central and paraventricular thalamic nuclei. Overall, this study shows a surprising lack of reversal of GHB-induced Fos expression by two relevant antagonists, both of which have marked intrinsic actions. This may reflect the limited doses tested but also suggests that GHB Fos expression reflects mechanisms independent of GHB and GABAB receptors.

  13. Spontaneous sleep and homeostatic sleep regulation in ghrelin knockout mice.

    PubMed

    Szentirmai, Eva; Kapás, Levente; Sun, Yuxiang; Smith, Roy G; Krueger, James M

    2007-07-01

    Ghrelin is well known for its feeding and growth hormone-releasing actions. It may also be involved in sleep regulation; intracerebroventricular administration and hypothalamic microinjections of ghrelin stimulate wakefulness in rats. Hypothalamic ghrelin, together with neuropeptide Y and orexin form a food intake-regulatory circuit. We hypothesized that this circuit also promotes arousal. To further investigate the role of ghrelin in the regulation of sleep-wakefulness, we characterized spontaneous and homeostatic sleep regulation in ghrelin knockout (KO) and wild-type (WT) mice. Both groups of mice exhibited similar diurnal rhythms with more sleep and less wakefulness during the light period. In ghrelin KO mice, spontaneous wakefulness and rapid-eye-movement sleep (REMS) were slightly elevated, and non-rapid-eye-movement sleep (NREMS) was reduced. KO mice had more fragmented NREMS than WT mice, as indicated by the shorter and greater number of NREMS episodes. Six hours of sleep deprivation induced rebound increases in NREMS and REMS and biphasic changes in electroencephalographic slow-wave activity (EEG SWA) in both genotypes. Ghrelin KO mice recovered from NREMS and REMS loss faster, and the delayed reduction in EEG SWA, occurring after sleep loss-enhanced increases in EEG SWA, was shorter-lasting compared with WT mice. These findings suggest that the basic sleep-wake regulatory mechanisms in ghrelin KO mice are not impaired and they are able to mount adequate rebound sleep in response to a homeostatic challenge. It is possible that redundancy in the arousal systems of the brain or activation of compensatory mechanisms during development allow for normal sleep-wake regulation in ghrelin KO mice. PMID:17409264

  14. Ghrelin Inhibits Oligodendrocyte Cell Death by Attenuating Microglial Activation

    PubMed Central

    Lee, Jee Youn

    2014-01-01

    Background Recently, we reported the antiapoptotic effect of ghrelin in spinal cord injury-induced apoptotic cell death of oligodendrocytes. However, how ghrelin inhibits oligodendrocytes apoptosis, is still unknown. Therefore, in the present study, we examined whether ghrelin inhibits microglia activation and thereby inhibits oligodendrocyte apoptosis. Methods Using total cell extracts prepared from BV-2 cells activated by lipopolysaccharide (LPS) with or without ghrelin, the levels of p-p38 phosphor-p38 mitogen-activated protein kinase (p-p38MAPK), phospho-c-Jun N-terminal kinase (pJNK), p-c-Jun, and pro-nerve growth factor (proNGF) were examined by Western blot analysis. Reactive oxygen species (ROS) production was investigated by using dichlorodihydrofluorescein diacetate. To examine the effect of ghrelin on oligodendrocyte cell death, oligodendrocytes were cocultured in transwell chambers of 24-well plates with LPS-stimulated BV-2 cells. After 48 hours incubation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and terminal deoxynucleotidyl transferase 2'-deoxyuridine, 5'-triphosphate nick end labeling staining were assessed. Results Ghrelin treatment significantly decreased levels of p-p38MAPK, p-JNK, p-c-Jun, and proNGF in LPS-stimulated BV-2 cells. ROS production increased in LPS-stimulated BV-2 cells was also significantly inhibited by ghrelin treatment. In addition, ghrelin significantly inhibited oligodendrocyte cell death when cocultured with LPS-stimulated BV-2 cells. Conclusion Ghrelin inhibits oligodendrocyte cell death by decreasing proNGF and ROS production as well as p38MAPK and JNK activation in activated microglia as an anti-inflammatory hormone. PMID:25309797

  15. Reduction in total plasma ghrelin levels following catecholamine depletion: relation to bulimic and depressive symptoms.

    PubMed

    Homan, Philipp; Grob, Simona; Milos, Gabriella; Schnyder, Ulrich; Hasler, Gregor

    2013-09-01

    There is increasing preclinical and clinical evidence of the important role played by the gastric peptide hormone ghrelin in the pathogenesis of symptoms of depression and eating disorders. To investigate the role of ghrelin and its considered counterpart, peptide tyrosine tyrosine (PYY), in the development of bulimic and depressive symptoms induced by catecholamine depletion, we administered the tyrosine hydroxylase inhibitor alpha-methyl-paratyrosine (AMPT) in a randomized, double-blind, placebo-controlled crossover, single-site experimental trial to 29 healthy controls and 20 subjects with fully recovered bulimia nervosa (rBN). We found a decrease between preprandial and postprandial plasma ghrelin levels (p<0.0001) and a postprandial rise in plasma PYY levels (p<0.0001) in both conditions in the entire study population. Plasma ghrelin levels decreased in the entire study population after treatment with AMPT compared to placebo (p<0.006). AMPT-induced changes in plasma ghrelin levels were negatively correlated with AMPT-induced depressive symptoms (p<0.004). Plasma ghrelin and plasma PYY levels were also negatively correlated (p<0.05). We did not observe a difference in ghrelin or PYY response to catecholamine depletion between rBN subjects and healthy controls, and there was no correlation between plasma ghrelin and PYY levels and bulimic symptoms induced by catecholamine depletion. These findings suggest a relationship between catecholamines and ghrelin with depressive symptoms.

  16. Ghrelin and the brain-gut axis as a pharmacological target for appetite control.

    PubMed

    Seim, Inge; El-Salhy, Magdy; Hausken, Trygve; Gundersen, Doris; Chopin, Lisa

    2012-01-01

    Appetite regulation is highly complex and involves a large number of orexigenic and anorexigenic peptide hormones. These are small, processed, secreted peptides derived from larger prepropeptide precursors. These peptides are important targets for the development of therapeutics for obesity, a global health epidemic. As a case study, we consider the ghrelin axis. The ghrelin axis is likely to be a particularly useful drug target, as it also plays a role in energy homeostasis, adipogenesis, insulin regulation and reward associated with food intake. Ghrelin is the only known circulating gut orexigenic peptide hormone. As it appears to play a role in diet-induced obesity, blocking the action of ghrelin is likely to be effective for treating and preventing obesity. The ghrelin peptide has been targeted using a number of approaches, with ghrelin mirror-image oligonucleotides (Spiegelmers) and immunotherapy showing some promise. The ghrelin receptor, the growth hormone secretagogue receptor, may also provide a useful target and a number of antagonists and inverse agonists have been developed. A particularly promising new target is the enzyme which octanoylates ghrelin, ghrelin O-acyltransferase (GOAT), and drugs that inhibit GOAT are likely to circumvent pharmacological issues associated with approaches that directly target ghrelin or its receptor.

  17. Endocrine Modulation of Olfactory Responsiveness: Effects of the Orexigenic Hormone Ghrelin.

    PubMed

    Loch, Diana; Breer, Heinz; Strotmann, Jörg

    2015-09-01

    Finding food sources is a prerequisite for an acute food intake. This process is initiated by ghrelin released from X/A-like cells of the gastrointestinal tract. Because food finding often depends on olfaction, the question arises whether ghrelin may affect the responsiveness of the olfactory system. Monitoring odor-induced activation of the mouse olfactory epithelium via Egr1 expression revealed that after a nasal application of ghrelin, more sensory neurons responded upon odor exposure indicating an increased responsiveness. The higher reactivity of olfactory neurons was accompanied with an increased activity of receptor-specific glomeruli. In search for mechanisms underlying the ghrelin-mediated sensitization of olfactory neurons, it was shown that Ghsr1a, the ghrelin receptor gene, but not the hormone itself was expressed in the olfactory epithelium. Further analysis of isolated cells revealed that the receptor was in fact expressed in mature olfactory sensory neurons. Treatment with a ghrelin receptor antagonist abolished the ghrelin effect, strengthening the notion that ghrelin and its receptor are responsible for the enhanced neuronal responsiveness. In contrast to the effects of the "hunger" hormone ghrelin, the short-term "satiety" hormone PYY3-36 did not affect olfactory responsiveness. The results demonstrate that ghrelin, which signals acute hunger, renders the olfactory system more responsive to odors.

  18. Ghrelin stimulates angiogenesis in human microvascular endothelial cells: Implications beyond GH release

    SciTech Connect

    Li Aihua; Cheng Guangli; Zhu Genghui; Tarnawski, Andrzej S. . E-mail: atarnawski@yahoo.com

    2007-02-09

    Ghrelin, a peptide hormone isolated from the stomach, releases growth hormone and stimulates appetite. Ghrelin is also expressed in pancreas, kidneys, cardiovascular system and in endothelial cells. The precise role of ghrelin in endothelial cell functions remains unknown. We examined the expression of ghrelin and its receptor (GHSR1) mRNAs and proteins in human microvascular endothelial cells (HMVEC) and determined whether ghrelin affects in these cells proliferation, migration and in vitro angiogenesis; and whether MAPK/ERK2 signaling is important for the latter action. We found that ghrelin and GHSR1 are constitutively expressed in HMVEC. Treatment of HMVEC with exogenous ghrelin significantly increased in these cells proliferation, migration, in vitro angiogenesis and ERK2 phosphorylation. MEK/ERK2 inhibitor, PD 98059 abolished ghrelin-induced in vitro angiogenesis. This is First demonstration that ghrelin and its receptor are expressed in human microvascular endothelial cells and that ghrelin stimulates HMVEC proliferation, migration, and angiogenesis through activation of ERK2 signaling.

  19. Effects of ghrelin on Cx43 regulation and electrical remodeling after myocardial infarction in rats.

    PubMed

    Yuan, Ming-Jie; Huang, He; Tang, Yan-Hong; Wu, Gang; Gu, Yong-Wei; Chen, Yong-Jun; Huang, Cong-Xin

    2011-11-01

    Ghrelin is a novel growth hormone-releasing peptide, which has been shown to exert beneficial effects on ventricular remodeling. In this study, we investigated whether ghrelin could decrease vulnerability to ventricular arrhythmias in rats with myocardial infarction and the possible mechanism. Twenty-four hours after ligation of the anterior descending artery, adult male Sprague-Dawley rats were randomized to ghrelin (100 μg/kg) and saline (control group) for 4 weeks. Sham animals underwent thoracotomy and pericardiotomy, but not LAD ligation. Myocardial endothelin-1 (ET-1) levels were significantly elevated in saline-treated rats at the border zone compared with sham-operated rats. Myocardial connexin43 (Cx43) expression at the border zone was significantly decreased in saline-treated infarcted rats compared with sham-operated rats. Ghrelin significantly decreased the inducibility of ventricular tachyarrhythmias compared with control group. Arrhythmias sores during programmed stimulation in saline-treated rats were significantly higher than scores in those treated with ghrelin. The electrophysiological improvement of fatal ventricular tachyarrhythmias was accompanied with increased immunofluorescence-stained Cx43, myocardial Cx43 protein and mRNA levels in ghrelin treated rats. We also shown that ghrelin significantly decreased tissue ET-1 levels at the infarcted border zone. Thus, ghrelin showed the protective effect on ventricular arrhythmias after myocardial infarction. Although the precise mechanism by which ghrelin modulates the dephosphorylation of Cx43 remains unknown, it is most likely that the ghrelin increased expression of Cx43 through the inhibition of ET-1.

  20. Transitional change in rat fetal cell proliferation in response to ghrelin and des-acyl ghrelin during the last stage of pregnancy

    SciTech Connect

    Inoue, Yoshiyuki; Nakahara, Keiko; Kangawa, Kenji; Murakami, Noboru

    2010-03-12

    Expression of mRNA for the ghrelin receptor, GHS-R1a, was detected in various peripheral and central tissues of fetal rats, including skin, bone, heart, liver, gut, brain and spinal cord, on embryonic day (ED)15 and ED17. However, its expression in skin, bone, heart and liver, but not in gut, brain and spinal cord, became relatively weak on ED19 and disappeared after birth (ND2). Ghrelin and des-acyl ghrelin facilitated the proliferation of cultured fetal (ED17, 19), but not neonatal (ND2), skin cells. On the other hand, with regard to cells from the spinal cord and hypothalamus, the proliferative effect of ghrelin continued after birth, whereas the effect of des-acyl ghrelin on neurogenesis in these tissues was lost at the ED19 fetal and ND2 neonatal stages. Immunohistochemistry revealed that the cells in the hypothalamus induced to proliferate by ghrelin at the ND2 stage were positive for nestin and glial fibrillary acidic protein. These results suggest that in the period immediately prior to, and after birth, rat fetal cells showing proliferation in response to ghrelin and des-acyl ghrelin are at a transitional stage characterized by alteration of the expression of GHS-R1a and an undefined des-acyl ghrelin receptor, their responsiveness varying among different tissues.

  1. Induction of apoptosis by c-Fos protein.

    PubMed Central

    Preston, G A; Lyon, T T; Yin, Y; Lang, J E; Solomon, G; Annab, L; Srinivasan, D G; Alcorta, D A; Barrett, J C

    1996-01-01

    The role of c-Fos in apoptosis was examined in two Syrian hamster embryo cell lines (sup+I and sup-II) and a human colorectal carcinoma cell line (RKO), using the chimeric Fos-estrogen receptor fusion protein c-FosER. As previously reported, contrasting responses were observed when these two cell lines were placed under growth factor deprivation conditions; sup+I cells were highly susceptible to apoptosis, whereas sup-II cells were resistant. In this report, we show that the activated c-FosER protein induces apoptosis in sup-II preneoplastic cells in serum-free medium, indicating that c-Fos protein can induce apoptotic cell death in these cells. c-Fos-induced apoptosis was not blocked by the protein synthesis inhibitor cycloheximide, suggesting that the c-Fos transcriptional activation activity is not involved. This conclusion was further supported by the observation that overexpression of v-Fos, which is highly proficient in transcriptional activation but deficient in the transcriptional repression activity associated with c-Fos, did not induce apoptosis. Constitutively expressed Bcl-2 delayed the onset of low-serum-induced apoptosis in sup+I cells and enhanced survival in sup-II cells. Further, coexpression of Bcl-2 and c-FosER in sup+I or sup-II cells protected the cells from c-FosER-induced apoptosis. The possibility that c-FosER-induced apoptosis requires a p53 function was examined. Colorectal carcinoma RKOp53+/+ cells, which do not normally undergo apoptosis in serum-free medium, showed apoptotic DNA fragmentation upon expression and activation of c-FosER. Further, when the wild-type p53 protein was diminished in the RKO cells by infection with the papillomavirus E6 gene, subsequent c-FosER-induced apoptosis was blocked. The data suggest that c-Fos protein plays a causal role in the activation of apoptosis in a p53-dependent manner. This activity does not require new protein synthesis and is blocked by overexpression of Bcl-2 protein. PMID:8524298

  2. The effects of RB101, a mixed inhibitor of enkephalin-catabolizing enzymes, on carrageenin-induced spinal c-Fos expression are completely blocked by beta-funaltrexamine, a selective mu-opioid receptor antagonist.

    PubMed

    Le Guen, S; Honoré, P; Catheline, G; Fournié-Zaluski, M C; Roques, B P; Besson, J M

    1999-07-10

    We have demonstrated that pre-administered RB101 (40 mg/kg, i.v.), a mixed inhibitor of enkephalin-catabolizing enzymes, decreased spinal c-Fos expression induced 1 h and 30 min after intraplantar (i.pl.) carrageenin (41% reduction, p<0.01). These effects were completely blocked by pre-administered beta-funaltrexamine (10 mg/kg, i.v., 24 h prior to stimulation), a selective long-lasting mu-opioid receptor antagonist. In conclusion, these results clearly demonstrate that the effects of endogenous enkephalins on noxiously evoked spinal c-Fos expression are essentially mediated via mu-opioid receptors.

  3. Growth hormone-releasing hormone stimulates GH release while inhibiting ghrelin- and sGnRH-induced LH release from goldfish pituitary cells.

    PubMed

    Grey, Caleb L; Chang, John P

    2013-06-01

    Goldfish GH-releasing hormone (gGHRH) has been recently identified and shown to stimulate GH release in goldfish. In goldfish, neuroendocrine regulation of GH release is multifactorial and known stimulators include goldfish ghrelin (gGRLN19) and salmon gonadotropin-releasing hormone (sGnRH), factors that also enhance LH secretion. To further understand the complex regulation of pituitary hormone release in goldfish, we examined the interactions between gGHRH, gGRLN19, and sGnRH on GH and LH release from primary cultures of goldfish pituitary cells in perifusion. Treatment with 100nM gGHRH for 55min stimulated GH release. A 5-min pulse of either 1nM gGRLN19 or 100nM sGnRH induced GH release in naïve cells, and these were just as effective in cells receiving gGHRH. Interestingly, gGHRH abolished both gGRLN19- and sGnRH-induced LH release and reduced basal LH secretion levels. These results suggest that gGHRH does not interfere with sGnRH or gGRLN19 actions in the goldfish somatotropes and further reveal, for the first time, that GHRH may act as an inhibitor of stimulated and basal LH release by actions at the level of pituitary cells.

  4. Obestatin partially suppresses ghrelin stimulation of appetite in "high-responders" grass carp, Ctenopharyngodon idellus.

    PubMed

    Yuan, Xiaochen; Cai, Wenjing; Liang, Xu-Fang; Su, Hang; Yuan, Yongchao; Li, Aixuan; Tao, Ya-Xiong

    2015-06-01

    Ghrelin and obestatin are two gastrointestinal peptides obtained by post-translational processing of a common precursor, preproghrelin. The effect of obestatin on food intake is still controversial. The aim of the present study was to investigate the effects of ghrelin and obestatin on food intake in grass carp, Ctenopharyngodon idellus. Fish received intraperitoneal (IP) injection of saline, ghrelin (100 ng g(-1)BW), obestatin-like (25 ng g(-1)BW) and ghrelin in combination with obestatin-like. Ghrelin stimulation of food intake varied considerably among individual fish with 70.8% eliciting a robust response. In these high-responders, food intake was significantly increased by IP ghrelin within 2 h. Co-administration of ghrelin and obestatin-like resulted in a decrease in food intake, indicating that obestatin was able to antagonize the effect of ghrelin. However, IP obestatin-like alone could not regulate food intake in grass carp. RT-PCR analysis demonstrated that IP ghrelin peptide led to a significant increase in mRNA abundance of NPY, Y8a and Y8b genes compared to saline injected fish, while in combination with obestatin-like peptide decreased ghrelin-induced gene expressions of these three genes. IP sole obestatin-like peptide did not modify the expression levels of NPY, Y8a, Y8b, CART and POMC compared to the control group. Therefore, IP administration of obestatin-like peptide, partially blocking the ghrelin-induced appetite, investigated the possible involvement of obestatin as a mediator of the ghrelin stimulatory action on food intake, at least in "high-responders" grass carp.

  5. Motilin Stimulates Gastric Acid Secretion in Coordination with Ghrelin in Suncus murinus.

    PubMed

    Goswami, Chayon; Shimada, Yoshiaki; Yoshimura, Makoto; Mondal, Anupom; Oda, Sen-ichi; Tanaka, Toru; Sakai, Takafumi; Sakata, Ichiro

    2015-01-01

    Motilin and ghrelin constitute a peptide family, and these hormones are important for the regulation of gastrointestinal motility. In this study, we examined the effect of motilin and ghrelin on gastric acid secretion in anesthetized suncus (house musk shrew, Suncus murinus), a ghrelin- and motilin-producing mammal. We first established a gastric lumen-perfusion system in the suncus and confirmed that intravenous (i.v.) administration of histamine (1 mg/kg body weight) stimulated acid secretion. Motilin (0.1, 1.0, and 10 μg/kg BW) stimulated the acid output in a dose-dependent manner in suncus, whereas ghrelin (0.1, 1.0, and 10 μg/kg BW) alone did not induce acid output. Furthermore, in comparison with the vehicle administration, the co-administration of low-dose (1 μg/kg BW) motilin and ghrelin significantly stimulated gastric acid secretion, whereas either motilin (1 μg/kg BW) or ghrelin (1 μg/kg BW) alone did not significantly induce gastric acid secretion. This indicates an additive role of ghrelin in motilin-induced gastric acid secretion. We then investigated the pathways of motilin/motilin and ghrelin-stimulated acid secretion using receptor antagonists. Treatment with YM 022 (a CCK-B receptor antagonist) and atropine (a muscarinic acetylcholine receptor antagonist) had no effect on motilin or motilin-ghrelin co-administration-induced acid output. In contrast, famotidine (a histamine H2 receptor antagonist) completely inhibited motilin-stimulated acid secretion and co-administration of motilin and ghrelin induced gastric acid output. This is the first report demonstrating that motilin stimulates gastric secretion in mammals. Our results also suggest that motilin and co-administration of motilin and ghrelin stimulate gastric acid secretion via the histamine-mediated pathway in suncus. PMID:26115342

  6. Motilin Stimulates Gastric Acid Secretion in Coordination with Ghrelin in Suncus murinus

    PubMed Central

    Goswami, Chayon; Shimada, Yoshiaki; Yoshimura, Makoto; Mondal, Anupom; Oda, Sen-ichi; Tanaka, Toru; Sakai, Takafumi; Sakata, Ichiro

    2015-01-01

    Motilin and ghrelin constitute a peptide family, and these hormones are important for the regulation of gastrointestinal motility. In this study, we examined the effect of motilin and ghrelin on gastric acid secretion in anesthetized suncus (house musk shrew, Suncus murinus), a ghrelin- and motilin-producing mammal. We first established a gastric lumen-perfusion system in the suncus and confirmed that intravenous (i.v.) administration of histamine (1 mg/kg body weight) stimulated acid secretion. Motilin (0.1, 1.0, and 10 μg/kg BW) stimulated the acid output in a dose-dependent manner in suncus, whereas ghrelin (0.1, 1.0, and 10 μg/kg BW) alone did not induce acid output. Furthermore, in comparison with the vehicle administration, the co-administration of low-dose (1 μg/kg BW) motilin and ghrelin significantly stimulated gastric acid secretion, whereas either motilin (1 μg/kg BW) or ghrelin (1 μg/kg BW) alone did not significantly induce gastric acid secretion. This indicates an additive role of ghrelin in motilin-induced gastric acid secretion. We then investigated the pathways of motilin/motilin and ghrelin-stimulated acid secretion using receptor antagonists. Treatment with YM 022 (a CCK-B receptor antagonist) and atropine (a muscarinic acetylcholine receptor antagonist) had no effect on motilin or motilin-ghrelin co-administration-induced acid output. In contrast, famotidine (a histamine H2 receptor antagonist) completely inhibited motilin-stimulated acid secretion and co-administration of motilin and ghrelin induced gastric acid output. This is the first report demonstrating that motilin stimulates gastric secretion in mammals. Our results also suggest that motilin and co-administration of motilin and ghrelin stimulate gastric acid secretion via the histamine-mediated pathway in suncus. PMID:26115342

  7. A FOOD PREDICTIVE CUE MUST BE ATTRIBUTED WITH INCENTIVE SALIENCE FOR IT TO INDUCE c-FOS mRNA EXPRESSION IN CORTICO-STRIATAL-THALAMIC BRAIN REGIONS

    PubMed Central

    Flagel, Shelly B.; Cameron, Courtney M.; Pickup, Kristen N.; Watson, Stanley J.; Akil, Huda; Robinson, Terry E.

    2011-01-01

    Cues associated with rewards acquire the ability to engage the same brain systems as rewards themselves. However, reward cues have multiple properties. For example, they not only act as predictors of reward capable of evoking conditional responses (CRs), but they may also acquire incentive motivational properties. As incentive stimuli they can evoke complex emotional and motivational states. Here we sought to determine whether the predictive value of a reward cue is sufficient to engage brain reward systems, or whether the cue must also be attributed with incentive salience. We took advantage of the fact that there are large individual differences in the extent to which reward cues are attributed with incentive salience. When a cue (conditional stimulus, CS) is paired with delivery of food (unconditional stimulus, US), the cue acquires the ability to evoke a CR in all rats; that is, it is equally predictive and supports learning the CS-US association in all. However, only in a subset of rats is the cue attributed with incentive salience, becoming an attractive and desirable incentive stimulus. We used in situ hybridization histochemistry to quantify the ability of a food cue to induce c-fos mRNA expression in rats that varied in the extent to which they attributed incentive salience to the cue. We found that a food cue induced c-fos mRNA in the orbitofrontal cortex, striatum (caudate and nucleus accumbens), thalamus (paraventricular, intermediodorsal and central medial nuclei) and lateral habenula, only in rats that attributed incentive salience to the cue. Furthermore, patterns of “connectivity” between these brain regions differed markedly between rats that did or did not attribute incentive salience to the food cue. These data suggest that the predictive value of a reward cue is not sufficient to engage brain reward systems - the cue must also be attributed with incentive salience. PMID:21945724

  8. Effect of rhynchophylline on the expression of p-CREB and sc-Fos in triatum and hippocampal CA1 area of methamphetamine-induced conditioned place preference rats.

    PubMed

    Liu, Wei; Peng, Qiu-Xian; Lin, Xiao-Liang; Luo, Chao-Hua; Jiang, Ming-Jin; Mo, Zhi-Xian; Yung, Ken Kin-Lam

    2014-01-01

    To explore the effect of rhynchophylline (Rhy) on the expression of p-CREB and c-Fos in the striatum and hippocampal CA1 area of methamphetamine-induced conditioned place preference (CPP) rat, methamphetamine (2 mg/kg) was injected to rats and the conditioned place preference was observed in these rats treated with or without Rhy. An immunohistochemistry assay was used to determine the expression of p-CREB and c-Fos in the striatum and hippocampal CA1 area. Methamphetamine induced significant behavior alteration in CPP, while after pretreatment with rhynchophylline or ketamine, the time of staying in methamphetamine-paired compartment of rats was significantly reduced. Methamphetamine also increased the number of p-CREB positive cells in the striatum and hippocampal CA1 zone, as well as p-Fos positive cells. However, the compound Rhy could attenuate the effect. These findings show that Rhy can suppress the acquisition of CPP in rats induced by methamphetamine and the action may be related with the reduced expression of p-CREB and p-Fos in the striatum and hippocampus.

  9. Growth hormone induces expression of c-jun and jun B oncogenes and employs a protein kinase C signal transduction pathway for the induction of c-fos oncogene expression.

    PubMed

    Slootweg, M C; de Groot, R P; Herrmann-Erlee, M P; Koornneef, I; Kruijer, W; Kramer, Y M

    1991-04-01

    Although the structure of several members of the GH receptor family has been defined, signal transduction following GH binding to its receptor has not been elucidated. Mouse osteoblasts were used to study the effect of GH on immediate early gene expression and, subsequently, the cellular signal(s) mediating this expression were analysed. GH rapidly and transiently induced the expression of c-jun and jun B in concert with the already reported expression of c-fos. The GH-induced expression of c-fos was completely blocked by the protein kinase inhibitors staurosporine and H7, indicating that the action of GH is mediated by one or several protein kinases. We next analysed the identity of the putative protein kinases in more detail by using a more specific protein kinase inhibitor, namely the ether-lipid 1-O-alkyl-2-O-methylglycerol, understood to be an inhibitor of protein kinase C (PKC). Data obtained from these studies revealed that GH-induced expression of c-fos is mediated by PKC. In addition, we observed a profound increase in formation of the PKC activator diacyglycerol upon addition of GH, a natural activator of PKC. In conclusion, upon binding of GH to mouse osteoblasts, the receptor-mediated cellular signal involves diacyglycerol formation and activation of PKC, leading to the induction of oncogene expression. Finally, the expression of c-fos, c-jun and jun B results in an increased binding of protein complexes to AP-1 binding sites.

  10. Fos-like protein is induced in neurons of the medulla oblongata after stimulation of the carotid sinus nerve in awake and anesthetized rats.

    PubMed

    Erickson, J T; Millhorn, D E

    1991-12-13

    The protooncogene c-fos is expressed rapidly, transiently and polysynaptically within neurons in response to synaptic activation and voltage-gated calcium entry into the cell. The nuclear protein product of this gene (Fos) is detectable immunohistochemically 20-90 min after cell activation and remains within the nucleus for hours after expression. The present study was undertaken to identify cells within the rat medulla oblongata that express Fos-like protein in response to stimulation of afferent fibers of the carotid sinus nerve (CSN). Direct electrical stimulation of the CSN in anesthetized animals or hypoxic stimulation in either anesthetized or awake animals resulted in a consistent and discrete distribution of Fos-like immunoreactivity (Fos-LI). Fos-LI was observed bilaterally within nucleus tractus solitarius (NTS) and the ventrolateral medulla (VLM), within area postrema and nucleus raphe pallidus, and bilaterally along the ventral medullary surface. Unstimulated animals were devoid of Fos-LI within the medulla oblongata. Furthermore, neither the surgical preparations alone nor the effects of anesthesia could account for the extent of Fos-LI observed. We believe these cells represent second- and higher-order neurons within the baroreceptor and chemoreceptor reflex pathways. PMID:1815818

  11. Physiological roles revealed by ghrelin and ghrelin receptor deficient mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ghrelin is a hormone made in the stomach and known primarily for its growth hormone releasing and orexigenic properties. Nevertheless, ghrelin through its receptor, the GHS-R1a, has been shown to exert many roles including regulation of glucose homeostasis, memory & learning, food addiction and neur...

  12. Ghrelin protects infarcted myocardium by induction of autophagy and AMP-activated protein kinase pathway.

    PubMed

    Yuan, Ming-Jie; Kong, Bin; Wang, Tao; Wang, Xin; Huang, He; Maghsoudi, Taneen

    2016-08-01

    The majority of studies have reported that enhancing autophagy in the myocardium is cardioprotective. Here, we tested the hypothesis that ghrelin, a growth hormone-releasing peptide, will protect infarcted myocardium by inducing of autophagy. Myocardial infarction was induced in mice by left coronary artery ligation the surviving mice 24 h after surgical were started on 2 week treatments with one of the following: vehicle, acylated ghrelin(50 mg/kg per day) or acylated ghrelin plus 3-MA(an autophagy inhibitor, 15 mg/kg, per day). We found that ghrelin significantly improved the cardiac function, and autophagy was enhanced by elevated LC3-II/LC-I ratio and mRNA expression of autophagy related protein. In vitro, cultured neonatal rat ventricular cardiomyocytes were subjected to simulate ischemia/reperfusion, 3-MA significantly attenuated ghrelin-induced autophagy, which was associated with activated AMP-activated protein kinase (AMPK) signal pathway. Moreover, ghrelin reduced cell death, and RNAi-mediated knockdown of autophagy protein 5 (Atg5) partly abolished ghrelin's cardioprotective effect. It is the first time to demonstrate that the cardioprotective effect of ghrelin on ischemia myocardium in part through regulating of autophagy signal pathway. PMID:27235554

  13. Caloric restriction stimulates autophagy in rat cortical neurons through neuropeptide Y and ghrelin receptors activation

    PubMed Central

    Carmo-Silva, Sara; Botelho, Mariana; de Almeida, Luís Pereira; Cavadas, Cláudia

    2016-01-01

    Caloric restriction is an anti-aging intervention known to extend lifespan in several experimental models, at least in part, by stimulating autophagy. Caloric restriction increases neuropeptide Y (NPY) in the hypothalamus and plasma ghrelin, a peripheral gut hormone that acts in hypothalamus to modulate energy homeostasis. NPY and ghrelin have been shown to be neuroprotective in different brain areas and to induce several physiological modifications similar to those induced by caloric restriction. However, the effect of NPY and ghrelin in autophagy in cortical neurons is currently not known. Using a cell culture of rat cortical neurons we investigate the involvement of NPY and ghrelin in caloric restriction-induced autophagy. We observed that a caloric restriction mimetic cell culture medium stimulates autophagy in rat cortical neurons and NPY or ghrelin receptor antagonists blocked this effect. On the other hand, exogenous NPY or ghrelin stimulate autophagy in rat cortical neurons. Moreover, NPY mediates the stimulatory effect of ghrelin on autophagy in rat cortical neurons. Since autophagy impairment occurs in aging and age-related neurodegenerative diseases, NPY and ghrelin synergistic effect on autophagy stimulation may suggest a new strategy to delay aging process. PMID:27441412

  14. Morphine-induced conditioned place preference and the alterations of p-ERK, p-CREB and c-fos levels in hypothalamus and hippocampus: the effects of physical stress.

    PubMed

    Pahlevani, P; Fatahi, Z; Moradi, M; Haghparast, A

    2014-12-08

    The hypothalamus and hippocampus are important areas involved in stress responses and reward processing. In addition, ERK/CREB pathway plays a critical role in the control of cellular responses to stress and reward. In the current study, effects of acute and subchronic stress on the alteration of p-ERK, p-CREB and c-fos levels in the hypothalamus and hippocampus of saline- or morphine-treated animals during morphine-induced conditioned place preference (CPP) procedure were investigated. Male Wistar rats were divided into two saline- and morphine-treated supergroups. Each supergroup includes of control, acute stress and subchronic stress groups. In all of groups, the CPP procedure was done, afterward the alternation of p-ERK/ERK ratio, p-CREB/CREB ratio and c-fos level in the hypothalamus and hippocampus were estimated by Western blot analysis. The results indicated that in saline- or morphine-treated animals, p-ERK/ERK ratio, p-CREB/CREB ratio and c-fos level increased after application of acute and subchronic stress (except for p-ERK/ERK ratio in morphine-control group). Our findings revealed that in saline- or morphine-treated animals, acute and subcronic stress increased the p-ERK/ERK ratio, p-CREB/CREB ratio and c-fos level in the hypothalamus and hippocampus and this enhancement in morphine-treated animals, was more considerable than that in saline-treated animals.

  15. FosB null mutant mice show enhanced methamphetamine neurotoxicity: potential involvement of FosB in intracellular feedback signaling and astroglial function.

    PubMed

    Kuroda, Kumi O; Ornthanalai, Veravej G; Kato, Tadafumi; Murphy, Niall P

    2010-02-01

    Previous studies show that (1) two members of fos family transcription factors, c-Fos and FosB, are induced in frontal brain regions by methamphetamine; (2) null mutation of c-Fos exacerbates methamphetamine-induced neurotoxicity; and (3) null mutation of FosB enhances behavioral responses to cocaine. Here we sought a role of FosB in responses to methamphetamine by studying FosB null mutant (-/-) mice. After a 10 mg/kg methamphetamine injection, FosB(-/-) mice were more prone to self-injury. Concomitantly, the intracellular feedback regulators of Sprouty and Rad-Gem-Kir (RGK) family transcripts had lower expression profiles in the frontoparietal cortex and striatum of the FosB(-/-) mice. Three days after administration of four 10 mg/kg methamphetamine injections, the frontoparietal cortex and striatum of FosB(-/-) mice contained more degenerated neurons as determined by Fluoro-Jade B staining. The abundance of the small neutral amino acids, serine, alanine, and glycine, was lower and/or was poorly induced after methamphetamine administration in the frontoparietal cortex and striatum of FosB(-/-) mice. In addition, methamphetamine-treated FosB(-/-) frontoparietal and piriform cortices showed more extravasation of immunoglobulin, which is indicative of blood-brain barrier dysfunction. Methamphetamine-induced hyperthermia, brain dopamine content, and loss of tyrosine hydroxylase immunoreactivity in the striatum, however, were not different between genotypes. These data indicate that FosB is involved in thermoregulation-independent protective functions against methamphetamine neurotoxicity in postsynaptic neurons. Our findings suggest two possible mechanisms of FosB-mediated neuroprotection: one is induction of negative feedback regulation within postsynaptic neurons through Sprouty and RGK. Another is supporting astroglial function such as maintenance of the blood-brain barrier, and metabolism of serine and glycine, which are important glial modulators of nerve cells

  16. Ghrelin and its interactions with growth hormone, leptin and orexins: implications for the sleep-wake cycle and metabolism.

    PubMed

    García-García, Fabio; Juárez-Aguilar, Enrique; Santiago-García, Juan; Cardinali, Daniel P

    2014-02-01

    Several studies have shown that ghrelin administration promotes wakefulness in rodents, while in human males it induces sleep but has no effect in women. Ghrelin also plays an important role in metabolism and appetite regulation, and as described in this review may participate in the energy balance during sleep. In this review, we summarize some of the effects induced by ghrelin administration on the sleep-wake cycle in relation to the effects of other hormones, such as growth hormone, leptin, and orexin. Finally we discuss the relationship between sleep deprivation, obesity and ghrelin secretion pattern.

  17. Sea bass ghrelin: molecular cloning and mRNA quantification during fasting and refeeding.

    PubMed

    Terova, Genciana; Rimoldi, Simona; Bernardini, Giovanni; Gornati, Rosalba; Saroglia, Marco

    2008-01-15

    Ghrelin is a novel appetite-inducing peptide hormone secreted by the stomach. The purpose of this study was first to identify the cDNA encoding sequence for ghrelin in sea bass (Dicentrarchus labrax). Using molecular cloning techniques we sequenced the cDNA corresponding to sea bass ghrelin mRNA. A total of 798 bases including a 5'-untranslated region (89 bp), an open reading frame (ORF) (324 bp), and a 3'-untranslated region (385 bp) were detected. Nucleotide sequence (ORF) encoded a 108 amino acid prepropeptide that demonstrated complete conservation of the N-terminal "biological active core" (GSSF) of the predicted mature ghrelin peptide. We also analyzed fasting-induced changes in the expression of ghrelin mRNA, using a one-tube two-temperature real-time RT-PCR with which the gene expression can be absolutely quantified using the standard curve method. Our results revealed that ghrelin was highly expressed in the stomach with much lower levels of expression in the proximal intestine and brain. Levels of ghrelin mRNA in the stomach were upregulated under conditions of negative energy balance, such as starvation, and downregulated during positive energy balance, such as refeeding. These findings offer new information about the sea bass ghrelin gene and support a role of this orexigenic hormone in the regulation of food intake in sea bass.

  18. The effect of ingested macronutrients on postprandial ghrelin response: a critical review of existing literature data.

    PubMed

    Koliaki, Chrysi; Kokkinos, Alexander; Tentolouris, Nicholas; Katsilambros, Nicholas

    2010-01-01

    Ghrelin is a powerful orexigenic gut hormone with growth hormone releasing activity. It plays a pivotal role for long-term energy balance and short-term food intake. It is also recognized as a potent signal for meal initiation. Ghrelin levels rise sharply before feeding onset, and are strongly suppressed by food ingestion. Postprandial ghrelin response is totally macronutrient specific in normal weight subjects, but is rather independent of macronutrient composition in obese. In rodents and lean individuals, isoenergetic meals of different macronutrient content suppress ghrelin to a variable extent. Carbohydrate appears to be the most effective macronutrient for ghrelin suppression, because of its rapid absorption and insulin-secreting effect. Protein induces prolonged ghrelin suppression and is considered to be the most satiating macronutrient. Fat, on the other hand, exhibits rather weak and insufficient ghrelin-suppressing capacity. The principal mediators involved in meal-induced ghrelin regulation are glucose, insulin, gastrointestinal hormones released in the postabsorptive phase, vagal activity, gastric emptying rate, and postprandial alterations in intestinal osmolarity. PMID:20798765

  19. Experimental healing of preexisting gastric ulcers induced by hormones controlling food intake ghrelin, orexin-A and nesfatin-1 is impaired under diabetic conditions. A key to understanding the diabetic gastropathy?

    PubMed

    Szlachcic, A; Majka, J; Strzalka, M; Szmyd, J; Pajdo, R; Ptak-Belowska, A; Kwiecien, S; Brzozowski, T

    2013-10-01

    Hormonal peptides like ghrelin, orexin A (OXA) or nesfatin-1 not only regulate appetite, which is their basic biological function, but also contribute to mechanisms responsible for maintaining integrity of the gastric mucosa. Previous studies including those from our laboratory have revealed that their gastroprotective effect results from cooperation with other factors responsible for protection of the gastric mucosa, including prostaglandin (PG) synthesis pathway, nitric oxide (NO) and the sensory afferent fibres releasing the vasoactive neurotransmitters. The aim of the present study was to determine whether ghrelin, orexin-A (OX-A) or nesfatin-1 with their protective effect on the gastric mucosa, also can modify the healing of chronic gastric ulcers. Furthermore, an attempt was made to explain participation of these peptides in healing processes of chronic gastric ulcers with comorbid conditions for the human beings resulted from diabetes mellitus. In our study, a model of gastric ulcers caused by concentrated acetic acid to induce the chronic gastric ulcers was used, while the clinical condition corresponding to diabetes was induced by single injection of streptozotocin (STZ). We found that ghrelin, OX-A and nesfatin-1 accelerate dynamics of the acetic acid ulcers healing, confirmed by a reduction in the ulcer area and this effect was accompanied by an increase in gastric blood flow at the ulcer margin. Destruction of sensory afferent fibres with capsaicin or blocking of vanilloid receptors with capsazepine resulted in a significant reduction of ghrelin, OX-A and nesfatin-1-induced acceleration of ulcer healing. Similar results were obtained when an NO-synthase blocker, L-NNA was used in a combination with these peptides. Moreover, it was found that OX-A and nesfatin-1 failed to accelerate the healing process under diabetic condition because both these hormones induced reduction in the ulcer area and the increase in blood flow in normal, non-diabetic rats were

  20. Cloning of a novel insulin-regulated ghrelin transcript in prostate cancer.

    PubMed

    Seim, Inge; Lubik, Amy A; Lehman, Melanie L; Tomlinson, Nadine; Whiteside, Eliza J; Herington, Adrian C; Nelson, Colleen C; Chopin, Lisa K

    2013-04-01

    Ghrelin is a multifunctional hormone, with roles in stimulating appetite and regulating energy balance, insulin secretion and glucose homoeostasis. The ghrelin gene locus (GHRL) is highly complex and gives rise to a range of novel transcripts derived from alternative first exons and internally spliced exons. The wild-type transcript encodes a 117 amino acid preprohormone that is processed to yield the 28 amino acid peptide ghrelin. Here, we identified insulin-responsive transcription corresponding to cryptic exons in intron 2 of the human ghrelin gene. A transcript, termed in2c-ghrelin (intron 2-cryptic), was cloned from the testis and the LNCaP prostate cancer cell line. This transcript may encode an 83 amino acid preproghrelin isoform that codes for ghrelin, but not obestatin. It is expressed in a limited number of normal tissues and in tumours of the prostate, testis, breast and ovary. Finally, we confirmed that in2c-ghrelin transcript expression, as well as the recently described in1-ghrelin transcript, is significantly upregulated by insulin in cultured prostate cancer cells. Metabolic syndrome and hyperinsulinaemia have been associated with prostate cancer risk and progression. This may be particularly significant after androgen deprivation therapy for prostate cancer, which induces hyperinsulinaemia, and this could contribute to castrate-resistant prostate cancer growth. We have previously demonstrated that ghrelin stimulates prostate cancer cell line proliferation in vitro. This study is the first description of insulin regulation of a ghrelin transcript in cancer and should provide further impetus for studies into the expression, regulation and function of ghrelin gene products.

  1. Ghrelin regulates cell cycle-related gene expression in cultured hippocampal neural stem cells.

    PubMed

    Chung, Hyunju; Park, Seungjoon

    2016-08-01

    We have previously demonstrated that ghrelin stimulates the cellular proliferation of cultured adult rat hippocampal neural stem cells (NSCs). However, little is known about the molecular mechanisms by which ghrelin regulates cell cycle progression. The purpose of this study was to investigate the potential effects of ghrelin on cell cycle regulatory molecules in cultured hippocampal NSCs. Ghrelin treatment increased proliferation assessed by CCK-8 proliferation assay. The expression levels of proliferating cell nuclear antigen and cell division control 2, well-known cell-proliferating markers, were also increased by ghrelin. Fluorescence-activated cell sorting analysis revealed that ghrelin promoted progression of cell cycle from G0/G1 to S phase, whereas this progression was attenuated by the pretreatment with specific inhibitors of MEK/extracellular signal-regulated kinase 1/2, phosphoinositide 3-kinase/Akt, mammalian target of rapamycin, and janus kinase 2/signal transducer and activator of transcription 3. Ghrelin-induced proliferative effect was associated with increased expression of E2F1 transcription factor in the nucleus, as determined by Western blotting and immunofluorescence. We also found that ghrelin caused an increase in protein levels of positive regulators of cell cycle, such as cyclin A and cyclin-dependent kinase (CDK) 2. Moreover, p27(KIP1) and p57(KIP2) protein levels were reduced when cell were exposed to ghrelin, suggesting downregulation of CDK inhibitors may contribute to proliferative effect of ghrelin. Our data suggest that ghrelin targets both cell cycle positive and negative regulators to stimulate proliferation of cultured hippocampal NSCs. PMID:27325242

  2. Rhythms of ghrelin, leptin, and sleep in rats: effects of the normal diurnal cycle, restricted feeding, and sleep deprivation.

    PubMed

    Bodosi, B; Gardi, J; Hajdu, I; Szentirmai, E; Obal, F; Krueger, J M

    2004-11-01

    To determine the relationships among plasma ghrelin and leptin concentrations and hypothalamic ghrelin contents, and sleep, cortical brain temperature (Tcrt), and feeding, we determined these parameters in rats in three experimental conditions: in free-feeding rats with normal diurnal rhythms, in rats with feeding restricted to the 12-h light period (RF), and in rats subjected to 5-h of sleep deprivation (SD) at the beginning of the light cycle. Plasma ghrelin and leptin displayed diurnal rhythms with the ghrelin peak preceding and the leptin peak following the major daily feeding peak in hour 1 after dark onset. RF reversed the diurnal rhythm of these hormones and the rhythm of rapid-eye-movement sleep (REMS) and significantly altered the rhythm of Tcrt. In contrast, the duration and intensity of non-REMS (NREMS) were hardly responsive to RF. SD failed to change leptin concentrations, but it promptly stimulated plasma ghrelin and induced eating. SD elicited biphasic variations in the hypothalamic ghrelin contents. SD increased plasma corticosterone, but corticosterone did not seem to influence either leptin or ghrelin. The results suggest a strong relationship between feeding and the diurnal rhythm of leptin and that feeding also fundamentally modulates the diurnal rhythm of ghrelin. The variations in hypothalamic ghrelin contents might be associated with sleep-wake activity in rats, but, unlike the previous observations in humans, obvious links could not be detected between sleep and the diurnal rhythms of plasma concentrations of either ghrelin or leptin in the rat. PMID:15475503

  3. Serotonin2C receptor stimulation inhibits cocaine-induced Fos expression and DARPP-32 phosphorylation in the rat striatum independently of dopamine outflow.

    PubMed

    Devroye, Céline; Cathala, Adeline; Maitre, Marlène; Piazza, Pier Vincenzo; Abrous, Djoher Nora; Revest, Jean-Michel; Spampinato, Umberto

    2015-02-01

    The serotonin(2C) receptor (5-HT(2C)R) is known to control dopamine (DA) neuron function by modulating DA neuronal firing and DA exocytosis at terminals. Recent studies assessing the influence of 5-HT(2C)Rs on cocaine-induced neurochemical and behavioral responses have shown that 5-HT2CRs can also modulate mesoaccumbens DA pathway activity at post-synaptic level, by controlling DA transmission in the nucleus accumbens (NAc), independently of DA release itself. A similar mechanism has been proposed to occur at the level of the nigrostriatal DA system. Here, using in vivo microdialysis in freely moving rats and molecular approaches, we assessed this hypothesis by studying the influence of the 5-HT(2C)R agonist Ro 60-0175 on cocaine-induced responses in the striatum. The intraperitoneal (i.p.) administration of 1 mg/kg Ro 60-0175 had no effect on the increase in striatal DA outflow induced by cocaine (15 mg/kg, i.p.). Conversely, Ro 60-0175 inhibited cocaine-induced Fos immunoreactivity and phosphorylation of the DA and c-AMP regulated phosphoprotein of Mr 32 kDa (DARPP-32) at threonine 75 residue in the striatum. Finally, the suppressant effect of Ro 60-0175 on cocaine-induced DARPP-32 phosphorylation was reversed by the selective 5-HT(2C)R antagonist SB 242084 (0.5 mg/kg, i.p.). In keeping with the key role of DARPP-32 in DA neurotransmission, our results demonstrate that 5-HT(2C)Rs are capable of modulating nigrostriatal DA pathway activity at post-synaptic level, by specifically controlling DA signaling in the striatum. PMID:25446572

  4. Stress-Induced Changes In C-Fos And Corticotropin Releasing Hormone Immunoreactivity In The Amygdala Of The Spontaneously Hypertensive Rat

    PubMed Central

    Porter, Karen; Hayward, Linda F

    2010-01-01

    The present study was undertaken to test the hypothesis that dysregulation of the amygdala contributes to the exaggerated autonomic response to stress in an animal model of essential hypertension. Spontaneously hypertensive (SHR) and normotensive Wistar male rats were chronically instrumented and exposed to 20 min of either air jet stress (AJS) or air noise alone (CON). AJS induced a significant increase in both heart rate and arterial pressure that was greater in the SHR. AJS induced a significant increase in c-Fos-like immunoreactivity (FLI) throughout the caudal-rostral extent of the basolateral, medial, and central (CEA) subnuclei of the amygdala. Differences in FLI between strains were localized to the rostral CEA and the SHR expressed significantly less FLI. AJS also induced a significant increase in the number of corticotrophin releasing hormone (CRH) positive neurons in the CEA. Differences between strains were localized to the caudal CEA and the number of CRH-positive cells was significantly greater in the SHR. The stress-induced increase in CRH-labeling in caudal CEA of the SHR was coupled to a greater increase in FLI in the rostral locus coeruleus (LC) of the SHR versus the Wistar. AJS also induced significant increases in FLI in several hypothalamus subnuclei, but no strain-related differences were identified. These results suggest for the first time that dysregulation of CRH-positive cells in the caudal CEA and reduced excitation and/or exaggerated inhibition of rostral CEA neurons may contribute to the exaggerated cardiovascular response to stress in the SHR, possibly through descending modulation of the rostral LC. PMID:20832430

  5. Ghrelin O-acyltransferase (GOAT) and energy metabolism.

    PubMed

    Li, Ziru; Mulholland, Michael; Zhang, Weizhen

    2016-03-01

    Ghrelin O-acyltransferase (GOAT), a member of MBOATs family, is essential for octanoylation of ghrelin, which is required for active ghrelin to bind with and activate its receptor. GOAT is expressed mainly in the stomach, pancreas and hypothalamus. Levels of GOAT are altered by energy status. GOAT contains 11 transmembrane helices and one reentrant loop. Its invariant residue His-338 and conserved Asn-307 are located in the endoplasmic reticulum lumen and cytosol respectively. GOAT contributes to the regulation of food intake and energy expenditure, as well as glucose and lipids homeostasis. Deletion of GOAT blocks the acylation of ghrelin leading to subsequent impairment in energy homeostasis and survival when mice are challenged with high energy diet or severe caloric restriction. GO-CoA-Tat, a peptide GOAT inhibitor, attenuates acyl-ghrelin production and prevents weight gain induced by a medium-chain triglycerides-rich high fat diet. Further, GO-CoA-Tat increases glucose- induced insulin secretion. Overall, inhibition of GOAT is a novel strategy for treatment of obesity and related metabolic disorders. PMID:26732975

  6. Sickness behaviour after lipopolysaccharide treatment in ghrelin deficient mice.

    PubMed

    Szentirmai, Éva; Krueger, James M

    2014-02-01

    Ghrelin is an orexigenic hormone produced mainly by the gastrointestinal system and the brain. Much evidence also indicates a role for ghrelin in sleep and thermoregulation. Further, ghrelin was recently implicated in immune system modulation. Administration of bacterial lipopolysaccharide (LPS) induces fever, anorexia, and increased non-rapid-eye movement sleep (NREMS) and these actions are mediated primarily by proinflammatory cytokines. Ghrelin reduces LPS-induced fever, suppresses circulating levels of proinflammatory cytokines and reduces the severity and mortality of various models of experimental endotoxemia. In the present study, we determined the role of intact ghrelin signaling in LPS-induced sleep, feeding, and thermoregulatory responses in mice. Sleep-wake activity was determined after intraperitoneal, dark onset administration of 0.4, 2 and 10 μg LPS in preproghrelin knockout (KO) and wild-type (WT) mice. In addition, body temperature, motor activity and changes in 24-h food intake and body weight were measured. LPS induced dose-dependent increases in NREMS, and suppressed rapid-eye movement sleep, electroencephalographic slow-wave activity, motor activity, food intake and body weight in both Ppg KO and WT mice. Body temperature changes showed a biphasic pattern with a decrease during the dark period followed by an increase in the light phase. The effects of the low and middle doses of LPS were indistinguishable between the two genotypes. Administration of 10 μg LPS, however, induced significantly larger changes in NREMS and wakefulness amounts, body temperature, food intake and body weight in the Ppg KO mice. These findings support a role for ghrelin as an endogenous modulator of inflammatory responses and a central component of arousal and feeding circuits.

  7. Sickness behaviour after lipopolysaccharide treatment in ghrelin deficient mice.

    PubMed

    Szentirmai, Éva; Krueger, James M

    2014-02-01

    Ghrelin is an orexigenic hormone produced mainly by the gastrointestinal system and the brain. Much evidence also indicates a role for ghrelin in sleep and thermoregulation. Further, ghrelin was recently implicated in immune system modulation. Administration of bacterial lipopolysaccharide (LPS) induces fever, anorexia, and increased non-rapid-eye movement sleep (NREMS) and these actions are mediated primarily by proinflammatory cytokines. Ghrelin reduces LPS-induced fever, suppresses circulating levels of proinflammatory cytokines and reduces the severity and mortality of various models of experimental endotoxemia. In the present study, we determined the role of intact ghrelin signaling in LPS-induced sleep, feeding, and thermoregulatory responses in mice. Sleep-wake activity was determined after intraperitoneal, dark onset administration of 0.4, 2 and 10 μg LPS in preproghrelin knockout (KO) and wild-type (WT) mice. In addition, body temperature, motor activity and changes in 24-h food intake and body weight were measured. LPS induced dose-dependent increases in NREMS, and suppressed rapid-eye movement sleep, electroencephalographic slow-wave activity, motor activity, food intake and body weight in both Ppg KO and WT mice. Body temperature changes showed a biphasic pattern with a decrease during the dark period followed by an increase in the light phase. The effects of the low and middle doses of LPS were indistinguishable between the two genotypes. Administration of 10 μg LPS, however, induced significantly larger changes in NREMS and wakefulness amounts, body temperature, food intake and body weight in the Ppg KO mice. These findings support a role for ghrelin as an endogenous modulator of inflammatory responses and a central component of arousal and feeding circuits. PMID:24309634

  8. The ghrelin/obestatin balance in the physiological and pathological control of growth hormone secretion, body composition and food intake.

    PubMed

    Hassouna, R; Zizzari, P; Tolle, V

    2010-07-01

    Ghrelin and obestatin are two gastrointestinal peptides obtained by post-translational processing of a common precursor, preproghrelin. Ghrelin is an orexigenic and adipogenic peptide and a potent growth hormone secretagogue (GHS) modified by the enzyme ghrelin-O-acyl-transferase to bind and activate its receptor, the GHS-R. The ghrelin/GHS-R pathway is complex and the effects of ghrelin on GH secretion, adiposity and food intake appear to be relayed by distinct mechanisms involving different transduction signals and constitutive activity for the GH-R, different cofactors as modulators of endogenous ghrelin signalling and/or alternative ghrelin receptors. The discovery of obestatin in 2005 brought an additional level of complexity to this fascinating system. Obestatin was initially identified as an anorexigenic peptide and as the cognate ligand for GPR39, but its effect on food intake and its ability to activate GPR39 are still controversial. Although several teams failed to reproduce the anorexigenic actions of obestatin, this peptide has been shown to antagonise GH secretion and food intake induced by ghrelin and could be an interesting pharmacological tool to counteract the actions of ghrelin. Ghrelin and obestatin immunoreactivities are recovered in the blood with an ultradian pulsatility and their concentrations in plasma vary with the nutritional status of the body. It is still a matter of debate whether both hormones are regulated by independent mechanisms and whether obestatin is a physiologically relevant peptide. Nevertheless, a significant number of studies show that the ghrelin/obestatin ratio is modified in anorexia nervosa and obesity. This suggests that the ghrelin/obestatin balance could be essential to adapt the body's response to nutritional challenges. Although measuring ghrelin and obestatin in plasma is challenging because many forms of the peptides circulate, more sensitive and selective assays to detect the different preproghrelin

  9. Effect of acute imipramine administration on the pattern of forced swim-induced c-Fos expression in the mouse brain.

    PubMed

    Yanagida, Satoru; Motomura, Keisuke; Ohashi, Ayako; Hiraoka, Kentaro; Miura, Tomofumi; Kanba, Shigenobu

    2016-08-26

    The forced swim test (FST) has been widely used for the preclinical evaluation of antidepressant drugs. Despite considerable differences in the protocol, equivalence of the FST for rats and mice has been rarely questioned. Previous research on the FST for rats revealed that repeated administration of antidepressant drugs attenuates the c-Fos response to swim stress in the hypothalamus and limbic regions. However, few studies have made similar investigations using the FST for mice. In the present study, we explored the mouse brain through immunohistochemistry staining for c-Fos after acute administration of imipramine or saline with or without a subsequent swim session. Imipramine enhanced the c-Fos density in regions of the central extended amygdala, while forced swim stress increased c-Fos expression in some hypothalamic (the ventrolateral preoptic nucleus and dorsomedial nucleus) and brain stem regions, which is consistent with previous reports. In contrast to previous literature with rats, swim stress brought a significant increase in c-Fos expression in the lateral septal nucleus and some other regions in the hypothalamus (the intermediate hypothalamic area, the paraventricular and arcuate nucleus) only in the imipramine-pretreated group, which has not been observed previously. In the arcuate nucleus, double immunostaining revealed that c-Fos was rarely co-expressed with proopiomelanocortin or tyrosine hydroxylase regardless of imipramine treatment. The present results suggest that the activation of several regions in the lateral septum and the hypothalamus underlies antidepressant-like effect in the mouse FST. PMID:27373591

  10. Ghrelin ameliorates intestinal barrier dysfunction in experimental colitis by inhibiting the activation of nuclear factor-kappa B

    SciTech Connect

    Cheng, Jian; Zhang, Lin; Dai, Weiqi; Mao, Yuqing; Li, Sainan; Wang, Jingjie; Li, Huanqing; Guo, Chuanyong; Fan, Xiaoming

    2015-02-27

    Aim: This study aimed to investigate the effect and underlying mechanism of ghrelin on intestinal barrier dysfunction in dextran sulfate sodium (DSS)-induced colitis. Methods and results: Acute colitis was induced in C57BL/6J mice by administering 2.5% DSS. Saline or 25, 125, 250 μg/kg ghrelin was administrated intraperitoneally (IP) to mice 1 day before colitis induction and on days 4, 5, and 6 after DSS administration. IP injection of a ghrelin receptor antagonist, [D-lys{sup 3}]-GHRP-6, was performed immediately prior to ghrelin injection. Ghrelin (125 or 250 μg/kg) could reduce the disease activity index, histological score, and myeloperoxidase activities in experimental colitis, and also prevented shortening of the colon. Ghrelin could prevent the reduction of transepithelial electrical resistance and tight junction expression, and bolstered tight junction structural integrity and regulated cytokine secretion. Ultimately, ghrelin inhibited nuclear factor kappa B (NF-κB), inhibitory κB-α, myosin light chain kinase, and phosphorylated myosin light chain 2 activation. Conclusions: Ghrelin prevented the breakdown of intestinal barrier function in DSS-induced colitis. The protective effects of ghrelin on intestinal barrier function were mediated by its receptor GHSR-1a. The inhibition of NF-κB activation might be part of the mechanism underlying the effects of ghrelin that protect against barrier dysfunction. - Highlights: • Ghrelin ameliorates intestinal barrier dysfunction in experimental colitis. • The effect of ghrelin is mediated by GHSR-1a. • Inhibition of NF-κB activation.

  11. Impaired wake-promoting mechanisms in ghrelin receptor-deficient mice.

    PubMed

    Esposito, Matthew; Pellinen, Jacob; Kapás, Levente; Szentirmai, Éva

    2012-01-01

    Ghrelin receptors are expressed by key components of the arousal system. Exogenous ghrelin induces behavioral activation, promotes wakefulness and stimulates eating. We hypothesized that ghrelin-sensitive mechanisms play a role in the arousal system. To test this, we investigated the responsiveness of ghrelin receptor knockout (KO) mice to two natural wake-promoting stimuli. Additionally, we assessed the integrity of their homeostatic sleep-promoting system using sleep deprivation. There was no significant difference in the spontaneous sleep-wake activity between ghrelin receptor KO and wild-type (WT) mice. WT mice mounted robust arousal responses to a novel environment and food deprivation. Wakefulness increased for 6 h after cage change accompanied by increases in body temperature and locomotor activity. Ghrelin receptor KO mice completely lacked the wake and body temperature responses to new environment. When subjected to 48 h food deprivation, WT mice showed marked increases in their waking time during the dark periods of both days. Ghrelin receptor KO mice failed to mount an arousal response on the first night and wake increases were attenuated on the second day. The responsiveness to sleep deprivation did not differ between the two genotypes. These results indicate that the ghrelin-receptive mechanisms play an essential role in the function of the arousal system but not in homeostatic sleep-promoting mechanisms.

  12. Chemosensory signalling pathways involved in sensing of amino acids by the ghrelin cell

    PubMed Central

    Vancleef, L.; Van Den Broeck, T.; Thijs, T.; Steensels, S.; Briand, L.; Tack, J.; Depoortere, I.

    2015-01-01

    Taste receptors on enteroendocrine cells sense nutrients and transmit signals that control gut hormone release. This study aimed to investigate the amino acid (AA) sensing mechanisms of the ghrelin cell in a gastric ghrelinoma cell line, tissue segments and mice. Peptone and specific classes of amino acids stimulate ghrelin secretion in the ghrelinoma cell line. Sensing of L-Phe occurs via the CaSR, monosodium glutamate via the TAS1R1-TAS1R3 while L-Ala and peptone act via 2 different amino acid taste receptors: CaSR & TAS1R1-TAS1R3 and CaSR & GPRC6A, respectively. The stimulatory effect of peptone on ghrelin release was mimicked ex vivo in gastric but not in jejunal tissue segments, where peptone inhibited ghrelin release. The latter effect could not be blocked by receptor antagonists for CCK, GLP-1 or somatostatin. In vivo, plasma ghrelin levels were reduced both upon intragastric (peptone or L-Phe) or intravenous (L-Phe) administration, indicating that AA- sensing is not polarized and is due to inhibition of ghrelin release from the stomach or duodenum respectively. In conclusion, functional AA taste receptors regulate AA-induced ghrelin release in vitro. The effects differ between stomach and jejunum but these local nutrient sensing mechanisms are overruled in vivo by indirect mechanisms inhibiting ghrelin release. PMID:26510380

  13. Chemosensory signalling pathways involved in sensing of amino acids by the ghrelin cell.

    PubMed

    Vancleef, L; Van Den Broeck, T; Thijs, T; Steensels, S; Briand, L; Tack, J; Depoortere, I

    2015-01-01

    Taste receptors on enteroendocrine cells sense nutrients and transmit signals that control gut hormone release. This study aimed to investigate the amino acid (AA) sensing mechanisms of the ghrelin cell in a gastric ghrelinoma cell line, tissue segments and mice. Peptone and specific classes of amino acids stimulate ghrelin secretion in the ghrelinoma cell line. Sensing of L-Phe occurs via the CaSR, monosodium glutamate via the TAS1R1-TAS1R3 while L-Ala and peptone act via 2 different amino acid taste receptors: CaSR &TAS1R1-TAS1R3 and CaSR &GPRC6A, respectively. The stimulatory effect of peptone on ghrelin release was mimicked ex vivo in gastric but not in jejunal tissue segments, where peptone inhibited ghrelin release. The latter effect could not be blocked by receptor antagonists for CCK, GLP-1 or somatostatin. In vivo, plasma ghrelin levels were reduced both upon intragastric (peptone or L-Phe) or intravenous (L-Phe) administration, indicating that AA- sensing is not polarized and is due to inhibition of ghrelin release from the stomach or duodenum respectively. In conclusion, functional AA taste receptors regulate AA-induced ghrelin release in vitro. The effects differ between stomach and jejunum but these local nutrient sensing mechanisms are overruled in vivo by indirect mechanisms inhibiting ghrelin release. PMID:26510380

  14. Ghrelin acts as an interface between physiological state and phasic dopamine signaling.

    PubMed

    Cone, Jackson J; McCutcheon, James E; Roitman, Mitchell F

    2014-04-01

    Brief, high-concentration (phasic) spikes in nucleus accumbens dopamine critically participate in aspects of food reward. Although physiological state (e.g., hunger, satiety) and associated hormones are known to affect dopamine tone in general, whether they modulate food-evoked, phasic dopamine specifically is unknown. Here, we used fast-scan cyclic voltammetry in awake, behaving rats to record dopamine spikes evoked by delivery of sugar pellets while pharmacologically manipulating central receptors for the gut "hunger" hormone ghrelin. Lateral ventricular (LV) ghrelin increased, while LV ghrelin receptor antagonism suppressed the magnitude of dopamine spikes evoked by food. Ghrelin was effective when infused directly into the lateral hypothalamus (LH), but not the ventral tegmental area (VTA). LH infusions were made in close proximity to orexin neurons, which are regulated by ghrelin and project to the VTA. Thus, we also investigated and found potentiation of food-evoked dopamine spikes by intra-VTA orexin-A. Importantly, intra-VTA blockade of orexin receptors attenuated food intake induced by LV ghrelin, thus establishing a behaviorally relevant connection between central ghrelin and VTA orexin. Further analysis revealed that food restriction increased the magnitude of dopamine spikes evoked by food independent of any pharmacological manipulations. The results support the regulation of food-evoked dopamine spikes by physiological state with endogenous fluctuations in ghrelin as a key contributor. Our data highlight a novel mechanism by which signals relating physiological state could influence food reinforcement and food-directed behavior. PMID:24695709

  15. Voluntary exercise contributed to an amelioration of abnormal feeding behavior, locomotor activity and ghrelin production concomitantly with a weight reduction in high fat diet-induced obese rats.

    PubMed

    Mifune, Hiroharu; Tajiri, Yuji; Nishi, Yoshihiro; Hara, Kento; Iwata, Shimpei; Tokubuchi, Ichiro; Mitsuzono, Ryouichi; Yamada, Kentaro; Kojima, Masayasu

    2015-09-01

    In the present study, effects of voluntary exercise in an obese animal model were investigated in relation to the rhythm of daily activity and ghrelin production. Male Sprague-Dawley rats were fed either a high fat diet (HFD) or a chow diet (CD) from four to 16 weeks old. They were further subdivided into either an exercise group (HFD-Ex, CD-Ex) with a running wheel for three days of every other week or sedentary group (HFD-Se, CD-Se). At 16 weeks old, marked increases in body weight and visceral fat were observed in the HFD-Se group, together with disrupted rhythms of feeding and locomotor activity. The induction of voluntary exercise brought about an effective reduction of weight and fat, and ameliorated abnormal rhythms of activity and feeding in the HFD-Ex rats. Wheel counts as voluntary exercise was greater in HFD-Ex rats than those in CD-Ex rats. The HFD-obese had exhibited a deterioration of ghrelin production, which was restored by the induction of voluntary exercise. These findings demonstrated that abnormal rhythms of feeding and locomotor activity in HFD-obese rats were restored by infrequent voluntary exercise with a concomitant amelioration of the ghrelin production and weight reduction. Because ghrelin is related to food anticipatory activity, it is plausible that ghrelin participates in the circadian rhythm of daily activity including eating behavior. A beneficial effect of voluntary exercise has now been confirmed in terms of the amelioration of the daily rhythms in eating behavior and physical activity in an animal model of obesity.

  16. Des-acyl ghrelin prevents heatstroke-like symptoms in rats exposed to high temperature and high humidity.

    PubMed

    Inoue, Yoshiyuki; Hayashi, Yujiro; Kangawa, Kenji; Suzuki, Yoshihiro; Murakami, Noboru; Nakahara, Keiko

    2016-02-26

    We have shown previously that des-acyl ghrelin decreases body temperature in rats through activation of the parasympathetic nervous system. Here we investigated whether des-acyl ghrelin ameliorates heatstroke in rats exposed to high temperature. Peripheral administration of des-acyl ghrelin significantly attenuated hyperthermia induced by exposure to high-temperature (35°C) together with high humidity (70-80%). Although biochemical analysis revealed that exposure to high temperature significantly increased hematocrit and the serum levels of aspartate amino transferase (AST), alanine transaminase (ALT), blood urea nitrogen (BUN), creatinine and electrolytes (Na(+), K(+), Cl(-)), most of these heatstroke-associated reactions were significantly reduced by treatment with des-acyl ghrelin. The level of des-acyl ghrelin in plasma was also found to be significantly increased under high-temperature conditions. These results suggest that des-acyl ghrelin could be useful for preventing heatstroke under high temperature condition. PMID:26773867

  17. Des-acyl ghrelin prevents heatstroke-like symptoms in rats exposed to high temperature and high humidity.

    PubMed

    Inoue, Yoshiyuki; Hayashi, Yujiro; Kangawa, Kenji; Suzuki, Yoshihiro; Murakami, Noboru; Nakahara, Keiko

    2016-02-26

    We have shown previously that des-acyl ghrelin decreases body temperature in rats through activation of the parasympathetic nervous system. Here we investigated whether des-acyl ghrelin ameliorates heatstroke in rats exposed to high temperature. Peripheral administration of des-acyl ghrelin significantly attenuated hyperthermia induced by exposure to high-temperature (35°C) together with high humidity (70-80%). Although biochemical analysis revealed that exposure to high temperature significantly increased hematocrit and the serum levels of aspartate amino transferase (AST), alanine transaminase (ALT), blood urea nitrogen (BUN), creatinine and electrolytes (Na(+), K(+), Cl(-)), most of these heatstroke-associated reactions were significantly reduced by treatment with des-acyl ghrelin. The level of des-acyl ghrelin in plasma was also found to be significantly increased under high-temperature conditions. These results suggest that des-acyl ghrelin could be useful for preventing heatstroke under high temperature condition.

  18. The NR2B antagonist, ifenprodil, corrects the l-DOPA-induced deficit of bilateral movement and reduces c-Fos expression in the subthalamic nucleus of hemiparkinsonian rats.

    PubMed

    Igarashi, Masakazu; Habata, Toshiya; Akita, Hisanao; Noda, Kazuko; Ogata, Masanori; Saji, Makoto

    2015-07-01

    The use of NR2B antagonists in Parkinsonism is still controversial. To examine their anti-parkinsonian effects, the NR2B antagonist, ifenprodil, and L-DOPA were administered together and separately in hemiparkinsonian rats (hemi-PD) that were subjected to a cylinder test. Recovery from hypoactivity was achieved by single administration of 3-7 mg/kg of L-DOPA; however, improvement in the deficit of bilateral forelimb use was not observed. When administered alone, ifenprodil had no anti-parkinsonian effects; however, combined administration of ifenprodil and 7 mg/kg of L-DOPA significantly reversed the deficit of bilateral forelimb use without adversely affecting the L-DOPA-induced improvement in motor activity. Next, in order to identify the brain area influenced by L-DOPA and ifenprodil, quantitative analysis of L-DOPA-induced c-Fos immunoreactivity was performed in various brain areas of hemi-PD following administration of L-dopa with and without ifenprodil. Among brain areas with robust c-Fos expression within the motor loop circuit in dopamine-depleted hemispheres, co-administered ifenprodil markedly attenuated L-DOPA-induced c-Fos expression in only the subthalamic nucleus (STN), suggesting that the STN is the primary target for the anti-parkinsonian action of NR2B antagonists.

  19. The ether lipid 1-octadecyl-2-methyl-rac-glycero-3-phosphocholine induces expression of fos and jun proto-oncogenes and activates AP-1 transcription factor in human leukaemic cells.

    PubMed Central

    Mollinedo, F; Gajate, C; Modolell, M

    1994-01-01

    The ether lipid analogue 1-octadecyl-2-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) has been recently shown to induce apoptosis in the human leukaemic HL-60 and U937 myeloid cell lines [Mollinedo, Martinez-Dalmau and Modolell (1993) Biochem. Biophys. Res. Commun. 192, 603-609]. We have found that ET-18-OCH3 is also able to promote apoptosis in the human leukaemic Jurkat T lymphoid cell line. This lymphoid cell line as well as the two myeloid HL-60 and U937 cell lines incorporated significant amounts of exogenously added radiolabelled ET-18-OCH3. Addition of ET-18-OCH3 to these human leukaemic cells induced an increase in the steady-state mRNA levels of fos and jun proto-oncogenes, components of the transcription factor AP-1. These increases in fos and jun mRNA levels were associated with the activation of the AP-1 transcription factor after addition of ET-18-OCH3 to human leukaemic cells, as assessed by an enhanced binding activity of transcription factor AP-1 to its cognate DNA sequence as well as by stimulation of transcription from an AP-1 enhancer element. These data demonstrate that the ether lipid ET-18-OCH3 can affect gene expression by inducing expression of fos and jun proto-oncogenes and by modulating the activity of transcription factor AP-1. Images Figure 2 Figure 3 Figure 4 PMID:8092982

  20. Ginkgo biloba Extract (EGb 761®) Inhibits Glutamate-induced Up-regulation of Tissue Plasminogen Activator Through Inhibition of c-Fos Translocation in Rat Primary Cortical Neurons.

    PubMed

    Cho, Kyu Suk; Lee, Ian Myungwon; Sim, Seobo; Lee, Eun Joo; Gonzales, Edson Luck; Ryu, Jong Hoon; Cheong, Jae Hoon; Shin, Chan Young; Kwon, Kyoung Ja; Han, Seol-Heui

    2016-01-01

    EGb 761(®) , a standardized extract of Ginkgo biloba leaves, has antioxidant and antiinflammatory properties in experimental models of neurodegenerative disorders such as stroke and Alzheimer's disease. Tissue plasminogen activator (tPA) acts a neuromodulator and plays a crucial role in the manifestation of neurotoxicity leading to exaggerated neuronal cell death in neurological insult conditions. In this study, we investigated the effects of EGb 761 on the basal and glutamate-induced activity and expression of tPA in rat primary cortical neurons. Under basal condition, EGb 761 inhibited both secreted and cellular tPA activities, without altering tPA mRNA level, as modulated by the activation of p38. Compared with basal condition, EGb 761 inhibited the glutamate-induced up-regulation of tPA mRNA resulting in the normalization of overt tPA activity and expression. c-Fos is a component of AP-1, which plays a critical role in the modulation of tPA expression. Interestingly, EGb 761 inhibited c-Fos nuclear translocation without affecting c-Fos expression in glutamate-induced rat primary cortical neurons. These results demonstrated that EGb 761 can modulate tPA activity under basal and glutamate-stimulated conditions by both translational and transcriptional mechanisms. Thus, EGb 761 could be a potential and effective therapeutic strategy in tPA-excessive neurotoxic conditions.

  1. Ghrelin does not affect gastrointestinal contractility in rainbow trout and goldfish in vitro.

    PubMed

    Kitazawa, Takio; Itoh, Kentaro; Yaosaka, Noriko; Maruyama, Keisuke; Matsuda, Kouhei; Teraoka, Hiroki; Kaiya, Hiroyuki

    2012-09-15

    Ghrelin has been identified in rainbow trout and goldfish, and it has been shown to regulate growth hormone release and food intake in these species as seen in mammals. The aim of this study was to investigate the functional role of ghrelin in regulation of gastrointestinal contractility in both fishes. Neither rainbow trout ghrelin nor rat ghrelin affected the contractility of gastrointestinal strips of rainbow trout. Similarly, goldfish ghrelin-17 and rat ghrelin did not cause marked contraction in the goldfish intestinal bulb. Detail examinations using the goldfish intestine revealed that human neurotensin, substance-P, goldfish neuromedine-U and carbachol showed apparent contractile activities in the intestinal strips. Electrical field stimulation (EFS, 1-20 Hz) caused a frequency-dependent contraction of the intestinal bulb. Atropine partially inhibited and tetrodotoxin abolished the EFS-induced contraction. Pretreatments with goldfish ghrelin-17 and rat ghrelin did not modify the EFS-induced contraction. The mRNAs of two types of growth hormone secretagogue receptor (GHS-R), GHS-R1a-1 and GHS-R1a-2, were detected in the goldfish intestine, and the expression level of GHS-R1a-2 was 4-times higher than that of GHS-R1a-1. The expression levels of GHS-R1a-1 and GHS-R1a-2 in four regions of the goldfish intestine (intestinal bulb, intestine-1, intestine-2 and intestine-3) were almost the same. In conclusion, ghrelin does not affect gastrointestinal contractility of the rainbow trout and goldfish, although GHSR-like receptor/GHS-R1a is expressed entire intestine. These results suggest diversity of ghrelin function in vertebrates.

  2. On the central mechanism underlying ghrelin's chronic pro-obesity effects in rats: new insights from studies exploiting a potent ghrelin receptor antagonist.

    PubMed

    Salomé, N; Hansson, C; Taube, M; Gustafsson-Ericson, L; Egecioglu, E; Karlsson-Lindahl, L; Fehrentz, J A; Martinez, J; Perrissoud, D; Dickson, S L

    2009-09-01

    In the present study, we explore the central nervous system mechanism underlying the chronic central effects of ghrelin with respect to increasing body weight and body fat. Specifically, using a recently developed ghrelin receptor antagonist, GHS-R1A (JMV2959), we investigate the role of GHS-R1A in mediating the effects of ghrelin on energy balance and on hypothalamic gene expression. As expected, in adult male rats, chronic central treatment with ghrelin for 14 days, when compared to vehicle-treated control rats, resulted in an increased body weight, lean mass and fat mass (assessed by dual X-ray absorptiometry), dissected white fat pad weight, cumulative food intake, food efficiency, respiratory exchange ratio and a decrease of energy expenditure. Co-administration of the ghrelin receptor antagonist JMV2959 suppressed/blocked the majority of these effects, with the notable exception of ghrelin-induced food intake and food efficiency. The hypothesis emerging from these data, namely that GHS-R1A mediates the chronic effects of ghrelin on fat accumulation, at least partly independent of food intake, is discussed in light of the accompanying data regarding the hypothalamic genes coding for peptides and receptors involved in energy balance regulation, which were found to have altered expression in these studies.

  3. Ghrelin and the cardiovascular system.

    PubMed

    Isgaard, Jörgen

    2013-01-01

    Although ghrelin was initially associated with regulation of appetite, the cardiovascular system has also been recognized as a potentially important target for its effects. Moreover, experimental and a limited number of clinical studies suggest a potential role for ghrelin in the treatment of congestive heart failure. So far, reported cardiovascular effects of growth hormone secretagogues and/or ghrelin include lowering of peripheral resistance, either direct at the vascular level and/or by modulating sympathetic nervous activity. Other observed effects indicate possible improvement of contractility and cardioprotective and anti-inflammatory effects both in vivo and in vitro. Taken together, these results offer an interesting perspective on the future where further studies aiming at evaluating a role of growth hormone secretagogues and ghrelin in the treatment of cardiovascular disease are warranted.

  4. Biochemical and histopathological evaluations of ghrelin effects following cadmium toxicity in the rat testis.

    PubMed

    Kheradmand, A; Alirezaei, M; Dezfoulian, O

    2015-08-01

    Numerous reports demonstrate that cadmium (Cd) induces oxidative stress by increasing lipid peroxidation and altering antioxidative enzymes status. Thirty male rats were subdivided into control-saline, Cd-saline and Cd-ghrelin groups. A single dose of Cd was injected to induce testicular injury and also ghrelin for 10 consecutive days to group 3. SOD activity decreased and lipid peroxidation increased by Cd administration. The mean activities of GPx and CAT as well as GSH content were lower in the Cd-saline rats; however, they did not statistically differ compared with the controls. Exposure to Cd resulted in complete degeneration of seminiferous tubules with severe depletion of germ cells and arrest in spermatogenesis. Notably, ghrelin treatment not only prevented reduction in SOD, GPx, CAT and GSH level, but also increased enzyme activities form their normal values. Moreover, TBARS concentration was significantly reduced by ghrelin administration. Furthermore, ghrelin pre-treatment resulted in partial but not significant prevention in testicular histopathological features damaged by Cd. In conclusion, the obtained results indicate for the first time the novel evidences of ghrelin ability in promotion of antioxidant enzyme activities and reduction of lipid peroxidation following Cd-induced oxidative stress in the rat testis. These observations also demonstrate that ghrelin may be considered as promising antioxidant agent in prevention and attenuation of testicular injury upon Cd toxicity. PMID:25059551

  5. Light pulses do not induce c-fos or per1 in the SCN of hamsters that fail to reentrain to the photocycle.

    PubMed

    Barakat, Monique T; O'Hara, Bruce F; Cao, Vinh H; Larkin, Jennie E; Heller, H Craig; Ruby, Norman F

    2004-08-01

    Circadian activity rhythms of most Siberian hamsters (Phodopus sungorus sungorus) fail to reentrain to a 5-h phase shift of the light-dark (LD) cycle. Instead, their rhythms free-run at periods close to 25 h despite the continued presence of the LD cycle. This lack of behavioral reentrainment necessarily means that molecular oscillators in the master circadian pacemaker, the SCN, were unable to reentrain as well. The authors tested the hypothesis that a phase shift of the LD cycle rendered the SCN incapable of responding to photic input. Animals were exposed to a 5-h phase delay of the photocycle, and activity rhythms were monitored until a lack of reentrainment was confirmed. Hamsters were then housed in constant darkness for 24 h and administered a 30-min light pulse 2 circadian hours after activity onset. Brains were then removed, and tissue sections containing the SCN were processed for in situ hybridization. Sections were probed with Siberian hamster c-fos and per1 mRNA probes because light rapidly induces these 2 genes in the SCN during subjective night but not at other circadian phases. Light pulses induced robust expression of both genes in all animals that reentrained to the LD cycle, but no expression was observed in any animal that failed to reentrain. None of the animals exhibited an intermediate response. This finding is the first report of acute shift in a photocycle eliminating photosensitivity in the SCN and suggests that a specific pattern of light exposure may desensitize the SCN to subsequent photic input.

  6. Ghrelin and anterior pituitary function.

    PubMed

    Lanfranco, Fabio; Motta, Giovanna; Baldi, Matteo; Gasco, Valentina; Grottoli, Silvia; Benso, Andrea; Broglio, Fabio; Ghigo, Ezio

    2010-01-01

    Ghrelin, a 28-amino-acid octanoylated peptide predominantly produced by the stomach, was discovered to be the natural ligand of the type 1a GH secretagogue receptor. Thus, it was considered as a natural GH secretagogue (GHS) additional to GHRH, although later on ghrelin has mostly been considered a major orexigenic factor. The GH-releasing action of ghrelin takes place both directly on pituitary cells and through modulation of GHRH from the hypothalamus; some functional anti-somatostatin action has also been shown. However, even at the neuroendocrine level, ghrelin is much more than a natural GHS. In fact, it significantly stimulates prolactin secretion in humans, independent of both gender and age and probably involving a direct action on somatomammotroph cells. Above all, ghrelin and synthetic GHS possess an acute stimulatory effect on the activity of the hypothalamus-pituitary-adrenal axis in humans, which is, at least, similar to that of the opioid antagonist naloxone, arginine vasopressin and even corticotropin-releasing hormone. Also, ghrelin plays a relevant role in the modulation of the hypothalamic-pituitary-gonadal function, with a predominantly CNS-mediated inhibitory effect upon the gonadotropin pulsatility both in animals and in humans.

  7. LPS-induced c-Fos activation in NTS neurons and plasmatic cortisol increases in septic rats are suppressed by bilateral carotid chemodenervation.

    PubMed

    Reyes, Edison-Pablo; Abarzúa, Sebastián; Martin, Aldo; Rodríguez, Jorge; Cortés, Paula P; Fernández, Ricardo

    2012-01-01

    Lipopolysaccharide (LPS) administered I.P. increases significantly the activation of c-Fos in neurons of the nucleus of the solitary tract (NTS), which in turn activates hypothalamus-pituitary-adrenal axis. The vagus nerve appears to play a role in conveying cytokines signals to the central nervous system (CNS), since -in rodent models of sepsis- bilateral vagotomy abolishes increases in plasmatic glucocorticoid levels, but does not suppress c-Fos NTS activation. Considering that NTS also receives sensory inputs from carotid body chemoreceptors, we evaluated c-Fos activation and plasmatic cortisol levels 90 min after I.P. administration of 15 mg/kg LPS. Experiments were performed in male Sprague-Dawley rats, in control conditions and after bilateral carotid neurotomy (BCN). LPS administration significantly increases the number of c-Fos positive NTS neurons and plasmatic cortisol levels in animals with intact carotid/sinus nerves. When LPS was injected after BCN, the number of c-Fos positive NTS neurons, and plasmatic cortisol levels were not significantly modified. Our data suggest that carotid body chemoreceptors might mediate CNS activation during sepsis.

  8. Schizothorax davidi ghrelin: cDNA cloning, tissue distribution and indication for its stimulatory character in food intake.

    PubMed

    Zhou, Chaowei; Zhang, Xingdong; Liu, Tao; Wei, Rongbin; Yuan, Dengyue; Wang, Tao; Lin, Fangjun; Wu, Hongwei; Chen, Fu; Yang, Shiyong; Chen, Defang; Wang, Yan; Li, Zhiqiong

    2014-01-15

    Ghrelin is a gut/brain hormone with a unique acyl modification and various biological functions in fish and mammals. The objectives of this project were to identify ghrelin gene organization, study tissue specific ghrelin mRNA expression and investigate the short- (0, 0.5, 1.5, 3, 6, 9, 12h post-fasting) and long- (1, 3, 5, 7 days) term fasting as well as refeeding after a 7 day fasting induced changes in the expression of ghrelin mRNA in Schizothorax davidi. Our reverse transcription polymerase chain reaction analysis confirmed the predicted ghrelin sequence available in the GenBank and identified ghrelin mRNA expression in several tissues including the gut, liver, brain, heart, spleen, head kidney, gill and muscle. Quantitative PCR studies indicated that the expression level of ghrelin mRNA presented ascendant trend in short-term fasting group compared to the fed group, but it did not reach the significant level on statistics, while there is a significant increase in ghrelin mRNA expression in the gut of Schizothorax davidi fasted for 3, 5 and 7 days when compared to the expression in ad libitum fed fish. Refeeding after a 7 day fasting caused a significant and dramatic decrease in ghrelin mRNA expression in the gut of Schizothorax davidi. An increase in the expression of ghrelin mRNA during fasting, and its decrease following refeeding suggests an orexigenic role for ghrelin in Schizothorax davidi. Overall, our results provide evidence for a highly conserved structure and biological actions of ghrelin during evolution.

  9. Systemic 5-Bromo-2-Deoxyuridine Induces Conditioned Flavor Aversion and C-Fos in the Visceral Neuraxis

    ERIC Educational Resources Information Center

    Kimbrough, Adam; Kwon, Bumsup; Eckel, Lisa A.; Houpt, Thomas A.

    2011-01-01

    5-bromo-2-deoxyuridine (BrdU) is often used in studies of adult neurogenesis and olfactory learning, but it can also have toxic effects on highly proliferative tissue. We found that pairing Kool-Aid flavors with acute systemic injections of BrdU induced strong conditioned flavor aversions. Intermittent injections during Kool-Aid-glucose…

  10. Intraportal infusion of ghrelin could inhibit glucose-stimulated GLP-1 secretion by enteric neural net in Wistar rat.

    PubMed

    Zhang, Xiyao; Li, Wensong; Li, Ping; Chang, Manli; Huang, Xu; Li, Qiang; Cui, Can

    2014-01-01

    As a regulator of food intake and energy metabolism, the role of ghrelin in glucose metabolism is still not fully understood. In this study, we determined the in vivo effect of ghrelin on incretin effect. We demonstrated that ghrelin inhibited the glucose-stimulated release of glucagon-like peptide-1 (GLP-1) when infused into the portal vein of Wistar rat. Hepatic vagotomy diminished the inhibitory effect of ghrelin on glucose-stimulated GLP-1 secretion. In addition, phentolamine, a nonselective α receptor antagonist, could recover the decrease of GLP-1 release induced by ghrelin infusion. Pralmorelin (an artificial growth hormone release peptide) infusion into the portal vein could also inhibit the glucose-stimulated release of GLP-1. And growth hormone secretagogue receptor antagonist, [D-lys3]-GHRP-6, infusion showed comparable increases of glucose stimulated GLP-1 release compared to ghrelin infusion into the portal vein. The data showed that intraportal infusion of ghrelin exerted an inhibitory effect on GLP-1 secretion through growth hormone secretagogue receptor 1α (GHS1α receptor), which indicated that the downregulation of ghrelin secretion after food intake was necessary for incretin effect. Furthermore, our results suggested that the enteric neural net involved hepatic vagal nerve and sympathetic nerve mediated inhibition effect of ghrelin on incretin effect. PMID:25247193

  11. Topography of methylphenidate (ritalin)-induced gene regulation in the striatum: differential effects on c-fos, substance P and opioid peptides.

    PubMed

    Yano, Motoyo; Steiner, Heinz

    2005-05-01

    Dopamine action alters gene regulation in striatal neurons. Methylphenidate increases extracellular levels of dopamine. We investigated the effects of acute methylphenidate treatment on gene expression in the striatum of adult rats. Molecular changes were mapped in 23 striatal sectors mostly defined by their predominant cortical inputs in order to determine the functional domains affected. Acute administration of 5 and 10 mg/kg (i.p.) of methylphenidate produced robust increases in the expression of the transcription factor c-fos and the neuropeptide substance P. Borderline effects were found with 2 mg/kg, but not with 0.5 mg/kg. For 5 mg/kg, c-fos mRNA levels peaked at 40 min and returned to baseline by 3 h after injection, while substance P mRNA levels peaked at 40-60 min and were back near control levels by 24 h. These molecular changes occurred in most sectors of the caudate-putamen, but were maximal in dorsal sectors that receive sensorimotor and medial agranular cortical inputs, on middle to caudal levels. In rostral and ventral striatal sectors, changes in c-fos and substance P expression were weaker or absent. No effects were seen in the nucleus accumbens, with the exception of c-fos induction in the lateral part of the shell. In contrast to c-fos and substance P, acute methylphenidate treatment had minimal effects on the opioid peptides dynorphin and enkephalin. These results demonstrate that acute methylphenidate alters the expression of c-fos and substance P preferentially in the sensorimotor striatum. These molecular changes are similar, but not identical, to those produced by other psychostimulants.

  12. Ghrelin Inhibition Restores Glucose Homeostasis in Hepatocyte Nuclear Factor-1α (MODY3)-Deficient Mice.

    PubMed

    Brial, François; Lussier, Carine R; Belleville, Karine; Sarret, Philippe; Boudreau, François

    2015-09-01

    Hepatocyte nuclear factor-1α (HNF1α) is a transcription factor expressed in tissues of endoderm origin. Mutations in HNF1A are associated with maturity-onset diabetes of the young 3 (MODY3). Mice deficient for Hnf1α are hyperglycemic, with their pancreatic β-cells being defective in glucose-sensing insulin secretion. The specific mechanisms involved in this defect are unclear. Gut hormones control glucose homeostasis. Our objective was to explore whether changes in these hormones play a role in glucose homeostasis in the absence of Hnf1α. An increase in ghrelin gene transcript and a decrease in glucose-dependent insulinotropic polypeptide (GIP) gene transcripts were observed in the gut of Hnf1α-null mice. These changes correlated with an increase of ghrelin and a decrease of GIP-labeled cells. Ghrelin serological levels were significantly induced in Hnf1α-null mice. Paradoxically, GIP levels were also induced in these mice. Treatment of Hnf1α-null mice with a ghrelin antagonist led to a recovery of the diabetic symptoms. We conclude that upregulation of ghrelin in the absence of Hnf1α impairs insulin secretion and can be reversed by pharmacological inhibition of ghrelin/GHS-R interaction. These observations open up on future strategies to counteract ghrelin action in a program that could become beneficial in controlling non-insulin-dependent diabetes. PMID:25979074

  13. Ghrelin protects musculocutaneous tissue from ischemic necrosis by improving microvascular perfusion.

    PubMed

    Rezaeian, F; Wettstein, R; Scheuer, C; Bäumker, K; Bächle, A; Vollmar, B; Menger, M D; Harder, Y

    2012-02-01

    Persistent ischemia in musculocutaneous tissue may lead to wound breakdown and necrosis. The objective of this experimental study was to analyze, whether the gastric peptide ghrelin prevents musculocutaneous tissue from necrosis and to elucidate underlying mechanisms. Thirty-two C57BL/6 mice equipped with a dorsal skinfold chamber containing ischemic musculocutaneous tissue were allocated to four groups: 1) ghrelin; 2) N(ω)-nitro-l-arginine methyl ester (l-NAME); 3) ghrelin and l-NAME; and 4) control. Microcirculation, inflammation, angiogenesis, and tissue survival were assessed by fluorescence microscopy. Inducible and endothelial nitric oxide synthase (iNOS I and eNOS), vascular endothelial growth factor (VEGF), as well as nuclear factor κB (NF-κB) were assessed by Western blot analysis. Ghrelin-treated animals showed an increased expression of iNOS and eNOS in critically perfused tissue compared with controls. This was associated with arteriolar dilation, increased arteriolar perfusion, and a sustained functional capillary density. Ghrelin further upregulated NF-κB and VEGF and induced angiogenesis. Finally, ghrelin reduced microvascular leukocyte-endothelial cell interactions, apoptosis, and overall tissue necrosis (P < 0.05 vs. control). Inhibition of nitric oxide by l-NAME did not affect the anti-inflammatory and angiogenic action of ghrelin but completely blunted the ghrelin-induced tissue protection by abrogating the arteriolar dilation, the improved capillary perfusion, and the increased tissue survival. Ghrelin prevents critically perfused tissue from ischemic necrosis. Tissue protection is the result of a nitric oxide synthase-mediated improvement of the microcirculation but not due to induction of angiogenesis or attenuation of inflammation. This might represent a promising, noninvasive, and clinically applicable approach to protect musculocutaneous tissue from ischemia. PMID:22159999

  14. Ghrelin inhibits the apoptosis of MC3T3-E1 cells through ERK and AKT signaling pathway

    SciTech Connect

    Liang, Qiu-Hua; Liu, Yuan; Wu, Shan-Shan; Cui, Rong-Rong; Yuan, Ling-Qing Liao, Er-Yuan

    2013-11-01

    Ghrelin is a 28-amino-acid peptide that acts as a natural endogenous ligand of the growth hormone secretagogue receptor (GHSR) and strongly stimulates the release of growth hormone from the hypothalamus–pituitary axis. Previous studies have identified the important physiological effects of ghrelin on bone metabolism, such as regulating proliferation and differentiation of osteoblasts, independent of GH/IGF-1 axis. However, research on effects and mechanisms of ghrelin on osteoblast apoptosis is still rare. In this study, we identified expression of GHSR in MC3T3-E1 cells and determined the effects of ghrelin on the apoptosis of osteoblastic MC3T3-E1 cells and the mechanism involved. Our data demonstrated that ghrelin inhibited the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, as determined by terminal deoxynucleotidyl transferase-mediated deoxyribonucleotide triphosphate nick end-labeling (TUNEL) and ELISA assays. Moreover, ghrelin upregulated Bcl-2 expression and downregulated Bax expression in a dose-dependent manner. Our study also showed decreased activated caspase-3 activity under the treatment of ghrelin. Further study suggested that ghrelin stimulated the phosphorylation of ERK and AKT. Pretreatment of cells with the ERK inhibitor PD98059, PI3K inhibitor LY294002, and GHSR-siRNA blocked the ghrelin-induced activation of ERK and AKT, respectively; however, ghrelin did not stimulate the phosphorylation of p38 or JNK. PD90859, LY294002 and GHSR-siRNA attenuated the anti-apoptosis effect of ghrelin in MC3T3-E1 cells. In conclusion, ghrelin inhibits the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, which may be mediated by activating the GHSR/ERK and GHSR/PI3K/AKT signaling pathways. - Highlights: • We explored the effects of ghrelin on serum deprivation-induced MC3T3-E1 cells apoptosis. • Both ELISA and TUNEL were used to detect the apoptosis. • The receptor of ghrelin, GHSR, was expressed in MC3T3-E1

  15. Diarylheptanoid from Curcuma comosa Roxb. suppresses RANKL-induced osteoclast differentiation by decreasing NFATc1 and c-Fos expression via MAPK pathway.

    PubMed

    Chawalitpong, Supatta; Sornkaew, Nilubon; Suksamrarn, Apichart; Palaga, Tanapat

    2016-10-01

    Osteoporosis is caused by a functional imbalance between osteoblasts and osteoclasts. The increased activation of osteoclasts that is a hallmark of osteoporosis results in the progressive loss of bone mass and therefore in an increased susceptibility to bone fractures. Diarylheptanoids are a group of phytoestrogens that have been isolated from a number of plant species, including the rhizomes of Curcuma comosa Roxb. In this study, the effect of one of diarylheptanoids, (3S)-1-(3,4-dihydroxyphenyl)-3-hydroxy-7-phenyl-(6E)-6-heptene (DHPH), was investigated for anti-inflammatory and anti-osteoclastogenic activity. DHPH significantly inhibited nitric oxide production in RAW264.7 cell line following their activation by lipopolysaccharide and interferon-γ, with no cytotoxicity. In primary mouse bone-marrow-derived macrophage precursors, DHPH suppressed osteoclastogenesis induced by receptor activator of nuclear factor-κB (RANK) ligand at an inhibitory concentration 50 of 325±1.37nM. DHPH treatment delayed and reduced the expression of master regulators of osteoclast differentiation, NFATc1 and c-Fos. Consistent with this result, the mRNA level of cathepsin K, associated with osteoclast differentiation, was decreased whereas the reduction in the mRNA of irf8, a negative regulator of osteoclast differentiation, was similar to that measured in the vehicle-treated control cells. DHPH reduced the phosphorylation of p38 MAPK, ERK (p44/42). Furthermore, DHPH suppressed the bone absorption activity of osteoclasts and enhanced osteoblast differentiation. Taken together, DHPH interrupts the immediate downstream signaling cascade of RANK and interferes with osteoclast differentiation and its function while enhances osteoblast differentiation. These results demonstrate the potential of this diarylheptanoid as a new therapeutic agent in osteoporosis. PMID:27523282

  16. Vesicular acetylcholine transporter knock down-mice are more susceptible to inflammation, c-Fos expression and sickness behavior induced by lipopolysaccharide.

    PubMed

    Leite, Hércules Ribeiro; Oliveira-Lima, Onésia Cristina de; Pereira, Luciana de Melo; Oliveira, Vinícius Elias de Moura; Prado, Vania Ferreira; Prado, Marco Antônio Máximo; Pereira, Grace Schenatto; Massensini, André Ricardo

    2016-10-01

    In addition to the well-known functions as a neurotransmitter, acetylcholine (ACh) can modulate of the immune system. Nonetheless, how endogenous ACh release inflammatory responses is still not clear. To address this question, we took advantage of an animal model with a decreased ACh release due a reduction (knockdown) in vesicular acetylcholine transporter (VAChT) expression (VAChT-KD(HOM)). These animals were challenged with lipopolysaccharide (LPS). Afterwards, we evaluated sickness behavior and quantified systemic and cerebral inflammation as well as neuronal activation in the dorsal vagal complex (DVC). VAChT-KD(HOM) mice that were injected with LPS (10mg/kg) showed increased mortality rate as compared to control mice. In line with this result, a low dose of LPS (0.1mg/kg) increased the levels of pro-inflammatory (TNF-α, IL-1β, and IL-6) and anti-inflammatory (IL-10) cytokines in the spleen and brain of VAChT-KD(HOM) mice in comparison with controls. Similarly, serum levels of TNF-α and IL-6 were increased in VAChT-KD(HOM) mice. This excessive cytokine production was completely prevented by administration of a nicotinic receptor agonist (0.4mg/kg) prior to the LPS injection. Three hours after the LPS injection, c-Fos expression increased in the DVC region of VAChT-KD(HOM) mice compared to controls. In addition, VAChT-KD(HOM) mice showed behavioral changes such as lowered locomotor and exploratory activity and reduced social interaction after the LPS challenge, when compared to control mice. Taken together, our results show that the decreased ability to release ACh exacerbates systemic and cerebral inflammation and promotes neural activation and behavioral changes induced by LPS. In conclusion, our findings support the notion that activity of cholinergic pathways, which can be modulated by VAChT expression, controls inflammatory and neural responses to LPS challenge.

  17. Thermogenic characterization of ghrelin receptor null mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ghrelin is the only known circulating orexigenic hormone that increases food intake and promotes adiposity, and these physiological functions of ghrelin are mediated through its receptor growth hormone secretagogue receptor (GHS-R). Ghrelin/GHS-R signaling plays a crucial role in energy homeostasis....

  18. Ghrelin: much more than a hunger hormone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ghrelin is a multifaceted gut hormone that activates its receptor, growth hormone secretagogue receptor (GHS-R). Ghrelin's hallmark functions are its stimulatory effects on growth hormone release, food intake and fat deposition. Ghrelin is famously known as the 'hunger hormone'. However, ample recen...

  19. Pyrroloquinoline quinine inhibits RANKL-mediated expression of NFATc1 in part via suppression of c-Fos in mouse bone marrow cells and inhibits wear particle-induced osteolysis in mice.

    PubMed

    Kong, Lingbo; Yang, Chongfei; Yu, Lifeng; Smith, Wanli; Zhu, Shu; Zhu, Jinyu; Zhu, Qingsheng

    2013-01-01

    The effects of pyrroloquinoline quinine (PQQ) on RANKL-induced osteoclast differentiation and on wear particle-induced osteolysis were examined in this study. PQQ inhibited RANKL-mediated osteoclast differentiation in bone marrow macrophages (BMMs) in a dose-dependent manner without any evidence of cytotoxicity. The mRNA expression of c-Fos, NFATc1, and TRAP in RANKL-treated BMMs was inhibited by PQQ treatment. Moreover, RANKL-induced c-Fos and NFATc1 protein expression was suppressed by PQQ. PQQ additionally inhibited the bone resorptive activity of differentiated osteoclasts. Further a UHMWPE-induced murine calvaria erosion model study was performed to assess the effects of PQQ on wear particle-induced osteolysis in vivo. Mice treated with PQQ demonstrated marked attenuation of bone erosion based on Micro-CT and histologic analysis of calvaria. These results collectively suggested that PQQ demonstrated inhibitory effects on osteoclast differentiation in vitro and may suppress wear particle-induced osteolysis in vivo, indicating that PQQ may therefore serve as a useful drug in the prevention of bone loss.

  20. Mechanism of Cytosolic Phospholipase A(2) Activation in Ghrelin Protection of Salivary Gland Acinar Cells against Ethanol Cytotoxicity.

    PubMed

    Slomiany, Bronislaw L; Slomiany, Amalia

    2010-01-01

    Ghrelin, a peptide hormone, newly identified in oral mucosal tissues, has emerged recently as an important mediator of the processes of mucosal defense. Here, we report on the mechanism of ghrelin protection against ethanol cytotoxicity in rat sublingual salivary gland cells. The protective effect of ghrelin was associated with the increase in NO and PGE2, and upregulation in cytosolic phospholipase A(2) (cPLA(2)) activity and arachidonic acid (AA) release. The loss in countering effect of ghrelin occurred with cNOS inhibitor, L-NAME, as well as indomethacin and COX-1 inhibitor, SC-560, while COX-2 inhibitor, NS-398, and iNOS inhibitor, 1400W, had no effect. The effect of L-NAME was reflected in the inhibition of ghrelin-induced cell capacity for NO production, cPLA(2) activation and PGE2 generation, whereas indomethacin caused only the inhibition in PGE2. Moreover, the ghrelin-induced up-regulation in AA release was reflected in the cPLA(2) phosphorylation and S-nitrosylation. Inhibition in ghrelin-induced S-nitrosylation was attained with L-NAME, whereas the ERK inhibitor, PD98059, caused the blockage in cPLA(2) protein phosphorylation as well as S-nitrosylation. Thus, ghrelin protection of salivary gland cells against ethanol involves cNOS-derived NO induction of cPLA(2) activation through S-nitrosylation for the increase in AA release at the site of COX-1 action for PGE2 synthesis.

  1. Ghrelin and the growth hormone secretagogue receptor in growth and development.

    PubMed

    Chanoine, J-P; De Waele, K; Walia, P

    2009-04-01

    The pancreas is a major source of ghrelin in the perinatal period, whereas gastric production progressively increases after birth. Loss of function of the genes for ghrelin or for the constitutively activated growth hormone secretagogue receptor (GHSR) does not affect birth weight and early postnatal growth. However, ghrl(-/-) or ghsr(-/-) mice fed a high fat diet starting soon after weaning are resistant to diet-induced obesity, suggesting that ghrelin affects the maturation of the metabolic axes involved in energy balance. In addition, animal and human studies suggest that GHSR plays a physiological role in linear growth. In mice, absence of the GHSR gene is associated with lower insulin-like growth factor 1 concentrations and lower body mass in adult animals, independently of food intake. In humans, a mutation of the GHSR gene that impairs the constitutive activity of the receptor was found in two families with short stature. Administration of acylated ghrelin to rat pups directly does not affect weight gain. In contrast, administration of ghrelin to pregnant or lactating rats results in greater fetal weight and postnatal weight gain, respectively, suggesting that maternal ghrelin may stimulate perinatal growth. These data point toward a physiological role for ghrelin and GHSR in growth and/or in the maturation of hormonal systems involved in the regulation of energy balance.

  2. Colocalization of Mating-Induced Fos and D2-Like Dopamine Receptors in the Medial Preoptic Area: Influence of Sexual Experience

    PubMed Central

    Nutsch, Victoria L.; Will, Ryan G.; Robison, Christopher L.; Martz, Julia R.; Tobiansky, Daniel J.; Dominguez, Juan M.

    2016-01-01

    Dopamine in the medial preoptic area (mPOA) stimulates sexual activity in males. This is evidenced by microdialysis and microinjection experiments revealing that dopamine receptor antagonists in the mPOA inhibit sexual activity, whereas agonists facilitate behavior. Microdialysis experiments similarly show a facilitative role for dopamine, as levels of dopamine in the mPOA increase with mating. While the majority of evidence suggests an important role for dopamine receptors in the mPOA in the regulation of male sexual behaviors, whether sexual activity or sexual experience influence dopamine receptor function in the mPOA has not been previously shown. Here we used immunohistochemical assays to determine whether varying levels of sexual activity or experience influence the number of cells containing Fos or D2 receptor immunoreactivity. Results show that sexual experience facilitated subsequent behavior, namely experience decreased latencies. Moreover, the number of cells with immunoreactivity for Fos or D2 correlated with levels of sexual experience and sexual activity. Sexual activity increased Fos immunoreactivity. Sexually experienced animals also had significantly more D2-positive cells. Sexually inexperienced animals copulating for the first time had a larger percentage of D2-positive cells containing Fos, when compared to sexually experienced animals. Finally, regardless of experience, animals that had sex prior to sacrifice had significantly more D2-positive cells that contained Fos, vs. animals that did not copulate. These findings are noteworthy because sexually experienced animals display increased sexual efficiency. The differences in activation of D2 and changes in receptor density may play a role in this efficiency and other behavioral changes across sexual experience. PMID:27147996

  3. Colocalization of Mating-Induced Fos and D2-Like Dopamine Receptors in the Medial Preoptic Area: Influence of Sexual Experience.

    PubMed

    Nutsch, Victoria L; Will, Ryan G; Robison, Christopher L; Martz, Julia R; Tobiansky, Daniel J; Dominguez, Juan M

    2016-01-01

    Dopamine in the medial preoptic area (mPOA) stimulates sexual activity in males. This is evidenced by microdialysis and microinjection experiments revealing that dopamine receptor antagonists in the mPOA inhibit sexual activity, whereas agonists facilitate behavior. Microdialysis experiments similarly show a facilitative role for dopamine, as levels of dopamine in the mPOA increase with mating. While the majority of evidence suggests an important role for dopamine receptors in the mPOA in the regulation of male sexual behaviors, whether sexual activity or sexual experience influence dopamine receptor function in the mPOA has not been previously shown. Here we used immunohistochemical assays to determine whether varying levels of sexual activity or experience influence the number of cells containing Fos or D2 receptor immunoreactivity. Results show that sexual experience facilitated subsequent behavior, namely experience decreased latencies. Moreover, the number of cells with immunoreactivity for Fos or D2 correlated with levels of sexual experience and sexual activity. Sexual activity increased Fos immunoreactivity. Sexually experienced animals also had significantly more D2-positive cells. Sexually inexperienced animals copulating for the first time had a larger percentage of D2-positive cells containing Fos, when compared to sexually experienced animals. Finally, regardless of experience, animals that had sex prior to sacrifice had significantly more D2-positive cells that contained Fos, vs. animals that did not copulate. These findings are noteworthy because sexually experienced animals display increased sexual efficiency. The differences in activation of D2 and changes in receptor density may play a role in this efficiency and other behavioral changes across sexual experience.

  4. cAMP and in vivo hypoxia induce tob, ifr1, and fos expression in erythroid cells of the chick embryo.

    PubMed

    Dragon, Stefanie; Offenhäuser, Nina; Baumann, Rosemarie

    2002-04-01

    During avian embryonic development, terminal erythroid differentiation occurs in the circulation. Some of the key events, such as the induction of erythroid 2,3-bisphosphoglycerate (2,3-BPG), carbonic anhydrase (CAII), and pyrimidine 5'-nucleotidase (P5N) synthesis are oxygen dependent (Baumann R, Haller EA, Schöning U, and Weber M, Dev Biol 116: 548-551, 1986; Dragon S and Baumann R, Am J Physiol Regulatory Integrative Comp Physiol 280: R870-R878, 2001; Dragon S, Carey C, Martin K, and Baumann R, J Exp Biol 202: 2787-2795, 1999; Dragon S, Glombitza S, Götz R, and Baumann R, Am J Physiol Regulatory Integrative Comp Physiol 271: R982-R989, 1996; Dragon S, Hille R, Götz R, and Baumann R, Blood 91: 3052-3058, 1998; Million D, Zillner P, and Baumann R, Am J Physiol Regulatory Integrative Comp Physiol 261: R1188-R1196, 1991) in an indirect way: hypoxia stimulates the release of norepinephrine (NE)/adenosine into the circulation (Dragon et al., J Exp Biol 202: 2787-2795, 1999; Dragon et al., Am J Physiol Regulatory Integrative Comp Physiol 271: R982-R989, 1996). This leads via erythroid beta-adrenergic/adenosine A(2) receptor activation to a cAMP signal inducing several proteins in a transcription-dependent manner (Dragon et al., Am J Physiol Regulatory Integrative Comp Physiol 271: R982-R989, 1996; Dragon et al., Blood 91: 3052-3058, 1998; Glombitza S, Dragon S, Berghammer M, Pannermayr M, and Baumann R, Am J Physiol Regulatory Integrative Comp Physiol 271: R973-R981, 1996). To understand how the cAMP-dependent processes are initiated, we screened an erythroid cDNA library for cAMP-regulated genes. We detected three genes that were strongly upregulated (>5-fold) by cAMP in definitive and primitive red blood cells. They are homologous to the mammalian Tob, Ifr1, and Fos proteins. In addition, the genes are induced in the intact embryo during short-term hypoxia. Because the genes are regulators of proliferation and differentiation in other cell types, we suggest that c

  5. Plasma ghrelin and growth hormone regulation in response to metabolic state in hybrid striped bass: effects of feeding, ghrelin and insulin-like growth factor-I on in vivo and in vitro GH secretion.

    PubMed

    Picha, Matthew E; Strom, Christina N; Riley, Larry G; Walker, Alicia A; Won, Eugene T; Johnstone, William M; Borski, Russell J

    2009-05-01

    The regulation of growth hormone (GH) secretion by ghrelin during variable metabolic states is poorly understood. We examined plasma GH and ghrelin in hybrid striped bass (HSB) undergoing seasonally-based feeding and temperature manipulations. Fasting for 21 days (d) at 24 degrees C resulted in catabolism and up-regulation of plasma GH and ghrelin relative to fed controls. Continued fasting during cold-banking (14 degrees C, 90 d) resulted in a further 43-fold increase in ghrelin while GH remained elevated. A subsequent 19 day refeeding period at 24 degrees C elicited hyperphagic and compensatory growth responses, accompanied by declines in ghrelin and GH. We then tested the role of ghrelin in stimulating GH release in vivo and in vitro. Intraperitoneal injections of ghrelin resulted in dose-dependent increases in plasma GH after 6 hours (h). Ghrelin also increased GH release from HSB pituitaries during 6h incubations. Lastly, we assessed how metabolic state, ghrelin and insulin-like growth factor-I (IGF-I) affect in vitro pituitary GH release. Spontaneous GH release was 5.2-fold higher from pituitaries of fasted compared with fed animals. Ghrelin was equally effective in stimulating GH release from pituitaries of fed and starved animals, while it was ineffective in enhancing GH release from pituitaries of starved (21 d) then refed (4d) HSB. Incubation with IGF-I inhibited GH release regardless of metabolic state. These studies are the first to show that seasonally-based periods of feed deprivation and low temperature yield sustained increases in GH secretion that are likely mediated, at least partially, through elevated ghrelin, reduced IGF-I negative feedback and fasting-induced spontaneous GH release.

  6. Ghrelin inhibits proliferation and increases T-type Ca{sup 2+} channel expression in PC-3 human prostate carcinoma cells

    SciTech Connect

    Diaz-Lezama, Nundehui; Hernandez-Elvira, Mariana; Sandoval, Alejandro; Monroy, Alma; Felix, Ricardo; Monjaraz, Eduardo

    2010-12-03

    Research highlights: {yields} Ghrelin decreases prostate carcinoma PC-3 cells proliferation. {yields} Ghrelin favors apoptosis in PC-3 cells. {yields} Ghrelin increase in intracellular free Ca{sup 2+} levels in PC-3 cells. {yields} Grelin up-regulates expression of T-type Ca{sup 2+} channels in PC-3 cells. {yields} PC-3 cells express T-channels of the Ca{sub V}3.1 and Ca{sub V}3.2 subtype. -- Abstract: Ghrelin is a multifunctional peptide hormone with roles in growth hormone release, food intake and cell proliferation. With ghrelin now recognized as important in neoplastic processes, the aim of this report is to present findings from a series of in vitro studies evaluating the cellular mechanisms involved in ghrelin regulation of proliferation in the PC-3 human prostate carcinoma cells. The results showed that ghrelin significantly decreased proliferation and induced apoptosis. Consistent with a role in apoptosis, an increase in intracellular free Ca{sup 2+} levels was observed in the ghrelin-treated cells, which was accompanied by up-regulated expression of T-type voltage-gated Ca{sup 2+} channels. Interestingly, T-channel antagonists were able to prevent the effects of ghrelin on cell proliferation. These results suggest that ghrelin inhibits proliferation and may promote apoptosis by regulating T-type Ca{sup 2+} channel expression.

  7. Is there an effect of ghrelin/ghrelin analogs on cancer? A systematic review

    PubMed Central

    Sever, Sakine; White, Donna L

    2016-01-01

    Ghrelin is a hormone with multiple physiologic functions, including promotion of growth hormone release, stimulation of appetite and regulation of energy homeostasis. Treatment with ghrelin/ghrelin-receptor agonists is a prospective therapy for disease-related cachexia and malnutrition. In vitro studies have shown high expression of ghrelin in cancer tissue, although its role including its impact in cancer risk and progression has not been established. We performed a systematic literature review to identify peer-reviewed human or animal in vivo original research studies of ghrelin, ghrelin-receptor agonists, or ghrelin genetic variants and the risk, presence, or growth of cancer using structured searches in PubMed database as well as secondary searches of article reference lists, additional reviews and meta-analyses. Overall, 45 (73.8%) of the 61 studies reviewed, including all 11 involving exogenous ghrelin/ghrelin-receptor agonist treatment, reported either a null (no statistically significant difference) or inverse association of ghrelin/ghrelin-receptor agonists or ghrelin genetic variants with cancer risk, presence or growth; 10 (16.7%) studies reported positive associations; and 6 (10.0%) reported both negative or null and positive associations. Differences in serum ghrelin levels in cancer cases vs controls (typically lower) were reported for some but not all cancers. The majority of in vivo studies showed a null or inverse association of ghrelin with risk and progression of most cancers, suggesting that ghrelin/ghrelin-receptor agonist treatment may have a favorable safety profile to use for cancer cachexia. Additional large-scale prospective clinical trials as well as basic bioscientific research are warranted to further evaluate the safety and benefits of ghrelin treatment in patients with cancer. PMID:27552970

  8. Is there an effect of ghrelin/ghrelin analogs on cancer? A systematic review.

    PubMed

    Sever, Sakine; White, Donna L; Garcia, José M

    2016-09-01

    Ghrelin is a hormone with multiple physiologic functions, including promotion of growth hormone release, stimulation of appetite and regulation of energy homeostasis. Treatment with ghrelin/ghrelin-receptor agonists is a prospective therapy for disease-related cachexia and malnutrition. In vitro studies have shown high expression of ghrelin in cancer tissue, although its role including its impact in cancer risk and progression has not been established. We performed a systematic literature review to identify peer-reviewed human or animal in vivo original research studies of ghrelin, ghrelin-receptor agonists, or ghrelin genetic variants and the risk, presence, or growth of cancer using structured searches in PubMed database as well as secondary searches of article reference lists, additional reviews and meta-analyses. Overall, 45 (73.8%) of the 61 studies reviewed, including all 11 involving exogenous ghrelin/ghrelin-receptor agonist treatment, reported either a null (no statistically significant difference) or inverse association of ghrelin/ghrelin-receptor agonists or ghrelin genetic variants with cancer risk, presence or growth; 10 (16.7%) studies reported positive associations; and 6 (10.0%) reported both negative or null and positive associations. Differences in serum ghrelin levels in cancer cases vs controls (typically lower) were reported for some but not all cancers. The majority of in vivo studies showed a null or inverse association of ghrelin with risk and progression of most cancers, suggesting that ghrelin/ghrelin-receptor agonist treatment may have a favorable safety profile to use for cancer cachexia. Additional large-scale prospective clinical trials as well as basic bioscientific research are warranted to further evaluate the safety and benefits of ghrelin treatment in patients with cancer. PMID:27552970

  9. Stress-induced differences in the limbic system Fos expression are more pronounced in rats differing in responsiveness to novelty than social position.

    PubMed

    Majkutewicz, Irena; Myślińska, Dorota; Jerzemowska, Grażyna; Plucińska, Karolina; Listowska, Magdalena; Grembecka, Beata; Podlacha, Magdalena; Wrona, Danuta

    2012-10-01

    We determined the interaction between such individual behavioural profiles as locomotor response to novelty or social position and the activation (Fos expression) of the brain's limbic regions following chronic laboratory and social interaction stress. Male Wistar rats (n=45), housed separately and handled for 2 weeks, were divided into high (HR) and low (LR) responders to novelty. Seven days later, 12 HRs and 12 LRs were subjected to a chronic 23 consecutive day social interaction test (Nov/SocI group), 5 HRs and 5 LRs were subjected to chronic laboratory stress: carrying from the vivarium to the laboratory for 23 consecutive days (Nov/Carr group) while the remaining rats stayed in the vivarium in their home cages (Nov/Home group). The highest limbic system activation was found 7 days later in the Nov/SocI rats. In comparison with the LRs, the HRs showed a higher number of Fos(+) cells in most of the limbic prosencephalic structures (24 areas) in the Nov/SocI group, and in 12 areas, especially in the amygdala and the hypothalamus, in the Nov/Carr group. There were no HR/LR differences in the limbic system's activity in the Nov/Home group. Within dominance/submission differences, a higher Fos expression was found in 6 structures, especially in the limbic cortex, in the dominant rather than the subordinate HRs. We conclude that chronic social and laboratory stress persistently activates the limbic system, with the largest effects in the brains of rats responding maximally to novelty. Social position was less predictive of Fos expression than was activity to novelty.

  10. Hepatic changes in metabolic gene expression in old ghrelin and ghrelin receptor knockout mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ghrelin knockout (GKO) and ghrelin receptor (growth hormone secretagogue receptor) knockout (GHSRKO) mice exhibit enhanced insulin sensitivity, but the mechanism is unclear. Insulin sensitivity declines with age and is inversely associated with accumulation of lipid in liver, a key glucoregulatory ...

  11. E2F1-Mediated FOS Induction in Arsenic Trioxide–Induced Cellular Transformation: Effects of Global H3K9 Hypoacetylation and Promoter-Specific Hyperacetylation in Vitro

    PubMed Central

    Rahman, Sunniyat; Housein, Zjwan; Dabrowska, Aleksandra; Mayán, Maria Dolores; Boobis, Alan R.

    2015-01-01

    Background: Aberrant histone acetylation has been observed in carcinogenesis and cellular transformation associated with arsenic exposure; however, the molecular mechanisms and cellular outcomes of such changes are poorly understood. Objective: We investigated the impact of tolerated and toxic arsenic trioxide (As2O3) exposure in human embryonic kidney (HEK293T) and urothelial (UROtsa) cells to characterize the alterations in histone acetylation and gene expression as well as the implications for cellular transformation. Methods: Tolerated and toxic exposures of As2O3 were identified by measurement of cell death, mitochondrial function, cellular proliferation, and anchorage-independent growth. Histone extraction, the MNase sensitivity assay, and immunoblotting were used to assess global histone acetylation levels, and gene promoter-specific interactions were measured by chromatin immunoprecipitation followed by reverse-transcriptase polymerase chain reaction. Results: Tolerated and toxic dosages, respectively, were defined as 0.5 μM and 2.5 μM As2O3 in HEK293T cells and 1 μM and 5 μM As2O3 in UROtsa cells. Global hypoacetylation of H3K9 at 72 hr was observed in UROtsa cells following tolerated and toxic exposure. In both cell lines, tolerated exposure alone led to H3K9 hyperacetylation and E2F1 binding at the FOS promoter, which remained elevated after 72 hr, contrary to global H3K9 hypoacetylation. Thus, promoter-specific H3K9 acetylation is a better predictor of cellular transformation than are global histone acetylation patterns. Tolerated exposure resulted in an increased expression of the proto-oncogenes FOS and JUN in both cell lines at 72 hr. Conclusion: Global H3K9 hypoacetylation and promoter-specific hyperacetylation facilitate E2F1-mediated FOS induction in As2O3-induced cellular transformation. Citation: Rahman S, Housein Z, Dabrowska A, Mayán MD, Boobis AR, Hajji N. 2015. E2F1-mediated FOS induction in arsenic trioxide–induced cellular

  12. Using c-fos to study neuronal ensembles in corticostriatal circuitry of addiction.

    PubMed

    Cruz, Fabio C; Javier Rubio, F; Hope, Bruce T

    2015-12-01

    Learned associations between drugs and environment play an important role in addiction and are thought to be encoded within specific patterns of sparsely distributed neurons called neuronal ensembles. This hypothesis is supported by correlational data from in vivo electrophysiology and cellular imaging studies in relapse models in rodents. In particular, cellular imaging with the immediate early gene c-fos and its protein product Fos has been used to identify sparsely distributed neurons that were strongly activated during conditioned drug behaviors such as drug self-administration and context- and cue-induced reinstatement of drug seeking. Here we review how Fos and the c-fos promoter have been employed to demonstrate causal roles for Fos-expressing neuronal ensembles in prefrontal cortex and nucleus accumbens in conditioned drug behaviors. This work has allowed identification of unique molecular and electrophysiological alterations within Fos-expressing neuronal ensembles that may contribute to the development and expression of learned associations in addiction.

  13. FosB in the suprachiasmatic nucleus of the Syrian and Siberian hamster.

    PubMed

    Ebling, F J; Maywood, E S; Mehta, M; Hancock, D C; McNulty, S; De Bono, J; Bray, S J; Hastings, M H

    1996-01-01

    The suprachiasmatic nucleus (SCN) generates circadian rhythms of behavior and hormone secretion in mammals, and integrates responses to light and nonphotic stimuli to synchronize such rhythms with the external environment. Previous studies have demonstrated a close association between the induction of the immediate early gene (IEG) c-fos in the SCN by light and phase shifts of circadian rhythms induced by light, but nonphotic stimuli (e.g., arousal), which also cause phase shifts, do not increase c-fos expression in the SCN. Because c-fos is now known to be a member of a large family of IEGs which can regulate transcription and thus cellular function, the aim of the current study was to determine whether induction of another member of this immediate early gene family, fosB, is associated with photic and nonphotic phase shifts. An antiserum that recognizes a unique peptide sequence derived from FosB was produced so that the expression of fosB could be investigated in cells within the SCN by immunocytochemical detection of its protein product. The regional distribution of FosB-immunoreactive (ir) cells in the SCN of Syrian and Siberian hamsters was broadly similar to that for c-Fos-ir cells. However, whereas c-fos expression in the SCN was constitutively low, but could be massively induced by light at particular circadian phases, FosB-ir cells were present at all circadian phases studied, irrespective of photic stimulation, and light only produced marginal increases in the number of FosB-ir cells compared with nonstimulated controls. Moreover, blockade of glutamatergic neurotransmission by pretreatment of hamsters with the NMDA receptor antagonist MK801 significantly reduced photic induction of c-Fos-ir cells, but did not influence the number of FosB-ir cells in the SCN. Finally, an arousing nonphotic stimulus known to cause phase advances in wheel-running behavior in Syrian hamsters did not alter significantly the number of FosB-ir cells in the SCN. These

  14. Crosstalking between the "gut-brain" hormone ghrelin and the circadian system in the goldfish. Effects on clock gene expression and food anticipatory activity.

    PubMed

    Nisembaum, Laura G; de Pedro, Nuria; Delgado, María J; Isorna, Esther

    2014-09-01

    Ghrelin is a potent orexigenic signal mainly synthesized in the stomach and foregut of vertebrates. Recent studies in rodents point out that ghrelin could also act as an input for the circadian system and/or as an output of peripheral food-entrainable oscillators, being involved in the food anticipatory activity (FAA). In this study we pursue the possible interaction of ghrelin with the circadian system in a teleost, the goldfish (Carassius auratus). First, we analyzed if ghrelin is able to modulate the core clock functioning by regulating clock gene expression in fish under a light/dark cycle 12L:12D and fed at 10 am. As expected the acute intraperitoneal (IP) injection of goldfish ghrelin (gGRL[1-19], 44 pmol/g bw) induced the expression of hypothalamic orexin. Moreover, ghrelin also induced (∼ 2-fold) some Per clock genes in hypothalamus and liver. This effect was partially counteracted in liver by the ghrelin antagonist ([D-Lys(3)]-GHRP-6, 100 pmol/g bw). Second, we investigated if ghrelin is involved in daily FAA rhythms. With this aim locomotor activity was studied in response to IP injections (5-10 days) of gGRL[1-19] and [D-Lys(3)]-GHRP-6 at the doses above indicated. Ghrelin and saline injected fish showed similar 24h activity patterns. However, ghrelin antagonist treatment abolished the FAA in schedule fed fish under 24h light, suggesting the involvement of the endogenous ghrelin system in this pre-feeding activity. Altogether these results suggest that ghrelin could be acting as an input for the entrainment of the food-entrainable oscillators in the circadian organization of goldfish.

  15. Effects of mGlu2 or mGlu3 receptor deletions on mGlu2/3 receptor agonist (LY354740)-induced brain c-Fos expression: specific roles for mGlu2 in the amygdala and subcortical nuclei, and mGlu3 in the hippocampus.

    PubMed

    Linden, Anni-Maija; Baez, Melvin; Bergeron, Marcelle; Schoepp, Darryle D

    2006-08-01

    LY354740 is a potent and selective mGlu2/3 receptor agonist with activity in models of psychiatric disorders (anxiety, psychosis), and early clinical studies in anxiety patients. However, the specific receptor subtypes and brain regions which mediate mGlu2/3 receptor agonist pharmacology/efficacy are not well understood. Here we investigate the effects of deleting mGlu2 or mGlu3 receptors on basal and LY354740-regulated c-Fos expression in mouse brain using mGlu2 or mGlu3 knockout mice. Consistent with our earlier findings, LY354740 administration (20 mg/kg, i.p.) to wild-type mice increased c-Fos expression in specific limbic (central amygdala, bed nucleus of the stria terminalis, midline thalamic nuclei) and non-limbic (thalamic dorsolateral geniculate nucleus, superior colliculus, Edinger-Westphal) structures, while modestly suppressing hippocampal c-Fos expression. The LY354740-induced increases in c-Fos expression in all the above regions were abolished by mGlu2, but not mGlu3, receptor deletion. Interestingly, basal c-Fos expression was significantly increased in the hippocampus of mGlu3, but not mGlu2, receptor knockouts compared to wild-type mice. Moreover, this increase was not suppressed by LY354740, such that in the CA3 region LY354740 now increased c-Fos expression in the mGlu3 knockouts. These results demonstrate that the LY354740-induced increases of c-Fos expression in specific brain regions, including the central and extended amygdala are specifically linked to mGlu2 receptors, and LY354740 suppressions of neuronal activity in the hippocampus are linked to mGlu3 receptors. PMID:16733060

  16. On the functional significance of c-fos induction during the sleep-waking cycle.

    PubMed

    Cirelli, C; Tononi, G

    2000-06-15

    A striking finding in recent years has been that the transition from sleep to waking is accompanied in many brain regions by a widespread activation of c-fos and other immediate-early genes (IEGs). IEGs are induced by various electrical or chemical signals to which neural cells are exposed and their protein products act as transcription factors to regulate the expression of other genes. After a few hours of sleep, the expression of these transcription factors in the brain is absent or restricted to very few cells. However, after a few hours of spontaneous waking or sleep deprivation, the expression of c-fos and other IEGs is high in cerebral cortex, hypothalamus, septum, and several thalamic and brainstem nuclei. While cells expressing c-fos during waking are widely distributed, they represent only a subset of all neurons in any given area. These observations raise several questions: Why is c-fos expressed during waking and not during sleep? Is waking always accompanied by c-fos induction? Which subset of cells express c-fos during waking and why only a subset? Once c-fos has been induced, what are the functional consequences of its activation? In this review, we summarize our current understanding of the meaning of c-fos activation in the brain in relation to the sleep-waking cycle and suggest that c-fos induction in the cerebral cortex during waking might be related to the occurrence of plastic phenomena.

  17. Correlation of Fos expression and circling asymmetry during gerbil vestibular compensation

    NASA Technical Reports Server (NTRS)

    Kaufman, G. D.; Shinder, M. E.; Perachio, A. A.

    1999-01-01

    Vestibular compensation is a central nervous system process resulting in recovery of functional movement and control following a unilateral vestibular lesion. Small pressure injections of phosphorothioate 20mer oligonucleotides were used to probe the role of the Fos transcription protein during vestibular compensation in the gerbil brainstem. During isoflurane gas anesthesia, antisense probes against the c-fos mRNA sequence were injected into the medial vestibular and prepositus nuclei unilaterally prior to a unilateral surgical labyrinthectomy. Anionic dyes, which did not interact with the oligonucleotides, were used to mark the injection site and help determine the extent of diffusion. The antiFos oligonucleotide injections reduced Fos expression at the injection site in neurons which normally express Fos after the lesion, and also affected circling behavior induced by hemilabyrinthectomy. With both ipsilateral and contralateral medial vestibular and prepositus nuclei injections, less ipsilateral and more contralateral circling was noted in animals injected with antiFos injections as compared to non-injected controls. The degree of change in these behaviors was dependent upon the side of the injection. Histologically, antiFos injections reduced the number of Fos immunolabeled neurons around the injection site, and increased Fos expression contralaterally. The correlation of the number of neurons with Fos expression to turning behavior was stronger for contralateral versus ipsilateral turns, and for neurons in the caudal and ipsilateral sub-regions of the medial vestibular and prepositus nuclei. The results are discussed in terms of neuronal firing activity versus translational activity based on the asymmetrical expression of the Fos inducible transcription factor in the medial vestibular and prepositus nuclei. Although ubiquitous in the brain, transcription factors like Fos can serve localized and specific roles in sensory-specific adaptive stimuli. Antisense

  18. Ghrelin Receptors in Non-Mammalian Vertebrates

    PubMed Central

    Kaiya, Hiroyuki; Kangawa, Kenji; Miyazato, Mikiya

    2012-01-01

    The growth hormone secretagogue-receptor (GHS-R) was discovered in humans and pigs in 1996. The endogenous ligand, ghrelin, was discovered 3 years later, in 1999, and our understanding of the physiological significance of the ghrelin system in vertebrates has grown steadily since then. Although the ghrelin system in non-mammalian vertebrates is a subject of great interest, protein sequence data for the receptor in non-mammalian vertebrates has been limited until recently, and related biological information has not been well organized. In this review, we summarize current information related to the ghrelin receptor in non-mammalian vertebrates. PMID:23882259

  19. Ghrelin Supresses Sympathetic Hyperexcitation in Acute Heart Failure in Male Rats: Assessing Centrally and Peripherally Mediated Pathways.

    PubMed

    Shirai, Mikiyasu; Joe, Natalie; Tsuchimochi, Hirotsugu; Sonobe, Takashi; Schwenke, Daryl O

    2015-09-01

    The hormone ghrelin prevents a dangerous increase in cardiac sympathetic nerve activity (SNA) after acute myocardial infarction (MI), although the underlying mechanisms remain unknown. This study aimed to determine whether ghrelin's sympathoinhibitory properties stem either from directly within the central nervous system, or via modulation of specific cardiac vagal inhibitory afferents. Cardiac SNA was recorded in urethane-anesthetized rats for 3 hours after the ligation of the left anterior descending coronary artery (ie, MI). Rats received ghrelin either sc (150 μg/kg) or intracerebroventricularly (5 μg/kg) immediately after the MI. In another two groups, the cervical vagi were denervated prior to the MI, followed by sc injection of either ghrelin or placebo. Acute MI induced a 188% increase in cardiac SNA, which was significantly attenuated in ghrelin-treated rats for both sc or intracerebroventricularly administration (36% and 76% increase, respectively). Consequently, mortality (47%) and the incidence of arrhythmic episodes (12 per 2 h) were improved with both routes of ghrelin administration (<13% and less than five per 2 h, respectively). Bilateral vagotomy significantly attenuated the cardiac SNA response to acute MI (99% increase). Ghrelin further attenuated the sympathetic response to MI in vagotomized rats so that the SNA response was comparable between vagotomized and vagal-intact MI rats treated with ghrelin. These results suggest that ghrelin may act primarily via a central pathway within the brain to suppress SNA after MI, although peripheral vagal afferent pathways may also contribute in part. The exact region(s) within the central nervous system whereby ghrelin inhibits SNA remains to be fully elucidated.

  20. Light-induced c-Fos expression in the SCN and behavioural phase shifts of Djungarian hamsters with a delayed activity onset.

    PubMed

    Schöttner, Konrad; Vuillez, Patrick; Challet, Etienne; Pévet, Paul; Weinert, Dietmar

    2015-06-01

    C-Fos expression in the suprachiasmatic nucleus (SCN) and phase shifts of the activity rhythm following photic stimulation were investigated in Djungarian hamsters (Phodopus sungorus) of two different circadian phenotypes. Wild-type (WT) hamsters display robust daily patterns of locomotor activity according to the light/dark conditions. Hamsters of the DAO (delayed activity onset) phenotype, however, progressively delay the activity onset, whereas activity offset remains coupled to "light-on". Although the exact reason for the delayed activity onset is not yet clarified, it is connected with a disturbed interaction between the light/dark cycle and the circadian clock. The aim was to test the link between photoreception and the behavioral output of the circadian system in hamsters of both phenotypes, to get further insight in the underlying mechanism of the DAO phenomenon. Animals were exposed to short light pulses at different times during the dark period to analyze phase shifts of the activity rhythm and expression of Fos protein in the SCN. The results indicate that the photosensitive phase in DAO hamsters is shifted like the activity onset. Also, phase shifts were significantly smaller in DAO hamsters. At the same time, levels of Fos expression did not differ between phenotypes regarding the circadian phase. The results provide evidence that the shifted photosensitivity of the circadian system in DAO hamsters does not differ from that of WT animals, and lead us to conclude that processes within the SCN that enable light information to reset the circadian pacemaker might offer an explanation for the DAO phenomenon.

  1. Reversal of novelty-induced hippocampal c-Fos expression in GluA1 subunit-deficient mice by chronic treatment targeting glutamatergic transmission.

    PubMed

    Maksimovic, Milica; Aitta-aho, Teemu; Korpi, Esa R

    2014-12-15

    Malfunction of glutamate transmission is implicated in several neuropsychiatric disorders. Gria1-/- mouse line with knocked-out GluA1 subunits of ionotropic AMPA glutamate receptor displays several behavioural features of schizoaffective disorder. Typically, these mice show hyperactivity provoked by environmental novelty, which is attenuated after 4-week treatment with the standard mood-stabilisers lithium and valproate and the mood-stabilising anticonvulsants topiramate and lamotrigine (Maksimovic, M., Vekovischeva, O.Y., Aitta-Aho, T., Korpi, E.R., 2014. Chronic treatment with mood-stabilizers attenuates abnormal hyperlocomotion of GluA1-subunit deficient mice. PloS One. 9, e100188). Here, we complement our study by treating these mice chronically with perampanel, a novel non-competitive antagonist of AMPA receptors, for 4 weeks at the dose of 60 mg/kg diet, and found reduced locomotor hyperactivity in the Gria1-/- animals, while not affecting the wild-type littermates. To study the cellular mechanism by which chronic treatments with glutamate-modulating mood-stabilizing drugs alleviate this hyperactivity, we used the immediate early gene c-Fos protein expression as a marker of neuronal activity in the brain. Chronic lithium, valproate and topiramate blunted the c-Fos expression especially in the dorsal hippocampus of the Gria1-/- mice, with all of them reducing the number of c-Fos-positive cells in the CA3 region and valproate and topiramate also in the dentate gyrus (DG). Lamotrigine and perampanel treatments had the same effect in the all CA1, CA3 and DG subfields of the dorsal hippocampus of Gria1-/- mice. The results suggest that abnormal (hippocampal) glutamatergic transmission underlies the hyperactive phenotype of the Gria1-/- mice in a novel environment, and based on the efficacies of the present chronic drug treatments, this mouse model may serve as a predictive tool for studying novel mood-stabilisers. PMID:25446922

  2. The role of the central ghrelin system in reward from food and chemical drugs.

    PubMed

    Dickson, Suzanne L; Egecioglu, Emil; Landgren, Sara; Skibicka, Karolina P; Engel, Jörgen A; Jerlhag, Elisabet

    2011-06-20

    Here we review recent advances that identify a role for the central ghrelin signalling system in reward from both natural rewards (such as food) and artificial rewards (that include alcohol and drugs of abuse). Whereas ghrelin emerged as a stomach-derived hormone involved in energy balance, hunger and meal initiation via hypothalamic circuits, it now seems clear that it also has a role in motivated reward-driven behaviours via activation of the so-called "cholinergic-dopaminergic reward link". This reward link comprises a dopamine projection from the ventral tegmental area (VTA) to the nucleus accumbens together with a cholinergic input, arising primarily from the laterodorsal tegmental area. Ghrelin administration into the VTA or LDTg activates the "cholinergic-dopaminergic" reward link, suggesting that ghrelin may increase the incentive value of motivated behaviours such as reward-seeking behaviour ("wanting" or "incentive motivation"). Further, direct injection of ghrelin into the brain ventricles or into the VTA increases the consumption of rewarding foods as well as alcohol in mice and rats. Studies in rodents show beneficial effects of ghrelin receptor (GHS-R1A) antagonists to suppress the intake of palatable food, to reduce preference for caloric foods, to suppress food reward and motivated behaviour for food. They have also been shown to reduce alcohol consumption, suppress reward induced by alcohol, cocaine and amphetamine. Furthermore, variations in the GHS-R1A and pro-ghrelin genes have been associated with high alcohol consumption, smoking and increased weight gain in alcohol dependent individuals as well as with bulimia nervosa and obesity. Thus, the central ghrelin signalling system interfaces neurobiological circuits involved in reward from food as well as chemical drugs; agents that directly or indirectly suppress this system emerge as potential candidate drugs for suppressing problematic over-eating that leads to obesity as well as for the

  3. Methyl Donor Deficiency Affects Fetal Programming of Gastric Ghrelin Cell Organization and Function in the Rat

    PubMed Central

    Bossenmeyer-Pourié, Carine; Blaise, Sébastien; Pourié, Grégory; Tomasetto, Catherine; Audonnet, Sandra; Ortiou, Sandrine; Koziel, Violette; Rio, Marie-Christine; Daval, Jean-Luc; Guéant, Jean-Louis; Beck, Bernard

    2010-01-01

    Methyl donor deficiency (MDD) during pregnancy influences intrauterine development. Ghrelin is expressed in the stomach of fetuses and influences fetal growth, but MDD influence on gastric ghrelin is unknown. We examined the gastric ghrelin system in MDD-induced intrauterine growth retardation. By using specific markers and approaches (such as periodic acid–Schiff, bromodeoxyuridine, homocysteine, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling, immunostaining, reverse transcription-polymerase chain reaction), we studied the gastric oxyntic mucosa cellular organization and ghrelin gene expression in the mucosa in 20-day-old fetuses and weanling pups, and plasma ghrelin concentration in weanling rat pups of dams either normally fed or deprived of choline, folate, vitamin B6, and vitamin B12 during gestation and suckling periods. MDD fetuses weighed less than controls; the weight deficit reached 57% at weaning (P < 0.001). Both at the end of gestation and at weaning, they presented with an aberrant gastric oxyntic mucosa formation with loss of cell polarity, anarchic cell migration, abnormal progenitor differentiation, apoptosis, and signs of surface layer erosion. Ghrelin cells were abnormally located in the pit region of oxyntic glands. At weaning, plasma ghrelin levels were decreased (−28%; P < 0.001) despite unchanged mRNA expression in the stomach. This decrease was associated with lower body weight. Taken together, these data indicate that one mechanism through which MDD influences fetal programming is the remodeling of gastric cellular organization, leading to dysfunction of the ghrelin system and dramatic effects on growth. PMID:19948829

  4. Effects of ghrelin and motilin on smooth muscle contractility of the isolated gastrointestinal tract from the bullfrog and Japanese fire belly newt.

    PubMed

    Kitazawa, Takio; Shimazaki, Misato; Kikuta, Ayumi; Yaosaka, Noriko; Teraoka, Hiroki; Kaiya, Hiroyuki

    2016-06-01

    Ghrelin has been identified in some amphibians and is known to stimulate growth hormone release and food intake as seen in mammals. Ghrelin regulates gastrointestinal motility in mammals and birds. The aim of this study was to determine whether ghrelin affects gastrointestinal smooth muscle contractility in bullfrogs (anuran) and Japanese fire belly newts (urodelian) in vitro. Neither bullfrog ghrelin nor rat ghrelin affected longitudinal smooth muscle contractility of gastrointestinal strips from the bullfrog. Expression of growth hormone secretagogue receptor 1a (GHS-R1a) mRNA was confirmed in the bullfrog gastrointestinal tract, and the expression level in the gastric mucosa was lower than that in the intestinal mucosa. In contrast, some gastrointestinal peptides, including substance P, neurotensin and motilin, and the muscarinic receptor agonist carbachol showed marked contraction, indicating normality of the smooth muscle preparations. Similar results were obtained in another amphibian, the Japanese fire belly newt. Newt ghrelin and rat ghrelin did not cause any contraction in gastrointestinal longitudinal muscle, whereas substance P and carbachol were effective causing contraction. In conclusion, ghrelin does not affect contractility of the gastrointestinal smooth muscle in anuran and urodelian amphibians, similar to results for rainbow trout and goldfish (fish) but different from results for rats and chickens. The results suggest diversity of ghrelin actions on the gastrointestinal tract across animals. This study also showed for the first time that motilin induces gastrointestinal contraction in amphibians. PMID:26704852

  5. Combined Administration of Human Ghrelin and Human Growth Hormone Attenuates Organ Injury and Improves Survival in Aged Septic Rats

    PubMed Central

    Yang, Weng-Lang; Ma, Gaifeng; Zhou, Mian; Aziz, Monowar; Yen, Hao-Ting; Marvropoulos, Spyros A; Ojamaa, Kaie; Wang, Ping

    2016-01-01

    Sepsis is a major healthcare concern, especially in the elderly population. The use of an animal model closely resembling clinical conditions in this population may provide a better prediction in translating bench studies to the bedside. Ghrelin inhibits sympathetic nerve activity and inflammation in young septic animals; however, aged animals become hyporesponsive to ghrelin. In this study, we evaluated the efficacy of combined human ghrelin and growth hormone (GH) for sepsis treatment in the elderly utilizing a clinically relevant animal model of sepsis. Male Fischer 344 rats 22 to 24 months old were subjected to cecal ligation and puncture (CLP). Human ghrelin plus GH or vehicle (normal saline) was administered subcutaneously at 5 h after CLP. At 20 h after CLP, blood and tissue samples were collected for various analyses. Combined treatment attenuated serum levels of lactate, lactate dehydrogenase, creatinine, blood urea nitrogen, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in aged septic rats. The integrity of the microscopic structure in the lungs, liver and kidneys was well preserved after treatment. Expression of IL-6, TNF-α, macrophage inflammatory protein-2 and keratinocyte-derived chemokine as well as myeloperoxidase activity and caspase-3 activation were significantly reduced in the lungs and liver of treated rats. Moreover, treated rats showed an improvement in cardiovascular function and increased expression of ghrelin receptor and c-fos in the brainstem. Finally, the 10-d survival of aged septic rats was increased from 29% to 64% after combined treatment and was associated with less body weight loss. Our findings warrant the development of combined human ghrelin and GH for sepsis treatment in the geriatric population. PMID:26835699

  6. Ghrelin receptor controls obesity by fat burning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emerging evidence show that brown fat in the body produces heat to burn energy, thus prompting weight loss. Ghrelin is the only known hormone which increases appetite and promotes weight gain. We have reported that mice that lack the receptor which mediates the functions of ghrelin are lean. Our fu...

  7. Plasma butyrylcholinesterase regulates ghrelin to control aggression.

    PubMed

    Chen, Vicky Ping; Gao, Yang; Geng, Liyi; Parks, Robin J; Pang, Yuan-Ping; Brimijoin, Stephen

    2015-02-17

    Ongoing mouse studies of a proposed therapy for cocaine abuse based on viral gene transfer of butyrylcholinesterase (BChE) mutated for accelerated cocaine hydrolysis have yielded surprising effects on aggression. Further investigation has linked these effects to a reduction in circulating ghrelin, driven by BChE at levels ∼ 100-fold above normal. Tests with human BChE showed ready ghrelin hydrolysis at physiologic concentrations, and multiple low-mass molecular dynamics simulations revealed that ghrelin's first five residues fit sterically and electrostatically into BChE's active site. Consistent with in vitro results, male BALB/c mice with high plasma BChE after gene transfer exhibited sharply reduced plasma ghrelin. Unexpectedly, such animals fought less, both spontaneously and in a resident/intruder provocation model. One mutant BChE was found to be deficient in ghrelin hydrolysis. BALB/c mice transduced with this variant retained normal plasma ghrelin levels and did not differ from untreated controls in the aggression model. In contrast, C57BL/6 mice with BChE gene deletion exhibited increased ghrelin and fought more readily than wild-type animals. Collectively, these findings indicate that BChE-catalyzed ghrelin hydrolysis influences mouse aggression and social stress, with potential implications for humans.

  8. Therapeutic potential of ghrelin in restricting-type anorexia nervosa.

    PubMed

    Hotta, Mari; Ohwada, Rina; Akamizu, Takashi; Shibasaki, Tamotsu; Kangawa, Kenji

    2012-01-01

    Anorexia nervosa (AN) is an eating disorder characterized by a decrease in caloric intake and malnutrition. It is associated with a variety of medical morbidities as well as significant mortality. Nutritional support is of paramount importance to prevent impaired quality of life later in life in affected patients. Some patients with restricting-type AN who are fully motivated to gain body weight cannot increase their food intake because of malnutrition-induced gastrointestinal dysfunction. Chronicity of AN prevents participation in social activities and leads to increased medical expenses. Therefore, there is a pressing need for effective appetite-stimulating therapies for patients with AN. Ghrelin is the only orexigenic hormone that can be given intravenously. Intravenous infusion of ghrelin is reported to increase food intake and body weight in healthy subjects as well as in patients with poor nutritional status. Here, we introduce the results of a pilot study that investigated the effects of ghrelin on appetite, energy intake, and nutritional parameters in five patients with restricting-type AN, who are fully motivated to gain body weight but could not increase their food intake because of malnutrition-induced gastrointestinal dysfunction.

  9. Ghrelin in female and male reproduction.

    PubMed

    Dupont, Joëlle; Maillard, Virginie; Coyral-Castel, Stéphanie; Ramé, Christelle; Froment, Pascal

    2010-01-01

    Ghrelin and one of its functional receptors, GHS-R1a (Growth Hormone Secretagogue Receptor 1a), were firstly studied about 15 years. Ghrelin is a multifunctional peptide hormone that affects several biological functions including food intake, glucose release, cell proliferation... Ghrelin and GHS-R1a are expressed in key cells of both male and female reproductive organs in several species including fishes, birds, and mammals suggesting a well-conserved signal through the evolution and a role in the control of fertility. Ghrelin could be a component of the complex series of nutrient sensors such as adipokines, and nuclear receptors, which regulate reproduction in function of the energy stores. The objective of this paper was to report the available information about the ghrelin system and its role at the level of the hypothalamic-pituitary-gonadal axis in both sexes.

  10. Ghrelin augments murine T-cell proliferation by activation of the phosphatidylinositol-3-kinase, extracellular signal-regulated kinase and protein kinase C signaling pathways.

    PubMed

    Lee, Jun Ho; Patel, Kalpesh; Tae, Hyun Jin; Lustig, Ana; Kim, Jie Wan; Mattson, Mark P; Taub, Dennis D

    2014-12-20

    Thymic atrophy occurs during normal aging, and is accelerated by exposure to chronic stressors that elevate glucocorticoid levels and impair the naïve T cell output. The orexigenic hormone ghrelin was recently shown to attenuate age-associated thymic atrophy. Here, we report that ghrelin enhances the proliferation of murine CD4+ primary T cells and a CD4+ T-cell line. Ghrelin induced activation of the ERK1/2 and Akt signaling pathways, via upstream activation of phosphatidylinositol-3-kinase and protein kinase C, to enhance T-cell proliferation. Moreover, ghrelin induced expression of the cell cycle proteins cyclin D1, cyclin E, cyclin-dependent kinase 2 (CDK2) and retinoblastoma phosphorylation. Finally, ghrelin activated the above-mentioned signaling pathways and stimulated thymocyte proliferation in young and older mice in vivo. PMID:25447526

  11. Ghrelin augments murine T-cell proliferation by activation of the phosphatidylinositol-3-kinase, extracellular signal-regulated kinase and protein kinase C signaling pathways

    PubMed Central

    Lee, Jun Ho; Patel, Kalpesh; Tae, Hyun Jin; Lustig, Ana; Kim, Jie Wan; Mattson, Mark P.; Taub, Dennis D.

    2014-01-01

    Thymic atrophy occurs during normal aging, and is accelerated by exposure to chronic stressors that elevate glucocorticoid levelsand impair the naïve T cell output. The orexigenic hormone ghrelin was recently shown to attenuate age-associated thymic atrophy. Here, we report that ghrelin enhances the proliferation of murine CD4+ primary T cells and a CD4+ T-cell line. Ghrelin induced activation of the ERK1/2 and Akt signaling pathways, via upstream activation of phosphatidylinositol-3-kinase and protein kinase C, to enhance T-cell proliferation. Moreover, ghrelin induced expression of the cell cycle proteins cyclin D1, cyclin E, cyclin-dependent kinase 2 (CDK2) and retinoblastoma phosphorylation. Finally, ghrelin activated the above-mentioned signaling pathways and stimulated thymocyte proliferation in young and older mice in vivo. PMID:25447526

  12. Microinjection of fos-specific antibodies blocks DNA synthesis in fibroblast cells

    SciTech Connect

    Riabowol, K.T.; Vosatka, R.J.; Ziff, E.B.; Lamb, N.J.; Feramisco, J.R.

    1988-04-01

    Transcription of the protooncogene c-fos is increased >10-fold within minutes of treatment of fibroblasts with serum or purified growth factors. Recent experiments with mouse 3T3 cell lines containing inducible fos antisense RNA constructs have shown that induced fos antisense RNA transcripts cause either a marked inhibition of growth in continuously proliferating cells or, conversely, a minimal effect except during the transition from a quiescent (G/sub o/) state into the cell cycle. Since intracellular production of large amounts of antisense RNA does not completely block gene expression, the authors microinjected affinity-purified antibodies raised against fos to determine whether and when during the cell cycle c-fos expression was required for cell proliferation. Using this independent method, they found that microinjected fos antibodies efficiently blocked serum-stimulated DNA synthesis when injected up to 6 to 8 h after serum stimulation of quiescent REF-52 fibroblasts. Furthermore, when fos antibodies were injected into asynchronously growing cells, a consistently greater number of cells was prevented from synthesizing DNA than when cells were injected with nonspecific immunoglobulins. Thus, whereas the activity of c-fos may be necessary for transition of fibroblasts from G/sub o/ to G/sub 1/ of the cell cycle, its function is also required during the early G/sub 1/ portion of the cell cycle to allow subsequent DNA synthesis.

  13. Anatomical markers of activity in neuroendocrine systems: are we all 'fos-ed out'?

    PubMed

    Hoffman, G E; Lyo, D

    2002-04-01

    It has now been nearly 15 years since the immediate early gene, c-fos, and its protein product, Fos, were introduced as tools for determining activity changes within neurones of the nervous system. In the ensuing years, this approach was applied to neuroendocrine study with success. With it have come advances in our understanding of which neuroendocrine neurones respond to various stimuli and how other central nervous system components interact with neuroendocrine neurones. Use of combined tract-tracing approaches, as well as double-labelling for Fos and transmitter markers, have added to characterization of neuroendocrine circuits. The delineation of the signal transduction cascades that induce Fos expression has led to establishment of the relationship between neurone firing and Fos expression. Importantly, we can now appreciate that Fos expression is often, but not always, associated with increased neuronal firing and vice versa. There are remaining gaps in our understanding of Fos in the nervous system. To date, knowledge of what Fos does after it is expressed is still limited. The transience of Fos expression after stimulation (especially if the stimulus is persistent) complicates design of experiments to assess the function of Fos and makes Fos of little value as a marker for long-term changes in neurone activity. In this regard, alternative approaches must be sought. Useful alternative approaches employed to date to monitor neuronal changes in activity include examination of (i) signal transduction intermediates (e.g. phosphorylated CREB); (ii) transcriptional/translational intermediates (e.g. heteronuclear RNA, messenger RNA (mRNA), prohormones); and (iii) receptor translocation. Another capitalizes on the fact that many neuroendocrine systems show striking stimulus-transcription coupling in the regulation of their transmitter or its synthetic enzymes. Together, as we move into the 21st Century, the use of multiple approach to study activity within

  14. A defect in nurturing in mice lacking the immediate early gene fosB.

    PubMed

    Brown, J R; Ye, H; Bronson, R T; Dikkes, P; Greenberg, M E

    1996-07-26

    Although expression of the Fos family of transcription factors is induced by environmental stimuli that trigger adaptive neuronal response, evidence that Fos family members mediate these responses is lacking. To address this issue, mice were generated with an inactivating mutation in the fosB gene. fosB mutant mice are profoundly deficient in their ability to nurture young animals but are normal with respect to other cognitive and sensory functions. The nurturing defect is likely due to the absence of FosB in the preoptic area, a region of the hypothalamus that is critical for nurturing. These observations suggest that a transcription factor controls a complex behavior by regulating a specific neuronal circuit and indicate that nurturing in mammals has a genetic component.

  15. Ghrelin receptor regulates adipose tissue inflammation in aging

    PubMed Central

    Buras, Eric D.; Yu, Kaijiang; Wang, Ruitao; Smith, C. Wayne; Wu, Huaizhu; Sheikh-Hamad, David; Sun, Yuxiang

    2016-01-01

    Aging is commonly associated with low-grade adipose inflammation, which is closely linked to insulin resistance. Ghrelin is the only circulating orexigenic hormone which is known to increase obesity and insulin resistance. We previously reported that the expression of the ghrelin receptor, growth hormone secretagogue receptor (GHS-R), increases in adipose tissues during aging, and old Ghsr−/− mice exhibit a lean and insulin-sensitive phenotype. Macrophages are major mediators of adipose tissue inflammation, which consist of pro-inflammatory M1 and anti-inflammatory M2 subtypes. Here, we show that in aged mice, GHS-R ablation promotes macrophage phenotypical shift toward anti-inflammatory M2. Old Ghsr−/− mice have reduced macrophage infiltration, M1/M2 ratio, and pro-inflammatory cytokine expression in white and brown adipose tissues. We also found that peritoneal macrophages of old Ghsr−/− mice produce higher norepinephrine, which is in line with increased alternatively-activated M2 macrophages. Our data further reveal that GHS-R has cell-autonomous effects in macrophages, and GHS-R antagonist suppresses lipopolysaccharide (LPS)-induced inflammatory responses in macrophages. Collectively, our studies demonstrate that ghrelin signaling has an important role in macrophage polarization and adipose tissue inflammation during aging. GHS-R antagonists may serve as a novel and effective therapeutic option for age-associated adipose tissue inflammation and insulin resistance. PMID:26837433

  16. Impaired barrier function by dietary fructo-oligosaccharides (FOS) in rats is accompanied by increased colonic mitochondrial gene expression

    PubMed Central

    Rodenburg, Wendy; Keijer, Jaap; Kramer, Evelien; Vink, Carolien; van der Meer, Roelof; Bovee-Oudenhoven, Ingeborg MJ

    2008-01-01

    Background Dietary non-digestible carbohydrates stimulate the gut microflora and are therefore presumed to improve host resistance to intestinal infections. However, several strictly controlled rat infection studies showed that non-digestible fructo-oligosaccharides (FOS) increase, rather than decrease, translocation of Salmonella towards extra-intestinal sites. In addition, it was shown that FOS increases intestinal permeability already before infection. The mechanism responsible for this adverse effect of FOS is unclear. Possible explanations are altered mucosal integrity due to changes in tight junctions or changes in expression of defense molecules such as antimicrobials and mucins. To examine the mechanisms underlying weakening of the intestinal barrier by FOS, a controlled dietary intervention study was performed. Two groups of 12 rats were adapted to a diet with or without FOS. mRNA was collected from colonic mucosa and changes in gene expression were assessed for each individual rat using Agilent rat whole genome microarrays. Results Among the 997 FOS induced genes we observed less mucosal integrity related genes than expected with the clear permeability changes. FOS did not induce changes in tight junction genes and only 8 genes related to mucosal defense were induced by FOS. These small effects are unlikely the cause for the clear increase in intestinal permeability that is observed. FOS significantly increased expression of 177 mitochondria-related genes. More specifically, induced expression of genes involved in all five OXPHOS complexes and the TCA cycle was observed. These results indicate that dietary FOS influences intestinal mucosal energy metabolism. Furthermore, increased expression of 113 genes related to protein turnover, including proteasome genes, ribosomal genes and protein maturation related genes, was seen. FOS upregulated expression of the peptide hormone proglucagon gene, in agreement with previous studies, as well as three other peptide

  17. c-Fos as a transcription factor: a stressful (re)view from a functional map.

    PubMed

    Kovács, K J

    1998-10-01

    This article summarizes the achievements that have been accumulated about the role of c-Fos as a transcription factor and as a functional marker of activated neurons. Since its discovery, more than a decade ago, as an inducible immediate-early gene encoding a transcription factor, or third messenger, involved in stimulus-transcription coupling and mediation of extracellular signals to long-term changes in cellular phenotype, c-fos became the most widely used powerful tool to delineate individual neurons as well as extended circuitries that are responsive to wide variety of external stimuli. There still remain uncertainties as to how general is the c-fos induction in the central neurons, and whether the threshold of c-fos induction is comparable along a certain neuronal circuit. The major limitation of this technology is that c-fos does not mark cells with a net inhibitory synaptic or transcriptional drive, and c-fos induction, as a generic marker of trans-synaptic activation, does not provide evidence for transcriptional activation of specific target genes in a certain cell type of interest. The first part of the review focuses on recent functional data on c-fos as transcription factor, while the second part discusses c-fos as a cellular marker of transcriptional activity in the stress-related circuitry.

  18. Differential activation of c-Fos in the paraventricular nuclei of the hypothalamus and thalamus following myocardial infarction in rats

    PubMed Central

    Tae, Hyun-Jin; Park, Seung Min; Cho, Jeong Hwi; Kim, In Hye; Ahn, Ji Hyeon; Park, Joon Ha; Won, Moo-Ho; Chen, Bai Hui; Shin, Bich-Na; Shin, Myoung Cheol; Lee, Choong Hyun; Hong, Seongkweon; Lee, Jae-Chul; Cho, Jun Hwi

    2016-01-01

    Proto-oncogene c-Fos (c-Fos) is frequently used to detect a pathogenesis in central nervous system disorders. The present study examined changes in the immunoreactivity of c-Fos in the paraventricular nucleus of the hypothalamus (PVNH) and paraventricular nucleus of the thalamus (PVNT) following myocardial infarction (MI) in rats. Infarction in the left ventricle was examined by Masson's trichrome staining. Neuronal degeneration was monitored for 56 days after MI using crystal violet and Fluoro-Jade B histofluorescence staining. Changes in the immunoreactivity of c-Fos were determined using immunohistochemistry for c-Fos. The average infarct size of the left ventricle circumference was ~44% subsequent to MI. Neuronal degeneration was not detected in PVNH and PVNT following MI. c-Fos immunoreactive (+) cells were infrequently observed in the nuclei of the sham-group. However, the number of c-Fos+ cells was increased in the nuclei following MI and peaked in the PVNH and PVNT at 3 and 14 days, respectively. The number of c-Fos+ cells were comparable with the sham group at 56 days after MI. Therefore, MI may induce c-Fos immunoreactivity in PVNH and PVNT, this increase of c-Fos expression levels may be associated with the stress that occurs in the brain following MI. PMID:27601012

  19. The ghrelin receptor agonist HM01 mimics the neuronal effects of ghrelin in the arcuate nucleus and attenuates anorexia-cachexia syndrome in tumor-bearing rats.

    PubMed

    Borner, Tito; Loi, Laura; Pietra, Claudio; Giuliano, Claudio; Lutz, Thomas A; Riediger, Thomas

    2016-07-01

    The gastric hormone ghrelin positively affects energy balance by increasing food intake and reducing energy expenditure. Ghrelin mimetics are a possible treatment against cancer anorexia-cachexia syndrome (CACS). This study aimed to characterize the action of the nonpeptidergic ghrelin receptor agonist HM01 on neuronal function, energy homeostasis and muscle mass in healthy rats and to evaluate its possible usefulness for the treatment of CACS in a rat tumor model. Using extracellular single-unit recordings, we tested whether HM01 mimics the effects of ghrelin on neuronal activity in the arcuate nucleus (Arc). Furthermore, we assessed the effect of chronic HM01 treatment on food intake (FI), body weight (BW), lean and fat volumes, and muscle mass in healthy rats. Using a hepatoma model, we investigated the possible beneficial effects of HM01 on tumor-induced anorexia, BW loss, muscle wasting, and metabolic rate. HM01 (10(-7)-10(-6) M) mimicked the effect of ghrelin (10(-8) M) by increasing the firing rate in 76% of Arc neurons. HM01 delivered chronically for 12 days via osmotic minipumps (50 μg/h) increased FI in healthy rats by 24%, paralleled by increased BW, higher fat and lean volumes, and higher muscle mass. Tumor-bearing rats treated with HM01 had 30% higher FI than tumor-bearing controls and were protected against BW loss. HM01 treatment resulted in higher muscle mass and fat mass. Moreover, tumor-bearing rats reduced their metabolic rate following HM01 treatment. Our studies substantiate the possible therapeutic usefulness of ghrelin receptor agonists like HM01 for the treatment of CACS and possibly other forms of disease-related anorexia and cachexia. PMID:27147616

  20. The ghrelin receptor agonist HM01 mimics the neuronal effects of ghrelin in the arcuate nucleus and attenuates anorexia-cachexia syndrome in tumor-bearing rats.

    PubMed

    Borner, Tito; Loi, Laura; Pietra, Claudio; Giuliano, Claudio; Lutz, Thomas A; Riediger, Thomas

    2016-07-01

    The gastric hormone ghrelin positively affects energy balance by increasing food intake and reducing energy expenditure. Ghrelin mimetics are a possible treatment against cancer anorexia-cachexia syndrome (CACS). This study aimed to characterize the action of the nonpeptidergic ghrelin receptor agonist HM01 on neuronal function, energy homeostasis and muscle mass in healthy rats and to evaluate its possible usefulness for the treatment of CACS in a rat tumor model. Using extracellular single-unit recordings, we tested whether HM01 mimics the effects of ghrelin on neuronal activity in the arcuate nucleus (Arc). Furthermore, we assessed the effect of chronic HM01 treatment on food intake (FI), body weight (BW), lean and fat volumes, and muscle mass in healthy rats. Using a hepatoma model, we investigated the possible beneficial effects of HM01 on tumor-induced anorexia, BW loss, muscle wasting, and metabolic rate. HM01 (10(-7)-10(-6) M) mimicked the effect of ghrelin (10(-8) M) by increasing the firing rate in 76% of Arc neurons. HM01 delivered chronically for 12 days via osmotic minipumps (50 μg/h) increased FI in healthy rats by 24%, paralleled by increased BW, higher fat and lean volumes, and higher muscle mass. Tumor-bearing rats treated with HM01 had 30% higher FI than tumor-bearing controls and were protected against BW loss. HM01 treatment resulted in higher muscle mass and fat mass. Moreover, tumor-bearing rats reduced their metabolic rate following HM01 treatment. Our studies substantiate the possible therapeutic usefulness of ghrelin receptor agonists like HM01 for the treatment of CACS and possibly other forms of disease-related anorexia and cachexia.

  1. An Indirect Action Contributes to C-Fos Induction in Paraventricular Hypothalamic Nucleus by Neuropeptide Y

    PubMed Central

    Fan, Shengjie; Dakshinamoorthy, Janani; Kim, Eun Ran; Xu, Yong; Huang, Cheng; Tong, Qingchun

    2016-01-01

    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 to examine the underlying NPY orexigenic neural pathways. However, PVH C-Fos induction is in discordance with the abundant expression of NPY receptors, a group of inhibitory Gi protein coupled receptors in the PVH, and with the overall role of PVH neurons in feeding inhibition, suggesting a mechanism of indirect action. Here we showed that the ability of NPY on C-Fos induction in the PVH was blunted in conditions of insulin deficiency and fasting, a condition associated with a high level of NPY and a low level of insulin. Moreover, insulin insufficiency blunted C-Fos induction in the PVH by fasting-induced re-feeding, and insulin and NPY induced c-Fos induction in the same group of PVH neurons. Finally, NPY produced normal C-Fos induction in the PVH with disruption of GABA-A receptors. Thus, our results revealed that PVH C-Fos induction by NPY is mediated by an indirect action, which is at least partially mediated by insulin action, but not GABA-A receptors. PMID:26813148

  2. Long Noncoding RNA FosDT Promotes Ischemic Brain Injury by Interacting with REST-Associated Chromatin-Modifying Proteins

    PubMed Central

    Mehta, Suresh L.; Kim, TaeHee

    2015-01-01

    Ischemia induces extensive temporal changes in cerebral transcriptome that influences the neurologic outcome after stroke. In addition to protein-coding RNAs, many classes of noncoding RNAs, including long noncoding RNAs (LncRNAs), also undergo changes in the poststroke brain. We currently evaluated the functional significance of an LncRNA called Fos downstream transcript (FosDT) that is cogenic with Fos gene. Following transient middle cerebral artery occlusion (MCAO) in adult rats, expression of FosDT and Fos was induced. FosDT knockdown significantly ameliorated the postischemic motor deficits and reduced the infarct volume. Focal ischemia also increased FosDT binding to chromatin-modifying proteins (CMPs) Sin3a and coREST (corepressors of the transcription factor REST). Furthermore, FosDT knockdown derepressed REST-downstream genes GRIA2, NFκB2, and GRIN1 in the postischemic brain. Thus, FosDT induction and its interactions with REST-associated CMPs, and the resulting regulation of REST-downstream genes might modulate ischemic brain damage. LncRNAs, such as FosDT, can be therapeutically targeted to minimize poststroke brain damage. SIGNIFICANCE STATEMENT Mammalian brain is abundantly enriched with long noncoding RNAs (LncRNAs). Functional roles of LncRNAs in normal and pathological states are not yet understood. This study identified that LncRNA FosDT induced after transient focal ischemia modulates poststroke behavioral deficits and brain damage. These effects of FosDT in part are due to its interactions with chromatin-modifying proteins Sin3a and coREST (corepressors of the transcription factor REST) and subsequent derepression of REST-downstream genes GRIA2, NFκB2, and GRIN1. Therefore, LncRNA-mediated epigenetic remodeling could determine stroke outcome. PMID:26674869

  3. Cadmium-induced cell transformation and tumorigenesis are associated with transcriptional activation of c-fos, c-jun, and c-myc proto-oncogenes: role of cellular calcium and reactive oxygen species.

    PubMed

    Joseph, P; Muchnok, T K; Klishis, M L; Roberts, J R; Antonini, J M; Whong, W Z; Ong, T

    2001-06-01

    The molecular mechanisms of carcinogenesis by cadmium were studied using BALB/c-3T3 cell transformation and nude mouse tumorigenesis models. BALB/c-3T3 cells transformed with cadmium chloride were subcutaneously injected into nude mice to develop tumors and the cell lines derived from these tumors were used in the present study. The proto-oncogenes c-fos and c-jun were overexpressed in 100% (10 out of 10) of the cell lines, while a statistically significant overexpression of c-myc was observed in 40% (4 out of 10) of the cell lines. Analysis of tumor cells stained with fluorescent dyes specific for reactive oxygen species revealed that these cells possessed markedly higher levels of superoxide anion and hydrogen peroxide compared with the nontransformed cells. Similarly, the intracellular calcium level was higher in the tumor cells compared with the nontransformed cells. Overexpression of the proto-oncogenes in these cells was blocked by treating the cells with superoxide dismutase, catalase, and 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetra acetoxy methyl ester (BAPTA/AM), which are scavengers of superoxide anion, hydrogen peroxide, and calcium, respectively. This confirmed that the overexpression of the proto-oncogenes in the tumor cells required elevated intracellular levels of reactive oxygen species and calcium. In addition to the scavengers of reactive oxygen species and calcium, inhibitors specific for transcription (actinomycin D), protein kinase C (RO-31-8220), and MAP kinase (PD 98059) also blocked the cadmium-induced overexpression of the proto-oncogenes in the tumor cells. Exposure of the nontransformed BALB/c-3T3 cells to 20 microM cadmium chloride for 1 h caused elevated intracellular levels of superoxide anion, hydrogen peroxide, and calcium, with corresponding increases in the expression levels of c-fos, c-jun, and c-myc. As in the case of the tumor cells, treating the nontransformed cells with the various modulators prior to their exposure to

  4. Pathogenesis of rheumatoid arthritis and c-Fos/AP-1.

    PubMed

    Shiozawa, Shunichi; Tsumiyama, Ken

    2009-05-15

    c-Fos/AP-1 controls the expression of inflammatory cytokines and matrix-degrading matrix metalloproteinases (MMPs) important in arthritis via promoter AP-1 binding motif. Among inflammatory cytokines, IL-1beta is the most important inducer of a variety of MMPs, and mainly responsible for cartilage breakdown and osteoclastogenesis. IL-1beta and c-Fos/AP-1 influence each other's gene expression and activity, resulting in an orchestrated cross-talk that is crucial to arthritic joint destruction, where TNFalpha can act synergistically with them. While how to stop the degradation of bone and cartilage, i.e., to control MMP, has long been the central issue in the research of rheumatoid arthritis (RA), selective inhibition of c-Fos/AP-1 does resolve arthritic joint destruction. Thus, the blockade of IL-1beta and/or c-Fos/AP-1 can be promising as an effective therapy for rheumatoid joint destruction in addition to the currently available TNFalpha blocking agents that act mainly on arthritis.

  5. Ghrelin binding to serum albumin and its biological impact.

    PubMed

    Lufrano, Daniela; Trejo, Sebastián A; Llovera, Ramiro E; Salgueiro, Mariano; Fernandez, Gimena; Martínez Damonte, Valentina; González Flecha, F Luis; Raingo, Jesica; Ermácora, Mario R; Perelló, Mario

    2016-11-15

    Ghrelin is an octanoylated peptide hormone that plays a key role in the regulation of the body weight and glucose homeostasis. In plasma, ghrelin circulates bound to larger proteins whose identities are partially established. Here, we used size exclusion chromatography, mass spectrometry and isothermal titration microcalorimetry to show that ghrelin interacts with serum albumin. Furthermore, we found that such interaction displays an estimated dissociation constant (KD) in the micromolar range and involves albumin fatty-acid binding sites as well as the octanoyl moiety of ghrelin. Notably, albumin-ghrelin interaction reduces the spontaneous deacylation of the hormone. Both in vitro experiments-assessing ghrelin ability to inhibit calcium channels-and in vivo studies-evaluating ghrelin orexigenic effects-indicate that the binding to albumin affects the bioactivity of the hormone. In conclusion, our results suggest that ghrelin binds to serum albumin and that this interaction impacts on the biological activity of the hormone. PMID:27431015

  6. Vomeronasal neuroepithelium and forebrain Fos responses to male pheromones in male and female mice.

    PubMed

    Halem, H A; Cherry, J A; Baum, M J

    1999-05-01

    Male urinary pheromones modulate behavioral and neuroendocrine function in mice after being detected by sensory neurons in the vomeronasal organ (VNO) neuroepithelium. We used nuclear Fos protein immunoreactivity (Fos-IR) as a marker of changes in neuronal activity to examine the processing of male pheromones throughout the VNO projection pathway to the hypothalamus. Sexually naive male and female Balb/c mice were gonadectomized and treated daily with estradiol benzoate (EB) or oil vehicle for 3 weeks. Subjects were then exposed to soiled bedding from gonadally intact Balb/c males or to clean bedding for 90 min prior to sacrifice and processing of their VNOs and forebrains for Fos-IR. Male pheromones induced similar numbers of Fos-IR cells in the VNO neuroepithelium of oil-treated male and female subjects; however, EB-treated females had significantly more Fos-IR neurons in the VNO than any other group. There was an equivalent neuronal Fos response to male odors in the mitral and granule cells of the anterior and posterior accessory olfactory bulb of males and females, regardless of hormone treatment. In central portions of the VNO projection pathway (i.e., bed nucleus of the stria terminalis, medial preoptic area) neuronal Fos responses to male pheromones were present in female but absent in male subjects, regardless of hormone treatment. In a separate experiment, mating induced neuronal Fos-IR in these brain regions at levels in gonadally intact male subjects which were equal to or greater than those seen in ovariectomized females primed with estrogen and progesterone. This suggests that neurons in the central portions of the male's VNO pathway are capable of expressing Fos. Our results suggest that sexually dimorphic central responses to pheromones exist in mice that may begin in the VNO neuroepithelium.

  7. Acylated and unacylated ghrelin impair skeletal muscle atrophy in mice.

    PubMed

    Porporato, Paolo E; Filigheddu, Nicoletta; Reano, Simone; Ferrara, Michele; Angelino, Elia; Gnocchi, Viola F; Prodam, Flavia; Ronchi, Giulia; Fagoonee, Sharmila; Fornaro, Michele; Chianale, Federica; Baldanzi, Gianluca; Surico, Nicola; Sinigaglia, Fabiola; Perroteau, Isabelle; Smith, Roy G; Sun, Yuxiang; Geuna, Stefano; Graziani, Andrea

    2013-02-01

    Cachexia is a wasting syndrome associated with cancer, AIDS, multiple sclerosis, and several other disease states. It is characterized by weight loss, fatigue, loss of appetite, and skeletal muscle atrophy and is associated with poor patient prognosis, making it an important treatment target. Ghrelin is a peptide hormone that stimulates growth hormone (GH) release and positive energy balance through binding to the receptor GHSR-1a. Only acylated ghrelin (AG), but not the unacylated form (UnAG), can bind GHSR-1a; however, UnAG and AG share several GHSR-1a-independent biological activities. Here we investigated whether UnAG and AG could protect against skeletal muscle atrophy in a GHSR-1a-independent manner. We found that both AG and UnAG inhibited dexamethasone-induced skeletal muscle atrophy and atrogene expression through PI3Kβ-, mTORC2-, and p38-mediated pathways in myotubes. Upregulation of circulating UnAG in mice impaired skeletal muscle atrophy induced by either fasting or denervation without stimulating muscle hypertrophy and GHSR-1a-mediated activation of the GH/IGF-1 axis. In Ghsr-deficient mice, both AG and UnAG induced phosphorylation of Akt in skeletal muscle and impaired fasting-induced atrophy. These results demonstrate that AG and UnAG act on a common, unidentified receptor to block skeletal muscle atrophy in a GH-independent manner.

  8. Persistent induction of c-fos and c-jun expression by asbestos

    SciTech Connect

    Heintz, N.H.; Mossman, B.T. ); Janssen, Y.M. Univ. of Limburg, Maastricht )

    1993-04-15

    To investigate the mechanisms of asbestos-induced carcinogenesis, expression of c-fos and c-jun protooncogenes was examined in rat pleural mesothelial cells and hamster tracheal epithelial cells after exposure to crocidolite or chrysotile asbestos. In contrast to phorbol 12-myristate 13-acetate, which induces rapid and transient increases in c-fos and c-jun mRNA, asbestos causes 2- to 5-fold increases in c-fos and c-jun mRNA that persist for at least 24 hr in mesothelial cells. The induction of c-fos and c-jun mRNA by asbestos in mesothelial cells is dose-dependent and is most pronounced with crocidolite, the type of asbestos most pathogenic in the causation of pleural mesothelioma. Induction of c-jun gene expression by asbestos occurs in tracheal epithelial cells but is not accompanied by a corresponding induction of c-fos gene expression. In both cell types, asbestos induces increases in protein factors that bind specifically to the DNA sites that mediate gene expression by the AP-1 family of transcription factors. The persistent induction of AP-1 transcription factors by asbestos suggests a model of asbestos-induced carcinogenesis involving chronic stimulation of cell proliferation through activation of the early response gene pathway that includes c-jun and/or c-fos. 30 refs., 5 figs.

  9. Multiple degradation pathways for Fos family proteins.

    PubMed

    Acquaviva, Claire; Bossis, Guillaume; Ferrara, Patrizia; Brockly, Frederique; Jariel-Encontre, Isabelle; Piechaczyk, Marc

    2002-11-01

    c-Fos protooncoprotein is a short-lived transcription factor with oncogenic potential. It is massively degraded by the proteasome in vivo under various experimental conditions. Those include consititutive expression in exponentially growing cells and transient induction in cells undergoing the G0/G1 phase transition upon stimulation by serum. Though there is evidence that c-Fos can be ubiquitinylated in vitro, the unambigous demonstration that prior ubiquitinylation is necessary for degradation by the proteasome in vivo is still lacking. c-Jun, one of the main dimerization partners of c-Fos within the AP-1 transcription complex, is also an unstable protein. Its degradation is clearly proteasome dependent. However, several lines of evidence indicate that the mechanisms by which it addresses the proteasome are different from those operating on c-Fos. Moreover, genetic analysis has indicated that c-Fos is addressed to the proteasome via pathways that differ depending on the conditions of expression. c-Fos has been transduced by two murine osteosarcomatogenic retroviruses in mutated forms, which are more stable and more oncogenic. The stabilization is not simply accounted for by simple deletion of one of the main c-Fos destabilizers but, rather, by a complex balance between opposing destabilizing and stabilizing mutations. However, although viral Fos proteins have acquired full resistance to proteasomal degradation, stabilization is limited because the mutations they have accumulated, during or after c-fos gene transduction, confer sensitivity to an unidentified proteolytic system(s). This observation is consistent with the idea that fos-expressing viruses have evolved expression machineries to ensure controlled protein levels in order to maintain an optimal balance between prooncogenic and proapoptotic activities of v-Fos proteins.

  10. The role of ΔfosB in the medial preoptic area: Differential effects of mating and cocaine history.

    PubMed

    McHenry, Jenna A; Robison, Christopher L; Bell, Genevieve A; Vialou, Vincent V; Bolaños-Guzmán, Carlos A; Nestler, Eric J; Hull, Elaine M

    2016-10-01

    The transcription factor deltaFosB (ΔFosB) is induced in the nucleus accumbens (NAc) by repeated exposure to drugs of abuse and natural rewards. Less is known about its role in other brain areas. Here, we compared the effects of mating versus cocaine history on induction of ΔFosB in the medial preoptic area (MPOA), an integral site for reproductive behavior, and in the NAc. ΔFosB immunoreactivity (ir) was increased in the MPOA of previously naïve and experienced male rats that mated the day before euthanasia, compared to unmated controls and experienced males with recent mating abstinence. Western immunoblots confirmed that the 35-37-kDa isoform of ΔFosB was increased more in recently mated males. Conversely, previous plus recent cocaine did not increase ΔFosB-ir in the MPOA, despite an increase in the NAc. Next, a viral vector expressing ΔFosB, its dominant negative antagonist ΔJunD, or green fluorescent protein (GFP) control, were microinjected bilaterally into the MPOA. ΔFosB overexpression impaired copulation and promoted female-directed aggression, compared to ΔJunD and control males. These data suggest that ΔFosB in the mPOA is expressed in an experience-dependent manner and affects systems that coordinate mating and aggression. (PsycINFO Database Record

  11. The role of ΔfosB in the medial preoptic area: Differential effects of mating and cocaine history.

    PubMed

    McHenry, Jenna A; Robison, Christopher L; Bell, Genevieve A; Vialou, Vincent V; Bolaños-Guzmán, Carlos A; Nestler, Eric J; Hull, Elaine M

    2016-10-01

    The transcription factor deltaFosB (ΔFosB) is induced in the nucleus accumbens (NAc) by repeated exposure to drugs of abuse and natural rewards. Less is known about its role in other brain areas. Here, we compared the effects of mating versus cocaine history on induction of ΔFosB in the medial preoptic area (MPOA), an integral site for reproductive behavior, and in the NAc. ΔFosB immunoreactivity (ir) was increased in the MPOA of previously naïve and experienced male rats that mated the day before euthanasia, compared to unmated controls and experienced males with recent mating abstinence. Western immunoblots confirmed that the 35-37-kDa isoform of ΔFosB was increased more in recently mated males. Conversely, previous plus recent cocaine did not increase ΔFosB-ir in the MPOA, despite an increase in the NAc. Next, a viral vector expressing ΔFosB, its dominant negative antagonist ΔJunD, or green fluorescent protein (GFP) control, were microinjected bilaterally into the MPOA. ΔFosB overexpression impaired copulation and promoted female-directed aggression, compared to ΔJunD and control males. These data suggest that ΔFosB in the mPOA is expressed in an experience-dependent manner and affects systems that coordinate mating and aggression. (PsycINFO Database Record PMID:27657309

  12. c-Fos activated phospholipid synthesis is required for neurite elongation in differentiating PC12 cells.

    PubMed

    Gil, Germán A; Bussolino, Daniela F; Portal, Maximiliano M; Alfonso Pecchio, Adolfo; Renner, Marianne L; Borioli, Graciela A; Guido, Mario E; Caputto, Beatriz L

    2004-04-01

    We have previously shown that c-Fos activates phospholipid synthesis through a mechanism independent of its genomic AP-1 activity. Herein, using PC12 cells induced to differentiate by nerve growth factor, the genomic effect of c-Fos in initiating neurite outgrowth is shown as distinct from its nongenomic effect of activating phospholipid synthesis and sustaining neurite elongation. Blocking c-Fos expression inhibited differentiation, phospholipid synthesis activation, and neuritogenesis. In cells primed to grow, blocking c-Fos expression determined neurite retraction. However, transfected cells expressing c-Fos or c-Fos deletion mutants with capacity to activate phospholipid synthesis sustain neurite outgrowth and elongation in the absence of nerve growth factor. Results disclose a dual function of c-Fos: it first releases the genomic program for differentiation and then associates to the endoplasmic reticulum and activates phospholipid synthesis. Because phospholipids are key membrane components, we hypothesize this latter phenomenon as crucial to support membrane genesis demands required for cell growth and neurite elongation. PMID:14767061

  13. Progress in Small Molecule and Biologic Therapeutics Targeting Ghrelin Signaling.

    PubMed

    McGovern, Kayleigh R; Darling, Joseph E; Hougland, James L

    2016-01-01

    Ghrelin is a circulating peptide hormone involved in regulation of a wide array of physiological processes. As an endogenous ligand for growth hormone secretagogue receptor (GHSR1a), ghrelin is responsible for signaling involved in energy homeostasis, including appetite stimulation, glucose metabolism, insulin signaling, and adiposity. Ghrelin has also been implicated in modulation of several neurological processes. Dysregulation of ghrelin signaling is implicated in diseases related to these pathways, including obesity, type II diabetes, and regulation of appetite and body weight in patients with Prader-Willi syndrome. Multiple steps in the ghrelin signaling pathway are available for targeting in the development of therapeutics for these diseases. Agonists and antagonists of GHS-R1a have been widely studied and have shown varying levels of effectiveness within ghrelin-related physiological pathways. Agents targeting ghrelin directly, either through depletion of ghrelin levels in circulation or inhibitors of ghrelin O-acyltransferase whose action is required for ghrelin to become biologically active, are receiving increasing attention as potential therapeutic options. We discuss the approaches utilized to target ghrelin signaling and highlight the current challenges toward developing small-molecule agents as potential therapeutics for ghrelin-related diseases. PMID:26202202

  14. Ghrelin signalling and obesity: at the interface of stress, mood and food reward.

    PubMed

    Schellekens, Harriët; Finger, Beate C; Dinan, Timothy G; Cryan, John F

    2012-09-01

    The neuronal circuitry underlying the complex relationship between stress, mood and food intake are slowly being unravelled and several studies suggest a key role herein for the peripherally derived hormone, ghrelin. Evidence is accumulating linking obesity as an environmental risk factor to psychiatric disorders such as stress, anxiety and depression. Ghrelin is the only known orexigenic hormone from the periphery to stimulate food intake. Plasma ghrelin levels are enhanced under conditions of physiological stress and ghrelin has recently been suggested to play an important role in stress-induced food reward behaviour. In addition, chronic stress or atypical depression has often demonstrated to correlate with an increase in ingestion of caloric dense 'comfort foods' and have been implicated as one of the major contributor to the increased prevalence of obesity. Recent evidence suggests ghrelin as a critical factor at the interface of homeostatic control of appetite and reward circuitries, modulating the hedonic aspects of food intake. Therefore, the reward-related feeding of ghrelin may reveal itself as an important factor in the development of addiction to certain foods, similar to its involvement in the dependence to drugs of abuse, including alcohol. This review will highlight the accumulating evidence demonstrating the close interaction between food, mood and stress and the development of obesity. We consider the ghrelinergic system as an effective target for the development of successful anti-obesity pharmacotherapies, which not only affects appetite but also selectively modulates the rewarding properties of food and impact on psychological well-being in conditions of stress, anxiety and depression.

  15. Fos, nociception and the dorsal horn.

    PubMed

    Coggeshall, Richard E

    2005-12-01

    The protooncogene c-fos is rapidly activated after noxious stimuli to express the protein Fos in spinal dorsal horn neurons that are in the 'correct' locations for nociceptive information transfer. As such, therefore, mapping Fos expression in these neurons is at present the best global marker for efficiently locating populations of neurons in the awake animal that respond to nociceptive input. This allows, among other things, precise behavioral measurements to be correlated with Fos expression. Two arenas where mapping dorsal horn Fos expression has made a major impact are in the anatomy of nociceptive systems and as a useful assay for the analgesic properties of various therapeutic regimens. Also Fos expression is the only way to map populations of neurons that are responding to non-localized input such as withdrawal after addiction and vascular occlusion. Another insight is that it shows a clear activation of neurons in superficial 'pain-processing' laminae by innocuous stimuli after nerve lesions, a finding that presumably bears on the allodynia that often accompanies these lesions. It is to be understood, however, that the Fos localizations are not sufficient unto themselves, but the major function of these studies is to efficiently locate populations of cells in nociceptive pathways so that powerful anatomic and physiologic techniques can be brought to bear efficiently. Thus, the purpose of this review is to summarize the studies whose numbers are geometrically expanding that deal with Fos in the dorsal horn and the conclusions therefrom.

  16. Controlling cytoplasmic c-Fos controls tumor growth in the peripheral and central nervous system.

    PubMed

    Gil, Germán A; Silvestre, David C; Tomasini, Nicolás; Bussolino, Daniela F; Caputto, Beatriz L

    2012-06-01

    Some 20 years ago c-Fos was identified as a member of the AP-1 family of inducible transcription factors (Angel and Karin in Biochim Biophys Acta 1072:129-157, 1991). More recently, an additional activity was described for this protein: it associates to the endoplasmic reticulum and activates the biosynthesis of phospholipids (Bussolino et al. in FASEB J 15:556-558, 2001), (Gil et al. in Mol Biol Cell 15:1881-1894, 2004), the quantitatively most important components of cellular membranes. This latter activity of c-Fos determines the rate of membrane genesis and consequently of growth in differentiating PC12 cells (Gil et al. in Mol Biol Cell 15:1881-1894, 2004). In addition, it has been shown that c-Fos is over-expressed both in PNS and CNS tumors (Silvestre et al. in PLoS One 5(3):e9544, 2010). Herein, it is shown that c-Fos-activated phospholipid synthesis is required to support membrane genesis during the exacerbated growth characteristic of brain tumor cells. Specifically blocking c-Fos-activated phospholipid synthesis significantly reduces proliferation of tumor cells in culture. Blocking c-Fos expression also prevents tumor progression in mice intra-cranially xeno-grafted human brain tumor cells. In NPcis mice, an animal model of the human disease Neurofibromatosis Type I (Cichowski and Jacks in Cell 104:593-604, 2001), animals spontaneously develop tumors of the PNS and the CNS, provided they express c-Fos (Silvestre et al. in PLoS One 5(3):e9544, 2010). Treatment of PNS tumors with an antisense oligonucleotide that specifically blocks c-Fos expression also blocks tumor growth in vivo. These results disclose cytoplasmic c-Fos as a new target for effectively controlling brain tumor growth.

  17. ΔFosB in brain reward circuits mediates resilience to stress and antidepressant responses

    PubMed Central

    Vialou, Vincent; Robison, Alfred J.; LaPlant, Quincey C.; Covington, Herb E.; Dietz, David M.; Ohnishi, Yoshinori N.; Mouzon, Ezekiell; Rush, Augustus J.; Watts, Emily L.; Wallace, Deanna L.; Iniguez, Sergio D.; Ohnishi, Yoko H.; Steiner, Michel A.; Warren, Brandon; Krishnan, Vaishnav; Neve, Rachael L.; Ghose, Subroto; Berton, Olivier; Tamminga, Carol A.; Nestler, Eric J.

    2010-01-01

    In contrast to the vast literature on stress effects on the brain, relatively little is known about the molecular mechanisms of resilience, the ability of some individuals to escape the deleterious effects of stress. Here we show that the transcription factor, ΔFosB, mediates an essential mechanism of resilience in mice. Induction of ΔFosB in the nucleus accumbens, a key brain reward region, in response to chronic social defeat stress is both necessary and sufficient for resilience. ΔFosB induction also is required for the ability of the standard antidepressant, fluoxetine, to reverse behavioral pathology induced by social defeat. ΔFosB produces these effects through the induction of the GluR2 AMPA glutamate receptor subunit, which decreases the responsiveness of nucleus accumbens neurons to glutamate, and through other synaptic proteins. Together, these findings establish a novel molecular pathway underlying both resilience and antidepressant action. PMID:20473292

  18. Ghrelin's second life: from appetite stimulator to glucose regulator.

    PubMed

    Verhulst, Pieter-Jan; Depoortere, Inge

    2012-07-01

    Ghrelin, a 28 amino acid peptide hormone produced by the stomach, was the first orexigenic hormone to be discovered from the periphery. The octanoyl modification at Ser³, mediated by ghrelin O-acyltransferase (GOAT), is essential for ghrelin's biological activity. Ghrelin stimulates food intake through binding to its receptor (GRLN-R) on neurons in the arcuate nucleus of the hypothalamus. Ghrelin is widely expressed throughout the body; accordingly, it is implicated in several other physiological functions, which include growth hormone release, gastric emptying, and body weight regulation. Ghrelin and GRLN-R expression are also found in the pancreas, suggesting a local physiological role. Accordingly, several recent studies now point towards an important role for ghrelin and its receptor in the regulation of blood glucose homeostasis, which is the main focus of this review. Several mechanisms of this regulation by ghrelin have been proposed, and one possibility is through the regulation of insulin secretion. Despite some controversy, most studies suggest that ghrelin exerts an inhibitory effect on insulin secretion, resulting in increased circulating glucose levels. Ghrelin may thus be a diabetogenic factor. Obesity-related type 2 diabetes has become an increasingly important health problem, almost reaching epidemic proportions in the world; therefore, antagonists of the ghrelin-GOAT signaling pathway, which will tackle both energy- and glucose homeostasis, may be considered as promising new therapies for this disease. PMID:22783041

  19. Ghrelin and its promoter variant associated with cardiac hypertrophy.

    PubMed

    Ukkola, O; Pääkkö, T; Kesäniemi, Y A

    2012-07-01

    The roles of ghrelin, a peptide hormone that has a role in regulating food intake and energy homeostasis, in the cardiovascular system have not yet been unambiguously established. We evaluated the association between plasma ghrelin concentrations and -501A>C single-nucleotide polymorphism (SNP) in the ghrelin gene 5' flanking area and echocardiographic measurements in 1037 middle-aged subjects. Left ventricular mass index (LVMI) was calculated according to Devereux's method. The ambulatory blood pressure (BP) was recorded using the fully automatic SpaceLabs 90207 oscillometric unit. Results suggested that plasma ghrelin was not related to mean ambulatory BP values. However, the highest plasma ghrelin tertile was associated with increased intraventricular septum (P=0.043) and posterior ventricular wall (P=0.002) thicknesses as well as left ventricular mass (P=0.05). After adjustment for age, sex, body mass index and systolic BP, the association persisted between ghrelin tertiles and intraventricular septum (P=0.05) and posterior ventricular wall (P=0.001) thicknesses. The SNP -501A>C polymorphism was associated with LVMI after adjustments for age, sex and systolic BP. In conclusion, ghrelin and its promoter variant are associated with cardiac hypertrophy indexes independent of BP. Positive correlation between ghrelin levels and increased wall thickness parameters may reflect compensatory up-regulation of ghrelin concentrations or direct effects of ghrelin on myocardium. The effects of the SNP seem not to be mediated through its effects on ghrelin plasma levels. PMID:21614024

  20. The Antidepressant-like Effects of Estrogen-mediated Ghrelin

    PubMed Central

    Wang, Pu; Liu, Changhong; Liu, Lei; Zhang, Xingyi; Ren, Bingzhong; Li, Bingjin

    2015-01-01

    Ghrelin, one of the brain-gut peptides, stimulates food-intake. Recently, ghrelin has also shown to play an important role in depression treatment. However, the mechanism of ghrelin’s antidepressant-like actions is unknown. On the other hand, sex differences in depression, and the fluctuation of estrogens secretion have been proved to play a key role in depression. It has been reported that women have higher level of ghrelin expression, and ghrelin can stimulate estrogen secretion while estrogen acts as a positive feedback mechanism to up-regulate ghrelin level. Ghrelin may be a potential regulator of reproductive function, and estrogen may have additional effect in ghrelin’s antidepressantlike actions. In this review, we summarize antidepressant-like effects of ghrelin and estrogen in basic and clinical studies, and provide new insight on ghrelin’s effect in depression. PMID:26412072

  1. Ghrelin Receptor Mutations and Human Obesity.

    PubMed

    Wang, W; Tao, Y-X

    2016-01-01

    Growth hormone secretagogue receptor (GHSR) was originally identified as an orphan receptor in porcine and rat anterior pituitary membranes. In 1999, GHSR was deorphanized and shown to be a receptor for ghrelin, a peptide hormone secreted from the stomach. Therefore, GHSR is also called ghrelin receptor. In addition to regulating growth hormone secretion, ghrelin receptor regulates various physiological processes, including food intake and energy expenditure, glucose metabolism, cardiovascular functions, gastric acid secretion and motility, and immune function. Several human genetic studies conducted in populations originated from Europe, Africa, South America, and East Asia identified rare mutations and single nucleotide polymorphisms that might be associated with human obesity and short stature. Functional analyses of mutant GHSRs reveal multiple defects, including cell surface expression, ligand binding, and basal and stimulated signaling. With growing understanding in the functionality of naturally occurring GHSR mutations, potential therapeutic strategies including pharmacological chaperones and novel ligands could be used to correct the GHSR mutants. PMID:27288828

  2. Effects of ghrelin on Kisspeptin mRNA expression in the hypothalamic medial preoptic area and pulsatile luteinising hormone secretion in the female rat.

    PubMed

    Forbes, Sarah; Li, Xiao Feng; Kinsey-Jones, James; O'Byrne, Kevin

    2009-08-28

    The orexigenic gut peptide ghrelin negatively modulates the hypothalamic-pituitary-gonadal (HPG) axis. Hyperghrelinaemia results during negative energy balance, a state often associated with delayed puberty and disrupted fertility, whilst exogenous ghrelin suppresses pulsatile luteinising hormone (LH) secretion. The recent identification of kisspeptin (Kiss1) and its G protein-coupled receptor (GPR)54 (Kiss1r) as an essential component of the HPG axis controlling gonadotrophin secretion raises the possibility that kisspeptin-Kiss1r signalling may play a critical role in the transduction of ghrelin-induced suppression of LH. Ovariectomised oestrogen-replaced rats were implanted with intravenous catheters and blood samples collected for detection of LH pulses prior to and after intravenous administration of ghrelin (3nM/250 microl) or saline (250 microl) during ad libitum feeding or after overnight fasting. Quantitative RT-PCR was used to determine Kiss1 and Kiss1r mRNA levels in brain punches of the key hypothalamic sites regulating gonadotrophin secretion, the medial preoptic area (mPOA) and arcuate nucleus (ARC), collected 6h following administration of ghrelin. Ghrelin significantly lowered LH pulse frequency in fed rats, an effect significantly enhanced by food deprivation. Fasting, ghrelin or their combination down-regulated Kiss1, without affecting Kiss1r, expression in the mPOA, and affected the expression of neither in the ARC. Considering the pivotal role for kisspeptin signalling in the activation of the HPG axis, the ability of ghrelin to down-regulate Kiss1 expression in mPOA may be a contributing factor in ghrelin-related suppression of pulsatile LH secretion.

  3. The Stomach-Derived Hormone Ghrelin Increases Impulsive Behavior

    PubMed Central

    Anderberg, Rozita H; Hansson, Caroline; Fenander, Maya; Richard, Jennifer E; Dickson, Suzanne L; Nissbrandt, Hans; Bergquist, Filip; Skibicka, Karolina P

    2016-01-01

    Impulsivity, defined as impaired decision making, is associated with many psychiatric and behavioral disorders, such as attention-deficit/hyperactivity disorder as well as eating disorders. Recent data indicate that there is a strong positive correlation between food reward behavior and impulsivity, but the mechanisms behind this relationship remain unknown. Here we hypothesize that ghrelin, an orexigenic hormone produced by the stomach and known to increase food reward behavior, also increases impulsivity. In order to assess the impact of ghrelin on impulsivity, rats were trained in three complementary tests of impulsive behavior and choice: differential reinforcement of low rate (DRL), go/no-go, and delay discounting. Ghrelin injection into the lateral ventricle increased impulsive behavior, as indicated by reduced efficiency of performance in the DRL test, and increased lever pressing during the no-go periods of the go/no-go test. Central ghrelin stimulation also increased impulsive choice, as evidenced by the reduced choice for large rewards when delivered with a delay in the delay discounting test. In order to determine whether signaling at the central ghrelin receptors is necessary for maintenance of normal levels of impulsive behavior, DRL performance was assessed following ghrelin receptor blockade with central infusion of a ghrelin receptor antagonist. Central ghrelin receptor blockade reduced impulsive behavior, as reflected by increased efficiency of performance in the DRL task. To further investigate the neurobiological substrate underlying the impulsivity effect of ghrelin, we microinjected ghrelin into the ventral tegmental area, an area harboring dopaminergic cell bodies. Ghrelin receptor stimulation within the VTA was sufficient to increase impulsive behavior. We further evaluated the impact of ghrelin on dopamine-related gene expression and dopamine turnover in brain areas key in impulsive behavior control. This study provides the first

  4. Nerve Growth Factor is Required for Induction of c-Fos Immunoreactivity by Serum, Depolarization, Cyclic AMP or Trauma in Cultured Rat Sympathetic Neurons.

    PubMed

    Buckmaster, A; Nobes, C D; Edwards, S N; Tolkovsky, A M

    1991-01-01

    Nerve growth factor (NGF) induces transient Fos-immunoreactivity (Fos-IR) independently of any other factor, both in newly isolated rat sympathetic neurons and in established cultures after NGF deprivation. The same proportion of neurons that express Fos-IR in response to NGF also survive. In addition to direct stimulation of Fos-IR expression, the presence or recent exposure to NGF is required to obtain Fos-IR expression by other stimuli. In newly isolated neurons no Fos-IR is detected in response to stimulation by serum alone and a response to depolarization or cyclic AMP is obtained only if neurons are stimulated within a short period after ganglion excision. In established cultures none of these stimuli, nor the trauma of cutting neurites or spiking cell bodies with a microinjection needle induce Fos-IR unless NGF is present or had been removed for <8 - 16 h. The lack of response is not due to a general decrease in the rate of protein or RNA synthesis. These findings show that in regenerating sympathetic neurons NGF induces c-Fos and suggest that NGF may activate a master trigger that is required for c-Fos expression to be induced by other stimuli.

  5. Central injection of CDP-choline suppresses serum ghrelin levels while increasing serum leptin levels in rats.

    PubMed

    Kiyici, Sinem; Basaran, Nesrin Filiz; Cavun, Sinan; Savci, Vahide

    2015-10-01

    In this study we aimed to test central administration of CDP-choline on serum ghrelin, leptin, glucose and corticosterone levels in rats. Intracerebroventricular (i.c.v.) 0.5, 1.0 and 2.0 µmol CDP-choline and saline were administered to male Wistar-Albino rats. For the measurement of serum leptin and ghrelin levels, blood samples were obtained baseline and at 5, 15, 30, 60 and 120 min following i.c.v. CDP-choline injection. Equimolar doses of i.c.v. choline (1.0 µmol) and cytidine (1.0 µmol) were administered and measurements were repeated throughout the second round of the experiment. Atropine (10 µg) and mecamylamine (50 µg) were injected intracerebroventricularly prior to CDP-choline and measurements repeated in the third round of the experiment. After 1 µmol CDP-choline injection, serum ghrelin levels were suppressed significantly at 60 min (P=0.025), whereas serum leptin levels were increased at 60 and 120 min (P=0.012 and P=0.017 respectively). CDP-choline injections also induced a dose- and time-dependent increase in serum glucose and corticosterone levels. The effect of choline on serum leptin and ghrelin levels was similar with CDP-choline while no effect was seen with cytidine. Suppression of serum ghrelin levels was eliminated through mecamylamine pretreatment while a rise in leptin was prevented by both atropine and mecamylamine pretreatments. In conclusion; centrally injected CDP-choline suppressed serum ghrelin levels while increasing serum leptin levels. The observed effects following receptor antagonist treatment suggest that nicotinic receptors play a role in suppression of serum ghrelin levels,whereas nicotinic and muscarinic receptors both play a part in the increase of serum leptin levels.

  6. Differential effects of ghrelin antagonists on alcohol drinking and reinforcement in mouse and rat models of alcohol dependence

    PubMed Central

    Gomez, Juan L.; Cunningham, Christopher L.; Finn, Deborah A.; Young, Emily A.; Helpenstell, Lily K.; Schuette, Lindsey M.; Fidler, Tara L.; Kosten, Therese A.; Ryabinin, Andrey E.

    2015-01-01

    An effort has been mounted to understand the mechanisms of alcohol dependence in a way that may allow for greater efficacy in treatment. It has long been suggested that drugs of abuse seize fundamental reward pathways and disrupt homeostasis to produce compulsive drug seeking behaviors. Ghrelin, an endogenous hormone that affects hunger state and release of growth hormone, has been shown to increased alcohol intake following administration, while antagonists decrease intake. Using rodent models of dependence, the current study examined the effects of two ghrelin receptor antagonists, [DLys3]-GHRP-6 (DLys) and JMV2959, on dependence-induced alcohol self-administration. In two experiments adult male C57BL/6J mice and Wistar rats were made dependent via intermittent ethanol vapor exposure. In another experiment, adult male C57BL/6J mice were made dependent using the intragastric alcohol consumption (IGAC) procedure. Ghrelin receptor antagonists were given prior to voluntary ethanol drinking. Ghrelin antagonists reduced ethanol intake, preference, and operant self-administration of ethanol and sucrose across these models, but did not decrease food consumption in mice. In experiments 1 and 2, voluntary drinking was reduced by ghrelin receptor antagonists, however this reduction did not persist across days. Despite the transient effects to ghrelin antagonists, the drugs had renewed effectiveness following a break in administration as seen in experiment 1. The results show the ghrelin system as a potential target for studies of alcohol abuse. Further research is needed to determine the central mechanisms of these drugs and their influence on addiction in order to design effective pharmacotherapies. PMID:26051399

  7. Differential effects of ghrelin antagonists on alcohol drinking and reinforcement in mouse and rat models of alcohol dependence.

    PubMed

    Gomez, Juan L; Cunningham, Christopher L; Finn, Deborah A; Young, Emily A; Helpenstell, Lily K; Schuette, Lindsey M; Fidler, Tara L; Kosten, Therese A; Ryabinin, Andrey E

    2015-10-01

    An effort has been mounted to understand the mechanisms of alcohol dependence in a way that may allow for greater efficacy in treatment. It has long been suggested that drugs of abuse seize fundamental reward pathways and disrupt homeostasis to produce compulsive drug seeking behaviors. Ghrelin, an endogenous hormone that affects hunger state and release of growth hormone, has been shown to increase alcohol intake following administration, while antagonists decrease intake. Using rodent models of dependence, the current study examined the effects of two ghrelin receptor antagonists, [DLys3]-GHRP-6 (DLys) and JMV2959, on dependence-induced alcohol self-administration. In two experiments adult male C57BL/6J mice and Wistar rats were made dependent via intermittent ethanol vapor exposure. In another experiment, adult male C57BL/6J mice were made dependent using the intragastric alcohol consumption (IGAC) procedure. Ghrelin receptor antagonists were given prior to voluntary ethanol drinking. Ghrelin antagonists reduced ethanol intake, preference, and operant self-administration of ethanol and sucrose across these models, but did not decrease food consumption in mice. In experiments 1 and 2, voluntary drinking was reduced by ghrelin receptor antagonists, however this reduction did not persist across days. Despite the transient effects of ghrelin antagonists, the drugs had renewed effectiveness following a break in administration as seen in experiment 1. The results show the ghrelin system as a potential target for studies of alcohol abuse. Further research is needed to determine the central mechanisms of these drugs and their influence on addiction in order to design effective pharmacotherapies.

  8. Induction of xanthine oxidase activity, endoplasmic reticulum stress and caspase activation by sodium metabisulfite in rat liver and their attenuation by Ghrelin.

    PubMed

    Ercan, Sevim; Kencebay, Ceren; Basaranlar, Goksun; Derin, Narin; Aslan, Mutay

    2015-02-01

    Sodium metabisulfite is used as a preservative in many food preparations but can oxidize to sulfite radicals initiating molecular oxidation. Ghrelin is a peptide hormone primarily produced in the stomach and has anti-inflammatory and anti-oxidant effects on gastrointestinal and cardiovascular systems. This study was performed to elucidate the effect of ghrelin on sulfite-induced endoplasmic reticulum (ER) stress and caspase activation in rat peripheral organs. Xanthine oxidase (XO), xanthine dehydrogenase (XDH) enzyme activities, ER stress markers [phosphorylated PKR-like ER kinase (pPERK); C/EBP-homologous protein (CHOP)], caspase-3, -8, -9 activities, nuclear factor kappa-B (NF-κB) levels were determined in liver, heart and kidney of rats treated with sodium metabisulfite and/or ghrelin for 5 weeks. Sodium metabisulfite treatment significantly elevated XO activity, induced expression of GRP78, CHOP and increased caspase-3, -8 and -9 activities in liver but had no significant effect in heart and kidney. Ghrelin treatment decreased XO activity to baseline levels and attenuated ER stress and caspase activation in liver tissue of sodium metabisulfite treated rats. In conclusion, metabolism of sodium metabisulfite in liver tissue increased XO activity, induced ER stress and caused caspase activation which was attenuated by ghrelin treatment. Ghrelin's hepatoprotective effect could be through modulation of XO activity. PMID:25486021

  9. Induction of xanthine oxidase activity, endoplasmic reticulum stress and caspase activation by sodium metabisulfite in rat liver and their attenuation by Ghrelin.

    PubMed

    Ercan, Sevim; Kencebay, Ceren; Basaranlar, Goksun; Derin, Narin; Aslan, Mutay

    2015-02-01

    Sodium metabisulfite is used as a preservative in many food preparations but can oxidize to sulfite radicals initiating molecular oxidation. Ghrelin is a peptide hormone primarily produced in the stomach and has anti-inflammatory and anti-oxidant effects on gastrointestinal and cardiovascular systems. This study was performed to elucidate the effect of ghrelin on sulfite-induced endoplasmic reticulum (ER) stress and caspase activation in rat peripheral organs. Xanthine oxidase (XO), xanthine dehydrogenase (XDH) enzyme activities, ER stress markers [phosphorylated PKR-like ER kinase (pPERK); C/EBP-homologous protein (CHOP)], caspase-3, -8, -9 activities, nuclear factor kappa-B (NF-κB) levels were determined in liver, heart and kidney of rats treated with sodium metabisulfite and/or ghrelin for 5 weeks. Sodium metabisulfite treatment significantly elevated XO activity, induced expression of GRP78, CHOP and increased caspase-3, -8 and -9 activities in liver but had no significant effect in heart and kidney. Ghrelin treatment decreased XO activity to baseline levels and attenuated ER stress and caspase activation in liver tissue of sodium metabisulfite treated rats. In conclusion, metabolism of sodium metabisulfite in liver tissue increased XO activity, induced ER stress and caused caspase activation which was attenuated by ghrelin treatment. Ghrelin's hepatoprotective effect could be through modulation of XO activity.

  10. Pathophysiologic basis of anorexia: focus on the interaction between ghrelin dynamics and the serotonergic system.

    PubMed

    Takeda, Hiroshi; Nakagawa, Koji; Okubo, Naoto; Nishimura, Mie; Muto, Shuichi; Ohnishi, Shunsuke; Sakamoto, Naoya; Hosono, Hidetaka; Asaka, Masahiro

    2013-01-01

    Anorexia is an important issue in the management of elderly patients with cancer because it contributes to the development of malnutrition, increases morbidity and mortality, and negatively affects patients' quality of life. This review summarizes the potential mechanisms of the development of anorexia in three animal models that mimic the situations commonly seen in elderly patients receiving chemotherapy. Cisplatin-induced anorexia is attributable to a decrease in peripheral and central ghrelin secretion caused by the stimulation of serotonin (5-hydroxytryptamine; 5-HT)2B and 5-HT2C receptors via 5-HT secretion. Age-associated anorexia is caused by an increase in plasma leptin, which results from disturbed reactivity of ghrelin in the hypothalamus and regulation of ghrelin secretion. Environmental change causes the activation of central 5-HT1B and 5-HT2C receptors and the melanocortin-4 receptor system, resulting in a decrease in circulating ghrelin levels which lowers food intake. New therapeutic approaches based on these pathophysiological mechanisms are warranted for the treatment of anorexia in cancer patients, especially elderly ones.

  11. Taking two to tango: a role for ghrelin receptor heterodimerization in stress and reward

    PubMed Central

    Schellekens, Harriët; Dinan, Timothy G.; Cryan, John F.

    2013-01-01

    The gut hormone, ghrelin, is the only known peripherally derived orexigenic signal. It activates its centrally expressed receptor, the growth hormone secretagogue receptor (GHS-R1a), to stimulate food intake. The ghrelin signaling system has recently been suggested to play a key role at the interface of homeostatic control of appetite and the hedonic aspects of food intake, as a critical role for ghrelin in dopaminergic mesolimbic circuits involved in reward signaling has emerged. Moreover, enhanced plasma ghrelin levels are associated with conditions of physiological stress, which may underline the drive to eat calorie-dense “comfort-foods” and signifies a role for ghrelin in stress-induced food reward behaviors. These complex and diverse functionalities of the ghrelinergic system are not yet fully elucidated and likely involve crosstalk with additional signaling systems. Interestingly, accumulating data over the last few years has shown the GHS-R1a receptor to dimerize with several additional G-protein coupled receptors (GPCRs) involved in appetite signaling and reward, including the GHS-R1b receptor, the melanocortin 3 receptor (MC3), dopamine receptors (D1 and D2), and more recently, the serotonin 2C receptor (5-HT2C). GHS-R1a dimerization was shown to affect downstream signaling and receptor trafficking suggesting a potential novel mechanism for fine-tuning GHS-R1a receptor mediated activity. This review summarizes ghrelin's role in food reward and stress and outlines the GHS-R1a dimer pairs identified to date. In addition, the downstream signaling and potential functional consequences of dimerization of the GHS-R1a receptor in appetite and stress-induced food reward behavior are discussed. The existence of multiple GHS-R1a heterodimers has important consequences for future pharmacotherapies as it significantly increases the pharmacological diversity of the GHS-R1a receptor and has the potential to enhance specificity of novel ghrelin-targeted drugs. PMID

  12. c-fos and its Consequences in Pain.

    PubMed

    Ahmad, Asma Hayati; Ismail, Zalina

    2002-01-01

    The discovery that c-fos, a proto-oncogene, has a role in pain, has triggered extensive research on the consequences of c-fos expression. It has been shown that c-fos, through its protein form, FOS, leads to expression of dynorphin gene and subsequently dynorphin protein which is implicated in the development of a pain state. This mini review looks at the properties of c-fos and the consequences of its expression following noxious (painful) stimulation.

  13. Postprandial ghrelin is elevated in black compared with white women.

    PubMed

    Brownley, Kimberly A; Light, Kathleen C; Grewen, Karen M; Bragdon, Edith E; Hinderliter, Alan L; West, Sheila G

    2004-09-01

    Ghrelin, a gut-brain peptide that signals hunger, is normally suppressed after meals. Subnormal suppression of postprandial ghrelin, previously noted in obese, insulin-resistant individuals, may contribute to increased food intake. Given the ethnic disparities in obesity and obesity-related cardiovascular morbidity in the United States, the present study compared a single postprandial ghrelin measure in 43 women (22 white, 21 black). Each completed a rigorously controlled 4-d dietary intervention designed to maintain weight and constant daily sodium and potassium intake (220 mEq Na, 40 mEq K). Two hours after consuming a test meal of identical content, blood samples were drawn to assess postprandial ghrelin, leptin, and norepinephrine; resting cardiovascular function was measured; and a 24-h urinary cortisol sample was obtained. Independent of body mass index, postprandial ghrelin was significantly higher in black vs. white women, and higher ghrelin was associated with higher cortisol in blacks, who failed to show the expected inverse relation between ghrelin and central obesity seen in whites. Higher ghrelin was correlated with higher blood pressure but lower norepinephrine in obese women. These findings suggest subnormal postprandial ghrelin suppression (or faster ghrelin rebound) in black women, especially the obese, that might play a role in their increased prevalence of obesity and cardiovascular disorders.

  14. The role of ghrelin in energy balance regulation in fish.

    PubMed

    Jönsson, Elisabeth

    2013-06-15

    Knowledge about the endocrine regulation of energy balance in fish is of interest for basic as well as aquaculture research. Ghrelin is a peptide hormone that was first identified in fish 10 years ago and has important roles in the control of food intake and metabolism. Both ghrelin and its receptor, the growth hormone secretagogue receptor (GHS-R), have been found in numerous fish species. Their tissue distributions support the idea that ghrelin has an integrative role in the regulation of energy balance at both the central nervous system level and systemic level. In tilapia and goldfish, ghrelin treatment appears to increase food intake and to stimulate lipogenesis and tissue fat deposition to promote a more positive energy status. In rainbow trout, on the other hand, ghrelin decreases food intake. Goldfish and rainbow trout are the fish species in which the mode of action of ghrelin on food intake has been most thoroughly investigated. The results from these studies indicate that ghrelin alters food intake by acting on well-known appetite signals, such as CRH, NPY and orexin, in the hypothalamus in a species-specific manner. In goldfish, sensory fibres of the vagus nerve convey the signal from gut-derived ghrelin to modulate appetite. The data also indicate that ghrelin may modulate foraging/swimming activity and the perception of food in fish. Results related to the effects of energy status, temperature, and stressors on plasma ghrelin/tissue ghrelin mRNA levels are occasionally inconsistent between short- and long-term studies, between the protein and mRNA, and between species. Recent data also imply a role of ghrelin in carbohydrate metabolism. More functional studies are required to understand the role of ghrelin and its mechanisms of action in the regulation of energy balance among fish.

  15. Male song quality modulates c-Fos expression in the auditory forebrain of the female canary

    PubMed Central

    Monbureau, Marie; Barker, Jennifer M.; Leboucher, Gérard; Balthazart, Jacques

    2015-01-01

    In canaries, specific phrases of male song (sexy songs, SS) that are difficult to produce are especially attractive for females. Females exposed to SS produce more copulation displays and deposit more testosterone into their eggs than females exposed to non-sexy songs (NS). Increased expression of the immediate early genes c-Fos or zenk (a.k.a. egr-1) has been observed in the auditory forebrain of female songbirds hearing attractive songs. C-Fos immunoreactive (Fos-ir) cell numbers were quantified here in the brain of female canaries that had been collected 30 min after they had been exposed for 60 min to the playback of SS or NS or control white noise. Fos-ir cell numbers increased in the caudomedial mesopallium (CMM) and caudomedial nidopallium (NCM) of SS birds as compared to controls. Song playback (pooled SS and NS) also tended to increase average Fos-ir cell numbers in the mediobasal hypothalamus (MBH) but this effect did not reach full statistical significance. At the individual level, Fos expression in CMM was correlated with its expression in NCM and in MBH but also with the frequency of calls that females produced in response to the playbacks. These data thus indicate that male songs of different qualities induce a differential metabolic activation of NCM and CMM. The correlation between activation of auditory regions and of the MBH might reflect the link between auditory stimulation and changes in behavior and reproductive physiology. PMID:25846435

  16. Male song quality modulates c-Fos expression in the auditory forebrain of the female canary.

    PubMed

    Monbureau, Marie; Barker, Jennifer M; Leboucher, Gérard; Balthazart, Jacques

    2015-08-01

    In canaries, specific phrases of male song (sexy songs, SS) that are difficult to produce are especially attractive for females. Females exposed to SS produce more copulation displays and deposit more testosterone into their eggs than females exposed to non-sexy songs (NS). Increased expression of the immediate early genes c-Fos or zenk (a.k.a. egr-1) has been observed in the auditory forebrain of female songbirds hearing attractive songs. C-Fos immunoreactive (Fos-ir) cell numbers were quantified here in the brain of female canaries that had been collected 30min after they had been exposed for 60min to the playback of SS or NS or control white noise. Fos-ir cell numbers increased in the caudomedial mesopallium (CMM) and caudomedial nidopallium (NCM) of SS birds as compared to controls. Song playback (pooled SS and NS) also tended to increase average Fos-ir cell numbers in the mediobasal hypothalamus (MBH) but this effect did not reach full statistical significance. At the individual level, Fos expression in CMM was correlated with its expression in NCM and in MBH but also with the frequency of calls that females produced in response to the playbacks. These data thus indicate that male songs of different qualities induce a differential metabolic activation of NCM and CMM. The correlation between activation of auditory regions and of the MBH might reflect the link between auditory stimulation and changes in behavior and reproductive physiology. PMID:25846435

  17. Energy transfer analysis of Fos-Jun dimerization and DNA binding.

    PubMed Central

    Patel, L R; Curran, T; Kerppola, T K

    1994-01-01

    The protooncogenes fos and jun encode proteins that bind to DNA as dimeric complexes and regulate gene expression. Protein dimerization is mediated by a leucine zipper and results in juxtaposition of regions of each protein rich in basic amino acids that comprise a bimolecular DNA binding domain. We have developed an approach based on resonance energy transfer for the quantitative analysis of dimerization and DNA binding by Fos and Jun in solution. Fos-(118-211) and Jun-(225-334) polypeptides were labeled with either 5-iodoacetamidofluorescein or rhodamine X iodoacetamide on unique cysteine residues located in their DNA binding domains. Formation of heterodimeric complexes between the labeled proteins allowed resonance energy transfer between the donor fluorescein and the acceptor rhodamine fluorophores. DNA binding induced a conformational transition that increased the efficiency of resonance energy transfer. This increase was consistent with a 3-A reduction in the distance between the fluorophores. Using this assay, we determined the affinity of the Fos-Jun interaction and examined the kinetics of dimerization and DNA binding as well as the rate of subunit exchange. Dimerization and DNA binding by Fos and Jun were rapid, with half-times of < 10 s. In the absence of DNA, Fos and Jun subunits exchanged rapidly, with a half-time of < 10 s. In contrast, in the presence of DNA, the complex was extremely stable. Thus, leucine zipper-containing transcription factors may exchange subunits readily when free in solution, but not when bound to DNA. Images PMID:8041795

  18. Degradation of cellular and viral Fos proteins.

    PubMed

    Acquaviva, C; Ferrara, P; Bossis, G; Brockly, F; Salvat, C; Jariel-Encontre, I; Piechaczyk, M

    2001-01-01

    c-Fos proto-oncoprotein is a short-lived transcription factor with oncogenic potential. We have shown that it is massively degraded by the proteasome in vivo under various experimental conditions. Other proteolytic systems including lysosomes and calpains, might, however, also marginally operate on it. Although there is evidence that c-Fos can be ubiquitinylated in vitro, the unambiguous demonstration that ubiquitinylation is necessary for its addressing to the proteasome in vivo is still lacking. c-Jun, one of the main dimerization partners of c-Fos within the AP-1 transcription complex, is also an unstable protein. Its degradation is clearly proteasome- and ubiquitin-dependent in vivo. Interestingly, several lines of evidence indicate that the addressing of c-Fos and c-Jun to the proteasome is, at least in part, governed by different mechanisms. c-Fos has been transduced by two murine osteosarcomatogenic retroviruses under mutated forms which are more stable and more oncogenic. The stabilization is not simply accounted for by simple deletion of c-Fos main destabilizer but, rather, by a complex balance between opposing destabilizing and stabilizing mutations. Though mutations in viral Fos proteins confer full resistance to proteasomal degradation, stabilization is limited because mutations also entail sensitivity to an unidentified proteolytic system. This observation is consistent with the idea that Fos-expressing viruses have evolved to ensure control protein levels to avoid high protein accumulation-linked apoptosis. In conclusion, the unveiling of the complex mechanism network responsible for the degradation of AP-1 family members is still at its beginning and a number of issues regarding the regulation of this process and the addressing to the proteasome are still unresolved.

  19. Long-Term Exercise Is a Potent Trigger for ΔFosB Induction in the Hippocampus along the dorso–ventral Axis

    PubMed Central

    Nishijima, Takeshi; Kawakami, Masashi; Kita, Ichiro

    2013-01-01

    Physical exercise improves multiple aspects of hippocampal function. In line with the notion that neuronal activity is key to promoting neuronal functions, previous literature has consistently demonstrated that acute bouts of exercise evoke neuronal activation in the hippocampus. Repeated activating stimuli lead to an accumulation of the transcription factor ΔFosB, which mediates long-term neural plasticity. In this study, we tested the hypothesis that long-term voluntary wheel running induces ΔFosB expression in the hippocampus, and examined any potential region-specific effects within the hippocampal subfields along the dorso–ventral axis. Male C57BL/6 mice were housed with or without a running wheel for 4 weeks. Long-term wheel running significantly increased FosB/ΔFosB immunoreactivity in all hippocampal regions measured (i.e., in the DG, CA1, and CA3 subfields of both the dorsal and ventral hippocampus). Results confirmed that wheel running induced region-specific expression of FosB/ΔFosB immunoreactivity in the cortex, suggesting that the uniform increase in FosB/ΔFosB within the hippocampus is not a non-specific consequence of running. Western blot data indicated that the increased hippocampal FosB/ΔFosB immunoreactivity was primarily due to increased ΔFosB. These results suggest that long-term physical exercise is a potent trigger for ΔFosB induction throughout the entire hippocampus, which would explain why exercise can improve both dorsal and ventral hippocampus-dependent functions. Interestingly, we found that FosB/ΔFosB expression in the DG was positively correlated with the number of doublecortin-immunoreactive (i.e., immature) neurons. Although the mechanisms by which ΔFosB mediates exercise-induced neurogenesis are still uncertain, these data imply that exercise-induced neurogenesis is at least activity dependent. Taken together, our current results suggest that ΔFosB is a new molecular target involved in regulating exercise-induced

  20. Spatial memory extinction: a c-Fos protein mapping study.

    PubMed

    Méndez-Couz, M; Conejo, N M; Vallejo, G; Arias, J L

    2014-03-01

    While the neuronal basis of spatial memory consolidation has been thoroughly studied, the substrates mediating the process of extinction remain largely unknown. This study aimed to evaluate the functional contribution of selected brain regions during the extinction of a previously acquired spatial memory task in the Morris water maze. For that purpose, we used adult male Wistar rats trained in a spatial reference memory task. Learning-related changes in c-Fos inmunoreactive cells after training were evaluated in cortical and subcortical regions. Results show that removal of the hidden platform in the water maze induced extinction of the previously reinforced escape behavior after 16 trials, without spontaneous recovery 24h later. Extinction was related with significantly higher numbers of c-Fos positive nuclei in amygdala nuclei and prefrontal cortex. On the other hand, the lateral mammillary bodies showed higher number of c-Fos positive cells than the control group. Therefore, in contrast with the results obtained in studies of classical conditioning, we show the involvement of diencephalic structures mediating this kind of learning. In summary, our findings suggest that medial prefrontal cortex, the amygdala complex and diencephalic structures like the lateral mammillary nuclei are relevant for the extinction of spatial memory. PMID:24315832

  1. Multi-species sequence comparison reveals conservation of ghrelin gene-derived splice variants encoding a truncated ghrelin peptide.

    PubMed

    Seim, Inge; Jeffery, Penny L; Thomas, Patrick B; Walpole, Carina M; Maugham, Michelle; Fung, Jenny N T; Yap, Pei-Yi; O'Keeffe, Angela J; Lai, John; Whiteside, Eliza J; Herington, Adrian C; Chopin, Lisa K

    2016-06-01

    The peptide hormone ghrelin is a potent orexigen produced predominantly in the stomach. It has a number of other biological actions, including roles in appetite stimulation, energy balance, the stimulation of growth hormone release and the regulation of cell proliferation. Recently, several ghrelin gene splice variants have been described. Here, we attempted to identify conserved alternative splicing of the ghrelin gene by cross-species sequence comparisons. We identified a novel human exon 2-deleted variant and provide preliminary evidence that this splice variant and in1-ghrelin encode a C-terminally truncated form of the ghrelin peptide, termed minighrelin. These variants are expressed in humans and mice, demonstrating conservation of alternative splicing spanning 90 million years. Minighrelin appears to have similar actions to full-length ghrelin, as treatment with exogenous minighrelin peptide stimulates appetite and feeding in mice. Forced expression of the exon 2-deleted preproghrelin variant mirrors the effect of the canonical preproghrelin, stimulating cell proliferation and migration in the PC3 prostate cancer cell line. This is the first study to characterise an exon 2-deleted preproghrelin variant and to demonstrate sequence conservation of ghrelin gene-derived splice variants that encode a truncated ghrelin peptide. This adds further impetus for studies into the alternative splicing of the ghrelin gene and the function of novel ghrelin peptides in vertebrates.

  2. Expression of c-fos gene in central nervous system of adult medaka (Oryzias latipes) after hypergravity stimulation

    NASA Astrophysics Data System (ADS)

    Shimomura, S.; Ijiri, K.

    The immediate-early genes serve as useful neurobiological tools for mapping brain activity induced by a sensory stimulation. In this study, we have examined brain activity related to gravity perception of medaka (Oryzias latipes) by use of c-fos. The gene, which is homologous to the c-fos genes of other vertebrates, was identified in medaka. Functionally important domains are highly conserved among all the vertebrate species analyzed. Intraperitoneal administration of kainic acid transiently induced the c-fos mRNAs in medaka brain. The results indicate that the expression of c-fos can be utilized as a suitable anatomical marker for the increased neural activities in the central nervous system of medaka. Fish were continuously exposed to 3G hypergravity by centrifugation. Investigation of c-fos mRNA expression showed that c-fos mRNA significantly increased 30 minutes after a start of 3G exposure. The distribution of its transcripts within brains was analyzed by an in situ hybridization method. The 3G-treated medakas displayed c-fos positive cells in their brainstem regions, which are related to vestibular function, such as torus semicircularis, posterior octavu nucleus, nucleus tangentialis and inferior olive. Our results established the method to trace the activated area in the fish brain following gravity stimulation. The method will be a useful tool for understanding gravity perception in the brain.

  3. Activation of immediate-early response gene c-Fos protein in the rat paralimbic cortices after myocardial infarction

    PubMed Central

    Ahn, Ji Yun; Tae, Hyun-Jin; Cho, Jeong-Hwi; Kim, In Hye; Ahn, Ji Hyeon; Park, Joon Ha; Kim, Dong Won; Cho, Jun Hwi; Won, Moo-Ho; Hong, Seongkweon; Lee, Jae-Chul; Seo, Jeong Yeol

    2015-01-01

    c-Fos is a good biological marker for detecting the pathogenesis of central nervous system disorders. Few studies are reported on the change in myocardial infarction-induced c-Fos expression in the paralimbic regions. Thus, in this study, we investigated the changes in c-Fos expression in the rat cingulate and piriform cortices after myocardial infarction. Neuronal degeneration in cingulate and piriform cortices after myocardial infarction was detected using cresyl violet staining, NeuN immunohistochemistry and Fluoro-Jade B histofluorescence staining. c-Fos-immunoreactive cells were observed in cingulate and piriform cortices at 3 days after myocardial infarction and peaked at 7 and 14 days after myocardial infarction. But they were hardly observed at 56 days after myocardial infarction. The chronological change of c-Fos expression determined by western blot analysis was basically the same as that of c-Fos immunoreactivity. These results indicate that myocardial infarction can cause the chronological change of immediate-early response gene c-Fos protein expression, which might be associated with the neural activity induced by myocardial infarction. PMID:26487852

  4. Estradiol modulates Kiss1 neuronal response to ghrelin

    PubMed Central

    Frazao, Renata; Lemko, Heather M. Dungan; da Silva, Regina P.; Ratra, Dhirender V.; Lee, Charlotte E.; Williams, Kevin W.; Zigman, Jeffrey M.

    2014-01-01

    Ghrelin is a metabolic signal regulating energy homeostasis. Circulating ghrelin levels rise during starvation and fall after a meal, and therefore, ghrelin may function as a signal of negative energy balance. Ghrelin may also act as a modulator of reproductive physiology, as acute ghrelin administration suppresses gonadotropin secretion and inhibits the neuroendocrine reproductive axis. Interestingly, ghrelin's effect in female metabolism varies according to the estrogen milieu predicting an interaction between ghrelin and estrogens, likely at the hypothalamic level. Here, we show that ghrelin receptor (GHSR) and estrogen receptor-α (ERα) are coexpressed in several hypothalamic sites. Higher levels of circulating estradiol increased the expression of GHSR mRNA and the co-xpression of GHSR mRNA and ERα selectively in the arcuate nucleus (ARC). Subsets of preoptic and ARC Kiss1 neurons coexpressed GHSR. Increased colocalization was observed in ARC Kiss1 neurons of ovariectomized estradiol-treated (OVX + E2; 80%) compared with ovariectomized oil-treated (OVX; 25%) mice. Acute actions of ghrelin on ARC Kiss1 neurons were also modulated by estradiol; 75 and 22% of Kiss1 neurons of OVX + E2 and OVX mice, respectively, depolarized in response to ghrelin. Our findings indicate that ghrelin and estradiol may interact in several hypothalamic sites. In the ARC, high levels of E2 increase GHSR mRNA expression, modifying the colocalization rate with ERα and Kiss1 and the proportion of Kiss1 neurons acutely responding to ghrelin. Our findings indicate that E2 alters the responsiveness of kisspeptin neurons to metabolic signals, potentially acting as a critical player in the metabolic control of the reproductive physiology. PMID:24473434

  5. Centrally Administered Ghrelin Acutely Influences Food Choice in Rodents

    PubMed Central

    Schéle, Erik; Bake, Tina; Rabasa, Cristina; Dickson, Suzanne L.

    2016-01-01

    We sought to determine whether the orexigenic hormone, ghrelin, is involved in the intrinsic regulation of food choice in rats. Ghrelin would seem suited to serve such a role given that it signals hunger information from the stomach to brain areas important for feeding control, including the hypothalamus and reward system (e.g. ventral tegmental area, VTA). Thus, in rats offered a choice of palatable foods (sucrose pellets and lard) superimposed on regular chow for 2 weeks, we explored whether acute central delivery of ghrelin (intracerebroventricular (ICV) or intra-VTA) is able to redirect their dietary choice. The major unexpected finding is that, in rats with high baseline lard intake, acute ICV ghrelin injection increased their chow intake over 3-fold, relative to vehicle-injected controls, measured at both 3 hr and 6 hr after injection. Similar effects were observed when ghrelin was delivered to the VTA, thereby identifying the VTA as a likely contributing neurobiological substrate for these effects. We also explored food choice after an overnight fast, when endogenous ghrelin levels are elevated, and found similar effects of dietary choice to those described for ghrelin. These effects of fasting on food choice were suppressed in models of suppressed ghrelin signaling (i.e. peripheral injection of a ghrelin receptor antagonist to rats and ghrelin receptor (GHSR) knock-out mice), implicating a role for endogenous ghrelin in the changes in food choice that occur after an overnight fast. Thus, in line with its role as a gut-brain hunger hormone, ghrelin appears to be able to acutely alter food choice, with notable effects to promote “healthy” chow intake, and identify the VTA as a likely contributing neurobiological substrate for these effects. PMID:26925974

  6. Early onset of ghrelin production in a marsupial.

    PubMed

    Menzies, Brandon R; Shaw, Geoff; Fletcher, Terry P; Renfree, Marilyn B

    2009-02-27

    Ghrelin regulates appetite in mammals and can stimulate growth hormone (GH) release from the pituitary. In rats and humans, ghrelin cells appear in the stomach during late fetal life. Nevertheless, the role of ghrelin in early mammalian development is not well understood. Marsupials deliver highly altricial young that weigh less than 1g so they must feed and digest milk at a comparatively immature stage of development. Since they complete their growth and differentiation while in the pouch, they are accessible models in which to determine the time course of ghrelin production during development. We examined the distribution of gastric ghrelin cells, plasma ghrelin concentrations and pituitary expression of the ghrelin receptor (ghsr-1alpha) and GH in the tammar wallaby, Macropus eugenii. There were ghrelin immunopositive cells in the developing mesenchyme of the stomach from day 10 post partum (pp) to day 150pp. Subsequently ghrelin protein in the fore-stomach declined and was absent by day 250pp but remained in the gastric cells of the hind-stomach. Ghrelin was detected in the developing pancreas from day 10pp but was absent by day 150pp and in the adult. Pituitary ghsr-1alpha expression and plasma concentrations of ghrelin increased significantly up to day 70-120pp while GH expression was also elevated, declining with GH to reach adult levels by day 180pp. These results demonstrate an early onset of gastric ghrelin expression in the tammar in concert with a functional stomach at a relatively earlier stage than that of developmentally more mature eutherian young.

  7. Intracellular pathways linking hypoxia to activation of c-fos and AP-1.

    PubMed

    Premkumar, D R; Adhikary, G; Overholt, J L; Simonson, M S; Cherniack, N S; Prabhakar, N R

    2000-01-01

    Organisms respond to hypoxia through detection of blood oxygen levels by sensors at peripheral chemoreceptors and by receptors in certain key cells of the body. The pathways over which peripheral chemoreceptor signals are transmitted to respiratory muscles are well established. However, the intracellular pathways that transmit hypoxic stimulus to gene activation are just being identified. Using anti-sense c-fos strategy, we have shown that c-fos is essential for the activation of activator protein-1 transcription factor complex (AP-1) and subsequent stimulation of downstream genes such as tyrosine hydroxylase (TH; Mishra et al. 1998). The purpose of the present study was to identify intracellular pathways that link hypoxia to activation of c-fos. The results of the present study show that hypoxia causes Ca2+ influx through L-type voltage gated Ca2+ channels and that hypoxia-induced c-fos gene expression is Ca2+/calmodulin dependent. We also demonstrate that hypoxia activates the extracellular-regulated kinase (ERK) and p38, but not JNK. Further, phosphorylation of ERK is essential for c-fos activation via SRE cis-element. Further characterization of nuclear signalling pathways provides evidence for the involvement of Src, a non receptor protein tyrosine kinase, and Ras, a small G protein, in the hypoxia-induced c-fos gene expression. These results suggest a possible role for non-receptor protein tyrosine kinases in propagating signals from G-protein coupled receptors to the activation of immediate early genes such as c-fos during hypoxia.

  8. 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

  9. 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.

  10. Abnormal ghrelin and pancreatic polypeptide responses in gastroparesis.

    PubMed

    Gaddipati, Kishore V; Simonian, Hrair P; Kresge, Karen M; Boden, Guenther H; Parkman, Henry P

    2006-08-01

    Vagal nerve dysfunction has been implicated in the pathogenesis of diabetic gastroparesis, but its role in idiopathic gastroparesis remains uncertain. The increase in pancreatic polypeptide with sham feeding is often used as a measure of vagal integrity. Ghrelin has been suggested to function as an appetite-stimulating hormone from the gut to the brain acting through vagal afferent pathways. Systemic ghrelin also rises in part due to vagal efferent pathways. Alterations in ghrelin and its effects on appetite could play a role in gastroparesis. In this study we aimed [1] to investigate the presence of vagal nerve dysfunction in patients with idiopathic and diabetic gastroparesis and [2] to determine if alterations in ghrelin concentrations occur in gastroparesis. Normal subjects and patients with diabetic, idiopathic, or postsurgical gastroparesis underwent a sham feeding protocol. Serial blood samples were obtained for plasma ghrelin and pancreatic polypeptide. Sham feeding was characterized by an increase in pancreatic polypeptide and ghrelin in normal controls and patients with idiopathic gastroparesis. The changes in pancreatic polypeptide and ghrelin levels in diabetic and postsurgical gastroparesis were significantly less than those in normal subjects. Vagal nerve dysfunction, as evidenced by an impaired pancreatic polypeptide response with sham feeding, is present in diabetic gastroparesis but not idiopathic gastroparesis. Systemic ghrelin concentrations increased with sham feeding in normal subjects and patients with idiopathic gastroparesis but not in diabetic or postsurgical gastroparesis. Vagal function and regulation of ghrelin levels are impaired in diabetic gastroparesis. PMID:16868831

  11. Neonatal alcohol exposure and the hippocampus in developing male rats: effects on behaviorally induced CA1 c-Fos expression, CA1 pyramidal cell number, and contextual fear conditioning

    PubMed Central

    Murawski, Nathen J.; Klintsova, Anna Y.; Stanton, Mark E.

    2012-01-01

    Rats exposed to a high binge-like dose of alcohol over postnatal days (PD) 4-9 show reductions in CA1 pyramidal cells and impairments on behavioral tasks that depend on the hippocampus. We first examined hippocampal c-Fos expression as a marker of neuronal activity in normally developing rats following different phases of the context preexposure facilitation effect (CPFE) paradigm (Exp. 1). During the CPFE, preexposure to the training context facilitates contextual conditioning to an immediate shock given on a subsequent occasion. We then examined the relationship between CPFE impairment, hippocampal cell loss and c-Fos expression in rats exposed to alcohol over PD 4-9 (Exp. 2). Normally developing (Exp. 1), sham-intubated control (SI), and PD 4-9 alcohol-exposed (4.00g and 5.25g/kg/day; Exp. 2) juvenile male rats were trained on the CPFE. The CPFE occurs over three phases separated by 24h. Starting on PD 31, rats were preexposed to Context A or Context B for five minutes. 24h later, all rats received an immediate, 1.5 mA foot shock in Context A. Finally, rats were tested for contextual conditioning in Context A on PD 33. Normally developing and SI rats preexposed to Context A showed enhanced contextual fear compared to those preexposed to Context B (Exp. 1) or alcohol-exposed rats preexposed to Context A (Exp. 2). Rats were sacrificed 2h following different phases of the CPFE and processed for c-Fos immunohistochemistry (Exp. 1 and 2) and CA1 pyramidal cell quantification (Exp. 2). In Exp. 1, c-Fos+ cells in the DG were consistently high among rats preexposed to Context A (Pre), Context B (No Pre), or sacrificed directly from their home cage (Home) and did not differ across CPFE phases. CA3 and CA1 c-Fos+ cells were highest during preexposure and decreased across training phases, with Group No Pre showing greater numbers of c-Fos+ cells during training than Group Pre and Controls. In Exp. 2, SI rats had greater numbers of CA1 c-Fos+ cells compared alcohol

  12. Effects of isoflurane and ethanol administration on c-Fos immunoreactivity in mice.

    PubMed

    Smith, M L; Li, J; Cote, D M; Ryabinin, A E

    2016-03-01

    Noninvasive functional imaging holds great promise for the future of translational research, due to the ability to directly compare between preclinical and clinical models of psychiatric disorders. Despite this potential, concerns have been raised regarding the necessity to anesthetize rodent and monkey subjects during these procedures, because anesthetics may alter neuronal activity. For example, in studies on drugs of abuse and alcohol, it is not clear to what extent anesthesia can interfere with drug-induced neural activity. Therefore, the current study investigated whole-brain c-Fos activation following isoflurane anesthesia as well as ethanol-induced activation of c-Fos in anesthetized mice. In the first experiment, we examined effects of one or three sessions of gaseous isoflurane on c-Fos activation across the brain in male C57BL/6J mice. Isoflurane administration led to c-Fos activation in several areas, including the piriform cortex and lateral septum. Lower or similar levels of activation in these areas were detected after three sessions of isoflurane, suggesting that multiple exposures may eliminate some of the enhanced neuronal activation caused by acute isoflurane. In the second experiment, we investigated the ability of ethanol injection (1.5 or 2.5g/kgi.p.) to induce c-Fos activation under anesthesia. Following three sessions of isoflurane, 1.5g/kg of ethanol induced c-Fos in the central nucleus of amygdala and the centrally-projecting Edinger-Westphal nucleus (EWcp). This induction was lower after 2.5g/kg of ethanol. These results demonstrate that ethanol-induced neural activation can be detected in the presence of isoflurane anesthesia. They also suggest, that while habituation to isoflurane helps reduce neuronal activation, interaction between effects of anesthesia and alcohol can occur. Studies using fMRI imaging could benefit from using habituated animals and dose-response analyses.

  13. Effects of isoflurane and ethanol administration on c-Fos immunoreactivity in mice.

    PubMed

    Smith, M L; Li, J; Cote, D M; Ryabinin, A E

    2016-03-01

    Noninvasive functional imaging holds great promise for the future of translational research, due to the ability to directly compare between preclinical and clinical models of psychiatric disorders. Despite this potential, concerns have been raised regarding the necessity to anesthetize rodent and monkey subjects during these procedures, because anesthetics may alter neuronal activity. For example, in studies on drugs of abuse and alcohol, it is not clear to what extent anesthesia can interfere with drug-induced neural activity. Therefore, the current study investigated whole-brain c-Fos activation following isoflurane anesthesia as well as ethanol-induced activation of c-Fos in anesthetized mice. In the first experiment, we examined effects of one or three sessions of gaseous isoflurane on c-Fos activation across the brain in male C57BL/6J mice. Isoflurane administration led to c-Fos activation in several areas, including the piriform cortex and lateral septum. Lower or similar levels of activation in these areas were detected after three sessions of isoflurane, suggesting that multiple exposures may eliminate some of the enhanced neuronal activation caused by acute isoflurane. In the second experiment, we investigated the ability of ethanol injection (1.5 or 2.5g/kgi.p.) to induce c-Fos activation under anesthesia. Following three sessions of isoflurane, 1.5g/kg of ethanol induced c-Fos in the central nucleus of amygdala and the centrally-projecting Edinger-Westphal nucleus (EWcp). This induction was lower after 2.5g/kg of ethanol. These results demonstrate that ethanol-induced neural activation can be detected in the presence of isoflurane anesthesia. They also suggest, that while habituation to isoflurane helps reduce neuronal activation, interaction between effects of anesthesia and alcohol can occur. Studies using fMRI imaging could benefit from using habituated animals and dose-response analyses. PMID:26742790

  14. The impact of weight loss on the 24-h profile of circulating peptide YY and its association with 24-h ghrelin in normal weight premenopausal women.

    PubMed

    Hill, Brenna R; De Souza, Mary Jane; Wagstaff, David A; Williams, Nancy I

    2013-11-01

    Peptide YY (PYY) and ghrelin exhibit a reciprocal association and antagonistic physiological effects in the peripheral circulation. Research has yet to clarify the effect of weight loss on the 24h profile of PYY or its association to 24h ghrelin. We sought to determine if diet- and exercise-induced weight loss affects the 24h profile of PYY and its association with 24h ghrelin in normal weight, premenopausal women. Participants (n = 13) were assessed at baseline (BL) and after a 3-month diet and exercise intervention (post). Blood samples obtained q10 min for 24h were assayed for total PYY and total ghrelin q60 min from 0800 to 1000 h and 2000 to 0800 h and q20 min from 1000 to 2000 h. The ghrelin/PYY ratio was used as an index of hormonal exposure. Statistical analyses included paired t-tests and linear mixed effects modeling. Body weight (-1.85 ± 0.67 kg; p = 0.02), and body fat (-2.53 ± 0.83%; p = 0.01) decreased from BL to post. Ghrelin AUC (5252 ± 2177 pg/ml/24h; p=0.03), 24h mean (216 ± 90 pg/ml; p = 0.03) and peak (300 ± 134 pg/ml; p = 0.047) increased from BL to post. No change occurred in PYY AUC (88.2 ± 163.7 pg/ml; p = 0.60), 24h mean (4.8 ± 6.9 pg/ml; p = 0.50) or peak (3.6 ± 6.4 pg/ml; p = 0.58). The 24h association between PYY and ghrelin at baseline (p = 0.04) was weakened at post (p = 0.14); however, the ghrelin/PYY lunch ratio increased (p = 0.01) indicating the potential for ghrelin predominance over PYY in the circulation. PYY and ghrelin are reciprocally associated during a period of weight stability, but not following weight loss. An "uncoupling" may have occurred, particularly at lunch, due to factors that modulate ghrelin in response to weight loss.

  15. Characterization of E-cadherin-dependent and -independent events in a new model of c-Fos-mediated epithelial-mesenchymal transition

    SciTech Connect

    Mejlvang, Jakob; Kriajevska, Marina; Berditchevski, Fedor; Bronstein, Igor; Lukanidin, Eugene M.; Pringle, J. Howard; Mellon, J. Kilian; Tulchinsky, Eugene M. . E-mail: et32@le.ac.uk

    2007-01-15

    Fos proteins have been implicated in control of tumorigenesis-related genetic programs including invasion, angiogenesis, cell proliferation and apoptosis. In this study, we demonstrate that c-Fos is able to induce mesenchymal transition in murine tumorigenic epithelial cell lines. Expression of c-Fos in MT1TC1 cells led to prominent alterations in cell morphology, increased expression of mesenchymal markers, vimentin and S100A4, DNA methylation-dependent down-regulation of E-cadherin and abrogation of cell-cell adhesion. In addition, c-Fos induced a strong {beta}-catenin-independent proliferative response in MT1TC1 cells and stimulated cell motility, invasion and adhesion to different extracellular matrix proteins. To explore whether loss of E-cadherin plays a role in c-Fos-mediated mesenchymal transition, we expressed wild-type E-cadherin and two different E-cadherin mutants in MT1TC1/c-fos cells. Expression of wild-type E-cadherin restored epithelioid morphology and enhanced cellular levels of catenins. However, exogenous E-cadherin did not influence expression of c-Fos-dependent genes, only partly suppressed growth of MT1TC1/c-fos cells and produced no effect on c-Fos-stimulated cell motility and invasion in matrigel. On the other hand, re-expression of E-cadherin specifically negated c-Fos-induced adhesion to collagen type I, but not to laminin or fibronectin. Of interest, mutant E-cadherin which lacks the ability to form functional adhesive complexes had an opposite, potentiating effect on cell adhesion to collagen I. These data suggest that cell adhesion to collagen I is regulated by the functional state of E-cadherin. Overall, our data demonstrate that, with the exception of adhesion to collagen I, c-Fos is dominant over E-cadherin in relation to the aspects of mesenchymal transition assayed in this study.

  16. Serum response factor promotes resilience to chronic social stress through the induction of ΔFosB

    PubMed Central

    Vialou, Vincent; Maze, Ian; Renthal, William; LaPlant, Quincey C.; Watts, Emily L.; Mouzon, Ezekiell; Ghose, Subroto; Tamminga, Carol A.; Nestler, Eric J.

    2010-01-01

    The molecular mechanisms underlying stress- and drug-induced neuronal adaptations are incompletely understood. One molecule implicated in such adaptations is ΔFosB, a transcription factor that accumulates in the rodent nucleus accumbens (NAc), a key brain reward region, in response to either chronic stress or repeated exposure to drugs of abuse. The upstream transcriptional mechanisms controlling ΔFosB induction by these environmental stimuli remain elusive. Here, we identify the activity-dependent transcription factor, serum response factor (SRF), as a novel upstream mediator of stress-, but not cocaine-, induced ΔFosB. SRF is downregulated in NAc of both human depressed patients and in mice chronically exposed to social defeat stress. This downregulation of SRF is absent in resilient animals. Through the use of inducible mutagenesis, we show that stress-mediated induction of ΔFosB, which occurs predominantly in resilient mice, is dependent on SRF expression in this brain region. Furthermore, NAc-specific genetic deletion of SRF promotes a variety of pro-depressant- and anxiety-like phenotypes and renders animals more sensitive to the deleterious effects of chronic stress. In contrast, we demonstrate that SRF does not play a role in ΔFosB accumulation in NAc in response to chronic cocaine exposure. Furthermore, NAc-specific knockout of SRF has no effect on cocaine-induced behaviors, indicating that chronic social defeat stress and repeated cocaine exposure regulate ΔFosB accumulation and behavioral sensitivity through independent mechanisms. PMID:20980616

  17. Ghrelin and cachexia in chronic kidney disease.

    PubMed

    Suzuki, Hajime; Asakawa, Akihiro; Amitani, Haruka; Nakamura, Norifumi; Inui, Akio

    2013-04-01

    Ghrelin is a growth hormone (GH) secretagogue and a potent orexigenic factor that stimulates feeding by interacting with hypothalamic feeding-regulatory nuclei. Its multifaceted effects are potentially beneficial as a treatment in human disease states. In both adult and pediatric chronic kidney disease (CKD) patients, decreased appetite plays a major role in wasting, which in turn is linked to morbidity and mortality; wasting has also been linked to high levels of leptin and proinflammatory cytokines. The beneficial effects of ghrelin treatment in CKD are potentially mediated by multiple concurrent actions, including the stimulation of appetite-regulating centers, anti-inflammatory effects, and direct kidney effects. Further evaluation of this appetite-regulating hormone in CKD is needed to confirm previous findings and to determine the underlying mechanisms.

  18. Identification, tissue distribution and functional characterization of the ghrelin receptor in West African lungfish, Protopterus annectens.

    PubMed

    Kaiya, Hiroyuki; Konno, Norifumi; Kangawa, Kenji; Uchiyama, Minoru; Miyazato, Mikiya

    2014-12-01

    We identified two ghrelin receptor isoforms, the ghrelin receptor type-1a (GHS-R1a) and its alternative splice form (GHS-R1b) for West African lungfish, Protopterus annectens. Lungfish GHS-R1a and 1b comprised 361 and 281 amino acids, respectively. Lungfish GHS-R1a showed the highest identity to coelacanth GHS-R1a (80.4%). The highest expression of GHS-R1a mRNAs was seen in the brain, liver, ovary, heart, intestine, and gills. GHS-R1b mRNAs were also detected in the same tissues with GHS-R1a, but their expression level was 1/20 that of GHS-R1a. In human embryonic kidney 293 cells transiently expressing lungfish GHS-R1a, rat and bullfrog ghrelin, and two GHS-R1a agonists, GHRP-6 and hexarelin, increased intracellular Ca(2+) concentrations. The intensity of the Ca(2+) increases induced by GHS-R1a agonists was twice when compared to that induced by ghrelin, although the median effective doses (ED50) were similar, suggesting a long-lasting effect of GHS-R1a agonists with similar affinity. We also examined changes in the GHS-R gene expression during an eight-week estivation. Body weight was slightly lowered, but plasma sodium and glucose concentrations decreased; plasma urea concentration increased significantly 4weeks after the start of estivation. Overall, expression of GHS-R1a mRNA decreased, but changes in GHS-R1b mRNA expression were inconsistent with those of GHS-R1a during estivation, suggesting an involvement of GHS-R in energy homeostasis, as seen in mammals. Our results suggest that the ghrelin-GHS-R1a system is present in this lungfish although ghrelin has not yet been found. The structure of GHS-R1a is closer to that of tetrapods than Actinopterygian fish, indicating a process of evolution that follows the Crossopterygii such as coelacanth.

  19. The gastric CB1 receptor modulates ghrelin production through the mTOR pathway to regulate food intake.

    PubMed

    Senin, Lucia L; Al-Massadi, Omar; Folgueira, Cintia; Castelao, Cecilia; Pardo, Maria; Barja-Fernandez, Silvia; Roca-Rivada, Arturo; Amil, Maria; Crujeiras, Ana B; Garcia-Caballero, Tomas; Gabellieri, Enrico; Leis, Rosaura; Dieguez, Carlos; Pagotto, Uberto; Casanueva, Felipe F; Seoane, Luisa M

    2013-01-01

    Over the years, the knowledge regarding the relevance of the cannabinoid system to the regulation of metabolism has grown steadily. A central interaction between the cannabinoid system and ghrelin has been suggested to regulate food intake. Although the stomach is the main source of ghrelin and CB1 receptor expression in the stomach has been described, little information is available regarding the possible interaction between the gastric cannabinoid and ghrelin systems in the integrated control of energy homeostasis. The main objective of the present work was to assess the functional interaction between these two systems in terms of food intake using a combination of in vivo and in vitro approaches. The present work demonstrates that the peripheral blockade of the CB1 receptor by rimonabant treatment decreased food intake but only in food-deprived animals. This anorexigenic effect is likely a consequence of decreases in gastric ghrelin secretion induced by the activation of the mTOR/S6K1 intracellular pathway in the stomach following treatment with rimonabant. In support of this supposition, animals in which the mTOR/S6K1 intracellular pathway was blocked by chronic rapamycin treatment, rimonabant had no effect on ghrelin secretion. Vagal communication may also be involved because rimonabant treatment was no longer effective when administered to animals that had undergone surgical vagotomy. In conclusion, to the best of our knowledge, the present work is the first to describe a CB1 receptor-mediated mechanism that influences gastric ghrelin secretion and food intake through the mTOR pathway. PMID:24303008

  20. Ghrelin stimulates gastric emptying but is without effect on acid secretion and gastric endocrine cells.

    PubMed

    Dornonville de la Cour, Charlotta; Lindström, Erik; Norlén, Per; Håkanson, Rolf

    2004-08-15

    Ghrelin, a recently discovered peptide hormone, is produced by endocrine cells in the stomach, the so-called A-like cells. Ghrelin binds to the growth hormone (GH) secretagogue receptor and releases GH. It is claimed to be orexigenic and to control gastric acid secretion and gastric motility. In this study, we examined the effects of ghrelin, des-Gln14-ghrelin, des-octanoyl ghrelin, ghrelin-18, -10 and -5 (and motilin) on gastric emptying in mice and on gastric acid secretion in chronic fistula rats and pylorus-ligated rats. We also examined whether ghrelin affected the activity of the predominant gastric endocrine cell populations, G cells, ECL cells and D cells. Ghrelin and des-Gln14-ghrelin stimulated gastric emptying in a dose-dependent manner while des-octanoyl ghrelin and motilin were without effect. The C-terminally truncated ghrelin fragments were effective but much less potent than ghrelin itself. Ghrelin, des-Gln14-ghrelin and des-octanoyl ghrelin neither stimulated nor inhibited gastric acid secretion, and ghrelin, finally, did not affect secretion from either G cells, ECL cells or D cells.

  1. Integrating GHS into the Ghrelin System

    PubMed Central

    Veldhuis, Johannes D.; Bowers, Cyril Y.

    2010-01-01

    Oligopeptide derivatives of metenkephalin were found to stimulate growth-hormone (GH) release directly by pituitary somatotrope cells in vitro in 1977. Members of this class of peptides and nonpeptidyl mimetics are referred to as GH secretagogues (GHSs). A specific guanosine triphosphatate-binding protein-associated heptahelical transmembrane receptor for GHS was cloned in 1996. An endogenous ligand for the GHS receptor, acylghrelin, was identified in 1999. Expression of ghrelin and homonymous receptor occurs in the brain, pituitary gland, stomach, endothelium/vascular smooth muscle, pancreas, placenta, intestine, heart, bone, and other tissues. Principal actions of this peptidergic system include stimulation of GH release via combined hypothalamopituitary mechanisms, orexigenesis (appetitive enhancement), insulinostasis (inhibition of insulin secretion), cardiovascular effects (decreased mean arterial pressure and vasodilation), stimulation of gastric motility and acid secretion, adipogenesis with repression of fat oxidation, and antiapoptosis (antagonism of endothelial, neuronal, and cardiomyocyte death). The array of known and proposed interactions of ghrelin with key metabolic signals makes ghrelin and its receptor prime targets for drug development. PMID:20798846

  2. Ghrelin role in hypothalamus-pituitary-ovarian axis.

    PubMed

    Rak-Mardyla, A

    2013-12-01

    Based on the available data, it was shown that ghrelin is involved in a series of physiological processes such as regulation of food intake, body weight, and cardiovascular or immune function. Recent studies have shown that ghrelin also plays an important role in the regulation of female reproduction. Information exists that its functional receptor, GHSR type 1a (GHS-R1a), is expressed in the hypothalamic-pituitary-ovarian axis. Ghrelin is synthesized locally in the hypothalamus, pituitary and ovaries of many species and has autocrine and/or paracrine effects. Most research indicates that ghrelin has inhibitory effect on gonadotropin secretion. Ghrelin also participates in the direct regulation of different ovarian functions such as steroid secretion, cell proliferation and apoptosis; these functions appear to be species-specific. Moreover, the importance of GHS-R1a or MAPK/IP3 pathway activation in ghrelin action in the ovary has been described. The article summarizes results of a series of recent studies on the effect of ghrelin on the hypothalamic-pituitary-ovarian axis, as well as on ovarian physiology with an indication that ghrelin via its biological functions such as energy metabolism and food intake could also be a key signal between animal energy status and control of ovarian function.

  3. Ghrelin receptor regulates adipose tissue inflammation in aging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aging is commonly associated with low-grade adipose inflammation, which is closely linked to insulin resistance. Ghrelin is the only circulating orexigenic hormone which is known to increase obesity and insulin resistance. We previously reported that the expression of the ghrelin receptor, growth ho...

  4. Effects of capsaicin on testis ghrelin expression in mice.

    PubMed

    Ilhan, T; Erdost, H

    2013-01-01

    Capsaicin (CAP), the active substance of red hot peppers, has been reported to stimulate development of the gonad. Ghrelin is an acylated polypeptide hormone that is secreted predominantly by endocrine cells of the stomach. There is evidence that ghrelin is involved in reproductive function. Ghrelin significantly inhibits testosterone secretion in a dose-dependent manner. We investigated the effect of CAP on ghrelin expression in testes of mice and on testosterone levels during pubertal and adult periods. We used a variety of morphometric, immunohistochemical and biochemical methods, and western blot analysis. The animals were divided into two age groups: puberty and adult. Control groups for both age groups were fed with standard diet and experimental groups were fed with a diet containing 0.02% CAP. Testes were collected quickly after sacrifice. After dehydration, the specimens were embedded in paraffin and 5 μm sections were cut, and Crossman's triple staining and immunohistochemical staining for ghrelin were applied. Immunohistochemical staining with ghrelin antibody for both age groups demonstrated immunoreaction especially in Leydig and Sertoli cells, but no reaction was observed in spermatogenic cells. Ghrelin immunoreaction was less intense in the experimental groups. Serum testosterone levels were increased in both experimental groups, especially in adults. More spermatocytes were observed in the experimental group compared to the control group. In both pubertal and adult experimental groups, the seminiferous epithelium was thick. CAP appears to enhance testicular cell proliferation and can affect the release of ghrelin and testosterone directly or indirectly.

  5. The effect of ghrelin on water intake during dipsogenic conditions.

    PubMed

    Mietlicki, Elizabeth G; Nowak, Erica L; Daniels, Derek

    2009-01-01

    Ghrelin has been studied extensively in the context of food intake and energy homeostasis, but less is known about its role in other ingestive behaviors. The present studies investigated the effects of this orexigenic peptide on both food and water intake during dipsogenic conditions. Specifically, animals were exposed to one of five dipsetic stimuli: (1) 24-h water deprivation, (2) replacement of drinking water with 2.5% NaCl, (3) peripheral administration of hypertonic saline, (4) ICV injection of angiotensin II (AngII), or (5) the combination of peripheral hypertonic saline and central AngII. Animals then were given an ICV injection of ghrelin (0.5 microg) or vehicle, and subsequent food and water intakes were measured. Ghrelin reliably increased food intake under each stimulus condition. Ghrelin also affected water intake, but with less consistency across the conditions. Specifically, ghrelin attenuated water intake stimulated by acute injection of AngII or hypertonic saline, but failed to affect drinking in the other three stimulus conditions. Investigation of the temporal pattern of food and water intakes in three of these dipsogenic conditions failed to support a role of different intake patterns in the observed differences in water intake by ghrelin-treated rats. Although the effect of ghrelin on water intake was not present in every dipsogenic condition, these data provide evidence that the actions of ghrelin are not limited to food intake, but can also include alterations in water intake.

  6. Gastrointestinal hormones (anorexigenic peptide YY and orexigenic ghrelin) influence neural tube development.

    PubMed

    Yuzuriha, Hideki; Inui, Akio; Asakawa, Akihiro; Ueno, Naohiko; Kasuga, Masato; Meguid, Michael M; Miyazaki, Jun-ichi; Ninomiya, Maiko; Herzog, Herbert; Fujimiya, Mineko

    2007-07-01

    Gastrointestinal (GI) hormones play an important role in GI secretion, motility, and eating behaviors. It was recently suggested that GI hormones may have a trophic role in GI tract. Here we demonstrate that two principal GI hormones, anorexigenic peptide YY (PYY) and orexigenic ghrelin, affect neural tube development. Chronic administration into the pregnant mice or transgenic overexpression of PYY led to a neural tube defect (NTD) in the embryos that was blocked by ghrelin. PYY Y1 receptor antagonist prevented the occurrence of NTD induced not only by PYY but also by vitamin A, a well-known teratogen in humans and animals. Y1 receptor deficiency also engendered NTDs, indicating the need to maintain normal Y1 receptor signaling. The present study is the first linking GI hormones to the leading cause of infant mortality and provides a novel insight for neurogenesis in which materno-fetal communication through GI hormones appears to be important. PMID:17400914

  7. Cholinergic input to the supraoptic nucleus increases Fos expression and body temperature in rats.

    PubMed

    Takahashi, A; Ishimaru, H; Ikarashi, Y; Kishi, E; Maruyama, Y

    2001-06-01

    To examine the role played by cholinergic input and processes in the supraoptic nucleus (SON) in the control of body temperature and water intake in rats, we used microdialysis to stimulate and analyze SON without disturbing the behavior of unanesthetized rats. After microdialysis, we also investigated immunoreactivity for c-Fos protein in the brain as an index of neuronal activation. Stimulation with neostigmine, an acetylcholine esterase inhibitor, through the microdialysis probe increased the extracellular concentration of acetylcholine in the SON. This cholinergic stimulation dose-dependently increased body temperature but did not significantly change the water intake. The stimulation markedly increased c-Fos-like immunoreactivity (Fos-IR) in the SON and certain hypothalamic areas, including the paraventricular nucleus (PVN) and median preoptic nucleus (MnPO). Fos-IR was also evident in certain regions of the pons and brainstem, including the locus ceruleus (LC), area postrema (AP), and nucleus of the solitary tract (NTS). Addition of atropine, a muscarinic receptor antagonist, to the dialysis medium containing neostigmine attenuated the increase of Fos-IR and suppressed the neostigmine-induced responses in body temperature. These results suggest that cholinergic input and activation of the muscarinic cholinoceptive neurons in the SON contribute to the regulation of body temperature. Activation of noradrenergic pathways in the brainstem including LC and NTS may be involved in the thermoregulation mechanism.

  8. Ghrelin: a metabolic signal affecting the reproductive system.

    PubMed

    Lorenzi, Teresa; Meli, Rosaria; Marzioni, Daniela; Morroni, Manrico; Baragli, Alessandra; Castellucci, Mario; Gualillo, Oreste; Muccioli, Giampiero

    2009-04-01

    Ghrelin, an acylated 28 amino acid gastric peptide, was isolated from the stomach as an endogenous ligand for growth hormone (GH) secretagogue receptor in 1999. Circulating ghrelin is mainly produced by specific cells in the stomach's oxyntic glands. Ghrelin potently stimulates GH release and food intake and exhibits diverse effects, including ones on glucose metabolism and on secretion and motility of the gastrointestinal tract. Besides these effects on food intake and energy homeostasis, ghrelin is also involved in controlling reproductive functions, and a role for it as a novel regulator of the hypothalamic-pituitary gonadal axis is clearly emerging. We review recent ghrelin research with emphasis on its roles in the reproductive axis.

  9. Fos expression in the vestibular brainstem: what one marker can tell us about the network.

    PubMed

    Kaufman, Galen D

    2005-12-01

    Fos inducible transcription factor expression in rodent brains (rats and gerbils) during manipulations of vestibular input is reviewed. Stimuli included centripetal hypergravity, unilateral labyrinth lesion or semicircular canal plugging, rotational axis cross-coupling (Coriolis forces), high and low rotational vestibulo-ocular reflex gain adaptation, translabyrinth galvanic stimulation, pharmacological manipulation, and combinations thereof. Each type of stimulation elicited unique but partially redundant response patterns in the vestibulo-olivo-cerebellar (VOC) network that reflect the origin and interaction of the labyrinth inputs. On the basis of these patterns, a trained observer can predict what the animal experienced during testing; the patterns of VOC Fos expression reveal a trace of recent genomic activity. Based on principal component analysis, VOC network modules associated with lesion recovery, spatial representation and the calibration of gravity, and optokinetic influences are proposed. Probable and possible gene targets of the Fos protein are also reviewed.

  10. Ghrelin ameliorates catabolic conditions and respiratory dysfunction in a chronic obstructive pulmonary disease model of chronic cigarette smoke-exposed rats.

    PubMed

    Kamiide, Yoshiyuki; Inomata, Norio; Furuya, Mayumi; Yada, Toshihiko

    2015-05-15

    Cigarette smoking, which is a well-known major risk factor for chronic obstructive pulmonary disease (COPD), causes both pulmonary and extrapulmonary abnormalities. Ghrelin is a gastric peptide that regulates energy homeostasis. In the present study, we investigated the effects of ghrelin on the catabolic changes, respiratory function and emphysema in an animal model of COPD induced by chronic exposure to cigarette smoke. Rats were exposed to cigarette smoke, and they were administered human ghrelin (0.1 or 1 mg/kg, subcutaneous, twice daily) for 12 weeks. Compared with air-exposed rats, body weight gain, food intake, food efficiency, tidal volume, peak expiratory flow rate, and forced expiratory volume at 100 ms were significantly lower, while functional residual capacity, lung capacity, and neutrophils in bronchoalveolar lavage fluid were significantly higher in cigarette smoke-exposed rats. These indicated that the systemic abnormalities associated with COPD developed after the exposure to cigarette smoke. Ghrelin significantly and dose-dependently increased the body weight gain and food efficiency in cigarette smoke-exposed rats. In ghrelin-treated rats, skeletal muscle strength, which tended to be lowered by cigarette smoke exposure, was improved. Ghrelin ameliorated respiratory function and emphysema in a dose-dependent manner, but did not inhibit the increase in neutrophils in the bronchoalveolar lavage fluid. The respiratory functional parameters and lung capacity were significantly correlated with body weight gain. These results suggest that ghrelin inhibited the development of the catabolic changes, respiratory dysfunction, and emphysema that were induced by cigarette smoke exposure in rats, at least in part, through the amelioration of nutritional status.

  11. Ghrelin ameliorates catabolic conditions and respiratory dysfunction in a chronic obstructive pulmonary disease model of chronic cigarette smoke-exposed rats.

    PubMed

    Kamiide, Yoshiyuki; Inomata, Norio; Furuya, Mayumi; Yada, Toshihiko

    2015-05-15

    Cigarette smoking, which is a well-known major risk factor for chronic obstructive pulmonary disease (COPD), causes both pulmonary and extrapulmonary abnormalities. Ghrelin is a gastric peptide that regulates energy homeostasis. In the present study, we investigated the effects of ghrelin on the catabolic changes, respiratory function and emphysema in an animal model of COPD induced by chronic exposure to cigarette smoke. Rats were exposed to cigarette smoke, and they were administered human ghrelin (0.1 or 1 mg/kg, subcutaneous, twice daily) for 12 weeks. Compared with air-exposed rats, body weight gain, food intake, food efficiency, tidal volume, peak expiratory flow rate, and forced expiratory volume at 100 ms were significantly lower, while functional residual capacity, lung capacity, and neutrophils in bronchoalveolar lavage fluid were significantly higher in cigarette smoke-exposed rats. These indicated that the systemic abnormalities associated with COPD developed after the exposure to cigarette smoke. Ghrelin significantly and dose-dependently increased the body weight gain and food efficiency in cigarette smoke-exposed rats. In ghrelin-treated rats, skeletal muscle strength, which tended to be lowered by cigarette smoke exposure, was improved. Ghrelin ameliorated respiratory function and emphysema in a dose-dependent manner, but did not inhibit the increase in neutrophils in the bronchoalveolar lavage fluid. The respiratory functional parameters and lung capacity were significantly correlated with body weight gain. These results suggest that ghrelin inhibited the development of the catabolic changes, respiratory dysfunction, and emphysema that were induced by cigarette smoke exposure in rats, at least in part, through the amelioration of nutritional status. PMID:25771457

  12. The induction of Fos-like proteins in the suprachiasmatic nuclei and intergeniculate leaflet by light pulses in degus (Octodon degus) and rats.

    PubMed

    Krajnak, K; Dickenson, L; Lee, T M

    1997-10-01

    In nocturnal rodents, exposure to light results in an increase in Fos expression in two regions that receive direct retinal input: the suprachiasmatic nuclei (SCN) of the hypothalamus and the intergeniculate leaflet (IGL) of the thalamus. The induction of Fos within the SCN of nocturnal rodents is phase dependent, with light presented during the subjective night increasing Fos expression and light presented during the subjective day having little effect. By contrast, Fos expression increases in the IGL when light is presented during the subjective day or night. It is unclear whether Fos is part of the pathway mediating light-induced phase shifts in diurnal rodents. In the present study, the ability of light to induce immunostaining for Fos in the SCN and IGL was compared in diurnal rodents, Octodon degus (degus), and nocturnal rats. Degus and rats were either maintained in constant darkness or exposed to a 1-h light pulse at circadian time (CT) 4 or 16. Degus exhibit robust phase shifts at each of those circadian hours, whereas rats demonstrate phase shifts only at CT 16. In degus, exposure to a 1-h light pulse at CT 16 resulted in an increase in the number of Fos-immunopositive (Fos+) cells in the ventrolateral SCN. By contrast, a 1-h light pulse at CT 4 resulted in a decrease in the number of Fos+ cells in the dorsomedial portion of the SCN. In rats, a light pulse presented at CT 16 resulted in an increase in Fos+ cells throughout the SCN, and a pulse at CT 4 had no effect on Fos staining. Both degus and rats showed increases in Fos expression in the IGL after light exposure at CTs 4 and 16. The authors conclude that light pulses presented at times that produce phase shifts in activity rhythms also alter Fos expression in the SCN and IGL of degus. Although these effects of light exposure on Fos expression are not identical in diurnal and nocturnal rodents, it is likely that Fos and other immediate early genes are part of the pathway mediating the effects of light

  13. Hyperosmolarity in the small intestine contributes to postprandial ghrelin suppression

    PubMed Central

    Overduin, Joost; Tylee, Tracy S.; Frayo, R. Scott

    2014-01-01

    Plasma levels of the orexigenic hormone ghrelin are suppressed by meals with an efficacy dependent on their macronutrient composition. We hypothesized that heterogeneity in osmolarity among macronutrient classes contributes to these differences. In three studies, the impact of small intestinal hyperosmolarity was examined in Sprague-Dawley rats. In study 1, isotonic, 2.5×, and 5× hypertonic solutions of several agents with diverse absorption and metabolism properties were infused duodenally at a physiological rate (3 ml/10 min). Jugular vein blood was sampled before and at 30, 60, 90, 120, 180, 240, and 300 min after infusion. Plasma ghrelin was suppressed dose dependently and most strongly by glucose. Hyperosmolar infusions of lactulose, which transits the small intestine unabsorbed, and 3-O-methylglucose (3-O-MG), which is absorbed like glucose but remains unmetabolized, also suppressed ghrelin. Glucose, but not lactulose or 3-O-MG, infusions increased plasma insulin. In study 2, intestinal infusions of hyperosmolar NaCl suppressed ghrelin, a response that was not attenuated by coinfusion with the neural blocker lidocaine. In study 3, we reconfirmed that the low-osmolar lipid emulsion Intralipid suppresses ghrelin more weakly than isocaloric (but hypertonic) glucose. Importantly, raising Intralipid's osmolarity to that of the glucose solution by nonabsorbable lactulose supplementation enhanced ghrelin suppression to that seen after glucose. Hyperosmolar ghrelin occurred particularly during the initial 3 postinfusion hours. We conclude that small intestinal hyperosmolarity 1) is sufficient to suppress ghrelin, 2) may combine with other postprandial mechanisms to suppress ghrelin, 3) might contribute to altered ghrelin regulation after gastric bypass surgery, and 4) may inform dietary modifications for metabolic health. PMID:24789208

  14. An indirect action contributes to c-fos induction in paraventricular hypothalamic nucleus by neuropeptide Y

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  15. Ablations of ghrelin and ghrelin receptor exhibit differential metabolic phenotypes and thermogenic capacity during aging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Obesity is a hallmark of aging in many Western societies, and is a precursor to numerous serious age-related diseases. Ghrelin ("Ghrl"), via its receptor (growth hormone secretagogue receptor, GHS-R), is shown to stimulate GH secretion and appetite. Surprisingly, our previous studies showed that "Gh...

  16. Interactions among LRF-1, JunB, c-Jun, and c-Fos define a regulatory program in the G1 phase of liver regeneration.

    PubMed Central

    Hsu, J C; Bravo, R; Taub, R

    1992-01-01

    In regenerating liver, a physiologically normal model of cell growth, LRF-1, JunB, c-Jun, and c-Fos among Jun/Fos/LRF-1 family members are induced posthepatectomy. In liver cells, high levels of c-Fos/c-Jun, c-Fos/JunB, LRF-1/c-Jun, and LRF-1/JunB complexes are present for several hours after the G0/G1 transition, and the relative level of LRF-1/JunB complexes increases during G1. We provide evidence for dramatic differences in promoter-specific activation by LRF-1- and c-Fos-containing complexes. LRF-1 in combination with either Jun protein strongly activates a cyclic AMP response element-containing promoter which c-Fos/Jun does not activate. LRF-1/c-Jun, c-Fos/c-Jun, and c-Fos/JunB activate specific AP-1 and ATF site-containing promoters, and in contrast, LRF-1/JunB potently represses c-Fos- and c-Jun-mediated activation of these promoters. Repression is dependent on a region in LRF-1 that includes amino acids 40 to 84 (domain R) and the basic/leucine zipper domain. As the relative level of LRF-1/JunB complexes increases posthepatectomy, c-Fos/Jun-mediated ATF and AP-1 site activation is likely to decrease with simultaneous transcriptional activation of the many liver-specific genes whose promoters contain cyclic AMP response element sites. Thus, through complex interactions among LRF-1, JunB, c-Jun, and c-Fos, control of delayed gene expression may be established for extended times during the G1 phase of hepatic growth. Images PMID:1406655

  17. ΔFosB induction in striatal medium spiny neuron subtypes in response to chronic pharmacological, emotional, and optogenetic stimuli.

    PubMed

    Lobo, Mary Kay; Zaman, Samir; Damez-Werno, Diane M; Koo, Ja Wook; Bagot, Rosemary C; DiNieri, Jennifer A; Nugent, Alexandria; Finkel, Eric; Chaudhury, Dipesh; Chandra, Ramesh; Riberio, Efrain; Rabkin, Jacqui; Mouzon, Ezekiell; Cachope, Roger; Cheer, Joseph F; Han, Ming-Hu; Dietz, David M; Self, David W; Hurd, Yasmin L; Vialou, Vincent; Nestler, Eric J

    2013-11-20

    The transcription factor, ΔFosB, is robustly and persistently induced in striatum by several chronic stimuli, such as drugs of abuse, antipsychotic drugs, natural rewards, and stress. However, very few studies have examined the degree of ΔFosB induction in the two striatal medium spiny neuron (MSN) subtypes. We make use of fluorescent reporter BAC transgenic mice to evaluate induction of ΔFosB in dopamine receptor 1 (D1) enriched and dopamine receptor 2 (D2) enriched MSNs in ventral striatum, nucleus accumbens (NAc) shell and core, and in dorsal striatum (dStr) after chronic exposure to several drugs of abuse including cocaine, ethanol, Δ(9)-tetrahydrocannabinol, and opiates; the antipsychotic drug, haloperidol; juvenile enrichment; sucrose drinking; calorie restriction; the serotonin selective reuptake inhibitor antidepressant, fluoxetine; and social defeat stress. Our findings demonstrate that chronic exposure to many stimuli induces ΔFosB in an MSN-subtype selective pattern across all three striatal regions. To explore the circuit-mediated induction of ΔFosB in striatum, we use optogenetics to enhance activity in limbic brain regions that send synaptic inputs to NAc; these regions include the ventral tegmental area and several glutamatergic afferent regions: medial prefrontal cortex, amygdala, and ventral hippocampus. These optogenetic conditions lead to highly distinct patterns of ΔFosB induction in MSN subtypes in NAc core and shell. Together, these findings establish selective patterns of ΔFosB induction in striatal MSN subtypes in response to chronic stimuli and provide novel insight into the circuit-level mechanisms of ΔFosB induction in striatum.

  18. ΔFosB Induction in Striatal Medium Spiny Neuron Subtypes in Response to Chronic Pharmacological, Emotional, and Optogenetic Stimuli

    PubMed Central

    Lobo, Mary Kay; Zaman, Samir; Damez-Werno, Diane M.; Koo, Ja Wook; Bagot, Rosemary C.; DiNieri, Jennifer A.; Nugent, Alexandria; Finkel, Eric; Chaudhury, Dipesh; Chandra, Ramesh; Riberio, Efrain; Rabkin, Jacqui; Mouzon, Ezekiell; Cachope, Roger; Cheer, Joseph F.; Han, Ming-Hu; Dietz, David M.; Self, David W.; Hurd, Yasmin L.; Vialou, Vincent

    2013-01-01

    The transcription factor, ΔFosB, is robustly and persistently induced in striatum by several chronic stimuli, such as drugs of abuse, antipsychotic drugs, natural rewards, and stress. However, very few studies have examined the degree of ΔFosB induction in the two striatal medium spiny neuron (MSN) subtypes. We make use of fluorescent reporter BAC transgenic mice to evaluate induction of ΔFosB in dopamine receptor 1 (D1) enriched and dopamine receptor 2 (D2) enriched MSNs in ventral striatum, nucleus accumbens (NAc) shell and core, and in dorsal striatum (dStr) after chronic exposure to several drugs of abuse including cocaine, ethanol, Δ(9)-tetrahydrocannabinol, and opiates; the antipsychotic drug, haloperidol; juvenile enrichment; sucrose drinking; calorie restriction; the serotonin selective reuptake inhibitor antidepressant, fluoxetine; and social defeat stress. Our findings demonstrate that chronic exposure to many stimuli induces ΔFosB in an MSN-subtype selective pattern across all three striatal regions. To explore the circuit-mediated induction of ΔFosB in striatum, we use optogenetics to enhance activity in limbic brain regions that send synaptic inputs to NAc; these regions include the ventral tegmental area and several glutamatergic afferent regions: medial prefrontal cortex, amygdala, and ventral hippocampus. These optogenetic conditions lead to highly distinct patterns of ΔFosB induction in MSN subtypes in NAc core and shell. Together, these findings establish selective patterns of ΔFosB induction in striatal MSN subtypes in response to chronic stimuli and provide novel insight into the circuit-level mechanisms of ΔFosB induction in striatum. PMID:24259563

  19. GPR39, a receptor of the ghrelin receptor family, plays a role in the regulation of glucose homeostasis in a mouse model of early onset diet-induced obesity.

    PubMed

    Verhulst, P J; Lintermans, A; Janssen, S; Loeckx, D; Himmelreich, U; Buyse, J; Tack, J; Depoortere, I

    2011-06-01

    GPR39, which may function as a Zn(2+) sensor, is a member of the G protein-coupled receptor family that also includes the receptor for the hunger hormone ghrelin. The down-regulation of GPR39 mRNA in adipose tissue of obese type 2 diabetic patients suggests that GPR39 may contribute to the pathogenesis of the disease. The present study aimed to investigate the role of GPR39 in the regulation of energy balance and glucose homeostasis in wild-type (GPR39(+/+) ) and GPR39 knockout mice (GPR39(-/-) ) with obesity-related type 2 diabetes. GPR39 mRNA levels in adipose tissue of fasted GPR39(+/+) mice fed a high-fat diet (HFD) for 30 weeks were reduced and correlated positively with blood glucose levels. Body weight, fat percentage and energy intake were increased in the HFD group but did not differ between both genotypes. Within the HFD group, blood glucose levels were lower in GPR39(-/-) than in GPR39(+/+) mice, despite significant reductions in prandial plasma insulin levels. The latter may not be a result of changes in β-cell hyperplasia because immunohistochemical staining of pancreata of mice on a HFD showed no differences between genotypes. The lower blood glucose levels may involve alterations in insulin sensitivity as revealed by glucose tolerance tests and respiratory quotient measurements that showed a preference of obese GPR39(-/-) mice for the use of carbohydrates as metabolic fuel. The increase in plasma ghrelin levels in GPR39(-/-) mice fed a HFD may contribute to the alterations in glucose homeostasis, whereas changes in gastric emptying or intestinal Zn(2+) absorption are not involved. The results obtained in the present study suggest that GPR39 plays a role in the pathogenesis of obesity-related type 2 diabetes by affecting the regulation of glucose homeostasis. PMID:21470317

  20. AP-1 (Fos/Jun) transcription factors in hematopoietic differentiation and apoptosis.

    PubMed

    Liebermann, D A; Gregory, B; Hoffman, B

    1998-03-01

    A combination of in vitro and in vivo molecular genetic approaches have provided evidence to suggest that AP-1 (Fos/Jun) transcription factors play multiple roles in functional development of hematopoietic precursor cells into mature blood cells along most, if not all, of the hematopoietic cell lineages. This includes the monocyte/macrophage, granulocyte, megakaryocyte, mastocyte and erythroid lineages. In addition, studies using c-fos knockout mice have established a unique role for Fos, as a member of the AP-1 transcription factor complex, in determining the differentiation and activity of progenitors of the osteoclast lineage, a population of bone-forming cells which are of hematopoietic origin as well. Evidence has also accumulated to implicate AP-1 (Fos/Jun) transcription factor complexes as both positive and negative modulators of distinct apoptotic pathways in many cell types, including cells of hematopoietic origin. Fos/Jun have been implicated as positive modulators of apoptosis induced in hematopoietic progenitor cells of the myeloid lineage, a function that may relate to the control of blood cell homeostasis, as well as in programmed cell death associated with terminal differentiation of many other cell types, and apoptosis associated with withdrawal of growth/survival factors. On the other hand, the study of apoptosis induced in mammalian cells has implicated AP-1 in the protection against apoptosis induced by DNA-damaging agents. However, evidence to the contrary has been obtained as well, suggesting that AP-1 may function to modulate stress-induced apoptosis either positively or negatively, depending on the microenvironment and the cell type in which the stress stimulus is induced.

  1. Induction of Fos expression in the circadian system by unsignaled light is attenuated as a result of previous experience with signaled light: a role for Pavlovian conditioning.

    PubMed

    Amir, S; Stewart, J

    1998-04-01

    A circadian clock responsive to light is located in the hypothalamic suprachiasmatic nucleus. In rodents, light induces the expression of the transcription factor Fos in cells of the suprachiasmatic nucleus and this effect is associated with light-induced resetting of the circadian clock. Until recently, it was thought that the induction of Fos in the suprachiasmatic nucleus was mediated by a mechanism uniquely sensitive to photic cues. We have shown, however, using Pavlovian conditioning procedures, that a nonphotic stimulus that has been repeatedly paired with light can, in the absence of light, induce Fos expression in the suprachiasmatic nucleus. In the present study we asked whether, as a result of conditioning, the ability of light alone to induce Fos expression in the suprachiasmatic nucleus might be altered. We suspected that once the mechanism mediating Fos expression in the suprachiasmatic nucleus had become tuned to receiving light signaled by a conditioned stimulus, the response to presentation of light alone would be diminished. To study this possibility we investigated whether induction of Fos expression in the suprachiasmatic nucleus by unsignaled light would be altered as a result of previous experience with signaled light. Consistent with our hypothesis, we found that a series of conditioning trials not only confers upon a nonphotic stimulus the ability to activate the mechanism mediating Fos expression in the suprachiasmatic nucleus, but also reduces the efficacy of light itself to activate this mechanism.

  2. Appetite suppression through smelling of dark chocolate correlates with changes in ghrelin in young women.

    PubMed

    Massolt, Elske T; van Haard, Paul M; Rehfeld, Jens F; Posthuma, Eduardus F; van der Veer, Eveline; Schweitzer, Dave H

    2010-04-01

    Cephalic effects on appetite are mediated by vagal tone and altered gastrointestinal hormones. The objective of this study is to explore the relationship between appetite and levels of gastrointestinal hormones after smelling chocolate and after melt-and-swallow 30 g chocolate (1.059 oz, 85% cocoa, 12.5 g of sugar per 100g product). Twelve female residents (BMI between 18 and 25 kg/m(2)) all participated in two 60-minute study sessions. In the first session, all 12 women ate chocolate; for the second session, they were randomized either to smell chocolate (n=6) or to serve as a control (no eating or smelling; n=6). At the start of the sessions, levels of insulin, glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK), but not glucose, correlated with appetite scored on a visual analogue scale (VAS). In contrast, ghrelin levels correlated inversely with scored appetite. Chocolate eating and smelling both induced a similar appetite suppression with a disappearance of correlations between VAS scores and insulin, GLP-1 and CCK levels. However, while the correlation between VAS score and ghrelin disappeared completely after chocolate eating, it reversed after chocolate smelling, that is, olfactory stimulation with dark chocolate (85%) resulted in a satiation response that correlated inversely with ghrelin levels.

  3. B-type natriuretic peptide modulates ghrelin, hunger, and satiety in healthy men.

    PubMed

    Vila, Greisa; Grimm, Gabriele; Resl, Michael; Heinisch, Birgit; Einwallner, Elisa; Esterbauer, Harald; Dieplinger, Benjamin; Mueller, Thomas; Luger, Anton; Clodi, Martin

    2012-10-01

    Chronic heart failure is accompanied by anorexia and increased release of B-type natriuretic peptide (BNP) from ventricular cardiomyocytes. The pathophysiological mechanisms linking heart failure and appetite regulation remain unknown. In this study, we investigated the impact of intravenous BNP administration on appetite-regulating hormones and subjective ratings of hunger and satiety in 10 healthy volunteers. Participants received in a randomized, placebo-controlled, crossover, single-blinded study (subject) placebo once and 3.0 pmol/kg/min human BNP-32 once administered as a continuous infusion during 4 h. Circulating concentrations of appetite-regulating peptides were measured hourly. Subjective ratings of hunger and satiety were evaluated by visual analog scales. BNP inhibited the fasting-induced increase in total and acylated ghrelin concentrations over time (P = 0.043 and P = 0.038, respectively). In addition, BNP decreased the subjective rating of hunger (P = 0.009) and increased the feeling of satiety (P = 0.012) when compared with placebo. There were no significant changes in circulating peptide YY, glucagon-like peptide 1, oxyntomodulin, pancreatic polypeptide, leptin, and adiponectin concentrations. In summary, our results demonstrate that BNP exerts anorectic effects and reduces ghrelin concentrations in men. These data, taken together with the known cardiovascular properties of ghrelin, support the existence of a heart-gut-brain axis, which could be therapeutically targeted in patients with heart failure and obesity.

  4. Expression of the nuclear factor-kappaB and proto-oncogenes c-fos and c-jun are induced by low extracellular Mg2+ in aortic and cerebral vascular smooth muscle cells: possible links to hypertension, atherogenesis, and stroke.

    PubMed

    Altura, Burton M; Kostellow, Adele B; Zhang, Aimin; Li, Wenyan; Morrill, Gene A; Gupta, Raj K; Altura, Bella T

    2003-09-01

    Proto-oncogene (c-fos, c-jun) and nuclear factor-kappa B (NF-kappaB) expression, as well as DNA synthesis, in aortic and cerebral vascular smooth muscle cells (VSMCs) were upregulated by a decrease in extracellular magnesium ions ([Mg2+]o). Upregulation of these transcriptional factors was inversely proportional to the [Mg2+]o and occurred over the pathophysiologic range of serum Mg2+ found in patients presenting with hypertension, ischemic heart disease, and stroke. Removal of extracellular Ca2+ ([Ca2+]o), use of nifedipine or protein kinase C (PKC) inhibitors prevented the upregulation of the proto-oncogenes and DNA synthesis in VSMCs. These data show that [Mg2+]o may be an important, heretofore, overlooked natural modulator of proto-oncogene and NF-kappaB expression in VSMCs and that Ca2+ and PKC may play critical roles in induction of c-fos and c-jun in VSMCs induced by a decrease in [Mg2+]o. These results point to a role for low serum Mg2+ in potential development of hypertension, atherogenesis, vascular disease, and stroke.

  5. Ghrelin Protection against Cytotoxic Effect of Ethanol on Rat Salivary Mucin Synthesis involves Cytosolic Phospholipase A2 Activation through S-Nitrosylation

    PubMed Central

    Slomiany, Bronislaw L.; Slomiany, Amalia

    2010-01-01

    Recent advances in identifying the salivary constituents of significance to the maintenance of soft oral tissue integrity have brought to focus the importance of a 28-amino acid peptide hormone, ghrelin. Here, we report on the role of ghrelin in countering the disturbances in salivary mucin synthesis caused by ethanol cytotoxicity in rat sublingual gland acinar cells. We show that the countering effect of ghrelin on mucin synthesis was associated with the increase in NO and PGE2 production, and the enhancement in cytosolic phospholipase A2 (cPLA2) activity. The ghrelin-induced up-regulation in mucin synthesis, like that of cPLA2 activity, was subject to suppression by Src inhibitor, PP2, ERK inhibitor, PD98059, as well as Akt inhibitor, SH-5 and ascorbate. Moreover, the loss in countering effect of ghrelin on the ethanol cytotoxicity and mucin synthesis was attained with cNOS inhibitor, L-NAME as well as COX-1 inhibitor, SC-560. Furthermore, while the effect of L-NAME was also reflected in the inhibition of the acinar cell capacity for NO and PGE2 generation, and cPLA2 S-nitrosylation, the COX-1 inhibitor caused the inhibition in PGE2 only. Our findings demonstrate that ghrelin protection of the acinar cells against ethanol cytotoxicity and the impairment in salivary mucin synthesis involves Src kinase activation of the Akt/cNOS pathway that leads to up-regulation in cNOS activity. We also show that cNOS-derived NO induction of the cPLA2 activation through S-nitrosylation, for the increase in PGE2 generation, is an essential element of the protective mechanism of ghrelin action. PMID:23675174

  6. Meal-related ghrelin suppression requires postgastric feedback.

    PubMed

    Williams, Diana L; Cummings, David E; Grill, Harvey J; Kaplan, Joel M

    2003-07-01

    Plasma ghrelin levels are rapidly suppressed by ingestion or gastric delivery of nutrients. Given that the majority of circulating ghrelin appears to be of gastric origin, we addressed the contribution of gastric distention or nutrient sensitivity to this response. Awake, unrestrained rats received intragastric infusions of glucose or water (1 ml/min for 12 min) with gastric emptying either proceeding normally or prevented by inflation of a pyloric cuff. When emptying was permitted, glucose infusion reduced ghrelin level by approximately 50%, and, in agreement with previous data, water infusions were without effect. Ghrelin level was not affected by either infusate when gastric emptying was prevented, thereby discounting a role for gastric distention in the meal-related ghrelin response. That glucose and water infusions were similarly ineffective when the pylorus was occluded shows, further, that gastric chemosensation is not a sufficient trigger for the ghrelin response. We conclude that the meal-related suppression of plasma ghrelin requires postgastric (pre- or postabsorptive) stimulation. PMID:12810528

  7. Role of ghrelin in the regulation of appetite in children.

    PubMed

    Savastio, S; Bellone, S; Baldelli, R; Ferraris, M; Lapidari, A; Zanetta, F; Sogni, S; Petri, A; Bona, G

    2006-02-01

    Ghrelin, the new recently discovered hormone, is a 28 amino-acid acylated peptide predominantly produced by the stomach characterized by a strong GH-releasing activity mediated by the hypothalamic-pituitary GH secretagogues (GHSs) receptors. Ghrelin and GHSs, acting on central and peripheral receptors, exert other actions such as stimulation of ACTH and prolactin secretion, influence on insulin secretion and glucose metabolism, orexigenic effect and modulatory activity on the neuroendocrine and metabolic response to starvation, influence on exocrine gastro-entero-pancreatic functions, cardiovascular activities and modulation of cell proliferation and apoptosis. The wide spectrum of ghrelin action requires further studies to provide critical information on the role of ghrelin and the potential perspectives of its analogues in the clinical practice. This point is of particular interest in the field of pediatric endocrinology and metabolism because the ghrelin story started focusing on GH deficiency and is now extending to aspects that once again are of major relevance such as obesity and eating disorders, regulation of the hypothalamus-pituitary-adrenal and gonadal axis. More studies are needed to evaluate the real impact of ghrelin in different non endocrine processes and the possible use of ghrelin analogues in different diseases condition.

  8. Ghrelin, food intake, and botanical extracts: A Review

    PubMed Central

    Rezaie, Peyman; Mazidi, Mohsen; Nematy, Mohsen

    2015-01-01

    A kind of growth hormone secretagogue (GHS), ghrelin, was first isolated from the rat stomach and plays a major role in the activation of the growth hormone secretagogue receptor 1a (GHS-R1a) resulting the release of growth hormone (GH). The preproghrelin gene is placed on chromosome 3, at locus 3p25 –2 in humans and constitutes five exons and three introns. Ghrelin is most plentifully expressed in particular cells in the oxyntic glands of the gastric epithelium, initially named X/A-like cells. Almost 60-70% of circulating ghrelin is secreted by the stomach. Plasma ghrelin concentration alters throughout the day. Ghrelin has been suggested to act as a meal initiator because of its appetite-stimulating influences in free feeding rats in short period. In addition to ghrelin’s function as a meal motivator, it seems to contribute in long-term energy balance and nutritional status. In addition, many studies have been carried out in order to investigate the effects of natural and medicinal plants and botanical extracts on appetite, food intake, energy hemostasis, and the level of related hormones including ghrelin. Due to the importance of ghrelin in nutritional and medical sciences, this review was performed to understand new aspects of this hormone’s function. PMID:26445708

  9. Higher postprandial serum ghrelin among African American females before puberty

    PubMed Central

    Ellis, Amy C.; Casazza, Krista; Chandler-Laney, Paula; Gower, Barbara A.

    2013-01-01

    Objective Recent reports suggest that ghrelin regulation may differ by ethnicity and age. This study was designed to examine circulating ghrelin among overweight African American females across different age groups. Methods Eleven overweight peri-pubertal girls, 17 overweight pubertal girls, and a control group of 18 overweight AA premenopausal women ingested a standard liquid meal following an overnight fast. Blood samples were obtained before the meal and for 4 hours post-challenge. Participants rated appetite by a visual analog scale. Results Peri-pubertal girls demonstrated higher postprandial ghrelin and lesser ghrelin suppression compared to adults (p<0.05), corresponding with greater desire to eat across the test period (p=0.017). Fasting ghrelin tended to be inversely related to fasting estradiol (r=−0.264, p=0.076). Conclusion Compared to overweight African American women, peri-pubertal girls had higher ghrelin as well as greater appetite after a standard meal. These results may suggest a dysregulation in ghrelin reflective of demands of growth. PMID:23155695

  10. Changes in acyl and total ghrelin concentrations and their association with dry matter intake, average daily gain, and feed efficiency of finishing beef steers and heifers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ghrelin is a peptide hormone produced in the gut that is implicated in signaling appetite and regulating DMI. The objective of this experiment was to determine the change in acyl ghrelin, total ghrelin, and the ghrelin ratio (acyl ghrelin/total ghrelin) over an 84-d DMI and ADG measurement period a...

  11. Potential ghrelin-mediated benefits and risks of hydrogen water.

    PubMed

    McCarty, Mark F

    2015-04-01

    Molecular hydrogen (H2) can scavenge hydroxyl radical and diminish the toxicity of peroxynitrite; hence, it has interesting potential for antioxidant protection. Recently, a number of studies have explored the utility of inhaled hydrogen gas, or of hydrogen-saturated water, administered parenterally or orally, in rodent models of pathology and in clinical trials, oftentimes with very positive outcomes. The efficacy of orally ingested hydrogen-rich water (HW) has been particularly surprising, given that only transient and rather small increments in plasma hydrogen can be achieved by this method. A recent study in mice has discovered that orally administered HW provokes increased gastric production of the orexic hormone ghrelin, and that this ghrelin mediates the favorable impact of HW on a mouse model of Parkinson's disease. The possibility that most of the benefits observed with HW in experimental studies are mediated by ghrelin merits consideration. Ghrelin is well known to function as an appetite stimulant and secretagogue for growth hormone, but it influences physiological function throughout the body via interaction with the widely express GHS-R1a receptor. Rodent and, to a more limited extent, clinical studies establish that ghrelin has versatile neuroprotective and cognitive enhancing activity, favorably impacts vascular health, exerts anti-inflammatory activity useful in autoimmune disorders, and is markedly hepatoprotective. The stimulatory impact of ghrelin on GH-IGF-I activity, while potentially beneficial in sarcopenia or cachectic disorders, does raise concerns regarding the long-term impact of ghrelin up-regulation on cancer risk. The impact of ingesting HW water on ghrelin production in humans needs to be evaluated; if HW does up-regulate ghrelin in humans, it may have versatile potential for prevention and control of a number of health disorders.

  12. Potential ghrelin-mediated benefits and risks of hydrogen water.

    PubMed

    McCarty, Mark F

    2015-04-01

    Molecular hydrogen (H2) can scavenge hydroxyl radical and diminish the toxicity of peroxynitrite; hence, it has interesting potential for antioxidant protection. Recently, a number of studies have explored the utility of inhaled hydrogen gas, or of hydrogen-saturated water, administered parenterally or orally, in rodent models of pathology and in clinical trials, oftentimes with very positive outcomes. The efficacy of orally ingested hydrogen-rich water (HW) has been particularly surprising, given that only transient and rather small increments in plasma hydrogen can be achieved by this method. A recent study in mice has discovered that orally administered HW provokes increased gastric production of the orexic hormone ghrelin, and that this ghrelin mediates the favorable impact of HW on a mouse model of Parkinson's disease. The possibility that most of the benefits observed with HW in experimental studies are mediated by ghrelin merits consideration. Ghrelin is well known to function as an appetite stimulant and secretagogue for growth hormone, but it influences physiological function throughout the body via interaction with the widely express GHS-R1a receptor. Rodent and, to a more limited extent, clinical studies establish that ghrelin has versatile neuroprotective and cognitive enhancing activity, favorably impacts vascular health, exerts anti-inflammatory activity useful in autoimmune disorders, and is markedly hepatoprotective. The stimulatory impact of ghrelin on GH-IGF-I activity, while potentially beneficial in sarcopenia or cachectic disorders, does raise concerns regarding the long-term impact of ghrelin up-regulation on cancer risk. The impact of ingesting HW water on ghrelin production in humans needs to be evaluated; if HW does up-regulate ghrelin in humans, it may have versatile potential for prevention and control of a number of health disorders. PMID:25649854

  13. Change in intrarenal Ghrelin expression in immune complex-mediated glomerular disease in dogs

    PubMed Central

    YABUKI, Akira; MIZUKAMI, Keijiro; TOKUNAGA, Satoshi; YAMATO, Osamu

    2015-01-01

    Ghrelin is a peptide hormone that is mainly produced by the stomach. The kidney is a major source of local ghrelin, and maintaining body fluid balance is considered a critical role of renal ghrelin. However, there are no reports on renal ghrelin in small animal medicine. The present study investigated the intrarenal localization of and change in ghrelin expression in dogs with immune complex-mediated glomerulonephritis (ICGN). Ghrelin immunoreactivity (IR) was observed in the distal tubules of normal kidneys. Ghrelin IR was weak in ICGN kidneys, and the quantitative ghrelin IR score was significantly lower in ICGN kidneys than in normal kidneys. In cases of ICGN, plasma creatinine concentrations showed a positive correlation with the ghrelin IR score. PMID:26256231

  14. Phosphorylation of c-Fos by members of the p38 MAPK family. Role in the AP-1 response to UV light.

    PubMed

    Tanos, Tamara; Marinissen, Maria Julia; Leskow, Federico Coluccio; Hochbaum, Daniel; Martinetto, Horacio; Gutkind, J Silvio; Coso, Omar A

    2005-05-13

    Exposure to sources of UV radiation, such as sunlight, induces a number of cellular alterations that are highly dependent on its ability to affect gene expression. Among them, the rapid activation of genes coding for two subfamilies of proto-oncoproteins, Fos and Jun, which constitute the AP-1 transcription factor, plays a key role in the subsequent regulation of expression of genes involved in DNA repair, cell proliferation, cell cycle arrest, death by apoptosis, and tissue and extracellular matrix remodeling proteases. Besides being regulated at the transcriptional level, Jun and Fos transcriptional activities are also regulated by phosphorylation as a result of the activation of intracellular signaling cascades. In this regard, the phosphorylation of c-Jun by UV-induced JNK has been readily documented, whereas a role for Fos proteins in UV-mediated responses and the identification of Fos-activating kinases has remained elusive. Here we identify p38 MAPKs as proteins that can associate with c-Fos and phosphorylate its transactivation domain both in vitro and in vivo. This phosphorylation is transduced into changes in its transcriptional ability as p38-activated c-Fos enhances AP1-driven gene expression. Our findings indicate that as a consequence of the activation of stress pathways induced by UV light, endogenous c-Fos becomes a substrate of p38 MAPKs and, for the first time, provide evidence that support a critical role for p38 MAPKs in mediating stress-induced c-Fos phosphorylation and gene transcription activation. Using a specific pharmacological inhibitor for p38alpha and -beta, we found that most likely these two isoforms mediate UV-induced c-Fos phosphorylation in vivo. Thus, these newly described pathways act concomitantly with the activation of c-Jun by JNK/MAPKs, thereby contributing to the complexity of AP1-driven gene transcription regulation.

  15. Genetic manipulation of the ghrelin signaling system in male mice reveals bone compartment specificity of acylated and unacylated ghrelin in the regulation of bone remodeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ghrelin receptor-deficient (Ghsr-/-) mice that lack acylated ghrelin (AG) signaling retain a metabolic response to unacylated ghrelin (UAG). Recently, we showed that Ghsr-deficiency affects bone metabolism. The aim of this study was to further establish the impact of AG and UAG on bone metabolism. W...

  16. Activation of the c-fos gene in prodynorphin- and proenkephalin-expressing cells of nucleus tractus solitarius after seizures.

    PubMed

    Kanter, R K; Erickson, J T; Millhorn, D E

    1994-10-01

    We performed studies to determine the anatomical regions and chemical phenotypes of neurons within the rat medulla oblongata activated by pentylenetetrazole-induced seizures. Activated cells were identified by their expression of the c-fos gene, detected by in situ hybridization for c-fos mRNA and immunocytochemistry for Fos protein. Activated cells were located predominantly in nucleus tractus solitarius (NTS), with c-fos mRNA appearing within 20 min after seizures (peak at 1-2 h), followed by Fos immunoreactivity visible at 1 h (peak at 2-4 h). Neither nonspecific noxious stimulation by intraperitoneal injection of saline nor brief exposure to hypoxic or hypercapnic gas mixtures to stimulate chemoreceptors reproduced this pattern of labeling. Prodynorphin or proenkephalin mRNA, detected by in situ hybridization, was colocalized with Fos immunoreactivity in many NTS cells. Thus, seizures activate neuronal pathways in the medulla oblongata which express genes for endogenous opioids. Potential long-term effects of seizures are suggested by the in situ hybridization finding that NTS prodynorphin mRNA increased 24 h after seizures compared to control levels. PMID:7957742

  17. Differential Expression of FosB Proteins and Potential Target Genes in Select Brain Regions of Addiction and Depression Patients

    PubMed Central

    Gajewski, Paula A.; Turecki, Gustavo; Robison, Alfred J.

    2016-01-01

    Chronic exposure to stress or drugs of abuse has been linked to altered gene expression throughout the body, and changes in gene expression in discrete brain regions are thought to underlie many psychiatric diseases, including major depressive disorder and drug addiction. Preclinical models of these disorders have provided evidence for mechanisms of this altered gene expression, including transcription factors, but evidence supporting a role for these factors in human patients has been slow to emerge. The transcription factor ΔFosB is induced in the prefrontal cortex (PFC) and hippocampus (HPC) of rodents in response to stress or cocaine, and its expression in these regions is thought to regulate their “top down” control of reward circuitry, including the nucleus accumbens (NAc). Here, we use biochemistry to examine the expression of the FosB family of transcription factors and their potential gene targets in PFC and HPC postmortem samples from depressed patients and cocaine addicts. We demonstrate that ΔFosB and other FosB isoforms are downregulated in the HPC but not the PFC in the brains of both depressed and addicted individuals. Further, we show that potential ΔFosB transcriptional targets, including GluA2, are also downregulated in the HPC but not PFC of cocaine addicts. Thus, we provide the first evidence of FosB gene expression in human HPC and PFC in these psychiatric disorders, and in light of recent findings demonstrating the critical role of HPC ΔFosB in rodent models of learning and memory, these data suggest that reduced ΔFosB in HPC could potentially underlie cognitive deficits accompanying chronic cocaine abuse or depression. PMID:27494187

  18. Novel spinal pathways identified by neuronal c-Fos expression after urethrogenital reflex activation in female guinea pigs.

    PubMed

    Yuan, S Y; Vilimas, P I; Zagorodnyuk, V P; Gibbins, I L

    2015-03-12

    Pudendal nerve-spinal pathways are involved in urethrogenital sensation, pain and sexual activity. However, details of these pathways and their modulation are unclear. We examined spinal pathways activated by the urethrogenital reflex (UGR) and visualized by c-Fos immunoreactivity in reflexly activated neurons within spinal cord. In anesthetized female guinea pigs, a balloon was inserted into the urethra and inflated with short-repeat or long-continuous distension to activate the UGR. A second balloon recorded reflex contractions of the vagina and uterus. Two control groups had either no balloon or a vaginal balloon (VB) only. Ninety minutes after UGR activation, c-Fos immunoreactivity in L3 and S2 spinal segments was examined. Reflex activated c-Fos immunoreactivity also was investigated in some animals with acute spinal transections at either L4 or T12 levels. There was no significant difference in spinal c-Fos expression between the control groups. Short-repeat distension reliably induced a UGR and a two- to threefold increase in c-Fos-expressing neurons throughout dorsal, intermediate and lateral spinal gray matter at S2 and about twofold increase in superficial dorsal horn at L3. T12 transection had little effect on c-Fos expression at either spinal level. However, after L4 transection, UGR generation was associated with a four- to sixfold increase in c-Fos-expressing neurons in lateral horn (LH) and central canal areas at S2, and but only 20-30% increase at L3. Thus, UGR activates preganglionic neurons projecting to pelvic viscera in both sacral and lumbar spinal cord. The reflex also must activate ascending and descending spinal inhibitory circuits that suppress c-Fos-expression in neurons at both sacral and lumbar spinal levels.

  19. Diacylglycerol Kinase ζ (DGKζ) Is a Critical Regulator of Bone Homeostasis Via Modulation of c-Fos Levels in Osteoclasts.

    PubMed

    Zamani, Ali; Decker, Corinne; Cremasco, Viviana; Hughes, Lindsey; Novack, Deborah V; Faccio, Roberta

    2015-10-01

    Increased diacylglycerol (DAG) levels are observed in numerous pathologies, including conditions associated with bone loss. However, the effects of DAG accumulation on the skeleton have never been directly examined. Because DAG is strictly controlled by tissue-specific diacylglycerol kinases (DGKs), we sought to examine the biological consequences of DAG accumulation on bone homeostasis by genetic deletion of DGKζ, a highly expressed DGK isoform in osteoclasts (OCs). Strikingly, DGKζ(-/-) mice are osteoporotic because of a marked increase in OC numbers. In vitro, DGKζ(-/-) bone marrow macrophages (BMMs) form more numerous, larger, and highly resorptive OCs. Surprisingly, although increased DAG levels do not alter receptor activator of NF-κB (RANK)/RANK ligand (RANKL) osteoclastogenic pathway, DGKζ deficiency increases responsiveness to the proliferative and pro-survival cytokine macrophage colony-stimulating factor (M-CSF). We find that M-CSF is responsible for increased DGKζ(-/-) OC differentiation by promoting higher expression of the transcription factor c-Fos, and c-Fos knockdown in DGKζ(-/-) cultures dose-dependently reduces OC differentiation. Using a c-Fos luciferase reporter assay lacking the TRE responsive element, we also demonstrate that M-CSF induces optimal c-Fos expression through DAG production. Finally, to demonstrate the importance of the M-CSF/DGKζ/DAG axis on regulation of c-Fos during osteoclastogenesis, we turned to PLCγ2(+/-) BMMs, which have reduced DAG levels and form fewer OCs because of impaired expression of the master regulator of osteoclastogenesis NFATc1 and c-Fos. Strikingly, genetic deletion of DGKζ in PLCγ2(+/-) mice rescues OC formation and normalizes c-Fos levels without altering NFATc1 expression. To our knowledge, this is the first report implicating M-CSF/DGKζ/DAG axis as a critical regulator of bone homeostasis via its actions on OC differentiation and c-Fos expression.

  20. Diacylglycerol kinase ζ (DGKζ) is a critical regulator of bone homeostasis via modulation of c-Fos levels in osteoclasts†

    PubMed Central

    Zamani, Ali; Decker, Corinne; Cremasco, Viviana; Hughes, Lindsey; Novack, Deborah V.; Faccio, Roberta

    2015-01-01

    Increased diacylglycerol (DAG) levels are observed in numerous pathologies, including conditions associated with bone loss. However, the effects of DAG accumulation on the skeleton have never been directly examined. Because DAG is strictly controlled by tissue specific diacylglycerol kinases (DGKs), we sought to examine the biological consequences of DAG accumulation on bone homeostasis by genetic deletion of DGKζ, a highly expressed DGK isoform in osteoclasts (OCs). Strikingly, DGKζ−/− mice are osteoporotic due to a marked increase in OC numbers. In vitro, DGKζ−/− bone marrow macrophages (BMMs) form more numerous, larger and highly resorptive OCs. Surprisingly, while increased DAG levels do not alter RANK/RANKL osteoclastogenic pathway, DGKζ deficiency increases responsiveness to the proliferative and pro-survival cytokine M-CSF. We find that M-CSF is responsible for increased DGKζ−/− OC differentiation by promoting higher expression of the transcription factor c-Fos, and c-Fos knockdown in DGKζ−/− cultures dose-dependently reduces OC differentiation. Using a c-Fos luciferase reporter assay lacking the TRE responsive element, we also demonstrate that M-CSF induces optimal c-Fos expression through DAG production. Finally, to demonstrate the importance of the M-CSF/DGKζ/DAG axis on regulation of c-Fos during osteoclastogenesis, we turned to PLCγ2+/− BMMs, which have reduced DAG levels and form fewer OCs due to impaired expression of the master regulator of osteoclastogenesis NFATc1 and c-Fos. Strikingly, genetic deletion of DGKζ in PLCγ2+/− mice rescues OC formation and normalizes c-Fos levels without altering NFATc1 expression. To our knowledge, this is the first report implicating M-CSF/DGKζ/DAG axis as a critical regulator of bone homeostasis via its actions on OC differentiation and c-Fos expression. PMID:25891971

  1. Differential Expression of FosB Proteins and Potential Target Genes in Select Brain Regions of Addiction and Depression Patients.

    PubMed

    Gajewski, Paula A; Turecki, Gustavo; Robison, Alfred J

    2016-01-01

    Chronic exposure to stress or drugs of abuse has been linked to altered gene expression throughout the body, and changes in gene expression in discrete brain regions are thought to underlie many psychiatric diseases, including major depressive disorder and drug addiction. Preclinical models of these disorders have provided evidence for mechanisms of this altered gene expression, including transcription factors, but evidence supporting a role for these factors in human patients has been slow to emerge. The transcription factor ΔFosB is induced in the prefrontal cortex (PFC) and hippocampus (HPC) of rodents in response to stress or cocaine, and its expression in these regions is thought to regulate their "top down" control of reward circuitry, including the nucleus accumbens (NAc). Here, we use biochemistry to examine the expression of the FosB family of transcription factors and their potential gene targets in PFC and HPC postmortem samples from depressed patients and cocaine addicts. We demonstrate that ΔFosB and other FosB isoforms are downregulated in the HPC but not the PFC in the brains of both depressed and addicted individuals. Further, we show that potential ΔFosB transcriptional targets, including GluA2, are also downregulated in the HPC but not PFC of cocaine addicts. Thus, we provide the first evidence of FosB gene expression in human HPC and PFC in these psychiatric disorders, and in light of recent findings demonstrating the critical role of HPC ΔFosB in rodent models of learning and memory, these data suggest that reduced ΔFosB in HPC could potentially underlie cognitive deficits accompanying chronic cocaine abuse or depression. PMID:27494187

  2. Prostaglandin E2 and the protein kinase A pathway mediate arachidonic acid induction of c-fos in human prostate cancer cells

    NASA Technical Reports Server (NTRS)

    Chen, Y.; Hughes-Fulford, M.

    2000-01-01

    Arachidonic acid (AA) is the precursor for prostaglandin E2 (PGE2) synthesis and increases growth of prostate cancer cells. To further elucidate the mechanisms involved in AA-induced prostate cell growth, induction of c-fos expression by AA was investigated in a human prostate cancer cell line, PC-3. c-fos mRNA was induced shortly after addition of AA, along with a remarkable increase in PGE2 production. c-fos expression and PGE2 production induced by AA was blocked by a cyclo-oxygenase inhibitor, flurbiprofen, suggesting that PGE2 mediated c-fos induction. Protein kinase A (PKA) inhibitor H-89 abolished induction of c-fos expression by AA, and partially inhibited PGE2 production. Protein kinase C (PKC) inhibitor GF109203X had no significant effect on c-fos expression or PGE2 production. Expression of prostaglandin (EP) receptors, which mediate signal transduction from PGE2 to the cells, was examined by reverse transcription polymerase chain reaction in several human prostate cell lines. EP4 and EP2, which are coupled to the PKA signalling pathway, were expressed in all cells tested. Expression of EP1, which activates the PKC pathway, was not detected. The current study showed that induction of the immediate early gene c-fos by AA is mediated by PGE2, which activates the PKA pathway via the EP2/4 receptor in the PC-3 cells.

  3. The forced swimming-induced behavioural immobility response involves histone H3 phospho-acetylation and c-Fos induction in dentate gyrus granule neurons via activation of the N-methyl-D-aspartate/extracellular signal-regulated kinase/mitogen- and stress-activated kinase signalling pathway.

    PubMed

    Chandramohan, Yalini; Droste, Susanne K; Arthur, J Simon C; Reul, Johannes M H M

    2008-05-01

    The hippocampus is involved in learning and memory. Previously, we have shown that the acquisition of the behavioural immobility response after a forced swim experience is associated with chromatin modifications and transcriptional induction in dentate gyrus granule neurons. Given that both N-methyl-D-aspartate (NMDA) receptors and the extracellular signal-regulated kinases (ERK) 1/2 signalling pathway are involved in neuroplasticity processes underlying learning and memory, we investigated in rats and mice whether these signalling pathways regulate chromatin modifications and transcriptional events participating in the acquisition of the immobility response. We found that: (i) forced swimming evoked a transient increase in the number of phospho-acetylated histone H3-positive [P(Ser10)-Ac(Lys14)-H3(+)] neurons specifically in the middle and superficial aspects of the dentate gyrus granule cell layer; (ii) antagonism of NMDA receptors and inhibition of ERK1/2 signalling blocked forced swimming-induced histone H3 phospho-acetylation and the acquisition of the behavioural immobility response; (iii) double knockout (DKO) of the histone H3 kinase mitogen- and stress-activated kinases (MSK) 1/2 in mice completely abolished the forced swimming-induced increases in histone H3 phospho-acetylation and c-Fos induction in dentate granule neurons and the behavioural immobility response; (iv) blocking mineralocorticoid receptors, known not to be involved in behavioural immobility in the forced swim test, did not affect forced swimming-evoked histone H3 phospho-acetylation in dentate neurons; and (v) the pharmacological manipulations and gene deletions did not affect behaviour in the initial forced swim test. We conclude that the forced swimming-induced behavioural immobility response requires histone H3 phospho-acetylation and c-Fos induction in distinct dentate granule neurons through recruitment of the NMDA/ERK/MSK 1/2 pathway.

  4. Associations of ghrelin with eating behaviors, stress, metabolic factors, and telomere length among overweight and obese women: preliminary evidence of attenuated ghrelin effects in obesity?

    PubMed

    Buss, Julia; Havel, Peter J; Epel, Elissa; Lin, Jue; Blackburn, Elizabeth; Daubenmier, Jennifer

    2014-05-01

    Ghrelin regulates homeostatic food intake, hedonic eating, and is a mediator in the stress response. In addition, ghrelin has metabolic, cardiovascular, and anti-aging effects. This cross-sectional study examined associations between total plasma ghrelin, caloric intake based on 3day diet diaries, hedonic eating attitudes, stress-related and metabolic factors, and leukocyte telomere length in overweight (n=25) and obese women (n=22). We hypothesized associations between total plasma ghrelin and eating behaviors, stress, metabolic, cardiovascular, and cell aging factors among overweight women, but not among obese women due to lower circulating ghrelin levels and/or central resistance to ghrelin. Confirming previous studies demonstrating lowered plasma ghrelin in obesity, ghrelin levels were lower in the obese compared with overweight women. Among the overweight, ghrelin was positively correlated with caloric intake, giving in to cravings for highly palatable foods, and a flatter diurnal cortisol slope across 3days. These relationships were non-significant among the obese group. Among overweight women, ghrelin was negatively correlated with insulin resistance, systolic blood pressure, and heart rate, and positively correlated with telomere length. Among the obese subjects, plasma ghrelin concentrations were negatively correlated with insulin resistance, but were not significantly correlated with blood pressure, heart rate or telomere length. Total plasma ghrelin and its associations with food intake, hedonic eating, and stress are decreased in obesity, providing evidence consistent with the theory that central resistance to ghrelin develops in obesity and ghrelin's function in appetite regulation may have evolved to prevent starvation in food scarcity rather than cope with modern food excess. Furthermore, ghrelin is associated with metabolic and cardiovascular health, and may have anti-aging effects, but these effects may be attenuated in obesity.

  5. Developments in ghrelin biology and potential clinical relevance.

    PubMed

    Smith, Roy G; Jiang, Hong; Sun, Yuxiang

    2005-11-01

    The spiropiperidine, MK0677, has been exploited to characterize and expression clone the growth hormone secretagogue receptor (GHS-R). Cloning of this receptor led to identification of its natural ligands, ghrelin and adenosine. Targeted disruption of the Ghsr gene demonstrated unambiguously that the GH-releasing and orexigenic properties of ghrelin are dependent on Ghsr expression and that the orexigenic signal is mediated through neuropeptide Y and agouti-related peptide neurons. This review summarizes new developments in our understanding of the physiological roles of ghrelin and its receptor (GHS-R). Recent discoveries of the effects of ghrelin on the thymus and proinflammatory and chemotactic cytokine pathways stimulate renewed interest in potential clinical applications, which include age-associated disorders, such as metabolic disease, sarcopenia, congestive heart failure, atherosclerosis and anorexia. PMID:16213742

  6. Ghrelin as a target for gastrointestinal motility disorders.

    PubMed

    Greenwood-Van Meerveld, Beverley; Kriegsman, Michael; Nelson, Richard

    2011-11-01

    The therapeutic potential of ghrelin and synthetic ghrelin receptor (GRLN-R) agonists for the treatment of gastrointestinal (GI) motility disorders is based on their ability to stimulate coordinated patterns of propulsive GI motility. This review focuses on the latest findings that support the therapeutic potential of GRLN-R agonists for the treatment of GI motility disorders. The review highlights the preclinical and clinical prokinetic effects of ghrelin and a series of novel ghrelin mimetics to exert prokinetic effects on the GI tract. We build upon a series of excellent reviews to critically discuss the evidence that supports the potential of GRLN-R agonists to normalize GI motility in patients with GI hypomotility disorders such as gastroparesis, post-operative ileus (POI), idiopathic chronic constipation and functional bowel disorders. PMID:21453735

  7. Ghrelin receptor in Japanese fire belly newt, Cynops pyrrhogaster.

    PubMed

    Kaiya, Hiroyuki; Kangawa, Kenji; Miyazato, Mikiya

    2015-11-01

    We identified cDNA encoding a functional ghrelin receptor (growth hormone secretagogue-receptor 1a (GHS-R1a)) in a urodele amphibian, the Japanese fire belly newt (Cynops pyrrhogaster). Two functional receptor proteins, composed of 378- and 362-amino acids, were deduced from the identified cDNA because two candidate initiation methionine sites were found. The long-chain receptor protein shared 80%, 69%, and 59% identities with the bullfrog GHS-R1a, human GHS-R1a and tilapia GHS-R1a-like receptor, respectively. Phylogenetic analysis suggested that the newt receptor is grouped to the clade of the tetrapod homologs, and very closed to anuran amphibians. In functional analyses, homologous newt ghrelin, heterologous bullfrog and rat ghrelin, and a GHS-R1a agonist, GHRP-6 increased intracellular Ca(2+) concentration in human embryonic kidney (HEK) 293 cells stably expressed newt GHS-R1a. The responsiveness was much greater in the short-chain receptor than in the long-chain receptor. Both receptors preferred to bind Ser(3)-ghrelin including newt and rat ghrelin than Thr(3)-ghrelin with bullfrog ghrelin. GHRP-6 has a similar affinity to bullfrog ghrelin. GHS-R1a mRNA was expressed in the brain, pituitary, intestine, pancreas, testis and fat body with high level, and eyes, heart, stomach, liver, gall bladder, kidney and dorsal skin with low level. In a fasting experiment, gene expression of GHS-R1a in the brain and pituitary increased 4days after fasting, and the increased level decreased to the initial level 2weeks after fasting. These changes are consistent with the change in ghrelin mRNA. In contrast, expression of ghrelin and GHS-R1a mRNA in the stomach decreased on day 4 after fasting, and increased 2weeks after fasting. These results indicate that ghrelin and its receptor system are present and altered by energy states in this newt. PMID:26172570

  8. Effect of hypergravity on expression of the immediate early gene, c-fos, in central nervous system of medaka (Oryzias latipes)

    NASA Astrophysics Data System (ADS)

    Sayaka, Shimomura-Umemura; Ijiri, Kenichi

    2006-01-01

    Immediate-early genes serve as useful neurobiological tools for mapping brain activity induced by a sensory stimulation. In this study, we have examined brain activity related to gravity perception of medaka (Oryzias latipes) by use of c-fos. The gene, which is homologous to the c-fos genes of other vertebrates, was identified in medaka. Functionally important domains are highly conserved among all the vertebrate species analyzed. Intraperitoneal administration of kainic acid transiently induced the c-fos mRNAs in medaka brains. The results indicate that the expression of c-fos can be utilized as a suitable anatomical marker for the increased neural activities in the central nervous system of medaka. Fish were continuously exposed to 3 g hypergravity by centrifugation. Investigation of c-fos mRNA expression indicated that c-fos mRNA significantly increased 30 min after a start of 3 g exposure. The distribution of its transcripts within the brains was analyzed by an in situ hybridization method. The 3-g treated medakas displayed c-fos positive cells in their brainstem regions, which are related to vestibular function, such as torus semicircularis, nucleus tangentialis, posterior octavu nucleus, and inferior olive. Our results established a method to follow the effect of gravity stimulation, which can be used to investigate gravity perception.

  9. c-FOS-like immunoreactivity in rat brainstem neurons following noxious chemical stimulation of the nasal mucosa.

    PubMed

    Anton, F; Herdegen, T; Peppel, P; Leah, J D

    1991-01-01

    It has previously been shown that noxious and non-noxious peripheral stimuli induce c-fos expression in spinal dorsal horn neurons. In the present study we have examined the expression of c-fos in brainstem neurons following noxious chemical stimulation of the respiratory region of the nasal mucosa. In urethane-anaesthetized rats we injected mustard oil or applied CO2 pulses to the right nasal cavity. In control animals we applied paraffin oil or a continuous flow of air. A further group of control animals was anaesthetized and not subjected to any experimental treatment. Two hours after the first stimulus the rats were perfused with 4% phosphate-buffered paraformaldehyde. Brainstem sections were incubated with primary antiserum against the FOS protein and processed according to the ABC method. Only the mustard oil-treated rats had obvious signs of rhinitis and displayed FOS-positive cells in laminae I and II of the subnucleus caudalis and in the subnucleus interpolaris of the trigeminal brainstem nuclear complex as well as in the medullary lateral reticular nucleus. These areas are known to be involved in the processing of nociceptive information. Although CO2 pulses applied to the nasal mucosa are known to evoke pain sensations in man we did not observe any FOS-positive neurons in trigeminal and reticular brainstem areas of CO2-treated rats. This lack of c-fos expression probably results from the fact that unlike mustard oil, CO2 did not induce any apparent inflammatory reactions. In all animals c-fos expression was found in the nucleus of the solitary tract and in the area postrema. Staining in these areas might partly result from factors related to anaesthesia, changed respiration parameters and stress. Since the mustard oil-treated rats displayed the highest levels of immunoreactivity in the nucleus of the solitary tract and in the area postrema, additional effects specifically related to nociceptive input are very likely.

  10. Influence of puberty on ghrelin and BMD in athletes.

    PubMed

    Jürimäe, J; Lätt, E; Haljaste, K; Purge, P; Cicchella, A; Jürimäe, T

    2009-06-01

    The aim of our study was to examine the influence of elevated energy expenditure on ghrelin and BMD in young male competitive swimmers advancing from prepubertal to pubertal maturation levels. The study included 19 healthy swimmers (pubertal stage 1) aged between 10 and 12 years. The participants were at the pubertal stages 2 and 3, and 3 and 4 at the second and third year, respectively. Ghrelin was decreased only after the first year. No changes were observed in leptin during the study period. Testosterone increased according to the pubertal development at each measurements. IGF-I was increased at the third measurement compared to the first two measurements. Total and lumbar spine BMDs increased according to the pubertal development in all boys at each measurements, while no changes in femoral neck BMD were observed. Ghrelin was not related to BMD after adjusting for pubertal status. We conclude that ghrelin was decreased at onset of puberty, while no further changes in ghrelin were seen with advancing pubertal stage. Total and lumbar spine BMD increased, while no changes in femoral neck BMD occurred. Ghrelin did not appear to have a direct influence on BMD in young male competitive swimmers. PMID:19199214

  11. Elevated ghrelin predicts food intake during experimental sleep restriction

    PubMed Central

    Broussard, Josiane L.; Kilkus, Jennifer M.; Delebecque, Fanny; Abraham, Varghese; Day, Andrew; Whitmore, Harry R.; Tasali, Esra

    2015-01-01

    Objective Sleep curtailment has been linked to obesity, but underlying mechanisms remain to be elucidated. We assessed whether sleep restriction alters 24-hour profiles of appetite-regulating hormones ghrelin, leptin and pancreatic polypeptide during a standardized diet, and whether these hormonal alterations predict food intake during ad libitum feeding. Methods Nineteen healthy, lean men were studied under normal sleep and sleep restriction in a randomized crossover design. Blood samples were collected for 24-hours during standardized meals. Subsequently, participants had an ad libitum feeding opportunity (buffet meals and snacks) and caloric intake was measured. Results Ghrelin levels were increased after sleep restriction as compared to normal sleep (p<0.01). Overall, sleep restriction did not alter leptin or pancreatic polypeptide profiles. Sleep restriction was associated with an increase in total calories from snacks by 328 ± 140 Kcal (p=0.03), primarily from carbohydrates (p=0.02). The increase in evening ghrelin during sleep restriction was correlated with higher consumption of calories from sweets (r=0.48, p=0.04). Conclusions Sleep restriction as compared to normal sleep significantly increases ghrelin levels. The increase in ghrelin is associated with more consumption of calories. Elevated ghrelin may be a mechanism by which sleep loss leads to increased food intake and the development of obesity. PMID:26467988

  12. Effect of repeated administration of dexfenfluramine on feeding and brain Fos in mice.

    PubMed

    Rowland, Neil E; Robertson, Kimberly; Green, D Joy

    2003-02-01

    The present study examines whether repeated administration of dexfenfluramine (DFEN) to mice is associated with progressive attenuation of its anorectic action and induction of Fos-immunoreactivity (Fos-ir) in some brain regions, both known effects in rats. ICR:Cd-1 mice were adapted to receiving for 30 min daily a sweetened milk gelatin dessert in addition to ad libitum access to chow. Mice were then injected with either DFEN (5-10 mg/kg) or saline vehicle every other day. These doses of DFEN acutely suppressed intake by approximately 50% and this action was sustained for at least eight injections. The anorectic effect of DFEN was no different between drug-naïve and DFEN-pretreated mice under conditions that produce complete tolerance in rats. In addition, unlike in rats, the acute anorectic effect of m-chlorophenylpiperazine (mCPP) was unaffected by prior DFEN treatment. Mice were perfused after the intake test on the final experimental day and their brain processed for Fos-ir. DFEN induced Fos-ir in brain regions analogous to those reported in rats and, also, as in rats, DFEN pretreatments reduced substantially the Fos-ir induced by acute DFEN in regions including central nucleus of amygdala, bed nucleus of stria terminalis, and the paraventricular hypothalamus (magno- and parvocellular divisions; PVN). Thus, while DFEN pretreatments reduce the effects of DFEN in many brain regions in both rats and mice, mice are unlike rats insofar as there is no tolerance to the anorectic action, at least in the nondeprivation protocol used here.

  13. Receptor systems mediating c-fos expression within trigeminal nucleus caudalis in animal models of migraine.

    PubMed

    Mitsikostas, D D; Sanchez del Rio, M

    2001-03-01

    In intracranial structures unmyelinated C- and Adelta-fibers of the trigeminal nerve transmit pain stimuli from meninges to the trigeminal nucleus caudalis (Sp5C). Peripheral nerve endings surround meningeal vessels (the so-called trigeminovascular system) and contain vasoactive neuropeptides (calcitonin gene-related peptide, substance P and neurokinin A). Activation of the trigeminovascular system promotes a meningeal sterile inflammatory response through the release of neuropeptides by peripheral endings. Orthodromic conduction along trigeminovascular fibers transmits information centrally with induction of immediate early c-fos gene within post-synaptic Sp5C neurons, as a marker of neuronal activity within central nociceptive pathways. In laboratory animals the system is activated by either electrical stimulation of the TG, chemical stimulation of the meninges, electrical or mechanical stimulation of the superior sagittal sinus or by induction of cortical spreading depression. All these techniques induce c-fos within Sp5C and are used as a rodent/feline model of vascular headache in humans. Up-to-date there is evidence that at least ten receptors (5-HT(1B), 5-HT(1D), 5-HT(lF), 5-HT(2B), NK-1, GABA(A), NMDA, AMPA, class III metabotropic glutamate receptors, and opioids mu receptors) modulate c-fos expression within Sp5C. These receptors represent potential targets for anti-migraine drugs as shown by triptans (5-HT(1B/1D/1F)) and ergot alkaloids (5-HT(1A1B/1D/1F)). This review discusses the importance of c-fos expression within Sp5C as a marker of cephalic nociception, the different cephalic pain models that induce c-fos within Sp5C, the receptors involved and their potential role as targets for anti-migraine drugs.

  14. Distinct roles of Jun : Fos and Jun : ATF dimers in oncogenesis.

    PubMed

    van Dam, H; Castellazzi, M

    2001-04-30

    Jun : Fos and Jun : ATF complexes represent two classes of AP-1 dimers that (1) preferentially bind to either heptameric or octameric AP-1 binding sites, and (2) are differently regulated by cellular signaling pathways and oncogene products. To discriminate between the functions of Jun : Fos, Jun : ATF and Jun : Jun, mutants were developed that restrict the ability of Jun to dimerize either to itself, or to Fos(-like) or ATF(-like) partners. Introduction of these mutants in chicken embryo fibroblasts shows that Jun : Fra2 and Jun : ATF2 dimers play distinct, complementary roles in in vitro oncogenesis by inducing either anchorage independence or growth factor independence, respectively. v-Jun : ATF2 rather than v-Jun : Fra2 triggers the development of primary fibrosarcomas in the chicken wing. Genes encoding extracellular matrix components seem to constitute an important subset of v-Jun : ATF2-target genes. Repression of the matrix component SPARC by Jun is essential for the induction of fibrosarcomas. Avian primary cells transformed by either Jun : Fra2 or Jun : ATF2 thus provide powerful tools for the investigation of the downstream pathways involved in oncogenesis. Further genetic studies with Jun dimerization mutants will be required to be precise and extend the specific roles of the Jun : Fos and Jun : ATF dimers during cancer progression in avian and mammalian systems.

  15. Associations of ghrelin with eating behaviors, stress, metabolic factors, and telomere length among overweight and obese women: Preliminary evidence of attenuated ghrelin effects in obesity?

    PubMed Central

    Buss, Julia; Havel, Peter J.; Epel, Elissa; Lin, Jue; Blackburn, Elizabeth; Daubenmier, Jennifer

    2014-01-01

    Ghrelin regulates homeostatic food intake, hedonic eating, and is a mediator in the stress response. In addition, ghrelin has metabolic, cardiovascular, and anti-aging effects. This cross-sectional study examined associations between total plasma ghrelin, caloric intake based on 3 day diet diaries, hedonic eating attitudes, stress-related and metabolic factors, and leukocyte telomere length in overweight (n=25) and obese women (n=22). We hypothesized associations between total plasma ghrelin and eating behaviors, stress, metabolic, cardiovascular, and cell aging factors among overweight women, but not among obese women due to lower circulating ghrelin levels and/or central resistance to ghrelin. Confirming previous studies demonstrating lowered plasma ghrelin in obesity, ghrelin levels were lower in the obese compared with overweight women. Among the overweight, ghrelin was positively correlated with caloric intake, giving in to cravings for highly palatable foods, and a flatter diurnal cortisol slope across 3 days. These relationships were non-significant among the obese group. Among overweight women, ghrelin was negatively correlated with insulin resistance, systolic blood pressure, and heart rate, and positively correlated with telomere length. Among the obese subjects, plasma ghrelin concentrations were negatively correlated with insulin resistance, but were not significantly correlated with blood pressure, heart rate or telomere length. Total plasma ghrelin and its associations with food intake, hedonic eating, and stress are decreased in obesity, providing evidence consistent with the theory that central resistance to ghrelin develops in obesity and ghrelin’s function in appetite regulation may have evolved to prevent starvation in food scarcity rather than cope with modern food excess. Furthermore, ghrelin is associated with metabolic and cardiovascular health, and may have anti-aging effects, but these effects may be attenuated in obesity. PMID:24462487

  16. Overexpression of DeltaFosB in nucleus accumbens mimics the protective addiction phenotype, but not the protective depression phenotype of environmental enrichment

    PubMed Central

    Zhang, Yafang; Crofton, Elizabeth J.; Li, Dingge; Lobo, Mary Kay; Fan, Xiuzhen; Nestler, Eric J.; Green, Thomas A.

    2014-01-01

    Environmental enrichment produces protective addiction and depression phenotypes in rats. ΔFosB is a transcription factor that regulates reward in the brain and is induced by psychological stress as well as drugs of abuse. However, the role played by ΔFosB in the protective phenotypes of environmental enrichment has not been well studied. Here, we demonstrate that ΔFosB is differentially regulated in rats reared in an isolated condition (IC) compared to those in an enriched condition (EC) in response to restraint stress or cocaine. Chronic stress or chronic cocaine treatment each elevates ΔFosB protein levels in the nucleus accumbens (NAc) of IC rats, but not of EC rats due to an already elevated basal accumulation of ΔFosB seen under EC conditions. Viral-mediated overexpression of ΔFosB in the NAc shell of pair-housed rats (i.e., independent of environmental enrichment/isolation) increases operant responding for sucrose when motivated by hunger, but decreases responding in satiated animals. Moreover, ΔFosB overexpression decreases cocaine self-administration, enhances extinction of cocaine seeking, and decreases cocaine-induced reinstatement of intravenous cocaine self-administration; all behavioral findings consistent with the enrichment phenotype. In contrast, however, ΔFosB overexpression did not alter responses of pair-housed rats in several tests of anxiety- and depression-related behavior. Thus, ΔFosB in the NAc the shell mimics the protective addiction phenotype, but not the protective depression phenotype of environmental enrichment. PMID:25221490

  17. ΔFosB regulates Ca²⁺ release and proliferation of goat mammary epithelial cells.

    PubMed

    Zheng, Huiling; Li, Hui; Li, Lihui; Ma, Shaoyang; Liu, Xuemei

    2014-07-25

    ΔFosB is a member of the family of transcription factor activating proteins-1 (AP-1) and is known to play important roles in Ca(2+) metabolism processes of osteoblast formation and differentiation in humans and rodents. The postpartum mammary gland is one of the significant organs for Ca(2+) metabolism processes. However, very little information is available on the role of ΔFosB in goat mammary gland. In this investigation, the full-length cDNA of ΔFosB from Xinong Saanen dairy goats was cloned, which contains an open-reading frame (ORF) of 723 bp encoding 240 amino acids. The amino acid sequence is highly homologous with cattle (99.17%). Quantitative real time PCR (QRT-PCR) and western blotting assays showed that ΔFosB was expressed in goat heart, liver, lung, and breast, but little in the hypophysis and spleen. The fluorescence signals revealed that the Ca(2+) was decreased in goat mammary epithelial cells (GMECs) over-expressed ΔFosB at 72h. Consistently, intracellular Ca(2+) was increased in GMECs suppressing expressed ΔFosB at 72 h. QRT-PCR assay showed that ΔFosB positively regulated the mRNA expression of runt related transcription factor 2 (Runx2), SMAD family member 4 (Smad4), S100 calcium binding protein A4 (S100A4) and S100 calcium binding protein A13 (S100A13) genes in GMECs, which had been proven to be relative to calcium metabolism in humans and rodents. Ca(2+) could induce a dose-dependent increase of the ΔFosB mRNA expression and a dose-dependent decrease in cell viability when the GMECs were treated with CaCl2. Suppressing ΔFosB expression in GMECs also inhibited the cell viability. These discoveries suggest that ΔFosB plays important roles in regulating Ca(2+) release and proliferation of the GMECs, which may prove useful in regulation of milk production. PMID:24831832

  18. Acute food deprivation enhances fear extinction but inhibits long-term depression in the lateral amygdala via ghrelin signaling.

    PubMed

    Huang, Chiung-Chun; Chou, Dylan; Yeh, Che-Ming; Hsu, Kuei-Sen

    2016-02-01

    Fear memory-encoding thalamic input synapses to the lateral amygdala (T-LA) exhibit dynamic efficacy changes that are tightly correlated with fear memory strength. Previous studies have shown that auditory fear conditioning involves strengthening of synaptic strength, and conversely, fear extinction training leads to T-LA synaptic weakening and occlusion of long-term depression (LTD) induction. These findings suggest that the mechanisms governing LTD at T-LA synapses may determine the behavioral outcomes of extinction training. Here, we explored this hypothesis by implementing food deprivation (FD) stress in mice to determine its effects on fear extinction and LTD induction at T-LA synapses. We found that FD increased plasma acylated ghrelin levels and enhanced fear extinction and its retention. Augmentation of fear extinction by FD was blocked by pretreatment with growth hormone secretagogue receptor type-1a antagonist D-Lys(3)-GHRP-6, suggesting an involvement of ghrelin signaling. Confirming previous findings, two distinct forms of LTD coexist at thalamic inputs to LA pyramidal neurons that can be induced by low-frequency stimulation (LFS) or paired-pulse LFS (PP-LFS) paired with postsynaptic depolarization, respectively. Unexpectedly, we found that FD impaired the induction of PP-LFS- and group I metabotropic glutamate receptor agonist (S)-3,5-dihydroxyphenylglycine (DHPG)-induced LTD, but not LFS-induced LTD. Ghrelin mimicked the effects of FD to impair the induction of PP-LFS- and DHPG-induced LTD at T-LA synapses, which were blocked by co-application of D-Lys(3)-GHRP-6. The sensitivity of synaptic transmission to 1-naphthyl acetyl spermine was not altered by either FD or ghrelin treatment. These results highlight distinct features of fear extinction and LTD at T-LA synapses.

  19. Seasonal and parity effects on ghrelin levels throughout the estrous cycle in dairy cows.

    PubMed

    Honig, Hen; Ofer, Lior; Elbaz, Michal; Kaim, Moshe; Shinder, Dima; Gershon, Eran

    2016-09-01

    In dairy cows, heat stress depresses appetite, leading to decreased food intake, a negative energy balance, and modifies ghrelin levels. Ghrelin is a gut-brain peptide with two major forms: acylated, with an O-n-octanoylated serine in position 3, and nonacylated. To date, the effect of heat stress and estrous cycle on ghrelin secretion in dairy cows has not been studied. We characterized ghrelin secretion during the estrous cycle in each, the winter and the summer seasons. We further examined the effects of parity on ghrelin secretion. Blood was collected from 10 primiparous or multiparous Israeli-Holstein dairy cows throughout the estrous cycle, in both, the hot and cold seasons. The levels of acylated and total ghrelin were measured in the blood samples. We found that both acylated and total ghrelin levels during heat stress were lower than their respective levels in the winter in both, primiparous and multiparous cows. No differences in acylated and total ghrelin levels were found between primiparous and multiparous cows in both seasons. We further found that in multiparous but not primiparous cows acylated ghrelin secretion oscillated during the estrous cycle in both seasons. Its levels peaked on the last days of the first follicular wave and on the days before and during ovulation. Interestingly, we found that elevated acylated ghrelin levels correlated with conception success and increased total ghrelin levels were associated with successful conception from first insemination. Our data is the first to demonstrate seasonal variation in ghrelin secretion. This study provides evidence for the yet unfamiliar link between heat stress, ghrelin and fertility. Increased circulating acylated ghrelin may contribute to improved fertility in dairy cows. It further raises the possibility of a link between ghrelin levels and successful inseminations. Further research is required to determine the effects of ghrelin on dairy cow performance.

  20. Seasonal and parity effects on ghrelin levels throughout the estrous cycle in dairy cows.

    PubMed

    Honig, Hen; Ofer, Lior; Elbaz, Michal; Kaim, Moshe; Shinder, Dima; Gershon, Eran

    2016-09-01

    In dairy cows, heat stress depresses appetite, leading to decreased food intake, a negative energy balance, and modifies ghrelin levels. Ghrelin is a gut-brain peptide with two major forms: acylated, with an O-n-octanoylated serine in position 3, and nonacylated. To date, the effect of heat stress and estrous cycle on ghrelin secretion in dairy cows has not been studied. We characterized ghrelin secretion during the estrous cycle in each, the winter and the summer seasons. We further examined the effects of parity on ghrelin secretion. Blood was collected from 10 primiparous or multiparous Israeli-Holstein dairy cows throughout the estrous cycle, in both, the hot and cold seasons. The levels of acylated and total ghrelin were measured in the blood samples. We found that both acylated and total ghrelin levels during heat stress were lower than their respective levels in the winter in both, primiparous and multiparous cows. No differences in acylated and total ghrelin levels were found between primiparous and multiparous cows in both seasons. We further found that in multiparous but not primiparous cows acylated ghrelin secretion oscillated during the estrous cycle in both seasons. Its levels peaked on the last days of the first follicular wave and on the days before and during ovulation. Interestingly, we found that elevated acylated ghrelin levels correlated with conception success and increased total ghrelin levels were associated with successful conception from first insemination. Our data is the first to demonstrate seasonal variation in ghrelin secretion. This study provides evidence for the yet unfamiliar link between heat stress, ghrelin and fertility. Increased circulating acylated ghrelin may contribute to improved fertility in dairy cows. It further raises the possibility of a link between ghrelin levels and successful inseminations. Further research is required to determine the effects of ghrelin on dairy cow performance. PMID:27288640

  1. Ablation of ghrelin receptor in leptin-deficient ob/ob mice has paradoxical effects on glucose homeostasis when compared with ablation of ghrelin in ob/ob mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The orexigenic hormone ghrelin is important in diabetes because it has an inhibitory effect on insulin secretion. Ghrelin ablation in leptin-deficient ob/ob (Ghrelin(-/-):ob/ob) mice increases insulin secretion and improves hyperglycemia. The physiologically relevant ghrelin receptor is the growth ...

  2. Rise of plasma ghrelin with weight loss is not sustained during weight maintenance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ghrelin is postulated to be an orexigenic signal that promotes weight regain after weight loss (WL). However, it is not known whether this putative effect of ghrelin is sustained after weight stabilization. The objective of this study was to investigate the relationship of plasma ghrelin concentrati...

  3. Dynamics of c-fos and ICER mRNA expression in rat forebrain following lithium chloride injection.

    PubMed

    Spencer, C M; Houpt, T A

    2001-09-30

    Lithium is commonly used as a treatment for affective disorders in humans and as a toxin to produce conditioned taste aversions in rats. LiCl administration in rats has been correlated with activation of c-fos and cAMP-mediated gene transcription in many brain regions; however, little is known about the timing or duration of gene activation. We hypothesized that c-fos gene transcription is rapidly stimulated by LiCl, followed later by the expression of the inducible cAMP early repressor (ICER) transcription factor, a negative modulator of cAMP-mediated gene transcription. By in situ hybridization, we analyzed the timecourse of c-fos and ICER mRNA expression in the central nucleus of the amygdala (CeA), the paraventricular nucleus of the hypothalamus (PVN) and the supraoptic nucleus (SON) at seven time points (0, 0.3, 1, 3, 6, 9 and 12 h) after intraperitoneal LiCl injection (0.15 M, 12 ml/kg, 76 mg/kg). Expression of c-fos mRNA peaked between 20 min and 1 h an