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Sample records for ghrelin induces fos

  1. Peripheral injection of ghrelin induces Fos expression in the dorsomedial hypothalamic nucleus in rats

    PubMed Central

    Kobelt, Peter; Wisser, Anna-Sophia; Stengel, Andreas; Goebel, Miriam; Inhoff, Tobias; Noetzel, Steffen; Veh, Rüdiger W.; Bannert, Norbert; van der Voort, Ivo; Wiedenmann, Bertram; Klapp, Burghard F.; Taché, Yvette; Mönnikes, Hubert

    2009-01-01

    Peripheral ghrelin has been shown to act as a gut–brain peptide exerting a potent orexigenic effect on food intake. The dorsomedial nucleus of the hypothalamus (DMH) is innervated by projections from other brain areas being part of the network of nuclei controlling energy homeostasis, among others NPY/AgRP-positive fibers arising from the arcuate nucleus (ARC). The aim of the study was to determine if peripherally administered ghrelin affects neuronal activity in the DMH, as assessed by Fos expression. The number of Fos positive neurons was determined in the DMH, paraventricular nucleus of the hypothalamus (PVN), ARC, ventromedial hypothalamic nucleus (VMH), nucleus of the solitary tract (NTS) and in the area postrema(AP) in non-fasted Sprague–Dawley rats in response to intraperitoneally (ip) injected ghrelin (3 nmol/rat) or vehicle (0.15 M NaCl). Peripheral ghrelin induced a significant increase in the number of Fos-ir positive neurons/section compared with vehicle in the ARC (mean±SEM: 49±2 vs. 23±2 neurons/section, p=0.001), PVN (69±5 vs. 34±3, p=0.001), and DMH (142±5 vs. 83±5, p<0.001). Fos-ir positive neurons were mainly localized within the ventral part of the DMH. No change in Fos expression was observed in the VMH (53±8 vs. 48±6, p=0.581), NTS (42±2 vs.40±3, p=0.603), and in the AP (7±1 vs. 5±1, p=0.096). Additional double-labelling with anti-Fos and anti-AgRP revealed that Fos positive neurons in the DMH were encircled by a network of AgRP-ir positive fibers. These data indicate that peripheral ghrelin activates DMH neurons and that NPY-/AgRP-positive fibers may be involved in the response. PMID:18329635

  2. 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.

  3. A circulating ghrelin mimetic attenuates light-induced phase delay of mice and light-induced Fos expression in the suprachiasmatic nucleus of rats.

    PubMed

    Yi, Chun-Xia; Challet, Etienne; Pévet, Paul; Kalsbeek, Andries; Escobar, Carolina; Buijs, Ruud M

    2008-04-01

    Anatomical evidence suggests that the ventromedial arcuate nucleus (vmARC) is a route for circulating hormonal communications to the suprachiasmatic nucleus (SCN). Whether this vmARC-SCN connection is involved in the modulation of circadian activity of the SCN is not yet known. We recently demonstrated, in rats, that intravenous (i.v.) injection of a ghrelin mimetic, GHRP-6, during the daytime activated neurons in the vmARC and reduced the normal endogenous daytime Fos expression in the SCN. In the present study we show that i.v. administration of GHRP-6 decreases light-induced Fos expression at ZT13 in the rat SCN by 50%, indicating that light-induced changes in the SCN Fos expression can also be reduced by GHRP-6. Because it is difficult to study light-induced phase changes in rats, we examined the functional effects of GHRP-6 on light-induced phase shifts in mice and demonstrated that peripherally injected GHRP-6 attenuates light-induced phase delays at ZT13 by 45%. However, light-induced Fos expression in the mice SCN was not blocked by GHRP-6. These results illustrate that acute stimulation of the ghrelinergic system may modulate SCN activity, but that its effect on light-induced phase shifts and Fos expression in the SCN might be species related.

  4. Peptide YY directly inhibits ghrelin-activated neurons of the arcuate nucleus and reverses fasting-induced c-Fos expression.

    PubMed

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

    2004-01-01

    The hypothalamic arcuate nucleus (Arc) monitors and integrates hormonal and metabolic signals involved in the maintenance of energy homeostasis. The orexigenic peptide ghrelin is secreted from the stomach during negative status of energy intake and directly activates neurons of the medial arcuate nucleus (ArcM) in rats. In contrast to ghrelin, peptide YY (PYY) is released postprandially from the gut and reduces food intake when applied peripherally. Neurons in the ArcM express ghrelin receptors and neuropeptide Y receptors. Thus, PYY may inhibit feeding by acting on ghrelin-sensitive Arc neurons. Using extracellular recordings, we (1) characterized the effects of PYY on the electrical activity of ghrelin-sensitive neurons in the ArcM of rats. In order to correlate the effect of PYY on neuronal activity with the energy status, we (2) investigated the ability of PYY to reverse fasting-induced c-Fos expression in Arc neurons of mice. In addition, we (3) sought to confirm that PYY reduces food intake under our experimental conditions. Superfusion of PYY reversibly inhibited 94% of all ArcM neurons by a direct postsynaptic mechanism. The PYY-induced inhibition was dose-dependent and occurred at a threshold concentration of 10(-8)M. Consistent with the opposite effects of ghrelin and PYY on food intake, a high percentage (50%) of Arc neurons was activated by ghrelin and inhibited by PYY. In line with this inhibitory action, peripherally injected PYY partly reversed the fasting-induced c-Fos expression in Arc neurons of mice. Similarly, refeeding of food-deprived mice reversed the fasting-induced activation in the Arc. Furthermore, peripherally injected PYY reduced food intake in 12-hour fasted mice. Thus the activity of Arc neurons correlated with the feeding status and was not only reduced by feeding but also by administration of PYY in non-refed mice. In conclusion, our current observations suggest that PYY may contribute to signaling a positive status of energy intake

  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. 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

  7. Diet-induced obesity causes ghrelin resistance in arcuate NPY/AgRP neurons.

    PubMed

    Briggs, Dana I; Enriori, Pablo J; Lemus, Moyra B; Cowley, Michael A; Andrews, Zane B

    2010-10-01

    Circulating ghrelin is decreased in obesity, and peripheral ghrelin does not induce food intake in obese mice. We investigated whether ghrelin resistance was a centrally mediated phenomenon involving dysregulated neuropeptide Y (NPY) and agouti-related peptide (AgRP) circuits. We show that diet-induced obesity (DIO) (12 wk) suppresses the neuroendocrine ghrelin system by decreasing acylated and total plasma ghrelin, decreasing ghrelin and Goat mRNA in the stomach, and decreasing expression of hypothalamic GHSR. Peripheral (ip) or central (intracerebroventricular) ghrelin injection was able to induce food intake and arcuate nucleus Fos immunoreactivity in chow-fed but not high-fat diet-fed mice. DIO decreased expression of Npy and Agrp mRNA, and central ghrelin was unable to promote expression of these genes. Ghrelin did not induce AgRP or NPY secretion in hypothalamic explants from DIO mice. Injection of NPY intracerebroventricularly increased food intake in both chow-fed and high-fat diet-fed mice, indicating that downstream NPY/AgRP neural targets are intact and that defective NPY/AgRP function is a primary cause of ghrelin resistance. Ghrelin resistance in DIO is not confined to the NPY/AgRP neurons, because ghrelin did not stimulate growth hormone secretion in DIO mice. Collectively, our data suggests that DIO causes ghrelin resistance by reducing NPY/AgRP responsiveness to plasma ghrelin and suppressing the neuroendocrine ghrelin axis to limit further food intake. Ghrelin has a number of functions in the brain aside from appetite control, including cognitive function, mood regulation, and protecting against neurodegenerative diseases. Thus, central ghrelin resistance may potentiate obesity-related cognitive decline, and restoring ghrelin sensitivity may provide therapeutic outcomes for maintaining healthy aging.

  8. Diet-induced obesity causes peripheral and central ghrelin resistance by promoting inflammation.

    PubMed

    Naznin, Farhana; Toshinai, Koji; Waise, T M Zaved; NamKoong, Cherl; Md Moin, Abu Saleh; Sakoda, Hideyuki; Nakazato, Masamitsu

    2015-07-01

    Ghrelin, a stomach-derived orexigenic peptide, transmits starvation signals to the hypothalamus via the vagus afferent nerve. Peripheral administration of ghrelin does not induce food intake in high fat diet (HFD)-induced obese mice. We investigated whether this ghrelin resistance was caused by dysfunction of the vagus afferent pathway. Administration (s.c.) of ghrelin did not induce food intake, suppression of oxygen consumption, electrical activity of the vagal afferent nerve, phosphorylation of ERK2 and AMP-activated protein kinase alpha in the nodose ganglion, or Fos expression in hypothalamic arcuate nucleus of mice fed a HFD for 12 weeks. Administration of anti-ghrelin IgG did not induce suppression of food intake in HFD-fed mice. Expression levels of ghrelin receptor mRNA in the nodose ganglion and hypothalamus of HFD-fed mice were reduced. Inflammatory responses, including upregulation of macrophage/microglia markers and inflammatory cytokines, occurred in the nodose ganglion and hypothalamus of HFD-fed mice. A HFD blunted ghrelin signaling in the nodose ganglion via a mechanism involving in situ activation of inflammation. These results indicate that ghrelin resistance in the obese state may be caused by dysregulation of ghrelin signaling via the vagal afferent. © 2015 The authors.

  9. DESACYL GHRELIN INHIBITS THE OREXIGENIC EFFECT OF PERIPHERALLY INJECTED GHRELIN IN RATS

    PubMed Central

    Inhoff, Tobias; Mönnikes, Hubert; Noetzel, Steffen; Stengel, Andreas; Goebel, Miriam; Dinh, Q. Thai; Riedl, Andrea; Bannert, Norbert; Wisser, Anna-Sophia; Wiedenmann, Bertram; Klapp, Burghard F.; Taché, Yvette

    2008-01-01

    Studies showed that the metabolic unlike the neuroendocrine effects of ghrelin could be abrogated by co-administered unacylated ghrelin. The aim was to investigate the interaction between ghrelin and desacyl ghrelin administered intraperitoneally on food intake and neuronal activity (c-Fos) in the arcuate nucleus in non-fasted rats. Ghrelin (13 μg/kg) significantly increased food intake within the first 30 min post injection. Desacyl ghrelin at 64 and 127 μg/kg injected simultaneously with ghrelin abolished the stimulatory effect of ghrelin on food intake. Desacyl ghrelin alone at both doses did not alter food intake. Both doses of desacyl ghrelin injected separately in the light phase had no effects on food intake when rats were fasted for 12 h. Ghrelin and desacyl ghrelin (64 μg/kg) injected alone increased the number of Fos positive neurons in the arcuate nucleus compared to vehicle. The effect on neuronal activity induced by ghrelin was significantly reduced when injected simultaneously with desacyl ghrelin. Double labeling revealed that nesfatin-1 immunoreactive neurons in the arcuate nucleus are activated by simultaneous injection of ghrelin and desacyl ghrelin. These results suggest that desacyl ghrelin suppresses ghrelin-induced food intake by curbing ghrelin-induced increased neuronal activity in the arcuate nucleus and recruiting nesfatin-1 immunopositive neurons. PMID:18938204

  10. Active ghrelin levels and active to total ghrelin ratio in cancer-induced cachexia.

    PubMed

    Garcia, Josè M; Garcia-Touza, Mariana; Hijazi, Rabih A; Taffet, George; Epner, Daniel; Mann, Douglas; Smith, Roy G; Cunningham, Glenn R; Marcelli, Marco

    2005-05-01

    Anorexia and weight loss are negative prognostic factors in patients with cancer. Although total ghrelin levels are increased in energy-negative states, levels of the biologically active octanoylated ghrelin and the anorexigenic peptide YY (PYY) have not been reported in patients with cancer-induced cachexia. We hypothesized that abnormal ghrelin and/or PYY levels contribute to cancer-induced cachexia. We evaluated 21 patients with cancer-induced cachexia; 24 cancer patients without cachexia; and 23 age-, sex-, race-, and BMI-matched subjects without cancer. Active ghrelin levels and the active to total ghrelin ratio were significantly increased in subjects with cancer-induced cachexia, compared with cancer and noncancer controls. PYY levels were similar among groups. Appetite measured by a visual analog scale was not increased in subjects with cachexia. The increase in active ghrelin levels is likely to be a compensatory response to weight loss. Cachexia may be a state of ghrelin resistance because appetite does not correlate with ghrelin levels. Changes in the active to total ghrelin ratio suggest that a mechanism other than increased secretion must be responsible for the increase in active ghrelin levels. PYY is unlikely to play an important role in cancer-induced cachexia.

  11. Ghrelin

    USDA-ARS?s Scientific Manuscript database

    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...

  12. 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.

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

    PubMed

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

    2014-07-01

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

  14. Ghrelin improves burn-induced delayed gastrointestinal transit in rats.

    PubMed

    Sallam, H S; Oliveira, H M; Gan, H T; Herndon, D N; Chen, J D Z

    2007-01-01

    Delayed gastrointestinal transit is common in patients with severe burn. Ghrelin is a potent prokinetic peptide. We aimed at testing the effect of ghrelin on burn-induced delayed gastrointestinal transit in rats. Gastric emptying (GE), intestinal transit (IT), and colonic transit (CT) studies were performed in male Sprague-Dawley rats. Rats were randomized into two main groups as follows: sham injury and ghrelin-treated burn injury with doses of 0, 2, 5, and 10 nmol/rat ip 6 h after burn. Sham/burn injury was induced under anesthesia. Rats received a phenol red meal 20 min following ghrelin injection. Based on the most effective ghrelin dose, 1 mg/kg sc atropine was given 30 min before the ghrelin in one group of rats for each study. The rats in each group were killed 30-90 min later; their stomachs, intestines, and colons were harvested immediately, and the amount of phenol red recovered was measured. Percentage of gastric emptying (GE%) and geometric center for IT and CT were calculated. We found 1) severe cutaneous burn injury significantly delayed GE, IT, and CT compared with sham injury (P < 0.05); 2) ghrelin normalized both GE and IT, but not the CT; 3) the most effective dose of ghrelin was 2 nmol/rat; and 4) atropine blocked the prokinetic effects of ghrelin on GE% and IT. In conclusion, ghrelin normalizes burn-induced delayed GE and IT but has no effect on CT in rats. The prokinetic effects of ghrelin are exerted via the cholinergic pathway. Ghrelin may have a therapeutic potential for burn patients with delayed upper gastrointestinal transit.

  15. Ghrelin.

    PubMed

    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

    2015-06-01

    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. 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. 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.

  16. Ghrelin-induced adiposity is independent of orexigenic effects

    PubMed Central

    Perez-Tilve, Diego; Heppner, Kristy; Kirchner, Henriette; Lockie, Sarah H.; Woods, Stephen C.; Smiley, David L.; Tschöp, Matthias; Pfluger, Paul

    2011-01-01

    Ghrelin is a hormone produced predominantly by the stomach that targets a number of specific areas in the central nervous system to promote a positive energy balance by increasing food intake and energy storage. In that respect, similarities exist with the effects of consuming a high-fat diet (HFD), which also increases caloric intake and the amount of stored calories. We determined whether the effects of ghrelin on feeding and adiposity are influenced by the exposure to an HFD. Chronic intracerebroventricular ghrelin (2.5 nmol/d) increased feeding in lean rats fed a low-fat control diet (CD) [192±5 g (ghrelin+CD) vs. 152±5 g (control i.c.v. saline+CD), P<0.001], but the combination of ghrelin plus HFD did not result in significantly greater hyperphagia [150±7 g (ghrelin+HFD) vs. 136±4 g (saline+HFD)]. Despite failing to increase food intake in rats fed the HFD, ghrelin nonetheless increased adiposity [fat mass increase of 14±2 g (ghrelin+HFD) vs. 1±1 g (saline+HFD), P<0.001] up-regulating the gene expression of lipogenic enzymes in white adipose tissue. Our findings demonstrate that factors associated with high-fat feeding functionally interact with pathways regulating the effect of ghrelin on food intake. We conclude that ghrelin's central effects on nutrient intake and nutrient partitioning can be separated and suggest an opportunity to identify respective independent neuronal pathways.—Perez-Tilve, D., Heppner, K., Kirchner, H., Lockie, S. H., Woods, S. C., Smiley, D. L., Tschöp, M., and Pfluger, P. Ghrelin-induced adiposity is independent of orexigenic effects. PMID:21543764

  17. 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

  18. Increased Ghrelin but Low Ghrelin-Reactive Immunoglobulins in a Rat Model of Methotrexate Chemotherapy-Induced Anorexia.

    PubMed

    François, Marie; Takagi, Kuniko; Legrand, Romain; Lucas, Nicolas; Beutheu, Stephanie; Bôle-Feysot, Christine; Cravezic, Aurore; Tennoune, Naouel; do Rego, Jean-Claude; Coëffier, Moïse; Inui, Akio; Déchelotte, Pierre; Fetissov, Sergueï O

    2016-01-01

    Cancer chemotherapy is commonly accompanied by mucositis, anorexia, weight loss, and anxiety independently from cancer-induced anorexia-cachexia, further aggravating clinical outcome. Ghrelin is a peptide hormone produced in gastric mucosa that reaches the brain to stimulate appetite. In plasma, ghrelin is protected from degradation by ghrelin-reactive immunoglobulins (Ig). To analyze possible involvement of ghrelin in the chemotherapy-induced anorexia and anxiety, gastric ghrelin expression, plasma levels of ghrelin, and ghrelin-reactive IgG were studied in rats treated with methotrexate (MTX). Rats received MTX (2.5 mg/kg, subcutaneously) for three consecutive days and were killed 3 days later, at the peak of anorexia and weight loss. Control rats received phosphate-buffered saline. Preproghrelin mRNA expression in the stomach was analyzed by in situ hybridization. Plasma levels of ghrelin and ghrelin-reactive IgG were measured by immunoenzymatic assays and IgG affinity kinetics by surface plasmon resonance. Anxiety- and depression-like behaviors in MTX-treated anorectic and in control rats were evaluated in the elevated plus-maze and the forced-swim test, respectively. In MTX-treated anorectic rats, the number of preproghrelin mRNA-producing cells was found increased (by 51.3%, p < 0.001) as well were plasma concentrations of both ghrelin and des-acyl-ghrelin (by 70.4%, p < 0.05 and 98.3%, p < 0.01, respectively). In contrast, plasma levels of total IgG reactive with ghrelin and des-acyl-ghrelin were drastically decreased (by 87.2 and 88.4%, respectively, both p < 0.001), and affinity kinetics of these IgG were characterized by increased small and big Kd, respectively. MTX-treated rats displayed increased anxiety- but not depression-like behavior. MTX-induced anorexia, weight loss, and anxiety are accompanied by increased ghrelin production and by a decrease of ghrelin-reactive IgG levels and affinity binding properties. Such changes of

  19. The Hormone Ghrelin Prevents Traumatic Brain Injury Induced Intestinal Dysfunction

    PubMed Central

    Bansal, Vishal; Ryu, Seok Yong; Blow, Chelsea; Costantini, Todd; Loomis, William; Eliceiri, Brian; Baird, Andrew; Wolf, Paul

    2010-01-01

    Abstract Intestinal barrier breakdown following traumatic brain injury (TBI) is characterized by increased intestinal permeability, leading to bacterial translocation, and inflammation. The hormone ghrelin may prevent intestinal injury and have anti-inflammatory properties. We hypothesized that exogenous ghrelin prevents intestinal injury following TBI. A weight-drop model created severe TBI in three groups of anesthetized Balb/c mice. Group TBI: animals underwent TBI only; Group TBI/ghrelin: animals were given 10 μg of ghrelin intraperitoneally prior and 1 h following TBI; Group sham: no TBI or ghrelin injection. Intestinal permeability was measured 6 h following TBI by detecting serum levels of FITC-Dextran after injection into the intact ileum. The terminal ileum was harvested for histology, expression of the tight junction protein MLCK and inflammatory cytokine TNF-α. Permeability increased in the TBI group compared to the sham group (109.7 ± 21.8 μg/mL vs. 32.2 ± 10.1 μg/mL; p < 0.002). Ghrelin prevented TBI-induced permeability (28.3 ± 4.2 μg/mL vs. 109.7 ± 21.8 μg/mL; p < 0.001). The intestines of the TBI group showed blunting and necrosis of villi compared to the sham group, while ghrelin injection preserved intestinal architecture. Intestinal MLCK increased 73% compared to the sham group (p < 0.03). Ghrelin prevented TBI-induced MLCK expression to sham levels. Intestinal TNF-α increased following TBI compared to the sham group (46.2 ± 7.1 pg/mL vs. 24.4 ± 2.2 pg/mL p < 0.001). Ghrelin reduced TNF-α to sham levels (29.2 ± 5.0 pg/mL; p = NS). We therefore conclude that ghrelin prevents TBI-induced injury, as determined by intestinal permeability, histology, and intestinal levels of TNF-α. The mechanism for ghrelin mediating intestinal protection is likely multifactorial, and further studies are needed to delineate these possibilities. PMID:20858122

  20. Interleukin-1 beta-induced anorexia is reversed by ghrelin.

    PubMed

    Gonzalez, Patricia Verónica; Cragnolini, Andrea Beatriz; Schiöth, Helgi Birgir; Scimonelli, Teresa Nieves

    2006-12-01

    Interleukins, in particular interleukin-1beta (IL-1beta), reduce food intake after peripheral and central administration, which suggests that they contribute to anorexia during various infectious, neoplastic, and autoimmune diseases. On the other hand, ghrelin stimulates food intake by acting on the central nervous system (CNS) and is considered an important regulator of food intake in both rodents and humans. In the present study, we investigated if ghrelin could reverse IL-1beta-induced anorexia. Intracerebroventricular (i.c.v.) injection of 15, 30 or 45 ng/microl of IL-1beta caused significant suppression of food intake in 20 h fasting animals. This effect lasted for a 24h period. Ghrelin (0.15 nmol or 1.5 nmol/microl) produced a significant increase in cumulative food intake in normally fed animals. However, it did not alter food intake in 20 h fasting animals. Central administration of ghrelin reduced the anorexic effect of IL-1beta (15 ng/microl). The effect was observed 30 min after injection and lasted for the next 24h. This study provides evidence that ghrelin is an orexigenic peptide capable of antagonizing IL-1beta-induced anorexia.

  1. Reduced ghrelin secretion in the hypothalamus of rats due to cisplatin-induced anorexia.

    PubMed

    Yakabi, Koji; Sadakane, Chiharu; Noguchi, Masamichi; Ohno, Shino; Ro, Shoki; Chinen, Katsuya; Aoyama, Toru; Sakurada, Tomoya; Takabayashi, Hideaki; Hattori, Tomohisa

    2010-08-01

    Although chemotherapy with cisplatin is a widely used and effective cancer treatment, the undesirable gastrointestinal side effects associated with it, such as nausea, vomiting, and anorexia, markedly decrease patients' quality of life. To elucidate the mechanism underlying chemotherapy-induced anorexia, focusing on the hypothalamic ghrelin secretion-anorexia association, we measured hypothalamic ghrelin secretion in fasted and cisplatin-treated rats. Hypothalamic ghrelin secretion changes after vagotomy or administration of cisplatin. Cisplatin + rikkunshito, a serotonin 2C receptor antagonist or serotonin 3 receptor antagonist, was investigated. The effects of intracerebroventricular (icv) administration of ghrelin or the serotonin 2C receptor antagonist SB242084 on food intake were also evaluated in cisplatin-treated rats. Hypothalamic ghrelin secretion significantly increased in 24-h-fasted rats compared to freely fed rats and was markedly reduced 24 and 48 h after cisplatin treatment in cisplatin-treated rats compared to saline-treated rats, although their plasma ghrelin levels were comparable. In cisplatin-treated rats, icv ghrelin administration reversed the decrease in food intake, vagotomy partially restored hypothalamic ghrelin secretion, and hypothalamic serotonin 2C receptor mRNA expression increased significantly. Administration of rikkunshito (an endogenous ghrelin enhancer) or a serotonin 2C receptor antagonist reversed the decrease in hypothalamic ghrelin secretion and food intake 24 h after cisplatin treatment. Cisplatin-induced anorexia is mediated through reduced hypothalamic ghrelin secretion. Cerebral serotonin 2C receptor activation partially induces decrease in hypothalamic ghrelin secretion, and rikkunshito suppresses cisplatin-induced anorexia by enhancing this secretion.

  2. Exercise-induced suppression of acylated ghrelin in humans.

    PubMed

    Broom, D R; Stensel, D J; Bishop, N C; Burns, S F; Miyashita, M

    2007-06-01

    Ghrelin is an orexigenic hormone secreted from endocrine cells in the stomach and other tissues. Acylation of ghrelin is essential for appetite regulation. Vigorous exercise induces appetite suppression, but this does not appear to be related to suppressed concentrations of total ghrelin. This study examined the effect of exercise and feeding on plasma acylated ghrelin and appetite. Nine male subjects aged 19-25 yr participated in two, 9-h trials (exercise and control) in a random crossover design. Trials began at 0800 in the morning after an overnight fast. In the exercise trial, subjects ran for 60 min at 72% of maximum oxygen uptake between 0800 and 0900. After this, they rested for 8 h and consumed a test meal at 1100. In the control trial, subjects rested for 9 h and consumed a test meal at 1100. Area under the curve values for plasma acylated ghrelin concentration (assessed from venous blood samples) were lower over the first 3 h and the full 9 h of the exercise trial compared with the control trial: 317+/-135 vs. 510+/-186 pg.ml(-1).3 h and 917+/-342 vs. 1,401+/-521 pg.ml(-1).9 h (means+/-SE) respectively (P<0.05). Area under the curve values for hunger (assessed using a visual scale) were lower over the first 3 h of the exercise trial compared with the control trial (P=0.013). These findings demonstrate that plasma acylated ghrelin concentration and hunger are suppressed during running.

  3. Altered ghrelin secretion in mice in response to diet-induced obesity and Roux-en-Y gastric bypass

    PubMed Central

    Uchida, Aki; Zechner, Juliet F.; Mani, Bharath K.; Park, Won-mee; Aguirre, Vincent; Zigman, Jeffrey M.

    2014-01-01

    The current study examined potential mechanisms for altered circulating ghrelin levels observed in diet-induced obesity (DIO) and following weight loss resulting from Roux-en-Y gastric bypass (RYGB). We hypothesized that circulating ghrelin levels were altered in obesity and after weight loss through changes in ghrelin cell responsiveness to physiological cues. We confirmed lower ghrelin levels in DIO mice and demonstrated elevated ghrelin levels in mice 6 weeks post-RYGB. In both DIO and RYGB settings, these changes in ghrelin levels were associated with altered ghrelin cell responsiveness to two key physiological modulators of ghrelin secretion – glucose and norepinephrine. In DIO mice, increases in ghrelin cell density within both the stomach and duodenum and in somatostatin-immunoreactive D cell density in the duodenum were observed. Our findings provide new insights into the regulation of ghrelin secretion and its relation to circulating ghrelin within the contexts of obesity and weight loss. PMID:25353000

  4. Altered ghrelin secretion in mice in response to diet-induced obesity and Roux-en-Y gastric bypass.

    PubMed

    Uchida, Aki; Zechner, Juliet F; Mani, Bharath K; Park, Won-Mee; Aguirre, Vincent; Zigman, Jeffrey M

    2014-10-01

    The current study examined potential mechanisms for altered circulating ghrelin levels observed in diet-induced obesity (DIO) and following weight loss resulting from Roux-en-Y gastric bypass (RYGB). We hypothesized that circulating ghrelin levels were altered in obesity and after weight loss through changes in ghrelin cell responsiveness to physiological cues. We confirmed lower ghrelin levels in DIO mice and demonstrated elevated ghrelin levels in mice 6 weeks post-RYGB. In both DIO and RYGB settings, these changes in ghrelin levels were associated with altered ghrelin cell responsiveness to two key physiological modulators of ghrelin secretion - glucose and norepinephrine. In DIO mice, increases in ghrelin cell density within both the stomach and duodenum and in somatostatin-immunoreactive D cell density in the duodenum were observed. Our findings provide new insights into the regulation of ghrelin secretion and its relation to circulating ghrelin within the contexts of obesity and weight loss.

  5. 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.

  6. 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

  7. Diet-induced obesity causes ghrelin resistance in reward processing tasks.

    PubMed

    Lockie, Sarah H; Dinan, Tara; Lawrence, Andrew J; Spencer, Sarah J; Andrews, Zane B

    2015-12-01

    Diet-induced obesity (DIO) causes ghrelin resistance in hypothalamic Agouti-related peptide (AgRP) neurons. However, ghrelin promotes feeding through actions at both the hypothalamus and mesolimbic dopamine reward pathways. Therefore, we hypothesized that DIO would also establish ghrelin resistance in the ventral tegmental area (VTA), a major site of dopaminergic cell bodies important in reward processing. We observed reduced sucrose and saccharin consumption in Ghrelin KO vs Ghrelin WT mice. Moreover, DIO reduced saccharin consumption relative to chow-fed controls. These data suggest that the deletion of ghrelin and high fat diet both cause anhedonia. To assess if these are causally related, we tested whether DIO caused ghrelin resistance in a classic model of drug reward, conditioned place preference (CPP). Chow or high fat diet (HFD) mice were conditioned with ghrelin (1mg/kg in 10ml/kg ip) in the presence or absence of food in the conditioning chamber. We observed a CPP to ghrelin in chow-fed mice but not in HFD-fed mice. HFD-fed mice still showed a CPP for cocaine (20mg/kg), indicating that they maintained the ability to develop conditioned behaviour. The absence of food availability during ghrelin conditioning sessions induced a conditioned place aversion, an effect that was still present in both chow and HFD mice. Bilateral intra-VTA ghrelin injection (0.33μg/μl in 0.5μl) robustly increased feeding in both chow-fed and high fat diet (HFD)-fed mice; however, this was correlated with body weight only in the chow-fed mice. Our results suggest that DIO causes ghrelin resistance albeit not directly in the VTA. We suggest there is impaired ghrelin sensitivity in upstream pathways regulating reward pathways, highlighting a functional role for ghrelin linking appropriate metabolic sensing with reward processing.

  8. Ghrelin induces fasted motor activity of the gastrointestinal tract in conscious fed rats

    PubMed Central

    Fujino, Kazunori; Inui, Akio; Asakawa, Akihiro; Kihara, Naoki; Fujimura, Masaki; Fujimiya, Mineko

    2003-01-01

    Ghrelin is a newly discovered orexigenic peptide originating from the stomach. However, its action in regulating the fed and fasted motor activity of the digestive tract is not fully understood. In the present study, we examined the effects of intracerebroventricular (i.c.v.) and intravenous (i.v.) injection of ghrelin on the physiological fed and fasted motor activities in the stomach and duodenum of freely moving conscious rats. i.c.v. and i.v. injection of ghrelin induced fasted motor activity in the duodenum in normal fed rats, while i.v. injection of ghrelin induced fasted motor activity in both the stomach and duodenum in vagotomized rats. The effects of i.c.v. and i.v. injected ghrelin were blocked by growth hormone secretagogue receptor (GHS-R) antagonist given by the same route and also blocked by immunoneutralization of neuropeptide Y (NPY) in the brain. The effects of i.v. injected ghrelin were not altered by i.c.v. injection of GHS-R antagonist in vagotomized rats. Injection of GHS-R antagonist blocked the fasted motor activity in both the stomach and duodenum in vagotomized rats but did not affect the fasted motor activity in normal rats. Low intragastric pH inhibited the effect of ghrelin. The present results indicate that ghrelin is involved in regulation of fasted motor activity in the stomach and duodenum. Peripheral ghrelin may induce the fasted motor activity by activating the NPY neurons in the brain, probably through ghrelin receptors on vagal afferent neurons. Once the brain mechanism is eliminated by truncal vagotomy, ghrelin might be primarily involved in the regulation of fasted motor activity through ghrelin receptors on the stomach and duodenum. The action of ghrelin to induce fasted motor activity is strongly affected by intragastric pH; low pH inhibits the action. PMID:12837928

  9. Acyl Ghrelin Induces Insulin Resistance Independently of GH, Cortisol, and Free Fatty Acids

    PubMed Central

    Vestergaard, Esben T.; Jessen, Niels; Møller, Niels; Jørgensen, Jens Otto Lunde

    2017-01-01

    Ghrelin produced in the gut stimulates GH and ACTH secretion from the pituitary and also stimulates appetite and gastric emptying. We have shown that ghrelin also induces insulin resistance via GH-independent mechanisms, but it is unknown if this effect depends on ambient fatty acid (FFA) levels. We investigated the impact of ghrelin and pharmacological antilipolysis (acipimox) on insulin sensitivity and substrate metabolism in 8 adult hypopituitary patients on stable replacement with GH and hydrocortisone using a 2 × 2 factorial design: Ghrelin infusion, saline infusion, ghrelin plus short-term acipimox, and acipimox alone. Peripheral and hepatic insulin sensitivity was determined with a hyperinsulinemic euglycemic clamp in combination with a glucose tracer infusion. Insulin signaling was assayed in muscle biopsies. Peripheral insulin sensitivity was reduced by ghrelin independently of ambient FFA concentrations and was increased by acipimox independently of ghrelin. Hepatic insulin sensitivity was increased by acipimox. Insulin signaling pathways in skeletal muscle were not consistently regulated by ghrelin. Our data demonstrate that ghrelin induces peripheral insulin resistance independently of GH, cortisol, and FFA. The molecular mechanisms remain elusive, but we speculate that ghrelin is a hitherto unrecognized direct regulator of substrate metabolism. We also suggest that acipimox per se improves hepatic insulin sensitivity. PMID:28198428

  10. Ghrelin-induced sleep responses in ad libitum fed and food-restricted rats.

    PubMed

    Szentirmai, E; Hajdu, I; Obal, F; Krueger, James M

    2006-05-09

    Ghrelin is an endogenous ligand for the growth hormone secretagogue receptor and a well-characterized food intake regulatory peptide. Hypothalamic ghrelin-, neuropeptide Y (NPY)-, and orexin-containing neurons form a feeding regulatory circuit. Orexins and NPY are also implicated in sleep-wake regulation. Sleep responses and motor activity after central administration of 0.2, 1, or 5 microg ghrelin in free-feeding rats as well as in feeding-restricted rats (1 microg dose) were determined. Food and water intake and behavioral responses after the light onset injection of saline or 1 microg ghrelin were also recorded. Light onset injection of ghrelin suppressed non-rapid-eye-movement sleep (NREMS) and rapid-eye-movement sleep (REMS) for 2 h. In the first hour, ghrelin induced increases in behavioral activity including feeding, exploring, and grooming and stimulated food and water intake. Ghrelin administration at dark onset also elicited NREMS and REMS suppression in hours 1 and 2, but the effect was not as marked as that, which occurred in the light period. In hours 3-12, a secondary NREMS increase was observed after some doses of ghrelin. In the feeding-restricted rats, ghrelin suppressed NREMS in hours 1 and 2 and REMS in hours 3-12. Data are consistent with the notion that ghrelin has a role in the integration of feeding, metabolism, and sleep regulation.

  11. Ghrelin secretion is not reduced by increased fat mass during diet-induced obesity.

    PubMed

    Qi, Xiang; Reed, Jason T; Wang, Guiyun; Han, Song; Englander, Ella W; Greeley, George H

    2008-08-01

    Ghrelin is a stomach hormone that stimulates growth hormone (GH) secretion, adiposity, and food intake. Gastric ghrelin production and secretion are regulated by caloric intake; ghrelin secretion increases during fasting, decreases with refeeding, and is reduced by diet-induced obesity. The aim of the present study was to test the hypotheses that 1) an increase in body adiposity will play an inhibitory role in the reduction of gastric ghrelin synthesis and secretion during chronic ingestion of a high-fat (HF) diet and 2) chronic ingestion of an HF diet will suppress the rise in circulating ghrelin levels in response to acute fasting. Adult male Sprague-Dawley rats were fed a standard AIN-76A (approximately 5-12% of calories from fat) or an HF (approximately 45% of calories from fat) diet. The effect of increased adiposity on gastric ghrelin homeostasis was assessed by comparison of stomach ghrelin production and plasma ghrelin levels in obese and nonobese rats fed the HF diet. HF diet-fed, nonobese rats were generated by administration of triiodothyronine to lower body fat accumulation. Our findings indicate that an increased fat mass per se does not exert an inhibitory effect on ghrelin homeostasis during ingestion of the HF diet. Additionally, the magnitude of change in plasma ghrelin in response to fasting was not blunted, indicating that a presumed, endogenous signal for activation of ingestive behavior remains intact, despite excess stored calories in HF-fed rats.

  12. Ghrelin receptors mediate ghrelin-induced excitation of agouti-related protein/neuropeptide Y but not pro-opiomelanocortin neurons.

    PubMed

    Chen, Shao-Rui; Chen, Hong; Zhou, Jing-Jing; Pradhan, Geetali; Sun, Yuxiang; Pan, Hui-Lin; Li, De-Pei

    2017-08-01

    Ghrelin increases food intake and body weight by stimulating orexigenic agouti-related protein (AgRP)/neuropeptide Y (NPY) neurons and inhibiting anorexic pro-opiomelanocortin (POMC) neurons in the hypothalamus. Growth hormone secretagogue receptor (Ghsr) mediates the effect of ghrelin on feeding behavior and energy homeostasis. However, the role of Ghsr in the ghrelin effect on these two populations of neurons is unclear. We hypothesized that Ghsr mediates the effect of ghrelin on AgRP and POMC neurons. In this study, we determined whether Ghsr similarly mediates the effects of ghrelin on AgRP/NPY and POMC neurons using cell type-specific Ghsr-knockout mice. Perforated whole-cell recordings were performed on green fluorescent protein-tagged AgRP/NPY and POMC neurons in the arcuate nucleus in hypothalamic slices. In Ghsr(+/+) mice, ghrelin (100 nM) significantly increased the firing activity of AgRP/NPY neurons but inhibited the firing activity of POMC neurons. In Ghsr(-/-) mice, the excitatory effect of ghrelin on AgRP/NPY neurons was abolished. Ablation of Ghsr also eliminated ghrelin-induced increases in the frequency of GABAergic inhibitory postsynaptic currents of POMC neurons. Strikingly, ablation of Ghsr converted the ghrelin effect on POMC neurons from inhibition to excitation. Des-acylated ghrelin had no such effect on POMC neurons in Ghsr(-/-) mice. In both Ghsr(+/+) and Ghsr(-/-) mice, blocking GABAA receptors with gabazine increased the basal firing activity of POMC neurons, and ghrelin further increased the firing activity of POMC neurons in the presence of gabazine. Our findings provide unequivocal evidence that Ghsr is essential for ghrelin-induced excitation of AgRP/NPY neurons. However, ghrelin excites POMC neurons through an unidentified mechanism that is distinct from conventional Ghsr. © 2017 International Society for Neurochemistry.

  13. Fourth ventricular administration of ghrelin induces relaxation of the proximal stomach in the rat.

    PubMed

    Kobashi, Motoi; Yanagihara, Mamoru; Fujita, Masako; Mitoh, Yoshihiro; Matsuo, Ryuji

    2009-02-01

    The effects of fourth ventricular administration of ghrelin on motility of the proximal stomach were examined in anesthetized rats. Intragastric pressure (IGP) was measured using a balloon situated in the proximal part of the stomach. Administration of ghrelin into the fourth ventricle induced relaxation of the proximal stomach in a dose-dependent manner. Significant reduction of IGP was observed at doses of 3, 10, or 30 pmol. The administration of ghrelin (10 or 30 pmol) with growth hormone secretagogue receptor (GHS-R) antagonist ([D-Lys3] GHRP-6; 1 nmol) into the fourth ventricle did not induce a significant change in IGP. The sole administration of [D-Lys3] GHRP-6 also did not induce a significant change in IGP. Bilateral sectioning of the vagi at the cervical level abolished the relaxation induced by the administration of ghrelin (10 or 30 pmol) into the fourth ventricle, suggesting that relaxation induced by ghrelin is mediated by vagal preganglionic neurons. Microinjections of ghrelin (200 fmol) into the caudal part of the dorsal vagal complex (DVC) induced obvious relaxation of the proximal stomach. Similar injections into the intermediate part of the DVC did not induce significant change. Dose-response analyses revealed that the microinjection of 2 fmol of ghrelin into the caudal DVC significantly reduced IGP. These results revealed that ghrelin induced relaxation in the proximal stomach via GHS-R situated in the caudal DVC.

  14. Ghrelin produces antidepressant-like effect in the estrogen deficient mice.

    PubMed

    Fan, Jie; Li, Bing Jin; Wang, Xue Feng; Zhong, Li Li; Cui, Ran Ji

    2017-08-29

    Recent evidence shows that ghrelin plays an important role in depression. However, it was little known whether ghrelin produces antidepressant-like effect in the ovariectomized mice. The present study was aimed to investigate the antidepressant-like effects of the ghrelin in ovariectomized mice. In the forced swim test, ghrelin significantly decreased immobility time, reversing the "depressive-like" effect observed in ovariectomized mice, and this effect was reversed by the tamoxifen. In addition, immunohistochemical study indicated that ghrelin treatment reversed the reductions in c-Fos expression induced by ovariectomy. An estrogen antagonist tamoxifen also antagonized the effect of ghrelin on the c-Fos expression. Furthermore, the western blotting indicated that brain-derived neurotrophic factor (BDNF) in the hippocampus, but not phosphorylated cAMP response element-binding protein (pCREB)/CREB in the frontal cortex, were affected by ghrelin treatment. Ghrelin treatment significantly increased BrdU expression. Therefore, these findings suggest that ghrelin produces antidepressant-like effects in ovariectomized mice, and estrogen receptor may be involved in the antidepressant-like effects of the ghrelin.

  15. Central but Not Systemic Administration of Ghrelin Induces Wakefulness in Mice

    PubMed Central

    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 (icv) 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. Icv 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. PMID:22815958

  16. 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.

  17. Diet-induced obesity suppresses ghrelin in rat gastrointestinal tract and serum.

    PubMed

    Sahin, Ibrahim; Aydin, Suleyman; Ozkan, Yusuf; Dagli, Adile Ferda; Akin, Kadir Okhan; Guzel, Saadet Pilten; Catak, Zekiye; Ozercan, Mehmet Resat

    2011-09-01

    The aims of the present study were to examine ghrelin expression in serum and gastrointestinal tract (GIT) tissues, and to measure tissue ghrelin levels and obesity-related alterations in some serum biochemical variables in rats with diet-induced obesity (DIO). The study included 12 male rats, 60 days old. The rats were randomly allocated to two groups (n = 6). Rats in the DIO group were fed a cafeteria-style diet to induce obesity, while those in the control group were fed on standard rat pellets. After a 12 week diet program including an adaptation period all rats were decapitated, tissues were individually fixed, ghrelin expression was examined by immunohistochemistry , and tissue and serum ghrelin levels were measured by radioimmunoassay. Serum biochemical variables were measured using an autoanalyzer. When the baseline and week 12 body mass index and GIT ghrelin expression were compared between DIO and control rats, BMI had increased and ghrelin expression decreased due to obesity. The RIA results were consistent with these findings. Serum glucose, LDL cholesterol, and total cholesterol levels were elevated and HDL cholesterol significantly decreased in the DIO group. A comparison of GIT tissues between the control and obese groups demonstrated that ghrelin was decreased in all tissues of the latter. This decrease was brought about a decline in the circulating ghrelin pool. This suggests that rather than being associated with a change in a single tissue, obesity is a pathological condition in which ghrelin expression is changed in all tissues.

  18. Peripheral ghrelin interacts with orexin neurons in glucostatic signalling.

    PubMed

    Solomon, Andrew; De Fanti, Brant A; Martínez, J Alfredo

    2007-12-04

    Ghrelin interactions with glycemia in appetite control as well as the potential mechanisms involving the orexin and melanin-concentrating hormone (MCH) neurons in the orexigenic ghrelin signals were investigated by using a specific anti-ghrelin antibody (AGA). Our results confirm that peripheral ghrelin is an important signal in meal initiation and appetite. Employing immunohistochemistry techniques, we found that c-fos positive neurons in the lateral hypothalamus (LH) and perifornical area (PFA) increased after insulin or 2-deoxyglucose administration. Moreover, we have also demonstrated that peripheral ghrelin blockade by the AGA, reduces the orexigenic signal induced by insulin and 2-DG administration probably partly producing a decrease of c-fos immunoreactivity in the LH and PFA as well as a lower activation of orexin neurons. In contrast, the c-fos positive MCH neurons were not apparently affected. In summary, our findings suggest that peripheral ghrelin plays an important role in regulatory "glucostatic" feeding mechanisms by means of its role as a "hunger" signal affecting the LH and PFA areas, which may contribute to energy homeostasis through orexin neurons.

  19. 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

  20. A ghrelin-growth hormone axis drives stress-induced vulnerability to enhanced fear

    PubMed Central

    Meyer, Retsina M.; Burgos-Robles, Anthony; Liu, Elizabeth; Correia, Susana S.; Goosens, Ki A.

    2014-01-01

    Hormones in the hypothalamus-pituitary-adrenal (HPA) axis mediate many of the bodily responses to stressors, yet there is not a clear relationship between the levels of these hormones and stress-associated mental illnesses such as post-traumatic stress disorder (PTSD). Therefore, other hormones are likely to be involved in this effect of stress. Here we used a rodent model of PTSD in which rats repeatedly exposed to a stressor display heightened fear learning following auditory Pavlovian fear conditioning. Our results show that stress-related increases in circulating ghrelin, a peptide hormone, are necessary and sufficient for stress-associated vulnerability to exacerbated fear learning and these actions of ghrelin occur in the amygdala. Importantly, these actions are also independent of the classic HPA stress axis. Repeated systemic administration of a ghrelin receptor agonist enhanced fear memory but did not increase either corticotropin releasing factor (CRF) or corticosterone. Repeated intra-amygdala infusion of a ghrelin receptor agonist produced a similar enhancement of fear memory. Ghrelin receptor antagonism during repeated stress abolished stress-related enhancement of fear memory without blunting stress-induced corticosterone release. We also examined links between ghrelin and growth hormone (GH), a major downstream effector of the ghrelin receptor. GH protein was upregulated in the amygdala following chronic stress, and its release from amygdala neurons was increased by ghrelin receptor stimulation. Virus-mediated overexpression of GH in the amygdala was also sufficient to increase fear. Finally, virus-mediated overexpression of a GH receptor antagonist was sufficient to block the fear enhancing effects of repeated ghrelin receptor stimulation. Thus, ghrelin requires GH in the amygdala to exert fear-enhancing effects. These results suggest that ghrelin mediates a novel branch of the stress response and highlight a previously unrecognized role for ghrelin

  1. The Influence of Ghrelin on the Development of Dextran Sodium Sulfate-Induced Colitis in Rats.

    PubMed

    Matuszyk, Aleksandra; Ceranowicz, Dagmara; Warzecha, Zygmunt; Ceranowicz, Piotr; Fyderek, Krzysztof; Gałązka, Krystyna; Cieszkowski, Jakub; Bonior, Joanna; Jaworek, Jolanta; Pihut, Małgorzata; Dembiński, Artur

    2015-01-01

    Ghrelin has protective and therapeutic effects in the gut. The aim of present studies was to investigate the effect of treatment with ghrelin on the development of colitis evoked by dextran sodium sulfate (DSS). Methods. Studies have been performed on rats. Colitis was induced by adding 5% DSS to the drinking water for 5 days. During this period animals were treated intraperitoneally twice a day with saline or ghrelin given at the dose of 8 nmol/kg/dose. On the sixth day, animals were anesthetized and the severity of colitis was assessed. Results. Treatment with ghrelin during administration of DSS reduced the development of colitis. Morphological features of colonic mucosa exhibited a reduction in the area and deep of mucosal damage. Ghrelin reversed the colitis-induced decrease in blood flow, DNA synthesis, and superoxide dismutase activity in colonic mucosa. These effects were accompanied by a decrease in the colitis-evoked increase in mucosal concentration of interleukin-1β and malondialdehyde. Treatment with ghrelin reversed the DSS-induced reduction in body weight gain. Conclusions. Administration of ghrelin exhibits the preventive effect against the development of DSS-induced colitis. This effect seems to be related to ghrelin's anti-inflammatory and antioxidative properties.

  2. The Influence of Ghrelin on the Development of Dextran Sodium Sulfate-Induced Colitis in Rats

    PubMed Central

    Matuszyk, Aleksandra; Ceranowicz, Dagmara; Warzecha, Zygmunt; Ceranowicz, Piotr; Fyderek, Krzysztof; Gałązka, Krystyna; Cieszkowski, Jakub; Bonior, Joanna; Jaworek, Jolanta; Pihut, Małgorzata; Dembiński, Artur

    2015-01-01

    Ghrelin has protective and therapeutic effects in the gut. The aim of present studies was to investigate the effect of treatment with ghrelin on the development of colitis evoked by dextran sodium sulfate (DSS). Methods. Studies have been performed on rats. Colitis was induced by adding 5% DSS to the drinking water for 5 days. During this period animals were treated intraperitoneally twice a day with saline or ghrelin given at the dose of 8 nmol/kg/dose. On the sixth day, animals were anesthetized and the severity of colitis was assessed. Results. Treatment with ghrelin during administration of DSS reduced the development of colitis. Morphological features of colonic mucosa exhibited a reduction in the area and deep of mucosal damage. Ghrelin reversed the colitis-induced decrease in blood flow, DNA synthesis, and superoxide dismutase activity in colonic mucosa. These effects were accompanied by a decrease in the colitis-evoked increase in mucosal concentration of interleukin-1β and malondialdehyde. Treatment with ghrelin reversed the DSS-induced reduction in body weight gain. Conclusions. Administration of ghrelin exhibits the preventive effect against the development of DSS-induced colitis. This effect seems to be related to ghrelin's anti-inflammatory and antioxidative properties. PMID:26713317

  3. Mice lacking ghrelin receptors resist the development of diet-induced obesity

    PubMed Central

    Zigman, Jeffrey M.; Nakano, Yoshihide; Coppari, Roberto; Balthasar, Nina; Marcus, Jacob N.; Lee, Charlotte E.; Jones, Juli E.; Deysher, Amy E.; Waxman, Amanda R.; White, Ryan D.; Williams, Todd D.; Lachey, Jennifer L.; Seeley, Randy J.; Lowell, Bradford B.; Elmquist, Joel K.

    2005-01-01

    Ghrelin is the endogenous ligand for the growth hormone secretagogue receptor (GHSR; ghrelin receptor). Since its discovery, accumulating evidence has suggested that ghrelin may play a role in signaling and reversing states of energy insufficiency. For example, ghrelin levels rise following food deprivation, and ghrelin administration stimulates feeding and increases body weight and adiposity. However, recent loss-of-function studies have raised questions regarding the physiological significance of ghrelin in regulating these processes. Here, we present results of a study using a novel GHSR-null mouse model, in which ghrelin administration fails to acutely stimulate food intake or activate arcuate nucleus neurons. We show that when fed a high-fat diet, both female and male GHSR-null mice eat less food, store less of their consumed calories, preferentially utilize fat as an energy substrate, and accumulate less body weight and adiposity than control mice. Similar effects on body weight and adiposity were also observed in female, but not male, GHSR-null mice fed standard chow. GHSR deletion also affected locomotor activity and levels of glycemia. These findings support the hypothesis that ghrelin-responsive pathways are an important component of coordinated body weight control. Moreover, our data suggest that ghrelin signaling is required for development of the full phenotype of diet-induced obesity. PMID:16322794

  4. Nitric oxide mediates Fos expression in the spinal cord induced by mechanical noxious stimulation.

    PubMed

    Lee, J H; Wilcox, G L; Beitz, A J

    1992-10-01

    Immunocytochemical localization of Fos protein was used to analyze the involvement of nitric oxide (NO) in the expression of Fos in the spinal cord, induced by mechanical noxious stimulation (NS). Mechanical NS was applied to the left hindpaw 30 minutes after intrathecal administration of the NO synthase inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME) and the resulting Fos expression in the spinal cord dorsal horn was compared with that obtained in rats exposed only to the mechanical NS. Pretreatment with L-NAME but not its stereoisomer N omega-nitro-D-arginine methyl ester (D-NAME), produced a dose-dependent suppression of Fos expression induced by mechanical noxious stimulation. These results indicate that NO modulates the expression of Fos in the dorsal horn induced by mechanical noxious stimulation and further support the hypothesis that NO is involved in nociceptive events occurring in the spinal cord in response to a peripheral noxious stimulus.

  5. Ghrelin induces abdominal obesity via GHS-R-dependent lipid retention.

    PubMed

    Davies, Jeffrey S; Kotokorpi, Pia; Eccles, Sinan R; Barnes, Sarah K; Tokarczuk, Pawel F; Allen, Sophie K; Whitworth, Hilary S; Guschina, Irina A; Evans, Bronwen A J; Mode, Agneta; Zigman, Jeffrey M; Wells, Timothy

    2009-06-01

    Circulating ghrelin elevates abdominal adiposity by a mechanism independent of its central orexigenic activity. In this study we tested the hypothesis that peripheral ghrelin induces a depot-specific increase in white adipose tissue (WAT) mass in vivo by GH secretagogue receptor (GHS-R(1a))-mediated lipolysis. Chronic iv infusion of acylated ghrelin increased retroperitoneal and inguinal WAT volume in rats without elevating superficial sc fat, food intake, or circulating lipids and glucose. Increased retroperitoneal WAT mass resulted from adipocyte enlargement probably due to reduced lipid export (ATP-binding cassette transporter G1 mRNA expression and circulating free fatty acids were halved by ghrelin infusion). In contrast, ghrelin treatment did not up-regulate biomarkers of adipogenesis (peroxisome proliferator-activated receptor-gamma2 or CCAAT/enhancer binding protein-alpha) or substrate uptake (glucose transporter 4, lipoprotein lipase, or CD36) and although ghrelin elevated sterol-regulatory element-binding protein 1c expression, WAT-specific mediators of lipogenesis (liver X receptor-alpha and fatty acid synthase) were unchanged. Adiposity was unaffected by infusion of unacylated ghrelin, and the effects of acylated ghrelin were abolished by transcriptional blockade of GHS-R(1a), but GHS-R(1a) mRNA expression was similar in responsive and unresponsive WAT. Microarray analysis suggested that depot-specific sensitivity to ghrelin may arise from differential fine tuning of signal transduction and/or lipid-handling mechanisms. Acylated ghrelin also induced hepatic steatosis, increasing lipid droplet number and triacylglycerol content by a GHS-R(1a)-dependent mechanism. Our data imply that, during periods of energy insufficiency, exposure to acylated ghrelin may limit energy utilization in specific WAT depots by GHS-R(1a)-dependent lipid retention.

  6. 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}.

  7. 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.

  8. 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.

  9. Ghrelin reduces rat myocardial calcification induced by nicotine and vitamin D3 in vivo.

    PubMed

    Wang, Fei; Jiang, Tao; Tang, Chaoshu; Su, Zijie; Zhang, Nong; Li, Guizhong

    2011-10-01

    Ghrelin, a newly discovered bioactive peptide, initially was identified as a strong stimulant for the release of growth hormone (GH) and that has improved cardiac function in patients suffering from end-stage chronic heart failure. Increasing evidence has demonstrated that ghrelin may have myocardial protective effects. However, the role of ghrelin in the pathogenesis of cardiovascular diseases remains unclear. In this study, an in vivo model of rat myocardial calcification induced by vitamin D3 and nicotine was used to study the possible mechanism in the regulatory action of ghrelin on the calcified myocardium. Calcification increased total Ca2+ content and 45Ca2+ deposition in the myocardium and alkaline phosphatase (ALP) activation in the plasma. Compared with the control group, ghrelin mRNA expression was up-regulated and the myocardium calcium content was significantly increased in vitamin D3 and nicotine-treated rats. Rats were subcutaneously injected with 1 or 10 nmol/kg ghrelin. Rats treated with both low- and high-dose ghrelin decreased total Ca2+ content and 45Ca2+ deposition in cardiac muscle and inhibited ALP activation in the myocardium and plasma, in a concentration-dependent manner. In addition, osteopontin (OPN) mRNA expression significantly decreased and that of endothelin (ET-1) significantly increased with myocardial calcification. Ghrelin treatment increased OPN expression at the mRNA level and reduced ET-1 mRNA expression in a dose-dependent manner. These results indicate that exogenous administration with ghrelin attenuates myocardial calcification induced by nicotine and vitamin D3, and that the possible mechanism is via the ghrelin-induced increase in the OPN mRNA levels and decrease in the ET-1 mRNA expression in the myocardium.

  10. 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

  11. 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

    2016-09-01

    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.

  12. Therapeutic effect of ghrelin in the course of cerulein-induced acute pancreatitis in rats.

    PubMed

    Warzecha, Z; Ceranowicz, P; Dembinski, A; Cieszkowski, J; Kusnierz-Cabala, B; Tomaszewska, R; Kuwahara, A; Kato, I

    2010-08-01

    Recent studies have shown that pretreatment with ghrelin exhibits protective effect in the gut. Administration of ghrelin reduces gastric mucosal damage, as well as inhibits the development of experimental pancreatitis. However, this protective effect requires administration of ghrelin before gastric or pancreatic damage and thus has a limited clinical value. The aim of present study was to assess the influence of ghrelin administered after development of acute pancreatitis on the course of this disease. Acute pancreatitis was induced by cerulein. Ghrelin was administered twice a day for 1, 2, 4, 6 or 9 days at the dose of 4, 8 or 16 nmol/kg/dose. The first dose of ghrelin was given 24 hours after last injection of cerulein. The severity of acute pancreatitis was assessed between 0 h and 10 days after cessation of cerulein administration. Administration of caerulein led to the development of acute edematous pancreatitis and maximal severity of this disease was observed 24 hours after induction of pancreatitis. Treatment with ghrelin reduced morphological signs of pancreatic damage such as pancreatic edema, leukocyte infiltration and vacuolization of acinar cells, and led to earlier regeneration of the pancreas. Also biochemical indexes of the severity of acute pancreatitis, serum activity of lipase and amylase were significantly reduced in animals treated with ghrelin. These effects were accompanied by an increase in the pancreatic DNA synthesis and a decrease in serum level of pro-inflammatory interleukin-1b. Administration of ghrelin improved pancreatic blood flow in rats with acute pancreatitis. We conclude that: (1) treatment with ghrelin exhibits therapeutic effect in caerulein-induced experimental acute pancreatitis; (2) this effect is related, at least in part, to the improvement of pancreatic blood flow, reduction in proinflammatory interleukin-1beta and stimulation of pancreatic cell proliferation.

  13. Ghrelin improves delayed gastrointestinal transit in alloxan-induced diabetic mice.

    PubMed

    Qiu, Wen-Cai; Wang, Zhi-Gang; Lv, Ran; Wang, Wei-Gang; Han, Xiao-Dong; Yan, Jun; Wang, Yu; Zheng, Qi; Ai, Kai-Xing

    2008-04-28

    To investigate the effects of ghrelin on delayed gastrointestinal transit in alloxan-induced diabetic mice. A diabetic mouse model was established by intraperitoneal injection with alloxan. Mice were randomized into two main groups: normal mice group and diabetic mice group treated with ghrelin at doses of 0, 20, 50, 100 and 200 mug/kg ip. Gastric emptying (GE), intestinal transit (IT), and colonic transit (CT) were studied in mice after they had a phenol red meal following injection of ghrelin. Based on the most effective ghrelin dosage, atropine was given at 1 mg/kg 15 min before the ghrelin injection for each measurement. The mice in each group were sacrificed 20 min later and their stomachs, intestines, and colons were harvested immediately. The amount of phenol red was measured. Percentages of GE, IT, and CT were calculated. Percentages of GE, IT, and CT were significantly decreased in diabetic mice as compared to control mice (22.9 +/- 1.4 vs 28.1 +/- 1.3, 33.5 +/- 1.2 vs 43.2 +/- 1.9, 29.5 +/- 1.9 vs 36.3 +/- 1.6, P < 0.05). In the diabetic mice, ghrelin improved both GE and IT, but not CT. The most effective dose of ghrelin was 100 mug/kg and atropine blocked the prokinetic effects of ghrelin on GE and IT. Ghrelin accelerates delayed GE and IT but has no effect on CT in diabetic mice. Ghrelin may exert its prokinetic effects via the cholinergic pathway in the enteric nervous system, and therefore has therapeutic potential for diabetic patients with delayed upper gastrointestinal transit.

  14. Striatal overexpression of ΔFosB reproduces chronic levodopa-induced involuntary movements

    PubMed Central

    Cao, Xuebing; Yasuda, Toru; Uthayathas, Subramaniam; Watts, Ray L.; Mouradian, M. Maral; Mochizuki, Hideki; Papa, Stella M.

    2010-01-01

    Long-term dopamine replacement therapy in Parkinson’s disease leads to the development of disabling involuntary movements named dyskinesias that are related to adaptive changes in striatal signaling pathways. The chronic transcription factor ΔFosB, which is overexpressed in striatal neurons after chronic dopaminergic drug exposure, is suspected to mediate these adaptive changes. Here, we sought to demonstrate the ability of ΔFosB to lead directly to the abnormal motor responses associated with chronic dopaminergic therapy. Using rAAV viral vectors, high levels of ΔFosB expression were induced in the striatum of dopamine-denervated rats naïve of chronic drug administration. Transgenic ΔFosB overexpression reproduced the entire spectrum of altered motor behaviors in response to acute levodopa tests, including different types of abnormal involuntary movements and hypersensitivity of rotational responses that are typically associated with chronic levodopa treatment. JunD, the usual protein partner of ΔFosB binding to AP-1 sites of genes, remained unchanged in rats with high ΔFosB expression induced by viral vectors. These findings demonstrate that the increase of striatal ΔFosB in the evolution of chronically treated Parkinson’s disease may be a trigger for the development of abnormal responsiveness to dopamine and the emergence of involuntary movements. PMID:20505100

  15. Ghrelin Protects against Renal Damages Induced by Angiotensin-II via an Antioxidative Stress Mechanism in Mice

    PubMed Central

    Fujimura, Keiko; Wakino, Shu; Minakuchi, Hitoshi; Hasegawa, Kazuhiro; Hosoya, Koji; Komatsu, Motoaki; Kaneko, Yuka; Shinozuka, Keisuke; Washida, Naoki; Kanda, Takeshi; Tokuyama, Hirobumi; Hayashi, Koichi; Itoh, Hiroshi

    2014-01-01

    We explored the renal protective effects by a gut peptide, Ghrelin. Daily peritoneal injection with Ghrelin ameliorated renal damages in continuously angiotensin II (AngII)-infused C57BL/6 mice as assessed by urinary excretion of protein and renal tubular markers. AngII-induced increase in reactive oxygen species (ROS) levels and senescent changes were attenuated by Ghrelin. Ghrelin also inhibited AngII-induced upregulations of transforming growth factor-β (TGF-β) and plasminogen activator inhibitor-1 (PAI-1), ameliorating renal fibrotic changes. These effects were accompanied by concomitant increase in mitochondria uncoupling protein, UCP2 as well as in a key regulator of mitochondria biosynthesis, PGC1α. In renal proximal cell line, HK-2 cells, Ghrelin reduced mitochondria membrane potential and mitochondria-derived ROS. The transfection of UCP2 siRNA abolished the decrease in mitochondria-derived ROS by Ghrelin. Ghrelin ameliorated AngII-induced renal tubular cell senescent changes and AngII-induced TGF-β and PAI-1 expressions. Finally, Ghrelin receptor, growth hormone secretagogue receptor (GHSR)-null mice exhibited an increase in tubular damages, renal ROS levels, renal senescent changes and fibrosis complicated with renal dysfunction. GHSR-null mice harbored elongated mitochondria in the proximal tubules. In conclusion, Ghrelin suppressed AngII-induced renal damages through its UCP2 dependent anti-oxidative stress effect and mitochondria maintenance. Ghrelin/GHSR pathway played an important role in the maintenance of ROS levels in the kidney. PMID:24747517

  16. A Significant Role of the Truncated Ghrelin Receptor GHS-R1b in Ghrelin-induced Signaling in Neurons.

    PubMed

    Navarro, Gemma; Aguinaga, David; Angelats, Edgar; Medrano, Mireia; Moreno, Estefanía; Mallol, Josefa; Cortés, Antonio; Canela, Enric I; Casadó, Vicent; McCormick, Peter J; Lluís, Carme; Ferré, Sergi

    2016-06-17

    The truncated non-signaling ghrelin receptor growth hormone secretagogue R1b (GHS-R1b) has been suggested to simply exert a dominant negative role in the trafficking and signaling of the full and functional ghrelin receptor GHS-R1a. Here we reveal a more complex modulatory role of GHS-R1b. Differential co-expression of GHS-R1a and GHS-R1b, both in HEK-293T cells and in striatal and hippocampal neurons in culture, demonstrates that GHS-R1b acts as a dual modulator of GHS-R1a function: low relative GHS-R1b expression potentiates and high relative GHS-R1b expression inhibits GHS-R1a function by facilitating GHS-R1a trafficking to the plasma membrane and by exerting a negative allosteric effect on GHS-R1a signaling, respectively. We found a preferential Gi/o coupling of the GHS-R1a-GHS-R1b complex in HEK-293T cells and, unexpectedly, a preferential Gs/olf coupling in both striatal and hippocampal neurons in culture. A dopamine D1 receptor (D1R) antagonist blocked ghrelin-induced cAMP accumulation in striatal but not hippocampal neurons, indicating the involvement of D1R in the striatal GHS-R1a-Gs/olf coupling. Experiments in HEK-293T cells demonstrated that D1R co-expression promotes a switch in GHS-R1a-G protein coupling from Gi/o to Gs/olf, but only upon co-expression of GHS-R1b. Furthermore, resonance energy transfer experiments showed that D1R interacts with GHS-R1a, but only in the presence of GHS-R1b. Therefore, GHS-R1b not only determines the efficacy of ghrelin-induced GHS-R1a-mediated signaling but also determines the ability of GHS-R1a to form oligomeric complexes with other receptors, promoting profound qualitative changes in ghrelin-induced signaling. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Peripheral ghrelin participates in glucostatic feeding mechanisms and in the anorexigenic signalling mediated by CART and CRF neurons.

    PubMed

    Solomon, Andrew; De Fanti, Brant A; Martínez, J Alfredo

    2005-01-01

    Ghrelin is upregulated under negative energy balance conditions, including starvation and hypoglycemia, while it is downregulated under situations of positive energy balance, such as feeding, hyperglycemia and obesity. The aims of this study were to assess potential ghrelin interactions with glucose levels in appetite control and to identify potential mechanisms involving orexigenic and anorexigenic ghrelin mediated signals by using a specific anti-ghrelin antibody. Our results confirm that peripheral ghrelin is an important signal in meal initiation and food intake stimulation. C-fos positive neurons in the PVN increased after insulin or 2-deoxyglucose administration. Moreover, we also demonstrate that peripheral ghrelin blockade with a specific anti-ghrelin antibody reduces, in part, the orexigenic signal induced by insulin and 2-DG administration. Furthermore, when we blocked peripheral ghrelin, c-fos positive CRF neurons and CART expression increased in the PVN, both under hypoglycemia or cytoglycopenia conditions, suggesting a neuronal activation (anorexigenic signalling) in this hypothalamic region. In summary, our findings imply that peripheral ghrelin plays an important role in regulatory "glucostatic" feeding mechanisms due to its role as a "hunger" signal affecting the PVN area, which may contribute to energy homeostasis through both orexigenic/anorexigenic pathways.

  18. Fos expression induced by cocaine-conditioned cues in male and female rats

    PubMed Central

    Zhou, Luyi; Pruitt, Carla; Shin, Christina B.; Garcia, Arturo D.; Zavala, Arturo R.; See, Ronald E.

    2013-01-01

    Previous studies have shown that female rats exhibit different patterns of drug seeking during multiple phases of cocaine addiction when compared with males. However, the underlying mechanisms for these sex differences remain largely unknown. Here, we used a cocaine self-administration/reinstatement model to examine neuronal activation, as determined by Fos expression, following cue-induced reinstatement of cocaine seeking in male and female rats. Fos expression revealed both similarities between sexes in some brain regions, as well as selective sexually dimorphic patterns. As compared to no cue control subjects, conditioned cues induced higher Fos expression in the Cg1 region of the anterior cingulate cortex, but lower expression in the nucleus accumbens in both males and females. Females exhibited higher Fos expression than males in multiple brain regions, including the agranular insular cortex, dorsal medial caudate-putamen, nucleus accumbens shell, ventral tegmental area, dorsal subiculum, and ventral CA1 and CA3 regions of the hippocampus. Notably, only Fos expression in the prelimbic cortex, nucleus accumbens shell, basolateral amygdala, and ventral subiculum correlated positively with lever responding in response to conditioned cues across males and females. These findings indicate that while sexually dimorphic Fos activation does occur, the relationship between cue-induced cocaine seeking and neuronal activation may be similar for males and females in key brain regions of the relapse circuit. PMID:23832598

  19. Fos expression induced by cocaine-conditioned cues in male and female rats.

    PubMed

    Zhou, Luyi; Pruitt, Carla; Shin, Christina B; Garcia, Arturo D; Zavala, Arturo R; See, Ronald E

    2014-09-01

    Previous studies have shown that female rats exhibit different patterns of drug seeking during multiple phases of cocaine addiction when compared with males. However, the underlying mechanisms for these sex differences remain largely unknown. Here, we used a cocaine self-administration/reinstatement model to examine neuronal activation, as determined by Fos expression, following cue-induced reinstatement of cocaine seeking in male and female rats. Fos expression revealed both similarities between sexes in some brain regions, as well as selective sexually dimorphic patterns. As compared to no cue control subjects, conditioned cues induced higher Fos expression in the Cg1 region of the anterior cingulate cortex, but lower expression in the nucleus accumbens in both males and females. Females exhibited higher Fos expression than males in multiple brain regions, including the agranular insular cortex, dorsal medial caudate-putamen, nucleus accumbens shell, ventral tegmental area, dorsal subiculum, and ventral CA1 and CA3 regions of the hippocampus. Notably, only Fos expression in the prelimbic cortex, nucleus accumbens shell, basolateral amygdala, and ventral subiculum correlated positively with lever responding in response to conditioned cues across males and females. These findings indicate that while sexually dimorphic Fos activation does occur, the relationship between cue-induced cocaine seeking and neuronal activation may be similar for males and females in key brain regions of the relapse circuit.

  20. Intrastriatal DNQX induces rotation and pallidal Fos in the 6-OHDA model of Parkinson's disease.

    PubMed

    Schuller, J J; Marshall, J F

    1995-12-15

    The 6-hydroxydopamine rat model of Parkinson's disease was combined with intracerebral drug infusions to examine the influence of glutamate receptors on striatal output activity. When infused into the dopamine-denervated striatum, the AMPA-kainate receptor antagonist DNQX dose-dependently elicited contralateral rotation and ipsilateral Fos immunoreactivity (Fos-IR) in the globus pallidus, a target nucleus of striatal output. DNQX did not elicit rotation or Fos-IR in unlesioned or partially lesioned rats. In addition, the NMDA receptor antagonist AP-5 failed to induce rotation and had minimal effects on pallidal Fos-IR in lesioned rats. These results suggest a role for striatal AMPA-kainate receptors in the pathology and treatment of Parkinson's disease.

  1. Propofol inhibits ketamine-induced c-fos expression in the rat posterior cingulate cortex.

    PubMed

    Nagata, A; Nakao, S; Miyamoto, E; Inada, T; Tooyama, I; Kimura, H; Shingu, K

    1998-12-01

    Ketamine, a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, has psychotomimetic activity. NMDA receptor antagonists cause morphological damage in the posterior cingulate cortex, which may be the brain region responsible for their psychotomimetic effects. Benzodiazepines are effective in preventing these effects through gamma-aminobutyric acid A (GABA(A)) receptor activation. We investigated the effect of propofol, which has both GABAA receptor-activating and NMDA receptor-suppressing activity, on ketamine-induced c-fos expression in the rat posterior cingulate cortex. Propofol or vehicle was continuously infused IV. Fifteen minutes later, 100 mg/kg ketamine or isotonic sodium chloride solution was injected intraperitoneally. Two hours later, brain sections were prepared, and c-fos expression was detected using immunohistochemical methods. Propofol significantly inhibited ketamine-induced c-fos expression in the posterior cingulate cortex. Propofol itself did not induce c-fos expression in this brain region. We conclude that propofol may be able to inhibit ketamine-induced psychotomimetic activity and neuronal damage. In the present study, we demonstrated that the clinically relevant dose of propofol significantly inhibited ketamine-induced c-fos expression in the rat posterior cingulate cortex. This finding implies that propofol may inhibit ketamine-induced psychotomimetic activity and neuronal damage.

  2. Ghrelin inhibits LPS-induced release of IL-6 from mouse dopaminergic neurones

    PubMed Central

    2013-01-01

    Background Ghrelin is an orexigenic stomach hormone that acts centrally to increase mid-brain dopamine neurone activity, amplify dopamine signaling and protect against neurotoxin-induced dopamine cell death in the mouse substantia nigra pars compacta (SNpc). In addition, ghrelin inhibits the lipopolysaccharide (LPS)-induced release of pro-inflammatory cytokines from peripheral macrophages, T-cells and from LPS stimulated microglia. Here we sought to determine whether ghrelin attenuates pro-inflammatory cytokine release from dopaminergic neurones. Findings The dopaminergic SN4741 cell-line, which derives from the mouse substantia nigra (SN) and expresses the ghrelin-receptor (growth hormone secretagogue receptor (GHS-R)) and the ghrelin-O-acyl transferase (GOAT) enzyme, was used to determine the neuro-immunomodulatory action of ghrelin. We induced innate immune activation via LPS challenge (1 μg/ml) of SN4741 neurones that had been pre-cultured in the presence or absence of ghrelin (1, 10, 100 nM) for 4 h. After 24 h supernatants were collected for detection of IL-1 beta (IL-1β ), TNF alpha (TNF-α) and IL-6 cytokines via enzyme linked immunosorbent assay (ELISA) analysis. Nuclear translocation of the transcription factor nuclear factor kappa B (NF-κB) was analyzed by Western blotting, and to determine viability of treatments a cell viability assay and caspase-3 immunohistochemistry were performed. We provide evidence that while IL-1β and TNF-α were not detectable under any conditions, SN4741 neurones constitutively released IL-6 under basal conditions and treatment with LPS significantly increased IL-6 secretion. Pre-treatment of neurones with ghrelin attenuated LPS-mediated IL-6 release at 24 h, an affect that was inhibited by the GHS-R antagonist [D-Lys3]-GHRP-6. However, while ghrelin pre-treatment attenuated the LPS-mediated increase in NF-κB, there was no alteration in its nuclear translocation. Cell viability assay and caspase-3 immunocytochemistry

  3. Ghrelin inhibits LPS-induced release of IL-6 from mouse dopaminergic neurones.

    PubMed

    Beynon, Amy L; Brown, M Rowan; Wright, Rhiannon; Rees, Mark I; Sheldon, I Martin; Davies, Jeffrey S

    2013-03-19

    Ghrelin is an orexigenic stomach hormone that acts centrally to increase mid-brain dopamine neurone activity, amplify dopamine signaling and protect against neurotoxin-induced dopamine cell death in the mouse substantia nigra pars compacta (SNpc). In addition, ghrelin inhibits the lipopolysaccharide (LPS)-induced release of pro-inflammatory cytokines from peripheral macrophages, T-cells and from LPS stimulated microglia. Here we sought to determine whether ghrelin attenuates pro-inflammatory cytokine release from dopaminergic neurones. The dopaminergic SN4741 cell-line, which derives from the mouse substantia nigra (SN) and expresses the ghrelin-receptor (growth hormone secretagogue receptor (GHS-R)) and the ghrelin-O-acyl transferase (GOAT) enzyme, was used to determine the neuro-immunomodulatory action of ghrelin. We induced innate immune activation via LPS challenge (1 μg/ml) of SN4741 neurones that had been pre-cultured in the presence or absence of ghrelin (1, 10, 100 nM) for 4 h. After 24 h supernatants were collected for detection of IL-1 beta (IL-1β ), TNF alpha (TNF-α) and IL-6 cytokines via enzyme linked immunosorbent assay (ELISA) analysis. Nuclear translocation of the transcription factor nuclear factor kappa B (NF-κB) was analyzed by Western blotting, and to determine viability of treatments a cell viability assay and caspase-3 immunohistochemistry were performed.We provide evidence that while IL-1β and TNF-α were not detectable under any conditions, SN4741 neurones constitutively released IL-6 under basal conditions and treatment with LPS significantly increased IL-6 secretion. Pre-treatment of neurones with ghrelin attenuated LPS-mediated IL-6 release at 24 h, an affect that was inhibited by the GHS-R antagonist [D-Lys3]-GHRP-6. However, while ghrelin pre-treatment attenuated the LPS-mediated increase in NF-κB, there was no alteration in its nuclear translocation. Cell viability assay and caspase-3 immunocytochemistry demonstrated that the

  4. Clitoral stimulation induces conditioned place preference and Fos activation in the rat.

    PubMed

    Parada, Mayte; Chamas, Liliane; Censi, Sabrina; Coria-Avila, Genaro; Pfaus, James G

    2010-02-01

    The present study examined the ability of clitoral stimulation (CLS) to induce conditioned place preference (CPP) and Fos protein in the brain. Ovariectomized, hormone-primed Long-Evans rats were randomly assigned to receive either distributed CLS (1 stimulation every 5 s for 1 min prior to being placed in one distinctive side of a nonbiased CPP box for 2 min, after which the cycle of stimulation and CPP exposure were repeated for 4 more cycles, totaling 60 stimulations) or continuous CLS (1 stimulation per second for 1 min with 2 min in one side of the CPP box, repeated for 4 more cycles, totaling 300 stimulations). Two days later, females were placed into the other side of the CPP box without prior stimulation. CPP was tested after 5 sequential exposures each of CLS and no stimulation. Females given distributed stimulation developed a significant CPP whereas females given continuous stimulation did not. CLS induced Fos in hypothalamic and limbic structures, including the nucleus accumbens, piriform cortex, arcuate nucleus, and dorsomedial portion of the ventromedial hypothalamus, compared to no stimulation. However, distributed CLS induced more Fos in the medial preoptic area than continuous CLS or no stimulation. In contrast, continuous CLS induced more Fos in the posteroventral medial amygdala compared to no stimulation. These data indicate that CLS induces a reward state in the rat and a pattern of Fos activation in regions of the brain that process genitosensory input, incentive salience, and reward. Copyright 2009 Elsevier Inc. All rights reserved.

  5. 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.

  6. 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.

  7. 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

  8. The atypical dopamine D1 receptor agonist SKF 83959 induces striatal Fos expression in rats.

    PubMed

    Wirtshafter, David; Osborn, Catherine V

    2005-12-28

    The effects of dopamine D1 receptor agonists are often presumed to result from an activation of adenylyl cyclase, but dopamine D1 receptors may also be linked to other signal transduction cascades and the relative importance of these various pathways is currently unclear. SKF 83959 is an agonist at dopamine D1 receptors linked to phospholipase C, but has been reported to be an antagonist at receptors linked to adenylyl cyclase. The current report demonstrates that SKF 83959 induces pronounced, nonpatchy, expression of the immediate-early gene product Fos in the striatum of intact rats which can be converted to a patchy pattern by pretreatment with the dopamine D2-like receptor agonist quinpirole. In rats with unilateral 6-hydroxydopamine lesions SKF 83959 induces strong behavioral rotation and a greatly potentiated Fos response. All of the responses to SKF 83959, in both intact and dopamine-depleted animals, can be blocked by pretreatment with the dopamine D1 receptor antagonist SCH-23390. In intact subjects, SKF 83959 induced Fos expression less potently than the standard dopamine D1 receptor agonist SKF 82958, but the two drugs were approximately equipotent in deinnervated animals. These results demonstrate for the first time that possession of full efficacy at dopamine D1 receptors linked to adenylyl cyclase is not a necessary requirement for the induction of striatal Fos expression in intact animals and suggest that alternative signal transduction pathways may play a role in dopamine agonist induced Fos expression, especially in dopamine-depleted subjects.

  9. Ghrelin ameliorates the human alveolar epithelial A549 cell apoptosis induced by lipopolysaccharide

    SciTech Connect

    Huang, Chunrong; Zheng, Haichong; He, Wanmei; Lu, Guifang; Li, Xia; Deng, Yubin; Zeng, Mian

    2016-05-20

    Ghrelin is a gastric acyl-peptide that plays an inhibitory role in cell apoptosis. Herein we investigate the protective effects of ghrelin in LPS-induced apoptosis of human alveolar epithelial A549 cells, along with the possible molecular mechanisms. LPS exposure impaired cell viability and increased apoptosis of A549 cells significantly in concentration- and time-dependent manners embodied in increased Bax and cleaved caspase-3 production, coupled with decreased Bcl-2 levels. Simultaneously, LPS remarkably decreased the expression of phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) and extracellular signal-regulated kinas (ERK) in A549 cells. However, ghrelin'pretreatment ameliorated LPS-caused alterations in the ratio of Bax/Bcl-2 and cleaved caspase-3 expression, whereas activated the PI3K/Akt and ERK signaling. These results demonstrate that ghrelin lightens LPS-induced apoptosis of human alveolar epithelial cells partly through activating the PI3K/Akt and ERK pathway and thereby might benefit alleviating septic ALI. -- Graphical abstract: Ghrelin ameliorates the human alveolar epithelial A549 cells apoptosis induced by lipopolysaccharide partly through activating the PI3K/Akt and ERK pathway. Display Omitted -- Highlights: •It has been observed that LPS insult significantly increased apoptosis in A549 cells. •Both Akt and ERK signaling are critical adapter molecules to mediate the ghrelin-mediated proliferative effect. •Ghrelin may have a therapeutic effect in the prevention of LPS-induced apoptosis.

  10. Lipopolysaccharide induces delayed FosB/DeltaFosB immunostaining within the mouse extended amygdala, hippocampus and hypothalamus, that parallel the expression of depressive-like behavior

    PubMed Central

    Frenois, François; Moreau, Maïté; Connor, Jason O’; Lawson, Marc; Micon, Charlotte; Lestage, Jacques; Kelley, Keith W.; Dantzer, Robert; Castanon, Nathalie

    2007-01-01

    Proinflammatory cytokines induce both sickness behavior and depression, but their respective neurobiological correlates are still poorly understood. The aim of the present study was therefore to identify in mice the neural substrates of sickness and depressive-like behavior induced by lipopolysaccharide (LPS, 830 μg/kg, intraperitoneal). LPS-induced depressive-like behavior was dissociated from LPS-induced sickness by testing mice either at 6 h (at which time sickness was expected to be maximal) or at 24 h post-LPS (at which time sickness was expected to be minimal and not to bias the measurement of depressive-like behavior). Concurrently, the expression of acute and chronic cellular reactivity markers (c-Fos and FosB/ΔFosB respectively) was mapped by immunohistochemistry at these two time points. In comparison to saline, LPS decreased motor activity in a new cage at 6 but not at 24 h. In contrast, the duration of immobility in the tail suspension test was increased at both 6 and 24 h. This dissociation between decreased motor activity and depressive-like behavior was confirmed at 24 h post-LPS in the forced swim test. LPS also decreased sucrose consumption at 24 and 48 h, despite normal food and water consumption by that time. At 24 h post-LPS, LPS-induced depressive-like behavior was associated with a delayed cellular activity (as assessed by FosB/ΔFosB immunostaining) in specific brain structures, particularly within the extended amygdala, hippocampus and hypothalamus, whereas c-Fos labeling was markedly decreased by that time in all the brain areas at 6 h post-LPS. These results provide the first evidence in favor of a functional dissociation between the brain structures that underlie cytokine-induced sickness behavior and cytokine-induced depressive-like behavior, and provide important cues about the neuroanatomical brain circuits through which cytokines could have an impact on affect. PMID:17482371

  11. Ghrelin induces leptin resistance by activation of suppressor of cytokine signaling 3 expression in male rats: implications in satiety regulation.

    PubMed

    Heldsinger, Andrea; Grabauskas, Gintautas; Wu, Xiaoyin; Zhou, ShiYi; Lu, Yuanxu; Song, Il; Owyang, Chung

    2014-10-01

    The anorexigenic adipocyte-derived hormone leptin and the orexigenic hormone ghrelin act in opposition to regulate feeding behavior via the vagal afferent pathways. The mechanisms by which ghrelin exerts its inhibitory effects on leptin are unknown. We hypothesized that ghrelin activates the exchange protein activated by cAMP (Epac), inducing increased SOCS3 expression, which negatively affects leptin signal transduction and neuronal firing in nodose ganglia (NG) neurons. We showed that 91 ± 3% of leptin receptor (LRb) -bearing neurons contained ghrelin receptors (GHS-R1a) and that ghrelin significantly inhibited leptin-stimulated STAT3 phosphorylation in rat NG neurons. Studies of the signaling cascades used by ghrelin showed that ghrelin caused a significant increase in Epac and suppressor of cytokine signaling 3 (SOCS3) expression in cultured rat NG neurons. Transient transfection of cultured NG neurons to silence SOCS3 and Epac genes reversed the inhibitory effects of ghrelin on leptin-stimulated STAT3 phosphorylation. Patch-clamp studies and recordings of single neuronal discharges of vagal primary afferent neurons showed that ghrelin markedly inhibited leptin-stimulated neuronal firing, an action abolished by silencing SOCS3 expression in NG. Plasma ghrelin levels increased significantly during fasting. This was accompanied by enhanced SOCS3 expression in the NG and prevented by treatment with a ghrelin antagonist. Feeding studies showed that silencing SOCS3 expression in the NG reduced food intake evoked by endogenous leptin. We conclude that ghrelin exerts its inhibitory effects on leptin-stimulated neuronal firing by increasing SOCS3 expression. The SOCS3 signaling pathway plays a pivotal role in ghrelin's inhibitory effect on STAT3 phosphorylation, neuronal firing, and feeding behavior.

  12. Ghrelin Induces Leptin Resistance by Activation of Suppressor of Cytokine Signaling 3 Expression in Male Rats: Implications in Satiety Regulation

    PubMed Central

    Heldsinger, Andrea; Grabauskas, Gintautas; Wu, Xiaoyin; Zhou, ShiYi; Lu, Yuanxu; Song, Il

    2014-01-01

    The anorexigenic adipocyte-derived hormone leptin and the orexigenic hormone ghrelin act in opposition to regulate feeding behavior via the vagal afferent pathways. The mechanisms by which ghrelin exerts its inhibitory effects on leptin are unknown. We hypothesized that ghrelin activates the exchange protein activated by cAMP (Epac), inducing increased SOCS3 expression, which negatively affects leptin signal transduction and neuronal firing in nodose ganglia (NG) neurons. We showed that 91 ± 3% of leptin receptor (LRb) –bearing neurons contained ghrelin receptors (GHS-R1a) and that ghrelin significantly inhibited leptin-stimulated STAT3 phosphorylation in rat NG neurons. Studies of the signaling cascades used by ghrelin showed that ghrelin caused a significant increase in Epac and suppressor of cytokine signaling 3 (SOCS3) expression in cultured rat NG neurons. Transient transfection of cultured NG neurons to silence SOCS3 and Epac genes reversed the inhibitory effects of ghrelin on leptin-stimulated STAT3 phosphorylation. Patch-clamp studies and recordings of single neuronal discharges of vagal primary afferent neurons showed that ghrelin markedly inhibited leptin-stimulated neuronal firing, an action abolished by silencing SOCS3 expression in NG. Plasma ghrelin levels increased significantly during fasting. This was accompanied by enhanced SOCS3 expression in the NG and prevented by treatment with a ghrelin antagonist. Feeding studies showed that silencing SOCS3 expression in the NG reduced food intake evoked by endogenous leptin. We conclude that ghrelin exerts its inhibitory effects on leptin-stimulated neuronal firing by increasing SOCS3 expression. The SOCS3 signaling pathway plays a pivotal role in ghrelin's inhibitory effect on STAT3 phosphorylation, neuronal firing, and feeding behavior. PMID:25060362

  13. 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.

  14. Circulating Ghrelin Acts on GABA Neurons of the Area Postrema and Mediates Gastric Emptying in Male Mice.

    PubMed

    Cabral, Agustina; Cornejo, María P; Fernandez, Gimena; De Francesco, Pablo N; Garcia-Romero, Guadalupe; Uriarte, Maia; Zigman, Jeffrey M; Portiansky, Enrique; Reynaldo, Mirta; Perello, Mario

    2017-05-01

    Ghrelin is known to act on the area postrema (AP), a sensory circumventricular organ located in the medulla oblongata that regulates a variety of important physiological functions. However, the neuronal targets of ghrelin in the AP and their potential role are currently unknown. In this study, we used wild-type and genetically modified mice to gain insights into the neurons of the AP expressing the ghrelin receptor [growth hormone secretagogue receptor (GHSR)] and their role. We show that circulating ghrelin mainly accesses the AP but not to the adjacent nucleus of the solitary tract. Also, we show that both peripheral administration of ghrelin and fasting induce an increase of c-Fos, a marker of neuronal activation, in GHSR-expressing neurons of the AP, and that GHSR expression is necessary for the fasting-induced activation of AP neurons. Additionally, we show that ghrelin-sensitive neurons of the AP are mainly γ-aminobutyric acid (GABA)ergic, and that an intact AP is required for ghrelin-induced gastric emptying. Overall, we show that the capacity of circulating ghrelin to acutely induce gastric emptying in mice requires the integrity of the AP, which contains a population of GABA neurons that are a target of plasma ghrelin. Copyright © 2017 Endocrine Society.

  15. Bicuculline, a GABAA-receptor antagonist, blocked HPA axis activation induced by ghrelin under an acute stress.

    PubMed

    Gastón, M S; Cid, M P; Salvatierra, N A

    2017-03-01

    Ghrelin is a peptide of 28 amino acids with a homology between species, which acts on the central nervous system to regulate different actions, including the control of growth hormone secretion and metabolic regulation. It has been suggested that central ghrelin is a mediator of behavior linked to stress responses and induces anxiety in rodents and birds. Previously, we observed that the anxiogenic-like behavior induced by ghrelin injected into the intermediate medial mesopallium (IMM) of the forebrain was blocked by bicuculline (a GABAA receptor competitive antagonist) but not by diazepam (a GABAA receptor allosteric agonist) in neonatal meat-type chicks (Cobb). Numerous studies have indicated that hypothalamic-pituitary-adrenal (HPA) axis activation mediates the response to stress in mammals and birds. However, it is still unclear whether this effect of ghrelin is associated with HPA activation. Therefore, we investigated whether anxiety behavior induced by intra-IMM ghrelin and mediated through GABAA receptors could be associated with HPA axis activation in the neonatal chick. In the present study, in an Open Field test, intraperitoneal bicuculline methiodide blocked anxiogenic-like behavior as well as the increase in plasma ACTH and corticosterone levels induced by ghrelin (30pmol) in neonatal chicks. Moreover, we showed for the first time that a competitive antagonist of GABAA receptor suppressed the HPA axis activation induced by an anxiogenic dose of ghrelin. These results show that the anxiogenic ghrelin action involves the activation of the HPA axis, with a complex functional interaction with the GABAA receptor.

  16. Ghrelin accelerates the healing of cysteamine-induced duodenal ulcers in rats.

    PubMed

    Warzecha, Zygmunt; Ceranowicz, Dagmara; Dembiński, Artur; Ceranowicz, Piotr; Cieszkowski, Jakub; Kuwahara, Atsukazu; Kato, Ikuo; Dembiński, Marcin; Konturek, Peter C

    2012-05-01

    Previous studies have shown that administration of ghrelin exhibits protective and therapeutic effects in the gut. The aim of the present investigation was to examine the influence of ghrelin administration on the course of cysteamine-induced duodenal ulcers, as well as effects on mucosal production of oxygen free radicals and duodenal antioxidant defense. Duodenal ulcers were induced in male Wistar rats by cysteamine administered intragastrically at the dose of 200 mg/kg in 1 ml of saline, 3 times at 4-h intervals. Starting 24 h after the first dose of cysteamine, rats were treated intraperitoneally twice a day with saline or ghrelin given at the dose of 4, 8 or 16 nmol/kg/dose. Seven days after administration of the first dose of cysteamine, the study was terminated. Induction of ulcers by cysteamine was accompanied by a reduction in duodenal blood flow, mucosal DNA synthesis and mucosal activity of superoxide dismutase (SOD); whereas mucosal concentration of interleukin-1β and malonyldialdehyde (MDA - an index of lipid peroxidation) were increased. Treatment with ghrelin increased healing rate of duodenal ulcers and enhanced duodenal blood flow, mucosal DNA synthesis and mucosal activity of SOD, and reduced mucosal concentration of interleukin-1β and MDA. Treatment with ghrelin increases the healing rate of duodenal ulcers and this effect is related, at least in part, to improvement of duodenal mucosal blood flow, mucosal cell proliferation and antioxidant defense, as well as being related to reduction in mucosal oxidative stress and inflammatory response.

  17. 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. Copyright 2002 IBRO

  18. Losartan blocks drinking and cFos expression induced by central ornithine vasotocin in rats.

    PubMed

    Fitts, Douglas A; Zierath, Dannielle K; Wilkins, Emily E; Bassett, John E

    2005-11-15

    We previously reported that an intracerebroventricular (icv) injection of the oxytocin receptor antagonist ornithine vasotocin (OVT) caused water and saline intakes, a pressor response, and Fos-like immunoreactivity (Fos-IR) in the median preoptic nucleus of the rat brain. In the present report, rats receiving an icv injection of isotonic saline vehicle followed by an icv injection of 10 microg of OVT 20 min later drank 5.5+/-1.1 ml of total water and saline intake in 60 min after the OVT; rats receiving 10 microg of losartan before the OVT drank only 0.9+/-0.3 ml of total fluid. In a separate study, rats were treated as above except that they were not allowed to drink and were perfused for analysis of Fos-IR in the median preoptic nucleus at 90 min. Fos-IR in the dorsal part of the median preoptic nucleus was significantly suppressed from 2.69+/-0.57 cells per 10,000 square mum in vehicle-treated rats to 0.89+/-0.20 in losartan-treated rats. Losartan alone had no effect on Fos-IR. Losartan did not reduce intake of saccharin in a dessert test. This suggests that the OVT-induced drinking may result from an activation or disinhibition of angiotensin type AT1 receptors in the median preoptic nucleus.

  19. Ghrelin Partially Protects Against Cisplatin-Induced Male Murine Gonadal Toxicity in a GHSR-1a-Dependent Manner1

    PubMed Central

    Whirledge, Shannon D.; Garcia, Jose M.; Smith, Roy G.; Lamb, Dolores J.

    2015-01-01

    ABSTRACT The chemotherapeutic drug cisplatin causes a number of dose-dependent side effects, including cachexia and testicular damage. Patients receiving a high cumulative dose of cisplatin may develop permanent azoospermia and subsequent infertility. Thus, the development of chemotherapeutic regimens with the optimal postsurvival quality of life (fertility) is of high importance. This study tested the hypothesis that ghrelin administration can prevent or minimize cisplatin-induced testicular damage and cachexia. Ghrelin and its receptor, the growth hormone secretagogue receptor (GHSR-1a), are expressed and function in the testis. Targeted deletion of ghrelin, or its receptor, significantly increases the rate of cell death in the testis, suggesting a protective role. Intraperitoneal administration of vehicle, ghrelin, or cisplatin alone or in combination with ghrelin, in cycles of 9 or 18 days, to adult male C57Bl/6 mice was performed. Body weight was measured daily and testicular and epididymal weight, sperm density and motility, testicular histology, and testicular cell death were analyzed at the time of euthanization. Ghrelin coadministration decreased the severity of cisplatin-induced cachexia and gonadal toxicity. Body, testicular, and epididymal weights significantly increased as testicular cell death decreased with ghrelin coadministration. The widespread damage to the seminiferous epithelium induced by cisplatin administration was less severe in mice simultaneously treated with ghrelin. Furthermore, ghrelin diminished the deleterious effects of cisplatin on testis and body weight homeostasis in wild-type but not Ghsr−/− mice, showing that ghrelin's actions are mediated via GHSR. Ghrelin or more stable GHSR agonists potentially offer a novel therapeutic approach to minimize the testicular damage that occurs after gonadotoxin exposure. PMID:25631345

  20. Context-induced reinstatement of methamphetamine seeking is associated with unique molecular alterations in Fos-expressing dorsolateral striatum neurons.

    PubMed

    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; Hope, Bruce T

    2015-04-08

    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.

  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. Age-dependent reduction of ghrelin- and motilin-induced contractile activity in the chicken gastrointestinal tract.

    PubMed

    Kitazawa, Takio; Yoshida, Akiko; Tamano, Takuya; Teraoka, Hiroki; Kaiya, Hiroyuki

    2013-05-01

    Ghrelin is an endogenous ligand for growth hormone secretagogue-receptor 1a (GHS-R1a) and stimulates gastrointestinal (GI) motility in the chicken. Since ghrelin stimulates GH release, which regulates growth, it might be interesting to compare ghrelin-induced responses in GI tract of different-aged chickens. Motilin is a ghrelin-related gut peptide that induces strong contraction in the small intestine. Aim of this study was to clarify age-dependent changes in ghrelin- and motilin-induced contractions of the chicken GI tract and expression of their receptor mRNAs. Chicken ghrelin caused contraction of the crop and proventriculus. Ghrelin-induced contraction in the proventriculus decreased gradually up to 100 days after hatching, but the responses to ghrelin in the crop were the same during the growth period. GHS-R1a mRNA expression in the crop tended to increase, but that in the proventriculus decreased depending on the age. Chicken motilin caused contraction of the chicken GI tract. Atropine decreased the responses to motilin in the proventriculus but not in the ileum. Motilin-induced contraction in the proventriculus but not that in the ileum decreased depending on post-hatching days. On the other hand, motilin receptor mRNA expression in every region of the GI tract decreased with age, but the decrease was more marked in the proventriculus than in the ileum. In conclusion, ghrelin- and motilin-induced GI contractions selectively decreased in the chicken proventriculus depending on post-hatching days, probably due to the age-related decrease in respective receptors expression. The results suggest an age-related contribution of ghrelin and motilin to the regulation of chicken GI motility.

  3. 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.

  4. 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.

  5. 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

  6. 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).

  7. Lack of estradiol modulation of sleep deprivation-induced c-Fos in the rat brain.

    PubMed

    Mashoodh, Rahia; Stamp, Jennifer A; Wilkinson, Michael; Rusak, Benjamin; Semba, Kazue

    2008-11-28

    Women recover from sleep deprivation more efficiently than men, but the mechanism for this difference is unknown. Effects of estrogen on sleep suggest that it could play a role, but the brain targets on which estrogen may act to have this effect have not been identified. Sleep deprivation increases levels of the immediate-early gene protein c-Fos in selected brain regions, but it is unknown whether estrogen modulates this response. We investigated the influence of different levels of exogenous estradiol on the c-Fos response to sleep deprivation in ovariectomized female rats. Female rats were treated with low or high levels of estradiol (mimicking diestrous and proestrous levels, respectively) delivered via subcutaneous silastic tubes. Control ovariectomized females and sham-operated males were implanted with tubes filled with cholesterol. One week after surgery, half of the rats underwent a 3 h period of sleep deprivation during the light phase in a motorized Wahmann activity wheel that rotated constantly at a slow speed, while half were confined to fixed wheels. Immediately after sleep deprivation, animals were killed and their brains processed to detect c-Fos using immunohistochemistry. Sleep deprivation increased the number of c-Fos positive cells in a number of brain areas, including the caudate putamen, medial preoptic area, perifornical hypothalamus, and anterior paraventricular thalamic nucleus. Other areas, including the suprachiasmatic nucleus, posterior paraventricular hypothalamic nucleus, posterior paraventricular thalamic nucleus, arcuate nucleus, and central amygdala, did not respond to 3 h sleep deprivation with a significant increase in c-Fos levels. Levels of c-Fos induced in the selected brain regions by sleep deprivation were not modulated by estrogen levels, nor by sex.

  8. 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).

  9. Ghrelin and Helicobacter pylori infection

    PubMed Central

    Osawa, Hiroyuki

    2008-01-01

    Ghrelin is primarily secreted from the stomach and has been implicated in the coordination of eating behavior and weight regulation. Ghrelin also plays an essential role in the mechanism of gastric mucosal defense. Thus, it is important to clarify which diseases primarily influence changes in plasma ghrelin concentrations. Helicobacter pylori (H pylori) infection is involved in the pathogenesis of gastritis, gastric and duodenal ulcer, gastric carcinoma, and mucosa-associated lymphoid tissue lymphoma. H pylori eradication is related to body weight change. Compared, H pylori infected and negative subjects with normal body mass index, plasma ghrelin concentration, gastric ghrelin mRNA, and the number of ghrelin producing cells in gastric mucosa are significantly lower in H pylori infected subjects than in H pylori-negative controls. Plasma ghrelin concentration decreases with the progression of gastric atrophy. Impaired gastric ghrelin production in association with atrophic gastritis induced by H pylori infection accounts for the decrease in plasma ghrelin concentration. However, the ratio of plasma acylated ghrelin to total ghrelin levels is higher in patients with chronic atrophic gastritis than in healthy subjects. This may result from the compensatory increase in plasma active ghrelin concentration in response to gastric atrophy. After H pylori eradication, gastric preproghrelin mRNA expression is increased nearly 4-fold in most cases. However, changes in plasma ghrelin concentrations before and after H pylori cure are not associated with the gastric ghrelin production. Plasma ghrelin changes are inversely correlated with both body weight change and initial plasma ghrelin levels. PMID:19009647

  10. Quercetin potentiates UVB-induced c-Fos expression: Implications for its use as a chemopreventive agent

    PubMed Central

    Olson, Erik R.; Melton, Tania; Dickinson, Sally E.; Dong, Zigang; Alberts, David S.; Bowden, G. Tim

    2010-01-01

    Quercetin (Qu) is currently being investigated as a chemopreventive agent for a number of cancers including non-melanoma skin cancer induced by ultraviolet (UV) light. We previously reported that Qu degradation has important consequences on signaling and cell biology. In the current study, we report that Qu induces c-Fos mRNA and protein expression through activation of p38 and CREB, and Qu potentiates UVB-induced c-Fos expression. Inclusion of ascorbic acid (AA) in cell culture medium stabilizes Qu and completely prevents both Qu- and UVB- induced p38 and CREB activation, leading to a blockade of c-fos gene expression through reduced CREB/CRE binding. AA stabilizes c-Fos mRNA, increasing steady state levels even when c-fos gene expression is suppressed, but this has no effect on c-Fos protein levels in either mock- or UVB-irradiated cells. We report that Qu blocks mTOR signaling and inhibits c-Fos protein expression directly through this mechanism, since co-treatment with Qu and AA resulted in complete suppression of UVB-induced c-Fos protein expression even in the presence of significantly increased mRNA levels. We further confirmed that this was not due to increased protein turnover since inhibition of proteasome activity with MG-132 did not raise c-Fos protein levels in Qu+AA treated cells. Together, these data indicate that while Qu has been reported to have some beneficial properties as a chemopreventive agent, it is also capable of inducing c-fos expression, a cellular event important for the promotion phase of tumor development, if it is not stabilized. PMID:20551291

  11. 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

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

    2012-01-01

    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. 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 transmission onto GHRH neurons. These data support

  12. 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

  13. THE EFFECTS OF Syzygium aromaticum-DERIVED TRITERPENES ON GASTROINTESTINAL GHRELIN EXPRESSION IN STREPTOZOTOCIN-INDUCED DIABETIC RATS.

    PubMed

    Luvuno, Mluleki; Mbongwa, Hlengiwe Prosperity; Khathi, Andile

    2016-01-01

    Diabetic polyphagia has been associated with elevated plasma ghrelin levels in experimental type 1 diabetes. This increase in food consumption contributes to chronic hyperglycaemia in diabetes thus contributing to the development of micro- and macrovascular complications. We have reported that plant-derived oleanolic acid (OA) and maslinic acid (MA) reduce blood glucose levels, in part, through the inhibition of intestinal carbohydrate hydrolyzing enzymes and glucose transporters. However, their effects on food intake and plasma ghrelin concentrations are unclear. Accordingly, we investigated the effects of these triterpenes on food intake and ghrelin expression in streptozotocin-induced diabetic rats. The effects of OA and MA on blood glucose concentration; food and water intake were monitored over five weeks after which plasma ghrelin concentrations were measured. Additionally, the expression of ghrelin in the various sections of the GIT was determined using Western blot analysis. Ghrelin concentrations in untreated STZ-induced diabetic rats were significantly higher in comparison to the non-diabetic control. Interestingly, the administration of OA and MA reduced food intake, blood glucose levels and plasma ghrelin levels in STZ-induced diabetic rats. This was further complemented by significant reductions in the gastrointestinal expression of ghrelin suggesting that the anti-diabetic properties of these triterpenes are mediated, in part, through the reduction of food intake and the modulation of ghrelin expression. The findings of the study suggest that the control of food intake through the reduction of ghrelin expression by plant-derived OA and MA may constitute an avenue of glycaemic control in diabetes mellitus.

  14. 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

  15. Spinal nociceptin inhibits AMPA-induced nociceptive behavior and Fos expression in rat spinal cord.

    PubMed

    Menéndez, Luis; Lastra, Ana; Villanueva, Noemí; Hidalgo, Agustín; Baamonde, Ana

    2003-02-01

    The effects of intrathecal nociceptin (NOCI) on the nociceptive behavior (biting, scratching and licking; BSL) and the spinal Fos expression induced by intrathecal administration of N-methyl-D-aspartate (NMDA, 4 microg/rat) or alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA, 2 microg/rat) were studied. Coadministration of NOCI (3 and 10 nmol/rat) with NMDA did not modify the NMDA-induced BSL or Fos expression. In contrast, NOCI (0.1-3 nmol/rat) dose-dependently inhibited the BSL behavior induced by AMPA. Furthermore, coadministration of NOCI (3 and 10 nmol/rat) significantly reduced the AMPA-induced expression of Fos protein in the superficial layers of the spinal dorsal horn. In order to test whether classical or opioid receptor-like type 1 (ORL1) receptors are involved in the inhibitions by NOCI of AMPA-evoked BSL, the corresponding antagonists were assayed. The administration of the nonselective opioid receptor antagonist, naloxone (10 mg/kg i.p.), did not modify the NOCI-induced inhibition of AMPA-evoked BSL. However, the selective ORL1 receptor antagonist, [N-Phe(1)]nociceptin-(1-13)-NH(2) (90 nmol/rat i.t.), completely prevented the NOCI-mediated inhibition of the nociceptive responses evoked by AMPA. In conclusion, NOCI, acting at ORL1 receptors can, at least in part, induce spinal analgesia by blocking the nociceptive responses produced through the stimulation of AMPA receptors.

  16. Effects of intrahippocampal injection of ghrelin on spatial memory in PTZ-induced seizures in male rats.

    PubMed

    Babri, Shirin; Amani, Mohammad; Mohaddes, Gisou; Mirzaei, Fariba; Mahmoudi, Fariba

    2013-10-01

    Ghrelin (gh) is a peptide hormone that may affect learning and memory. There is some evidence that ghrelin can have antiepileptic effects. So we decided to investigate the possible effects of ghrelin on spatial memory following PTZ-induced seizures in male rats. Ninety male rats were divided into 9 groups including control, saline, ghrelin (0.3, 1.5 or 3 nmol) and pentylenetetrazol (PTZ, 50 mg/kg, i.p.) plus saline or ghrelin (0.3, 1.5 or 3 nmol). All groups were trained in Morris water maze (MWM) for two consecutive days. Our results showed that ghrelin significantly improves spatial memory at the doses of 1.5 or 3 nmol (P<0.05) in normal rats. We also demonstrated the significant impairment of spatial memory in PTZ group (P<0.05). Intrahippocampal injection of ghrelin at the dose of 3 nmol significantly improved spatial memory in PTZ+gh group compared to PTZ group (P<0.05). These findings suggest that ghrelin as a neuropeptide can improve spatial memory in PTZ-treated rats.

  17. 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.

  18. 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.

  19. Effect of bee venom acupuncture on methamphetamine-induced hyperactivity, hyperthermia and Fos expression in mice.

    PubMed

    Kim, Kee Won; Kim, Hyun Woo; Li, Jing; Kwon, Young Bae

    2011-01-15

    Acupuncture has been used to treat drug addiction by nicotine, alcohol, cocaine and morphine. This study was designed to investigate the effect of bee venom (BV) acupuncture on hyperactivity and hyperthermia induced by acute exposure to methamphetamine (METH, 1mg/kg, s.c.) in mice. Diluted BV (20μl of 0.01, 0.1, 1 and 10mg/ml in saline, s.c.) was administered bilaterally into the Zusanli acupoint (ST36) or control points (SP9 or GB39 or tail base). BV injection into ST36 dose dependently reduced METH-induced hyperactivity and hyperthermia, while BV injection (1mg/ml) into control points did not produce these suppressive effects. METH injection significantly increased Fos expression in several brain regions including nucleus accumbens (NA), caudate putamen (CPU), ventral tegmental area (VTA), substantia nigra (SN) and locus coeruleus (LC). Interestingly, BV (1mg/ml) injection into ST36 further increased METH-induced Fos expression in NA (core and shell), SN and LC. When we performed sciatic denervation or combination treatment of BV and lidocaine (BV diluted in 5% lidocaine solution), the enhancement of Fos elevation by BV was completely blocked in the NA, SN and LC in METH-injected mice, indicating that BV-induced peripheral nerve stimulation played an important role in the BV effect. Furthermore, the effects of BV were completely blocked by the α₂-adrenoceptor antagonist, idazoxan (3mg/kg, i.p.), but not by β-adrenoceptor antagonist, propranolol (10mg/kg, i.p.). Taken together, these findings suggest that BV acupuncture into ST36 may modulate METH-induced hyperactivity, hyperthermia and Fos expression through activation of the peripheral nerve and the central α₂-adrenergic activation. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. 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.

  1. Ghrelin Receptor Deficiency does not Affect Diet-Induced Atherosclerosis in Low-Density Lipoprotein Receptor-Null Mice

    PubMed Central

    Habegger, Kirk M.; Grant, Erin; Pfluger, Paul Thomas; Perez-Tilve, Diego; Daugherty, Alan; Bruemmer, Dennis; Tschöp, Matthias H.; Hofmann, Susanna M.

    2011-01-01

    Objective: Ghrelin, a stomach-derived, secreted peptide, and its receptor (growth hormone secretagogue receptor, GHSR) are known to modulate food intake and energy homeostasis. The ghrelin system is also expressed broadly in cardiovascular tissues. Since ghrelin has been associated with anti-inflammatory and anti-atherogenic properties, but is also well known to promote obesity and impair glucose metabolism, we investigated whether ghrelin has any impact on the development of atherosclerosis. The hypothesis that endogenous ghrelin signaling may be involved in atherosclerosis has not been tested previously. Methods and Results: We crossed ghrelin receptor knockout mice (GHSr−/−) into a low-density lipoprotein receptor-null (Ldlr−/−) mouse line. In this model, atherosclerotic lesions were promoted by feeding a high-fat, high-cholesterol Western-type diet for 13 months, following a standard protocol. Body composition and glucose homeostasis were similar between Ldlr−/− and Ldlr/GHSR−/−ko mice throughout the study. Absence or presence of GHSr did not alter the apolipoprotein profile changes in response to diet exposure on an LDLRko background. Atherosclerotic plaque volume in the aortic arch and thoracic aorta were also not affected differentially in mice without ghrelin signaling due to GHSR gene disruption as compared to control LDLRko littermates. In light of the associations reported for ghrelin with cardiovascular disease in humans, the lack of a phenotype in these loss-of-function studies in mice suggests no direct role for endogenous ghrelin in either the inhibition or the promotion of diet-induced atherosclerosis. Conclusion: These data indicate that, surprisingly, the complex and multifaceted actions of endogenous ghrelin receptor mediated signaling on the cardiovascular system have minimal direct impact on atherosclerotic plaque progression as based on a loss-of-function mouse model of the disease. PMID:22649381

  2. Immunomodulatory actions of central ghrelin in diet-induced energy imbalance.

    PubMed

    Stevanovic, Darko; Starcevic, Vesna; Vilimanovich, Urosh; Nesic, Dejan; Vucicevic, Ljubica; Misirkic, Maja; Janjetovic, Kristina; Savic, Emina; Popadic, Dusan; Sudar, Emina; Micic, Dragan; Sumarac-Dumanovic, Mirjana; Trajkovic, Vladimir

    2012-01-01

    We investigated the effects of centrally administered orexigenic hormone ghrelin on energy imbalance-induced inflammation. Rats were subjected for four weeks to three different dietary regimes: normal (standard food), high-fat (standard food with 30% lard) or food-restricted (70%, 50%, 40% and 40% of the expected food intake in 1st, 2nd, 3rd and 4th week, respectively). Compared to normal-weight controls, starved, but not obese rats had significantly higher levels of proinflammatory cytokines (TNF, IL-1β, IFN-γ) in the blood. When compared to normally fed animals, the hearts of starved and obese animals expressed higher levels of mRNAs encoding proinflammatory mediators (TNF, IL-1β, IL-6, IFN-γ, IL-17, IL-12, iNOS), while mRNA levels of the anti-inflammatory TGF-β remained unchanged. Intracerebroventricular (ICV) injection of ghrelin (1 μg/day) for five consecutive days significantly reduced TNF, IL-1β and IFN-γ levels in the blood of starved rats, as well as TNF, IL-17 and IL-12p40 mRNA expression in the hearts of obese rats. Conversely, ICV ghrelin increased the levels of IFN-γ, IL-17, IL-12p35 and IL-12p40 mRNA in the heart tissue of food-restricted animals. This was associated with an increase of immunosuppressive ACTH/corticosterone production in starved animals and a decrease of the immunostimulatory adipokine leptin both in food-restricted and high-fat groups. Ghrelin activated the energy sensor AMP-activated protein kinase (AMPK) in the hypothalamus and inhibited extracellular signal-regulated kinase (ERK) in the hearts of obese, but not starved rats. Therefore, central ghrelin may play a complex role in energy imbalance-induced inflammation by modulating HPA axis, leptin and AMPK/ERK signaling pathways.

  3. Ghrelin accelerates the healing of cysteamine-induced duodenal ulcers in rats

    PubMed Central

    Warzecha, Zygmunt; Ceranowicz, Dagmara; Dembiński, Artur; Ceranowicz, Piotr; Cieszkowski, Jakub; Kuwahara, Atsukazu; Kato, Ikuo; Dembiński, Marcin; Konturek, Peter C.

    2012-01-01

    Summary Background Previous studies have shown that administration of ghrelin exhibits protective and therapeutic effects in the gut. The aim of the present investigation was to examine the influence of ghrelin administration on the course of cysteamine-induced duodenal ulcers, as well as effects on mucosal production of oxygen free radicals and duodenal antioxidant defense. Material/Methods Duodenal ulcers were induced in male Wistar rats by cysteamine administered intragastrically at the dose of 200 mg/kg in 1 ml of saline, 3 times at 4-h intervals. Starting 24 h after the first dose of cysteamine, rats were treated intraperitoneally twice a day with saline or ghrelin given at the dose of 4, 8 or 16 nmol/kg/dose. Seven days after administration of the first dose of cysteamine, the study was terminated. Results Induction of ulcers by cysteamine was accompanied by a reduction in duodenal blood flow, mucosal DNA synthesis and mucosal activity of superoxide dismutase (SOD); whereas mucosal concentration of interleukin-1β and malonyldialdehyde (MDA – an index of lipid peroxidation) were increased. Treatment with ghrelin increased healing rate of duodenal ulcers and enhanced duodenal blood flow, mucosal DNA synthesis and mucosal activity of SOD, and reduced mucosal concentration of interleukin-1β and MDA. Conclusions Treatment with ghrelin increases the healing rate of duodenal ulcers and this effect is related, at least in part, to improvement of duodenal mucosal blood flow, mucosal cell proliferation and antioxidant defense, as well as being related to reduction in mucosal oxidative stress and inflammatory response. PMID:22534700

  4. Ghrelin prevents tumour- and cisplatin-induced muscle wasting: characterization of multiple mechanisms involved

    PubMed Central

    Chen, Ji-an; Splenser, Andres; Guillory, Bobby; Luo, Jiaohua; Mendiratta, Meenal; Belinova, Blaga; Halder, Tripti; Zhang, Guohua; Li, Yi-Ping; Garcia, Jose M

    2015-01-01

    Background Cachexia and muscle atrophy are common consequences of cancer and chemotherapy administration. The novel hormone ghrelin has been proposed as a treatment for this condition. Increases in food intake and direct effects on muscle proteolysis and protein synthesis are likely to mediate these effects, but the pathways leading to these events are not well understood. Methods We characterized molecular pathways involved in muscle atrophy induced by Lewis lung carcinoma (LLC) tumour implantation in c57/bl6 adult male mice and by administration of the chemotherapeutic agent cisplatin in mice and in C2C12 myotubes. The effects of exogenous ghrelin administration and its mechanisms of action were examined in these settings. Results Tumour implantation and cisplatin induced muscle atrophy by activating pro-inflammatory cytokines, p38-C/EBP-β, and myostatin, and by down-regulating Akt, myoD, and myogenin, leading to activation of ubiquitin-proteasome-mediated proteolysis and muscle weakness. Tumour implantation also increased mortality. In vitro, cisplatin up-regulated myostatin and atrogin-1 by activating C/EBP-β and FoxO1/3. Ghrelin prevented these changes in vivo and in vitro, significantly increasing muscle mass (P < 0.05 for LLC and P < 0.01 for cisplatin models) and grip strength (P = 0.038 for LLC and P = 0.001 for cisplatin models) and improving survival (P = 0.021 for LLC model). Conclusion Ghrelin prevents muscle atrophy by down-regulating inflammation, p38/C/EBP-β/myostatin, and activating Akt, myogenin, and myoD. These changes appear, at least in part, to target muscle cells directly. Ghrelin administration in this setting is associated with improved muscle strength and survival. PMID:26136189

  5. Attenuation of systemic morphine-induced analgesia by central administration of ghrelin and related peptides in mice.

    PubMed

    Zeng, Ping; Chen, Jia-Xiang; Yang, Bei; Zhi, Xing; Guo, Fa-Xian; Sun, Meng-Li; Wang, Jing-Lei; Wei, Jie

    2013-12-01

    Ghrelin, an acylated 28-amino peptide secreted in the gastric endocrine cells, has been demonstrated to stimulate the release of growth hormone, increase food intake, and inhibit pro-inflammatory cascade, etc. Ghrelin mainly combines with its receptor (GHS-R1α) to play the role in physiological and pathological functions. It has been reported that ghrelin plays important roles in the control of pain through interaction with the opioid system in inflammatory pain and acute pain. However, very few studies show the effect of supraspinal ghrelin system on antinociception induced by intraperitoneal (i.p.) administration of morphine. In the present study, intracerebroventricular (i.c.v.) injection of ghrelin (0.1, 1, 10 and 100 nmol/L) produced inhibition of systemic morphine (6 mg/kg, i.p.) analgesia in the tail withdrawal test. Similarly, i.c.v. injection GHRP-6 and GHRP-2 which are the agonists of GHS-R1α, also decreased analgesia effect induced by morphine injected intraperitoneally in mice. Furthermore, these anti-opioid activities of ghrelin and related peptides were not blocked by pretreatment with the GHS-R1α selective antagonist [d-Lys(3)]-GHRP-6 (100 nmol/L, i.c.v.). These results demonstrated that central ghrelin and related peptides could inhibit the analgesia effect induced by intraperitoneal (i.p.) administration of morphine. The anti-opioid effects of ghrelin and related peptides do not interact with GHS-R1a. These findings may pave the way for a new strategy on investigating the interaction between ghrelin system and opioids on pain modulation.

  6. The transcription activation domains of Fos and Jun induce DNA bending through electrostatic interactions.

    PubMed Central

    Kerppola, T K; Curran, T

    1997-01-01

    Transcription factor-induced DNA bending is essential for the assembly of active transcription complexes at many promoters. However, most eukaryotic transcription regulatory proteins have modular DNA-binding and activation domains, which appeared to exclude DNA bending as a mechanism of transcription activation by these proteins. We show that the transcription activation domains of Fos and Jun induce DNA bending. In chimeric proteins, the transcription activation domains induce DNA bending independent of the DNA-binding domains. DNA bending by the chimeric proteins is directed diametrically away from the transcription activation domains. Therefore, the opposite directions of DNA bending by Fos and Jun are caused, in part, by the opposite locations of the transcription activation domains relative to the DNA-binding domains in these proteins. DNA bending is reduced in the presence of multivalent cations, indicating that electrostatic interactions contribute to DNA bending by Fos and Jun. Consequently, regions outside the minimal DNA-binding domain can influence DNA structure, and may thereby contribute to the architectural reorganization of the promoter region required for gene activation. PMID:9184234

  7. 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

  8. Acidity induces c-Fos expression in a subpopulation of human colonic submucosal neurons.

    PubMed

    Tixier, Emmanuelle; Galmiche, Jean-Paul; Neunlist, Michel

    2006-08-14

    Enteric neurons responding to chemical challenge of the mucosa have been characterized in animal models mainly in the myenteric plexus. However, in humans, the existence of enteric neurons responding to chemical stimulation of the mucosa remains currently unknown. Therefore, the aim of our study was to identify and characterize human submucosal neurons activated by mucosal challenge with butyrate or hydrochloric acid. Segments of human colon were placed in a modified Ussing chamber and incubated on the mucosal side with butyric acid (20 mM, pH 6.5), sodium butyrate (20 mM, pH 7.5), hydrochloric acid (10 mM, pH 6.5) or culture medium (pH 7.5). After 90 min of culture, tissues were fixed and microdissected to obtain whole mount preparation of submucosa containing the Meissner's plexus. Neuron specific enolase (NSE), c-Fos, vasoactive intestinal peptide (VIP) and substance P (SP) were detected using immunohistochemical methods. Tetrodotoxin (TTX, 1 microM) was used to inhibit neuronal activity. After 90 min of culture, butyric acid induced a significant 5.6-fold increase in the proportion of c-Fos-immunoreactive neurons compared to control (19 +/- 4% versus 4 +/- 1%, respectively, p < 0.001). 41 +/- 5% of c-Fos-immunoreactive neurons were VIP-immunoreactive and 3 +/- 2% were SP-immunoreactive. Butyric acid did not modify the proportion of VIP-immunoreactive neurons. The increase in c-Fos-immunoreactive neurons induced by butyric acid was reproduced with hydrochloric acid at the same pH but not with sodium butyrate. Finally, preincubation of the tissue with TTX prevented the effect of butyric acid. In conclusion, our results demonstrate that acidic mucosal challenge induced the activation of a population of human submucosal neurons with a specific neurochemical coding.

  9. Compression Induces Ephrin-A2 in PDL Fibroblasts via c-fos

    PubMed Central

    Sen, S.; Diercke, K.; Zingler, S.; Lux, C. J.

    2015-01-01

    Ephrin-A2–EphA2 and ephrin-B2–EphB4 interactions have been implicated in the regulation of bone remodeling. We previously demonstrated a potential role for members of the Eph-ephrin family of receptor tyrosine kinases for bone remodeling during orthodontic tooth movement: compression-dependent upregulation of ephrin-A2 in fibroblasts of the periodontal ligament (PDL) attenuated osteogenesis in osteoblasts of the alveolar bone. However, factors affecting the regulation of ephrin-A2 expression upon the application of compressive forces remained unclear. Here, we report a mechano-dependent pathway of ephrin-A2 induction in PDL fibroblasts (PDLFs) involving extracellular signal–regulated kinases (ERK) 1/2 and c-fos. PDLF subjected to compressive forces (30.3 g/cm2) upregulated c-fos and ephrin-A2 mRNA and protein expression and displayed increased ERK1/2 phosphorylation. Inhibition of the MAP kinase kinase (MEK)/ERK1/2 pathway using the specific MEK inhibitor U0126 significantly reduced ephrin-A2 messenger RNA upregulation upon compression. Silencing of c-fos using a small interfering RNA approach led to a significant inhibition of ephrin-A2 induction upon the application of compressive forces. Interestingly, ephrin-A2 stimulation of PDLF induced c-fos expression and led also to the induction of ephrin-A2 expression. Using a reporter gene construct in murine 3T3 cells, we found that ephrin-A2 was able to stimulate serum response element (SRE)–dependent luciferase activity. As the regulation of c-fos is SRE dependent, ephrin-A2 might induce c-fos via SRE activation. Taken together, we provide evidence for an ERK1/2- and c-fos–dependent regulation of ephrin-A2 in compressed PDLF and suggest a novel pathway for ephrin-A2 induction emanating from ephrin-A2 itself. We showed previously that ephrin-A2 at compression sites might contribute to tooth movement by inhibiting osteogenic differentiation. The regulatory pathway of ephrin-A2 induction during tooth movement

  10. [Drinking behavior and c-fos expression induced by chemical or electrical stimulation of SFO in rat brain].

    PubMed

    Li, Xu-Ping; Jiang, Xing-Hong

    2002-08-01

    To compare the drinking behavior and c-fos expression induced by chemical or electrical stimulation of subfornical organ (SFO) in rat brain. L-glutamic acid microinjection and constant electrical current were used as chemical and electrical stimulation of SFO, respectively. The water intake over 1 h was recorded and Fos expression was examined immunohistochemically. A similar volume of water intake and Fos expression pattern were induced by both methods of stimulation of SFO. These include 11 forebrain areas (organum vasculosum of the lamina terminalis, median preoptic nucleus, hypothalamic paraventricular nucleus, supraoptic nucleus and lateral hypothalamic area, paraventricular nucleus, reunions nucleus and central medial nucleus of thalamus, bed nucleus of the stria terminalis, perifornical dorsal area and substantia innominata) and 4 areas of hindbrain (area postrema, nucleus solitary tract, lateral parabrachial nucleus and dorsal raphe nucleus). The drinking behavior and Fos expression in brain induced by SFO stimulation are the results of activation of the neuronal bodies in SFO.

  11. Unique gene alterations are induced in FACS-purified Fos-positive neurons activated during cue-induced relapse to heroin seeking

    PubMed Central

    Fanous, Sanya; Guez-Barber, Danielle H; Goldart, Evan M; Schrama, Regina; Theberge, Florence RM; Shaham, Yavin; Hope, Bruce T

    2012-01-01

    Cue-induced heroin seeking after prolonged withdrawal is associated with neuronal activation and altered gene expression in prefrontal cortex (PFC). However, these previous studies assessed gene expression in all neurons regardless of their activity state during heroin seeking. Using Fos as a marker of neural activity, we describe distinct molecular alterations induced in activated versus non-activated neurons during cue-induced heroin seeking after prolonged withdrawal. We trained rats to self-administer heroin for 10 days (6-h/day) and assessed cue-induced heroin seeking in extinction tests after 14 or 30 days. We used fluorescent-activated cell-sorting (FACS) to purify Fos-positive and Fos-negative neurons from PFC 90 min after extinction testing. Flow cytometry showed that Fos-immunoreactivity was increased in less than 10% of sparsely distributed PFC neurons. mRNA levels of the immediate early genes fosB, arc, egr1, and egr2, as well as npy and map2k6, were increased in Fos-positive, but not Fos-negative, neurons. In support of these findings, double-label immunohistochemistry indicated substantial co-expression of NPY- and Arc-immunoreactivity in Fos-positive neurons. Our data indicate that cue-induced relapse to heroin seeking after prolonged withdrawal induces unique molecular alterations within activated PFC neurons that are distinct from those observed in the surrounding majority of non-activated neurons. PMID:23113797

  12. Unique gene alterations are induced in FACS-purified Fos-positive neurons activated during cue-induced relapse to heroin seeking.

    PubMed

    Fanous, Sanya; Guez-Barber, Danielle H; Goldart, Evan M; Schrama, Regina; Theberge, Florence R M; Shaham, Yavin; Hope, Bruce T

    2013-01-01

    Cue-induced heroin seeking after prolonged withdrawal is associated with neuronal activation and altered gene expression in prefrontal cortex (PFC). However, these previous studies assessed gene expression in all neurons regardless of their activity state during heroin seeking. Using Fos as a marker of neural activity, we describe distinct molecular alterations induced in activated versus non-activated neurons during cue-induced heroin seeking after prolonged withdrawal. We trained rats to self-administer heroin for 10 days (6 h/day) and assessed cue-induced heroin seeking in extinction tests after 14 or 30 days. We used fluorescent-activated cell sorting (FACS) to purify Fos-positive and Fos-negative neurons from PFC 90 min after extinction testing. Flow cytometry showed that Fos-immunoreactivity was increased in less than 10% of sparsely distributed PFC neurons. mRNA levels of the immediate early genes fosB, arc, egr1, and egr2, as well as npy and map2k6, were increased in Fos-positive, but not Fos-negative, neurons. In support of these findings, double-label immunohistochemistry indicated substantial coexpression of neuropeptide Y (NPY)- and Arc-immunoreactivity in Fos-positive neurons. Our data indicate that cue-induced relapse to heroin seeking after prolonged withdrawal induces unique molecular alterations within activated PFC neurons that are distinct from those observed in the surrounding majority of non-activated neurons.

  13. 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. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Decreased ghrelin-induced GH release in thyrotoxicosis: comparison with GH-releasing peptide-6 (GHRP-6) and GHRH.

    PubMed

    Nascif, Sergio Oliva; Correa-Silva, Silvia Regina; Silva, Marcos Roberto; Lengyel, Ana-Maria Judith

    2007-01-01

    In thyrotoxicosis GH response to several stimuli is impaired, but there is no data on ghrelin-induced GH release in these patients. Ghrelin is a potent GH secretagogue and it also increases glucose levels in men. The aim of this study was to evaluate the effects of ghrelin (1 microg/kg), GHRP-6 (1 mug/kg) and GHRH (100 microg), i.v., on GH levels in 10 hyperthyroid patients and in 8 controls. Glucose levels were also measured during ghrelin and GHRP-6 administration. In control subjects and hyperthyroid patients peak GH (microg/l; mean +/- SE) values after ghrelin injection (controls: 66.7 +/- 13.6; hyper: 19.3 +/- 2.4) were significantly higher than those obtained after GHRP-6 (controls: 26.7 +/- 5.1; hyper: 12.6 +/- 1.3) and GHRH (controls: 13.5 +/- 4.3; hyper: 5.3 +/- 1.3). There was a significant decrease in GH responsiveness to ghrelin, GHRP-6 and GHRH in the hyperthyroid group compared to controls. In control subjects and hyperthyroid patients basal glucose (mmol/l) values were 4.5 +/- 0.1 and 4.7 +/- 0.2, respectively. There was a significant increase in glucose levels 30 min after ghrelin injection (controls: 4.9 +/- 0.1; hyper: 5.2 +/- 0.2), which remained elevated up to 120 min. When the two groups were compared no differences in glucose values were observed. GHRP-6 administration was not able to increase glucose levels in both groups. Our data shows that GH release after ghrelin, GHRP-6 and GHRH administration is decreased in thyrotoxicosis. This suggests that thyroid hormone excess interferes with GH-releasing pathways activated by these peptides. Our results also suggest that ghrelin's ability to increase glucose levels is not altered in thyrotoxicosis.

  15. c-Fos and Dusp1 confer non-oncogene addiction in BCR-ABL induced leukemia

    PubMed Central

    Kesarwani, Meenu; Kincaid, Zachary; Gomaa, Ahmed; Huber, Erika; Rohrabaugh, Sara; Siddiqui, Zain; Bouso, Muhammad F.; Latif, Tahir; Xu, Ming; Komurov, Kakajan; Mulloy, James C.; Cancelas, Jose A.; Grimes, H. Leighton; Azam, Mohammad

    2017-01-01

    Tyrosine kinase inhibitor (TKI) therapy for human cancers is not curative, with relapse due to the continuing presence of tumor cells, referred to as minimal residual disease (MRD) cells. MRD stem or progenitor cells survival in the absence of oncogenic kinase signaling, a phenomenon referred to as intrinsic resistance, depends on diverse growth factors. Here, we report that oncogenic kinase and growth factor signaling converge to induce the expression of the signaling proteins c-Fos and Dusp1. Genetic deletion of c-Fos and Dusp1 suppressed tumor growth in a BCR-ABL-induced mouse model of chronic myeloid leukemia (CML). Pharmacological inhibition of c-Fos, Dusp1 and BCR-ABL eradicated MRD in multiple in vivo models, as well as in primary CML patient xenotransplanted mice. Growth factor signaling also conferred TKI resistance and induced c-FOS and DUSP1 expression in tumor cells modeling other types of kinase-driven leukemias. Our data demonstrate that c-Fos and Dusp1 expression levels determine the threshold of TKI efficacy, such that growth factor-induced expression of c-Fos and Dusp1 confers intrinsic resistance to TKI therapy in a wide-ranging set of leukemias, and may represent a unifying Achilles heel of kinase-driven cancers. PMID:28319094

  16. Ethanol-induced alterations of c-Fos immunoreactivity in specific limbic brain regions following ethanol discrimination training.

    PubMed

    Besheer, Joyce; Schroeder, Jason P; Stevenson, Rebekah A; Hodge, Clyde W

    2008-09-26

    The discriminative stimulus properties of ethanol are functionally regulated by ionotropic GABA(A) and NMDA receptors in specific limbic brain regions including the nucleus accumbens, amygdala, and hippocampus, as determined by microinjection studies. The purpose of the present work was to further investigate potential neural substrates of ethanol's discriminative stimulus effects by examining if ethanol discrimination learning produces changes in brain regional response to ethanol. To accomplish this goal, immunohistochemistry was used to assess the effects of ethanol (2 g/kg) on c-Fos immunoreactivity (Fos-IR). Comparisons in ethanol-induced Fos-IR were made between a group of rats that was trained to discriminate the stimulus properties of ethanol (2 g/kg, IG) from water (IG) and a drug/behavior-matched control group that did not receive differential reinforcement for lever selection, which precluded acquisition of discriminative stimulus control by ethanol. In some brain regions discrimination training had no effect on ethanol-induced Fos-IR changes (caudate putamen, bed nucleus of the stria terminalis, and CA1 region of the hippocampus). In contrast, discrimination training altered the pattern of ethanol-induced Fos-IR in the nucleus accumbens (core), medial septum, and the hippocampus (dentate and CA3). These results indicate that having behavior under the stimulus control of ethanol can change ethanol-induced Fos-IR in some brain regions. This suggests that learning about the subjective properties of ethanol produces adaptive changes in how the brain responds to acute ethanol exposure.

  17. Tactile Experience Induces c-fos Expression in Rat Barrel Cortex

    PubMed Central

    Filipkowski, Robert K.; Rydz, Marek; Berdel, Bozena; Morys, Janusz; Kaczmarek, Leszek

    2000-01-01

    Understanding gene expression that is responsive to sensory stimulation is central to elucidate molecular mechanisms underlying neuronal plasticity. In this study we demonstrate two new methods of stimulating whiskers that provide major sensory input to rat neocortex. In the first paradigm, animals were placed on the top of a cylinder and their vibrissae were brushed by hand. In the second paradigm, animals were placed for a brief period of time into a new, wired cage resulting in vibrissae stimulation when they explored the new environment. Both approaches induced c-Fos expression in barrel cortex corresponding to the stimulated vibrissae, especially in layer IV. Layers II/III and V/VI also showed c-Fos induction, but there were no detectable changes in layer VIb. The majority of c-Fos-expressing cells are probably not inhibitory neurons, because they do not show parvalbumin staining. Both paradigms, in contrast to the previous methods, are simple to use and do not require anesthesia, restraint of animals, or elaborate experimental setups. PMID:10753978

  18. Nesfatin-1 induces Fos expression and elicits dipsogenic responses in subfornical organ.

    PubMed

    Moreau, Jason M; Ciriello, John

    2013-08-01

    Nesfatin-1 (Nes-1), an 82-amino acid protein cleaved from nucleobindin-2, has been suggested to play a role in ingestive behaviors. Intracerebroventricular (icv) injections of Nes-1 reduce water intake, although the sites of action for this effect are not known. Two series of experiments were done to identify potential sites of action of Nes-1 in drinking behavior. In the first series, icv injections of Nes-1 were made in urethane-anesthetized rats to investigate the distribution of neurons containing Fos-like immunoreactivity (Fos-ir) within the forebrain. Circumventricular organs, including subfornical organ (SFO), were found to contain neurons expressing Fos-ir. Additionally, several hypothalamic, thalamic and limbic nuclei also contained Fos-labeled neurons. As SFO is a pivotal central site in the regulation of water intake, a second series of experiments was done to investigate the role of direct injections of Nes-1 into SFO on water intake in conscious, freely moving rats. Nes-1 (2pmol) injections into SFO induced an increase in water intake compared to vehicle injections. However, when food was made available for ingestion after the Nes-1 injection, the dipsogenic effects of Nes-1 were attenuated. Additionally, the drinking response to Nes-1 was found to be more potent than that observed after injections of ANG II into SFO. Neither simultaneous injections ANG II nor the ANG II type-1 receptor blocker losartan affected the Nes-1 dipsogenic response. Taken together, these results suggest that Nes-1 is a potent dipsogenic agent in SFO, and that Nes-1 may act independently of the SFO angiotensinergic system to elicit the dipsogenic effect. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Ghrelin may reduce radiation-induced mucositis and anorexia in head-neck cancer.

    PubMed

    Guney, Yildiz; Ozel Turkcu, Ummuhani; Hicsonmez, Ayse; Nalca Andrieu, Meltem; Kurtman, Cengiz

    2007-01-01

    Body weight loss is common in cancer patients, and is often associated with poor prognosis, it greatly impairs quality of life (QOL). Radiation therapy (RT) is used in head and neck cancers (HNC) either as a primary treatment or as an adjuvant therapy to surgery. Patients with HNC are most susceptible to malnutrition especially due to anorexia, which is aggravated by RT. Multiple pro-inflammatory cytokines, such as interleukin-6 (IL-6), interleukin-1beta (IL-1beta), interferon (IFN)-gamma and tumor necrosis factor-alpha(TNF-alpha), have been all associated with the development of both anorexia and oral mucositis. Radiation-induced mucositis occurs in almost all patients, who are treated for HNC, it could also cause weight loss. Ghrelin is a novel 28-amino acid peptide, which up-regulates body weight through appetite control, increase food intake, down-regulate energy expenditure and induces adiposity. Furthermore, ghrelin inhibits pro-inflammatory cytokines such as IL-1alpha, IL-1beta, TNF-alpha which may cause oral mucositis and aneroxia, which are the results of weight loss. Thus weight loss during RT is an early indicator of nutritional decline, we propose that recombinant ghrelin used prophylactically could be useful as an appetite stimulant; and preventive of mucositis because of its anti-inflammatory effect, it might help patients maintain weight over the course of curative RT of the HNC and can improve specific aspects of QOL. This issue warrants further studies.

  20. Protective effect of leptin and ghrelin against toxicity induced by amyloid-β oligomers in a hypothalamic cell line.

    PubMed

    Gomes, S; Martins, I; Fonseca, A C R G; Oliveira, C R; Resende, R; Pereira, C M F

    2014-03-01

    In addition to cognitive decline, Alzheimer's disease (AD) patients also exhibit an unexplained weight loss that correlates with disease progression. In young and middle-aged AD patients, large amounts of amyloid-β (Aβ) deposits were observed in the hypothalamus, a brain region involved in the control of feeding and body weight through the action of peripheral metabolic peptides, which have recently been shown to have neuroprotective effects. Moreover, levels of peripheral metabolic peptides, such as leptin and ghrelin, are changed in AD patients. The present study aimed to investigate the role of Aβ peptide in the survival of hypothalamic cells and to explore the receptor-mediated protective effect of leptin and ghrelin against Aβ-induced toxicity in these cells. Using the mHypoE-N42 cell line, we demonstrated for the first time that oligomeric Aβ is toxic to hypothalamic cells, leading to cell death. It was also demonstrated that leptin and ghrelin protect these cells against AβO-induced cell death through the activation of the leptin and ghrelin receptors, respectively. Furthermore, ghrelin and leptin prevented superoxide production, calcium rise and mitochondrial dysfunction triggered by AβO. Taken together, these results suggest that peripheral metabolic peptides, in particular leptin and ghrelin, might be considered as preventive strategies for ameliorating hypothalamic alterations in AD.

  1. 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.

  2. GHRP-6 mimics ghrelin-induced stimulation of food intake and suppression of locomotor activity in goldfish.

    PubMed

    Yahashi, Satowa; Kang, Ki Sung; Kaiya, Hiroyuki; Matsuda, Kouhei

    2012-04-01

    Ghrelin was first identified and characterized from rat stomach as an endogenous ligand for the growth hormone secretagogue (GHS) receptor (GHS-R). Ghrelin also acts as an orexigenic factor and regulates energy balance in rodents. In goldfish, native ghrelin consists of 11 molecular variants, the major form being a 17-residue peptide with n-octanoic acid modification (n-octanoyl ghrelin17), and intraperitoneal (IP) administration of n-octanoyl ghrelin17 induces central actions such as stimulation of food intake and suppression of locomotor activity through capsaicin-sensitive afferents. Four types of GHS-Rs (1a-1, 1a-2, 2a-1 and 2a-2) have been identified in goldfish, and one GHS, GHRP-6, can activate only GHS-R2a-1 in vitro. However, there is no information about the effect of GHRP-6 on food intake and locomotor activity in goldfish in vivo. Therefore, in the present study, we examined whether IP-administered GHRP-6 would mimic the orexigenic action of n-octanoyl ghrelin17 and its suppression of locomotor activity. IP administration of GHRP-6 at 1pmol/g body weight (BW) stimulated food intake, and was equipotent to the orexigenic action of n-octanoyl ghrelin17 at 10 pmol/g BW. IP-injected GHRP-6 at 1 pmol/g BW also induced a significant decrease of locomotor activity, as was the case for IP-injected n-octanoyl ghrelin17 at 10 pmol/g BW. The action of GHRP-6 was blocked by IP-preinjected capsaicin at 160 nmol/g BW. These results suggest that the central action of GHRP-6 might be mediated via the GHS-R2a-1-signaling pathway, and subsequently through capsaicin-sensitive afferents in goldfish.

  3. The appetite-inducing peptide, ghrelin, induces intracellular store-mediated rises in calcium in addiction and arousal-related laterodorsal tegmental neurons in mouse brain slices.

    PubMed

    Hauberg, Katrine; Kohlmeier, Kristi A

    2015-03-01

    Ghrelin, a gut and brain peptide, has recently been shown to be involved in motivated behavior and regulation of the sleep and wakefulness cycle. The laterodorsal tegmental nucleus (LDT) is involved in appetitive behavior and control of the arousal state of an organism, and accordingly, behavioral actions of ghrelin could be mediated by direct cellular actions within this nucleus. Consistent with this interpretation, postsynaptically mediated depolarizing membrane actions of ghrelin on LDT neurons have been reported. Direct actions were ascribed solely to closure of a potassium conductance however this peptide has been shown in other cell types to lead to rises in calcium via release of calcium from intracellular stores. To determine whether ghrelin induced intracellular calcium rises in mouse LDT neurons, we conducted calcium imaging studies in LDT brain slices loaded with the calcium binding dye, Fura-2AM. Ghrelin elicited TTX-insensitive changes in dF/F indicative of rises in calcium, and a portion of these rises were independent of membrane depolarization, as they persisted in conditions of high extracellular potassium solutions and were found to involve SERCA-pump mediated intracellular calcium stores. Involvement of the ghrelin receptor (GHR-S) in these actions was confirmed. Taken together with other studies, our data suggest that ghrelin has multiple cellular actions on LDT cells. Ghrelin's induction of calcium via intracellular release in the LDT could play a role in behavioral actions of this peptide as the LDT governs processes involved in stimulation of motivated behavior and control of cortical arousal.

  4. Diet and gastrointestinal bypass-induced weight loss: the roles of ghrelin and peptide YY.

    PubMed

    Chandarana, Keval; Gelegen, Cigdem; Karra, Efthimia; Choudhury, Agharul I; Drew, Megan E; Fauveau, Veronique; Viollet, Benoit; Andreelli, Fabrizio; Withers, Dominic J; Batterham, Rachel L

    2011-03-01

    Bariatric surgery causes durable weight loss. Gut hormones are implicated in obesity pathogenesis, dietary failure, and mediating gastrointestinal bypass (GIBP) surgery weight loss. In mice, we determined the effects of diet-induced obesity (DIO), subsequent dieting, and GIBP surgery on ghrelin, peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). To evaluate PYY's role in mediating weight loss post-GIBP, we undertook GIBP surgery in PyyKO mice. Male C57BL/6 mice randomized to a high-fat diet or control diet were killed at 4-week intervals. DIO mice underwent switch to ad libitum low-fat diet (DIO-switch) or caloric restriction (CR) for 4 weeks before being killed. PyyKO mice and their DIO wild-type (WT) littermates underwent GIBP or sham surgery and were culled 10 days postoperatively. Fasting acyl-ghrelin, total PYY, active GLP-1 concentrations, stomach ghrelin expression, and colonic Pyy and glucagon expression were determined. Fasting and postprandial PYY and GLP-1 concentrations were assessed 30 days postsurgery in GIBP and sham pair-fed (sham.PF) groups. DIO progressively reduced circulating fasting acyl-ghrelin, PYY, and GLP-1 levels. CR and DIO-switch caused weight loss but failed to restore circulating PYY to weight-appropriate levels. After GIBP, WT mice lost weight and exhibited increased circulating fasting PYY and colonic Pyy and glucagon expression. In contrast, the acute effects of GIBP on body weight were lost in PyyKO mice. Fasting PYY and postprandial PYY and GLP-1 levels were increased in GIBP mice compared with sham.PF mice. PYY plays a key role in mediating the early weight loss observed post-GIBP, whereas relative PYY deficiency during dieting may compromise weight-loss attempts.

  5. Differences in basal and morphine-induced FosB/DeltaFosB and pCREB immunoreactivities in dopaminergic brain regions of alcohol-preferring AA and alcohol-avoiding ANA rats.

    PubMed

    Kaste, Kristiina; Kivinummi, Tanja; Piepponen, T Petteri; Kiianmaa, Kalervo; Ahtee, Liisa

    2009-06-01

    Besides alcohol, alcohol-preferring AA and alcohol-avoiding ANA rats differ also with respect to other abused drugs. To study the molecular basis of these differences, we examined the expression of two transcription factors implicated in addiction, DeltaFosB and pCREB, in brain dopaminergic regions of AA and ANA rats. The effects of morphine and nicotine were studied to relate the behavioral and molecular changes induced by these drugs. Baseline FosB/DeltaFosB immunoreactivity (IR) in the nucleus accumbens core and pCREB IR in the prefrontal cortex (PFC) were elevated in AA rats. Morphine increased DeltaFosB-like IR more readily in the caudate-putamen of AA rats than in ANA rats. In the PFC morphine decreased pCREB IR in AA rats, but increased it in ANA rats. In addition to enhanced locomotor response, the development of place preference to morphine was enhanced in AA rats. The enhanced nicotine-induced locomotor sensitization found in AA compared with ANA rats seems to depend in addition to dopamine and DeltaFosB on other mechanisms. These findings suggest that enhanced sensitivity of AA rats to morphine is related to augmented morphine-induced expression of FosB/DeltaFosB and morphine-induced reduction of pCREB levels. Moreover, altered innate expression of FosB/DeltaFosB and pCREB in AA rats is likely to affect the sensitivity of these rats to abused drugs.

  6. Nicotine-conditioned place preference induced CREB phosphorylation and Fos expression in the adult rat brain.

    PubMed

    Pascual, Mariano M; Pastor, Veronica; Bernabeu, Ramon O

    2009-11-01

    Experimental evidence indicates that nicotine causes long-lasting changes in the brain associated with behavior. Although much has been learned about factors participating in this process, less is known concerning the mechanisms and brain areas involved in nicotine preference. The objective of this study is to examine the participation of brain structures during the development of nicotine-conditioned place preference (CPP). To identify brain regions activated in CPP, we have measured the levels of phosphorylated cyclic AMP response element binding protein (pCREB) and Fos protein using a behavioral CPP and conditioned place aversion (CPA) paradigms. Rats developed reliable and robust CPP and also CPA. During nicotine preference and reinstatement behaviors, a significant increase of both pCREB and Fos protein expression occurs in the nucleus accumbens (NAc) and ventral tegmental area (VTA) and also in the prefrontal cortex (PFC), dorsal striatum (DStr), amygdala, and hippocampus. These increases were abolished by the administration of mecamylamine or by a CPA protocol, showing a specific activation of pCREB in drug preference animals, mediated by nicotinic receptors. Specifically in the VTA, nicotine-induced preference and reinstatement of the preference caused the activation of dopaminergic and GABAergic cells in different proportions. The results indicate that the phosphorylation of CREB and expression of Fos protein, as indicators of neural activity, accompany the acquisition and maintenance of nicotine-induced CPP but not CPA in mesolimbic areas (NAc, VTA, PFC, and DStr) as well as in memory consolidation structures (hippocampus and amygdala) and nicotinic receptor are involved in this process. Taken together, these studies identify the brain regions where pCREB activity is essential for nicotine preference.

  7. 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.

  8. Examination of the tissue ghrelin expression of rats with diet-induced obesity using radioimmunoassay and immunohistochemical methods.

    PubMed

    Aydin, Suleyman; Sahin, Ibrahim; Ozkan, Yusuf; Dag, Ersel; Gunay, Ahmet; Guzel, Saadet Pilten; Catak, Zekiye; Ozercan, Mehmet Resat

    2012-06-01

    Currently, obesity is an important health problem in all countries, both developed and developing. Dietary habits and neurohormonal imbalances play a critical role in obesity. Circulating amounts of ghrelin, which is a neurohormonal hormone, decrease with obesity and increase with weight loss. Although it is known that both mRNA and peptide version of the ghrelin hormone are expressed in almost all tissues of both humans and animals, it is not known how obesity changes the expression of this hormone in the tissues, with the exception of the gastrointestinal system tissues. Therefore, the objective of the present study is to show how diet-induced obesity in rats changes ghrelin expression in all system tissues, and thus, to shed light on the etiopathology of obesity. The study included 12 male and 12 female 2-month-old Wistar albino species rats. The animals in the control group were fed on standard rat pellet, while those in the experiment group were fed ad libitum on a cafeteria-style diet for 2 months. When their body mass index reached 1 g/cm(2), diet-induced obese (DIO) rats were sacrificed in a sterile environment after one night fasting. Ghrelin localizations in the tissues were studied immunohistochemically using avidin-biotin-peroxidase complex (ABC) method, while tissue ghrelin amounts were analyzed using radioimmunoassay (RIA) method. When the ghrelin amounts in the urogenital system (with the exception of kidney tissues), sensory organs, respiratory system, immune system, skeletal muscle system, cardiovascular system, nervous system, and adipose tissue of rats analyzed by RIA method were compared to those in the control group, tissue ghrelin amounts in the DIO group were found lower. Immunohistochemical findings which showed a similar fall in ghrelin concentrations in the tissues were parallel to RIA results. In addition, ghrelin was shown to be synthesized in the cardiovascular system, heart muscle cells, tails of the sperms, hair follicles, lacrimal

  9. Fasting-induced increase in plasma ghrelin is blunted by intravenous alcohol administration: a within-subject placebo-controlled study.

    PubMed

    Leggio, Lorenzo; Schwandt, Melanie L; Oot, Emily N; Dias, Alexandra A; Ramchandani, Vijay A

    2013-12-01

    Ghrelin is a 28-amino acid peptide produced mainly by mucosal neuroendocrine cells lining the fundus of the stomach. Preclinical and clinical studies suggest that ghrelin plays a role in alcoholism. Furthermore, human laboratory studies indicate that acute oral administration of alcohol results in reduced circulating ghrelin. As ghrelin is primarily produced in the stomach, one question never previously explored is whether alcohol administered intravenously (IV) results in similar decrease in ghrelin levels. Thus, this study analyzed the potential effects of IV alcohol administration on plasma ghrelin levels in healthy nonsmoking social drinkers (n=44) who received either a 180-min IV infusion of 6% (v/v) alcohol or 0.9% normal saline in two separate counterbalanced sessions. At each session, participants arrived having fasted for ~7 h and received a light breakfast 60 min before the infusion. The percent change (%Δ) in ghrelin levels was 4.5-fold less in the alcohol condition than the saline condition. In fact, there was only a modest change in ghrelin levels from baseline in the IV alcohol condition (9.6%Δghrelin) while in the IV saline condition there was a robust change (43.4%Δghrelin). There was a trend toward significance in %Δghrelin in the alcohol condition compared to the placebo condition (F[1,33]=3.3, p=0.07). While the exact mechanisms by which alcohol influences ghrelin levels are unclear, alcohol may act directly in the stomach by inhibiting ghrelin secretion and/or release, and may also attenuate ghrelin levels systemically. Although IV alcohol did not reduce circulating ghrelin levels, as seen in previous studies with oral alcohol administration, the present findings suggest that, despite bypassing the stomach, alcohol still attenuated circulating ghrelin levels, i.e. the fasting-induced increase in circulating ghrelin was blunted by IV alcohol administration. These findings lead us to hypothesize that alcohol might affect ghrelin signaling not

  10. Effects of monocular deprivation on the spatial pattern of visually induced expression of c-Fos protein.

    PubMed

    Nakadate, K; Imamura, K; Watanabe, Y

    2012-01-27

    We studied the pattern of expression of a protein product (c-Fos) of immediate-early gene (IEG) in the visual cortex of rats and mice. The basal expression of c-Fos was very low and visual exposure revealed a large number of c-Fos immunopositive cells in the visual cortex. We found that monocular deprivation during the sensitive period of ocular dominance (OD) plasticity significantly changed both the amount and pattern of c-Fos expression upon monocular stimulation of either eye. The number of immunopositive cells in layer IV of binocular subfields of the primary visual cortex (Oc1B) ipsilateral to the stimulated eye was found to be the most sensitive index of the effects of monocular deprivation during the sensitive period, that is, opened eye stimulation induced significantly larger numbers of c-Fos immunopositive cells, whereas closed eye stimulation induced significantly smaller numbers compared with those induced by monocular stimulation in control animals. In the lateral geniculate nucleus and superior colliculus, the pattern of expression of c-Fos following monocular stimulation was not affected by preceding monocular deprivation. Monocular deprivation imposed after the sensitive period did not affect the pattern of induction of c-Fos. Notably, in age-matched old animals that had been raised in total darkness and then experienced monocular deprivation, the distribution and numbers of c-Fos-expressing cells in visual cortex exhibited the same alterations as found in young animals during the sensitive period. These findings suggest that the present activity mapping method using c-Fos as a molecular marker is useful for examining the activity-dependent regulation of cortical plasticity, and provides an alternative method to conventional electrophysiological recording. This method is particularly powerful when applied to knockout or transgenic mice in which sampling biases in electrophysiological recording have been considered inevitable. Furthermore, these

  11. Social and environmental contexts modulate sleep deprivation-induced c-Fos activation in rats.

    PubMed

    Deurveilher, Samuel; Ryan, Nathan; Burns, Joan; Semba, Kazue

    2013-11-01

    People often sleep deprive themselves voluntarily for social and lifestyle reasons. Animals also appear to stay awake longer as a result of their natural curiosity to explore novel environments and interact socially with conspecifics. Although multiple arousal systems in the brain are known to act jointly to promote and maintain wakefulness, it remains unclear whether these systems are similarly engaged during voluntary vs. forced wakefulness. Using c-Fos immunohistochemistry, we compared neuronal responses in rats deprived of sleep for 2 h by gentle sensory stimulation, exploration under social isolation, or exploration with social interaction, and rats under undisturbed control conditions. In many arousal, limbic, and autonomic nuclei examined (e.g., anterior cingulate cortex and locus coeruleus), the two sleep deprivation procedures involving exploration were similarly effective, and both were more effective than sleep deprivation with sensory stimulation, in increasing the number of c-Fos immunoreactive neurons. However, some nuclei (e.g., paraventricular hypothalamic nucleus and select amygdala nuclei) were more responsive to exploration with social interaction, while others (e.g., histaminergic tuberomammillary nucleus) responded more strongly to exploration in social isolation. In the rostral basal forebrain, cholinergic and GABAergic neurons responded preferentially to exploration with social interaction, whereas resident neurons in general responded most strongly to exploration without social interaction. These results indicate that voluntary exploration with/without social interaction is more effective than forced sleep deprivation with gentle sensory stimulation for inducing c-Fos in arousal and limbic/autonomic brain regions, and suggest that these nuclei participate in different aspects of arousal during sustained voluntary wakefulness.

  12. Effects of Intracerebroventricularly (ICV) Injected Ghrelin on Cardiac Inducible Nitric Oxide Synthase Activity/Expression in Obese Rats.

    PubMed

    Sudar Milovanovic, E; Jovanovic, A; Misirkic-Marjanovic, M; Vucicevic, Lj; Janjetovic, K; Isenovic, E R

    2015-11-01

    The aim of this study was to examine the effects of ghrelin on regulation of cardiac inducible nitric oxide synthase (iNOS) activity/expression in high fat (HF), obese rats.For this study, male Wistar rats fed with HF diet (30% fat) for 4 weeks were injected every 24 h for 5 days intracerebroventricularly (ICV) with ghrelin (0.3 nmol/5 µl) or with an equal volume of phosphate buffered saline (PBS). Control rats were ICV injected with an equal volume of PBS. Glucose, insulin and nitric oxide (NO) concentrations were measured in serum, while arginase activity and citrulline concentrations were measured in heart lysate. Protein iNOS and regulatory subunit of nuclear factor-κB (NFκB-p65), phosphorylation of enzymes protein kinase B (Akt) at Ser(473), and extracellular signal-regulated kinases 1/2 (ERK1/2) at Tyr(202)/Tyr(204) were determined in heart lysate by Western blot. For gene expression of iNOS qRT-PCR was used.Results show significantly (p<0.01) higher serum NO production in ghrelin treated HF rats compared with HF rats. Ghrelin significantly reduced citrulline concentration (p<0.05) and arginase activity (p<0.01) in HF rats. In ghrelin treated HF rats, gene and protein expression of iNOS and NFκB-p65 levels were significantly (p<0.05) increased compared with HF rats. Increased phosphorylation of Akt (p<0.01) and decreased (p<0.05) ERK1/2 phosphorylation were detected in HF ghrelin treated rats compared with HF rats hearts.Results from this study indicate that exogenous ghrelin induces expression and activity of cardiac iNOS via Akt phosphorylation followed by NFκB activation in HF rats.

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

    PubMed Central

    Gross, Noah B.; Marshall, John F.

    2009-01-01

    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

  14. Acylated and unacylated ghrelin protect MC3T3-E1 cells against tert-butyl hydroperoxide-induced oxidative injury: pharmacological characterization of ghrelin receptor and possible epigenetic involvement.

    PubMed

    Dieci, Elisa; Casati, Lavinia; Pagani, Francesca; Celotti, Fabio; Sibilia, Valeria

    2014-07-01

    Increasing evidence suggests a role for oxidative stress in age-related decrease in osteoblast number and function leading to the development of osteoporosis. This study was undertaken to investigate whether ghrelin, previously reported to stimulate osteoblast proliferation, counteracts tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in MC3T3-E1 osteoblastic cells as well as to characterize the ghrelin receptor (GHS-R) involved in such activity. Pretreatment with ghrelin (10(-7)-10(-11)M) significantly increased viability and reduced apoptosis of MC3T3-E1 cells cultured with t-BHP (250 μM) for three hours at the low concentration of 10(-9)M as shown by MTT assay and Hoechst-33258 staining. Furthermore, ghrelin prevented t-BHP-induced osteoblastic dysfunction and changes in the cytoskeleton organization evidenced by the staining of the actin fibers with Phalloidin-FITC by reducing reactive oxygen species generation. The GHS-R type 1a agonist, EP1572 (10(-7)-10(-11)M), had no effect against t-BHP-induced cytotoxicity and pretreatment with the selective GHS-R1a antagonist, D-Lys(3)-GHRP-6 (10(-7)M), failed to remove ghrelin (10(-9) M)-protective effects against oxidative injury, indicating that GHS-R1a is not involved in such ghrelin activity. Accordingly, unacylated ghrelin (DAG), not binding GHS-R1a, displays the same protective actions of ghrelin against t-BHP-induced cytotoxicity. Preliminary observations indicate that ghrelin increased the trimethylation of lys4 on histones H3, a known epigenetic mark activator, which may regulate the expression of some genes limiting oxidative damage. In conclusion, our data demonstrate that ghrelin and DAG promote survival of MC3T3-E1 cell exposed to t-BHP-induced oxidative damage. Such effect is independent of GHS-R1a and is likely mediated by a common ghrelin/DAG binding site.

  15. Involvement of stomach ghrelin and hypothalamic neuropeptides in tumor necrosis factor-alpha-induced hypophagia in mice.

    PubMed

    Endo, Mizuki; Masaki, Takayuki; Seike, Masataka; Yoshimatsu, Hironobu

    2007-04-05

    This study aimed to clarify the interaction of tumor necrosis factor-alpha (TNF-alpha), an anorexigenic cytokine, with ghrelin, an orexigenic peptide secreted by the stomach lining, and hypothalamic neuropeptides in the regulation of food intake in mice. The peripheral administration of TNF-alpha dose-dependently decreased the 24-h cumulative food intake compared with the administration of saline. Reduced food intake was observed at 6 h and 24 h. The same TNF-alpha treatment significantly decreased the plasma level of ghrelin at 6 h and 24 h after treatment compared with the control levels. These changes were accompanied by a significant reduction in the expression of ghrelin mRNA in the stomach at 24 h after treatment. TNF-alpha treatment also resulted in a significant increase in expression of pro-opiomelanocortin (POMC) mRNA and a significant decrease in expression of agouti-related protein (AGRP) mRNA in the hypothalamus at 6 h after treatment. Finally, the pre-administration of ghrelin, reversed the TNF-alpha-induced hypophagia in mice at 6 and 24 h. Taken together, these findings suggest that hypothalamic POMC and AGRP and stomach ghrelin may be involved in TNF-alpha-induced hypophagia in mice.

  16. Ghrelin inhibition of ethanol-induced gastric epithelial cell apoptosis is mediated by miR-21

    PubMed Central

    Jiang, Miao; Gao, Peng-Fei; Li, Huan-Qing; Tian, Pei-Ying; Fan, Xiao-Ming

    2015-01-01

    Aim: To investigate the underlying mechanism of ghrelin-induced gastro-protection in a cell culture model of ethanol-induced gastric epithelial cell injury. Methods: The human gastric epithelial cell line GES-1 was incubated with ghrelin (0.01-1 µM), 1 µM ghrelin and 1 µM D-Lys3-growth hormone releasing peptide-6 (GHRP-6), or 1 µM ghrelin and 400 nM antagomiR-21 for 24 h, followed by treatment with 8% ethanol for 3 h to induce apoptosis. Cell viability was determined by MTT assays and flow cytometry was used for detection of apoptosis rates. miR-21 transcription was analyzed by qRT-PCR and Akt, Bcl-2, Bax and caspase 3 expressions were measured by Western blot. Results: Flow cytometry and a quantitative RT-PCR analysis of the expression of miR-21 showed that ghrelin inhibited apoptosis in a dose dependent manner through a signaling pathway that was both growth hormone secretagogue receptor (GHS-R) and miR-21 dependent, as the antiapoptotic effect of ghrelin was blocked by both D-Lys3-GHRP-6 and antagomiR-21, respectively. Western blotting of Akt, Bcl-2, Bax, and caspase 3 showed that the levels of the antiapoptotic proteins, Akt and Bcl-2, in the cells pretreated with ghrelin alone were higher than those in the cells pretreated with D-Lys3-GHRP-6 or antagomiR-21. By contrast, the levels of the proapoptotic proteins, Bax and caspase 3, in the cells pretreated with ghrelin alone were lower than those in the cells pretreated with D-Lys3-GHRP-6 or antagomiR-21. Conclusion: Ghrelin inhibits GES-1 cell apoptosis through GHS-R-dependent signaling in which miR-21 activates the PI3K/Akt pathway, which upregulates Bcl-2 and downregulates Bax and caspase 3 expression. PMID:26191156

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

    USDA-ARS?s Scientific Manuscript database

    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...

  18. 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

  19. Effects of simulated weightlessness on intramuscular hypertonic saline induced muscle nociception and spinal Fos expression in rats.

    PubMed

    Lei, Jing; Pertovaara, Antti; You, Hao-Jun

    2015-01-12

    We assessed the effects of simulated weightlessness, hindlimb unloading (HU) by 7 days of tail suspension, on noxious mechanically and heat evoked spinal withdrawal reflexes and spinal Fos expression during muscle nociception elicited by intramuscular (i.m.) injection of hypertonic (HT; 5.8%) saline into gastrocnemius muscle in rats. In HU rats, i.m. HT saline-induced secondary mechanical hyperalgesia was enhanced, and secondary heat hypoalgesia was significantly delayed. After 7 days of HU, basal Fos expression in spinal L4-6 segments was bilaterally enhanced only in superficial (I-II) but not middle and deep laminae (III-VI) of the spinal dorsal horn, which finding was not influenced by tail denervation. Unilateral i.m. HT saline injection increased spinal Fos expression bilaterally in both the control rats and 7 days of HU rats. The HT saline-induced bilateral increase of spinal Fos occurred within 0.5h and reached its peak within 1h, after which it gradually returned to the control levels within 8h. Spatial patterns of spinal Fos expression differed between the control group and 7 days of HU group. In superficial laminae, the HT saline-induced increases in Fos expression were higher and in the middle and deep laminae V-VI lower in the 7 days of HU than control rats. It is suggested that supraspinal mechanisms presumably underlie the effects of HU on spinally-organized nociception. Simulated weightlessness may enhance descending facilitation and weaken descending inhibition of nociception. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Site specific effects of anosmia and cloacal gland anesthesia on Fos expression induced in male quail brain by sexual behavior

    PubMed Central

    Taziaux, Mélanie; Keller, Matthieu; Ball, Gregory F.; Balthazart, Jacques

    2008-01-01

    In rats, expression of the immediate early gene, c-fos observed in the brain following male copulatory behavior relates mostly to the detection of olfactory information originating from the female and to somatosensory feedback from the penis. However, quail, like most birds, are generally considered to have a relatively poorly developed sense of smell. Furthermore, quail have no intromittent organ (e.g., penis). It is therefore intriguing that expression of male copulatory behavior induces in quail and rats a similar pattern of c-fos expression in the medial preoptic area (mPOA), bed nucleus of the stria terminalis (BSTM) and parts of the amygdala. We analyzed here by immunocytochemistry Fos expression in the mPOA/BSTM/amygdala of male quail that had been allowed to copulate with a female during standardized tests. Before these tests, some of the males had either their nostrils plugged, or their cloacal area anesthetized, or both. A control group was not exposed to females. These manipulations did not affect frequencies of male sexual behavior and all birds exposed to a female copulated normally. In the mPOA, the increased Fos expression induced by copulation was not affected by the cloacal gland anesthesia but was markedly reduced in subjects deprived of olfactory input. Both manipulations affected copulation-induced Fos expression in the BSTM. No change in Fos expression was observed in the amygdala. Thus immediate early gene expression in the mPOA and BSTM of quail is modulated at least in part by olfactory cues and/or somatosensory stimuli originating from the cloacal gland. Future work should specify the nature of these stimuli and their function in the expression of avian male sexual behavior. PMID:18638505

  1. Airjet and FG-7142-induced Fos expression differs in rats selectively bred for high and low anxiety-related behavior.

    PubMed

    Salchner, Peter; Sartori, Simone B; Sinner, Catrin; Wigger, Alexandra; Frank, Elisabeth; Landgraf, Rainer; Singewald, Nicolas

    2006-06-01

    We reported recently that two rat lines bred for either high (HAB) or low (LAB) anxiety-related behavior display differential Fos expression in restricted parts of the fear/anxiety circuitry when exposed to mild anxiety evoked in exploratory anxiety tests. Since different forms of anxiety are thought to activate different parts of the anxiety circuitry, we investigated now whether (1) an aversive stimulus which elicits escape behavior (airjet) and (2) the anxiogenic/panicogenic drug FG-7142 would reveal further differences in Fos expression as a marker of neuronal activation between HAB and LAB rats. Both airjet exposure and FG-7142 induced Fos expression in both lines in various anxiety-related brain areas. HAB rats, which displayed exaggerated escape responses during airjet exposure, exhibited increased Fos expression in brain areas including the hypothalamus, periaqueductal gray and locus coeruleus, as well as blunted Fos activation in the cingulate cortex in response to airjet and/or FG-7142. The results corroborate previous findings showing that trait anxiety affects neuronal excitability in hypothalamic and medial prefrontal areas. Furthermore, by using airjet as well as FG-7142, we now reveal that enhanced trait anxiety is also associated with neuronal hyperexcitability in the locus coeruleus and the periaqueductal gray, suggesting that investigation of an array of different anxiogenic stimuli is important for the detection of altered neuronal processing in trait anxiety.

  2. Ghrelin Protection against Lipopolysaccharide-Induced Gastric Mucosal Cell Apoptosis Involves Constitutive Nitric Oxide Synthase-Mediated Caspase-3 S-Nitrosylation

    PubMed Central

    Slomiany, Bronislaw L.; Slomiany, Amalia

    2010-01-01

    Ghrelin, a peptide hormone produced mainly in the stomach, has emerged as an important modulator of the inflammatory responses that are of significance to the maintenance of gastric mucosal integrity. Here, we report on the role of ghrelin in controlling the apoptotic processes induced in gastric mucosal cells by H. pylori lipopolysaccharide (LPS). The countering effect of ghrelin on the LPS-induced mucosal 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 (NOS-2). 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. Moreover, the effect of ghrelin on the LPS-induced changes in cNOS activity was reflected in the increased cNOS phosphorylation that was sensitive to 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 L-NAME. Therefore, ghrelin protection of gastric mucosal cells against H. pylori LPS-induced apoptosis involves Src/Akt-mediated up-regulation in cNOS activation that leads to the apoptotic signal inhibition through the NO-induced caspase-3 S-nitrosylation. PMID:20369000

  3. 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

  4. Environmental Enrichment and Gut Inflammation Modify Stress-Induced c-Fos Expression in the Mouse Corticolimbic System

    PubMed Central

    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

  5. Endomorphins suppress nociception-induced c-Fos and Zif/268 expression in the rat spinal dorsal horn.

    PubMed

    Tateyama, Shingo; Ikeda, Tetsuya; Kosai, Kazuko; Nakamura, Tadashi; Kasaba, Toshiharu; Takasaki, Mayumi; Nishimori, Toshikazu

    2002-09-06

    We evaluated the potency of endomorphin-1 and -2 as endogenous ligands on c-Fos and Zif/268 expression in the spinal dorsal horn by formalin injection to the rat hind paw. Endomorphin-1, -2, or morphine was administered intrathecally or intracerebroventricularly 5 min before formalin injection (5%, 100 microl). All drugs produced marked reductions of formalin-induced c-Fos and Zif/268 immunoreactivity in laminae I and II, and laminae V and VI in the rat lumbar spinal cord. The reductions of Zif/268 expression by endomorphins were greater than those by morphine, while the reductions of c-Fos expression by endomorphins were smaller than those by morphine. These effects of endomorphins were attenuated by pretreatment with naloxone. These results indicate that endomorphin-1 and -2 act as endogenous ligands of mu-opioid receptor in neurons of the spinal dorsal horn and suppress the processing of nociceptive information in the central nervous system.

  6. Estradiol replacement enhances sleep deprivation-induced c-Fos immunoreactivity in forebrain arousal regions of ovariectomized rats.

    PubMed

    Deurveilher, S; Cumyn, E M; Peers, T; Rusak, B; Semba, K

    2008-10-01

    To understand how female sex hormones influence homeostatic mechanisms of sleep, we studied the effects of estradiol (E(2)) replacement on c-Fos immunoreactivity in sleep/wake-regulatory brain areas after sleep deprivation (SD) in ovariectomized rats. Adult rats were ovariectomized and implanted subcutaneously with capsules containing 17beta-E(2) (10.5 microg; to mimic diestrous E(2) levels) or oil. After 2 wk, animals with E(2) capsules received a single subcutaneous injection of 17beta-E(2) (10 microg/kg; to achieve proestrous E(2) levels) or oil; control animals with oil capsules received an oil injection. Twenty-four hours later, animals were either left undisturbed or sleep deprived by "gentle handling" for 6 h during the early light phase, and killed. E(2) treatment increased serum E(2) levels and uterus weights dose dependently, while attenuating body weight gain. Regardless of hormonal conditions, SD increased c-Fos immunoreactivity in all four arousal-promoting areas and four limbic and neuroendocrine nuclei studied, whereas it decreased c-Fos labeling in the sleep-promoting ventrolateral preoptic nucleus (VLPO). Low and high E(2) treatments enhanced the SD-induced c-Fos immunoreactivity in the laterodorsal subnucleus of the bed nucleus of stria terminalis and the tuberomammillary nucleus, and in orexin-containing hypothalamic neurons, with no effect on the basal forebrain and locus coeruleus. The high E(2) treatment decreased c-Fos labeling in the VLPO under nondeprived conditions. These results indicate that E(2) replacement modulates SD-induced or spontaneous c-Fos expression in sleep/wake-regulatory and limbic forebrain nuclei. These modulatory effects of E(2) replacement on neuronal activity may be, in part, responsible for E(2)'s influence on sleep/wake behavior.

  7. Vaginocervical stimulation induces Fos in glutamate neurons in the ventromedial hypothalamus: attenuation by estrogen and progesterone.

    PubMed

    Georgescu, Michaela; Sabongui, Camille; Del Corpo, Adina; Marsan, Lina; Pfaus, James G

    2009-10-01

    Vaginocervical stimulation (VCS) induces the immediate-early gene product Fos in the ventromedial hypothalamus (VMH) of female rats. However, this induction is lower in ovariectomized rats that receive estradiol benzoate (EB) and progesterone (P) relative to an oil vehicle. We have observed that a substantial proportion of cells activated in the VMH by VCS stain for glutamate, and infusions of glutamate or its selective receptor agonists to the VMH inhibit both appetitive and consummatory sexual behaviors in females. This raises the possibility that VCS activates an inhibitory glutamate system in the VMH, and that ovarian steroids blunt the activation, although it is not known whether EB or P, alone or in combination, lead to this effect. The present experiment examined the ability of VCS to induce Fos in glutamate neurons in the VMH of ovariectomized rats under 4 hormonal regimens: oil, EB alone, P alone, or EB+P, following 1 or 50 distributed VCSs administered with a lubricated glass rod over the course of 1 h. Treatment with EB or P alone significantly reduced the number of glutamate neurons activated by 1 VCS, with P being more effective than EB. Treatment with EB+P also produced a significant reduction, but not to the extent of EB or P alone. Although EB and P work in synergy to activate sexual behavior in female rats, actions of EB or P alone are sufficient to blunt the ability of VCS to activate glutamate neurons in the VMH. It thus appears that ovarian steroids may "disinhibit" sexual responding, in part, by dampening the ability of VCS to activate glutamate neurons in the VMH. In turn, this may allow females to receive a sufficient number of intromissions for the activation of sexual reward and the facilitation of pregnancy.

  8. High ambient temperature increases 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy")-induced Fos expression in a region-specific manner.

    PubMed

    Hargreaves, G A; Hunt, G E; Cornish, J L; McGregor, I S

    2007-03-16

    3,4-Methylenedioxymethamphetamine (MDMA, "Ecstasy") is a popular drug that is often taken under hot conditions at dance clubs. High ambient temperature increases MDMA-induced hyperthermia and recent studies suggest that high temperatures may also enhance the rewarding and prosocial effects of MDMA in rats. The present study investigated whether ambient temperature influences MDMA-induced expression of Fos, a marker of neural activation. Male Wistar rats received either MDMA (10 mg/kg i.p.) or saline, and were placed in test chambers for 2 h at either 19 or 30 degrees C. MDMA caused significant hyperthermia at 30 degrees C and a modest hypothermia at 19 degrees C. The 30 degrees C ambient temperature had little effect on Fos expression in vehicle-treated rats. However MDMA-induced Fos expression was augmented in 15 of 30 brain regions at the high temperature. These regions included (1) sites associated with thermoregulation such as the median preoptic nucleus, dorsomedial hypothalamus and raphe pallidus, (2) the supraoptic nucleus, a region important for osmoregulation and a key mediator of oxytocin and vasopressin release, (3) the medial and central nuclei of the amygdala, important in the regulation of social and emotional behaviors, and (4) the shell of the nucleus accumbens and (anterior) ventral tegmental area, regions associated with the reinforcing effects of MDMA. MDMA-induced Fos expression was unaffected by ambient temperature at many other sites, and was diminished at high temperature at one site (the islands of Calleja), suggesting that the effect of temperature on MDMA-induced Fos expression was not a general pharmacokinetic effect. Overall, these results indicate that high temperatures accentuate key neural effects of MDMA and this may help explain the widespread use of the drug under hot conditions at dance parties as well as the more hazardous nature of MDMA taken under such conditions.

  9. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. NMDA preconditioning and neuroprotection in vivo: delayed onset of kainic acid-induced neurodegeneration and c-Fos attenuation in CA3a neurons.

    PubMed

    Mohammadi, Shirin; Pavlik, Alfred; Krajci, Dimitrolos; Al-Sarraf, Hameed

    2009-02-23

    Intraventricular (i.c.v.) kainic acid (KA) causes an acute excitotoxic lesion to the CA3 region of rodent hippocampus. Recent evidence implicated c-fos gene in regulating neuron survival and death following an excitotoxic insult. In this study we attempted to prevent KA-induced damage in CA3 neurons with NMDA preconditioning, which produced a marked expression of c-fos in the hippocampus. NMDA (0.6-6 microg, i.c.v.) was injected to anesthetized rats alone or 1 h before KA (0.15 microg, i.c.v.). Following KA injection, vibratome sections were processed for immunohistochemistry/electron microscopy. c-Fos and Nissl staining were used to estimate the extent of neuronal excitation and damage, respectively. Quantitative evaluation of c-Fos-labeled cells showed significantly less c-Fos in CA3a than in neighboring CA3b and CA2 from 1 to 4 h after KA alone. Attenuation of expressed c-Fos in CA3a was accompanied by damage of neurons with more apoptotic than necrotic signs. NMDA preconditioning elevated CA3a c-Fos expression and at 1 and 2 h exceeded markedly that after KA alone. However, at 4 h after KA, NMDA-preconditioned c-Fos induction in CA3a diminished to the same level as that seen after KA alone. The onset of neuronal degeneration was delayed in similar way. While NMDA-induced c-Fos expression in CA3a could be blocked by MK-801 completely, MK-801 and CNQX were both without significant effect on KA-induced c-Fos expression and neuronal damage. In conclusion, inhibition of c-Fos expression and onset of neuronal damage in CA3a following icv KA injection might be transiently delayed by i.c.v. NMDA preconditioning.

  11. Ghrelin, a natural GH secretagogue produced by the stomach, induces hyperglycemia and reduces insulin secretion in humans.

    PubMed

    Broglio, F; Arvat, E; Benso, A; Gottero, C; Muccioli, G; Papotti, M; van der Lely, A J; Deghenghi, R; Ghigo, E

    2001-10-01

    Ghrelin, a 28 amino acid gastric hormone is a natural ligand of the GH Secretagogue (GHS) receptor (GHS-R) and strongly stimulates GH secretion though, like synthetic GHS, it shows other endocrine and non-endocrine activities. Aim of the present study was to clarify whether ghrelin administration influences insulin and glucose levels in humans. To this goal, we compared the effects of ghrelin, hexarelin, a synthetic GHS, or placebo on insulin and glucose as well as on GH levels in 11 normal young volunteers (age [mean +/- SEM]: 28.5 +/- 3.1 yr; BMI: 22.2 +/- 0.9 Kg/m(2)). Ghrelin induced very marked increase in GH secretion (DeltaAUC(0-180): 5777.1 +/- 812.6 microg/l/h; p < 0.01) which was not modified by placebo. Placebo administration did not modify insulin and glucose levels. On the other hand, ghrelin administration induced a prompt increase in glucose levels (DeltaAUC(0-180): 1343.1 +/- 443.5 mg/dl/h; p < 0.01 vs. saline). Absolute glucose levels at +15' were already higher than those at baseline (93.9 +/- 7.1 mg/dl; p < 0.01) and persisted elevated up to 165' (90.3 +/- 5.8 mg/dl; p < 0.01 vs. 0'). Ghrelin administration was also followed by a decrease in serum insulin levels (DeltaAUC(0-180): -207.1 +/- 70.5 mU/l/h; p < 0.05 vs. saline). Absolute insulin levels were significantly reduced from 30' (11.4 +/- 0.9 mU/l, p < 0.1 vs. 0'), showed the nadir at +45' (10.0 +/- 0.6 mU/l, p < 0.01 vs. 0') and then persisted lower (p < 0.01) than baseline up to +105'. Hexarelin administration did not modify glucose and insulin levels despite its marked GH-releasing effect (DeltaAUC(0-180): 4156.8 +/- 1180.3 microg/l/h; p < 0.01 vs. saline) that was slightly lower (p < 0.05) than that of ghrelin. In conclusion, these findings show that, besides stimulating GH secretion, ghrelin is a gastric hormone possessing metabolic actions such as hyperglycemic effect and lowering effect on insulin secretion in humans, at least after acute administration.

  12. Ghrelin-induced hypothermia: A Physiological basis but no clinical risk

    PubMed Central

    Wiedmer, Petra; Strasser, Florian; Horvath, Tamas L.; Blum, David; DiMarchi, Richard; Lutz, Thomas; Schürmann, Annette; Joost, Hans-Georg; Tschöp, Matthias H.; Tong, Jenny

    2011-01-01

    Ghrelin increases food intake and decreases energy expenditure, promoting a positive energy balance. We observed a single case of serious hypothermia during sustained ghrelin treatment in a male subject, suggesting that ghrelin may play a role in the regulation of body temperature. We therefore investigated the effect of ghrelin treatment on body temperature in rodents and humans under controlled conditions. Intriguingly, we could demonstrate ghrelin binding in axon terminals of the medial preoptic area of the hypothalamus located in the vicinity of cold-sensitive neurons. This localization of ghrelin receptors provides a potential anatomical basis for the regulation of body temperature by ghrelin. However, our follow-up studies also indicated that neither a chronic i.c.v. application of ghrelin in rats, nor a single s.c. injection under cold exposure in mice resulted in a relevant decrease in body core temperature. In addition, a four-hour intravenous ghrelin infusion did not decrease body surface temperature in healthy humans. We concluded that while there is a theoretical molecular basis for ghrelin to modify body temperature in mammals, its magnitude is irrelevant under physiologic circumstances. Hypothermia is not likely to represent a serious risk associated with this agent and pathway. PMID:21513721

  13. 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

  14. Fos protein-like immunoreactive neurons induced by electrical stimulation in the trigeminal sensory nuclear complex of rats with chronically injured peripheral nerve.

    PubMed

    Fujisawa, Naoko; Terayama, Ryuji; Yamaguchi, Daisuke; Omura, Shinji; Yamashiro, Takashi; Sugimoto, Tomosada

    2012-06-01

    The rat trigeminal sensory nuclear complex (TSNC) was examined for Fos protein-like immunoreactive (Fos-LI) neurons induced by electrical stimulation (ES) of the lingual nerve (LN) at 2 weeks after injury to the LN or the inferior alveolar nerve (IAN). Intensity-dependent increase in the number of Fos-LI neurons was observed in the subnucleus oralis (Vo) and caudalis (Vc) of the spinal trigeminal tract nucleus irrespective of nerve injury. The number of Fos-LI neurons induced by ES of the chronically injured LN at A-fiber intensity (0.1 mA) was significantly increased in the Vo but not the Vc. On the other hand, in rats with chronically injured IAN, the number of Fos-LI neurons induced by ES of the LN at C-fiber intensity (10 mA) was significantly increased in the Vc but not the Vo. These results indicated that injury of a nerve innervating intraoral structures increased the c-Fos response of Vo neurons to A-fiber intensity ES of the injured nerve. A similar nerve injury enhanced the c-Fos response of Vc neurons to C-fiber intensity ES of a spared uninjured nerve innervating an intraoral territory neighboring that of the injured nerve. The present result show that nerve injury causes differential effects on c-Fos expression in the Vo and Vc, which may explain complexity of neuropathic pain symptoms in clinical cases.

  15. Magnesium sulphate attenuates tourniquet-induced hypertension and spinal c-fos mRNA expression: a comparison with ketamine.

    PubMed

    Lee, D H; Jee, D L; Kim, S Y; Kim, J M; Lee, H M

    2006-01-01

    Magnesium and ketamine are well-known N-methyl-D-aspartic acid receptor antagonists. The aim of this study was to determine whether magnesium, in comparison with ketamine, attenuates tourniquet-induced hypertension and spinal c-fos mRNA expression. Rats were divided into four treatment groups: normal (baseline for c-fos mRNA expression); control (saline injection); magnesium injection; and ketamine injection. Arterial blood pressure and c-fos mRNA expression at 60 min were higher in the control than in the magnesium and ketamine groups. Human patients under sevoflurane-oxygen/nitrous oxide anaesthesia were also assigned to receive similar treatments. In humans, arterial blood pressure was increased in the control group at 50 min and thereafter compared with the magnesium and ketamine groups; the magnesium and ketamine groups did not differ. Magnesium and ketamine are equally effective in attenuating tourniquet-induced hypertension and spinal c-fos mRNA expression, suggesting that this effect may be due to reduced pain transmission.

  16. 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

  17. Pattern of Fos expression in the brain induced by selective activation of somatostatin receptor 2 in rats

    PubMed Central

    Goebel, Miriam; Stengel, Andreas; Wang, Lixin; Coskun, Tamer; Alsina-Fernandez, Jorge; Rivier, Jean; Taché, Yvette

    2010-01-01

    Central activation of somatostatin (sst) receptors by oligosomatostatin analogs inhibits growth hormone and stress-related rise in catecholamine plasma levels while stimulating grooming, feeding behaviors, gastric transit and acid secretion, which can be mimicked by selective sst2 receptor agonist. To evaluate the pattern of neuronal activation induced by peptide sst receptor agonists, we assessed Fos-expression in rat brain after intracerebroventricular (icv) injection of a newly developed selective sst2 agonist compared to the oligosomatostatin agonist, ODT8-SST, a pan-sst1–5 agonist. Ninety min after injection of vehicle (10µl) or previously established maximal orexigenic dose of peptides (1µg=1nmol/rat), brains were assessed for Fos-immunohistochemistry and doublelabeling. Food and water were removed after injection. The sst2 agonist and ODT8-SST induced a similar Fos distribution pattern except in the arcuate nucleus where only the sst2 agonist increased Fos. Compared to ODT8-SST, the sst2 agonist induced higher Fos-expression by 3.7-fold in the basolateral amygdaloid nucleus, 1.2-fold in the supraoptic nucleus (SON), 1.6-fold in the magnocellular paraventricular hypothalamic nucleus (mPVN), 4.1-fold in the external lateral parabrachial nucleus, and 2.6-fold in both the inferior olivary nucleus and superficial layer of the caudal spinal trigeminal nucleus. Doublelabeling in the hypothalamus showed that ODT8-SST activates 36% of oxytocin, 63% of vasopressin and 79% of sst2 immunoreactive neurons in the mPVN and 28%, 55% and 25% in the SON, respectively. Selective activation of sst2 receptor results in a more robust neuronal activation than the pan-sst1–5 agonist in various brain regions that may have relevance in sst2 mediated alterations of behavioral, autonomic and endocrine functions. PMID:20637739

  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. 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.

  20. Ghrelin-Induced Enhancement of Vasopressin and Oxytocin Secretion in Rat Neurohypophyseal Cell Cultures.

    PubMed

    Gálfi, M; Radács, M; Molnár, Zs; Budai, I; Tóth, G; Pósa, A; Kupai, K; Szalai, Z; Szabó, R; Molnár, H A; Gardi, J; László, Ferenc A; Varga, Cs

    2016-12-01

    The effects of ghrelin on vasopressin and oxytocin secretion were studied in 13-14-day cell cultures of isolated rat neurohypophyseal tissue. The vasopressin and oxytocin contents of the supernatant were determined by radioimmunoassay after a 1- or 2-h incubation. Significantly increased levels of vasopressin and oxytocin production were detected in the cell culture media following ghrelin administration, depending on the ghrelin doses. The oxytocin level proved to be more elevated than that of vasopressin. The increase of vasopressin and oxytocin secretion could be totally blocked by previous administration of the ghrelin receptor antagonist ([D-Lys(3)]-growth hormone-releasing peptide-6). Application of the ghrelin receptor antagonist after ghrelin administration proved ineffective. The results indicate that vasopressin and oxytocin release is influenced directly by the ghrelin system, and the effects of ghrelin on vasopressin and oxytocin secretion from the neurohypophyseal tissue in rats can occur at the level of the posterior pituitary. Our observations lend support to the view that neurohypophysis contains ghrelin receptors.

  1. Intravenous injection of urocortin 1 induces a CRF2 mediated increase in circulating ghrelin and glucose levels through distinct mechanisms in rats.

    PubMed

    Wang, Lixin; Stengel, Andreas; Goebel-Stengel, Miriam; Shaikh, Almaas; Yuan, Pu-Qing; Taché, Yvette

    2013-01-01

    Urocortins (Ucns) injected peripherally decrease food intake and gastric emptying through peripheral CRF(2) receptors in rodents. However, whether Ucns influence circulating levels of the orexigenic and prokinetic hormone, ghrelin has been little investigated. We examined plasma levels of ghrelin and blood glucose after intravenous (iv) injection of Ucn 1, the CRF receptor subtype involved and underlying mechanisms in ad libitum fed rats equipped with a chronic iv cannula. Ucn 1 (10 μg/kg, iv) induced a rapid onset and long lasting increase in ghrelin levels reaching 68% and 219% at 0.5 and 3h post injection respectively and a 5-h hyperglycemic response. The selective CRF(2) agonist, Ucn 2 (3 μg/kg, iv) increased fasting acyl (3h: 49%) and des-acyl ghrelin levels (3h: 30%) compared to vehicle while the preferential CRF(1) agonist, CRF (3 μg/kg, iv) had no effect. Ucn 1's stimulatory actions were blocked by the selective CRF(2) antagonist, astressin(2)-B (100 μg/kg, iv). Hexamethonium (10 mg/kg, sc) prevented Ucn 1-induced rise in total ghrelin levels while not altering the hyperglycemic response. These data indicate that systemic injection of Ucns induces a CRF(2)-mediated increase in circulating ghrelin levels likely via indirect actions on gastric ghrelin cells that involves a nicotinic pathway independently from the hyperglycemic response.

  2. Exaggerated C-fiber activation prevents peripheral nerve injury-induced hyperinducibility of c-Fos in partially deafferented spinal dorsal horn.

    PubMed

    Sugimoto, T; Funahashi, M; Xiao, C; Adachi, A; Ichikawa, H

    1997-02-01

    Dorsal horn neurons chronically deafferented by peripheral nerve injuries acquire hypersensitivity to noxious input from outside the original receptive field. This study examines the effect of electrical nerve stimulation at the time of injury on such injury-induced hypersensitivity. The medial 3/8 of the dorsal horn laminae I/II around the junction of 4th and 5th lumbar segments (the tibial territory) was deafferented by transection of the ipsilateral tibial nerve in rats. At 2 days or 3 weeks postinjury, the hindpaw was injected with formalin to induce c-fos. At 2 days, neurons with induced c-Fos protein-like immunoreactivity (fos-neurons) were largely confined in the lateral 5/8 of laminae I/II (the peroneal and hip, thus P and H territory). At 3 weeks, fos-neurons significantly increased in the deafferented tibial territory. A similar increase was also noted in the P and H territory. Thus the dorsal horn neurons exhibited c-fos hyperinducibility, an indication of hypersensitivity. Electrical stimulation with a train of 150 shocks (10 V, 2 ms) of the proximal nerve stump immediately after transection prevented the c-fos hyperinducibility. The effect was greater with the stimulation frequency of 0.5 Hz than 0.1 Hz or 10 Hz. The stimulation had no effect on the c-fos inducibility at 2 days postinjury.

  3. Continuous administration of antisense oligonucleotides to c-fos reduced the development of seizure susceptibility after ethacrynic acid-induced seizure in mice.

    PubMed

    Suzukawa, Junko; Omori, Kyoko; Yang, Li; Inagaki, Chiyoko

    2003-09-25

    We previously demonstrated that seizure susceptibility developed by the 14th day post-ethacrynic acid (EA)-induced seizure in mice, with a prolonged increase in the expression of c-fos mRNA in the brain during days 10-14. To examine whether such c-fos increase contributes to the development of seizure susceptibility, we administered antisense oligodeoxynucleotide to c-fos by continuous infusion into the lateral ventricle of mice that had shown a moderate stage of EA seizure, and evaluated the seizure susceptibility to kainic acid (10 mg/kg) on the 14th day. Antisense-infused mice displayed significant reduction of the c-Fos level in the hippocampus and cerebral cortex on the 7th and 14th days, and a significant decrease in seizure severity. These findings suggest that the prolonged increase in c-fos expression after EA seizure may lead to the development of seizure susceptibility.

  4. [Ghrelin: beyond hunger regulation].

    PubMed

    Milke García, Maria del Pilar

    2005-01-01

    Man ingests food to mitigate hunger (mediated by physiological and biochemical signals), satisfy appetite (subjective sensation) and because of psychosocial reasons. Satiation biomarkers (stop feeding) are gastric distention and hormones (CCK, GLP-1) and satiety biomarkers (induce feeding) are food-induced thermogenesis, body temperature, glycaemia and also hormones (insulin, leptin and ghrelin). Oxidative metabolism/body composition, tryptophan/serotonin and proinflammatory cytokines are also implicated on hunger physiology. At the present time, ghrelin is the only known circulating orexigenic with potential on hunger/body weight regulation. It is a neuropeptide (endogenous ligand for the GH secretagogue) recently isolated from the oxyntic mucosa and synthesized mainly in the stomach. Its blood concentration depends on diet, hyperglucemia and adiposity/leptin. It is secreted 1-2 hours preprandially and its concentration decreases drastically during the postprandium. Ghrelin acts on the lateral hypothalamus and theoretically inhibits proinflammatory cytokine secretion and antagonizes leptin. Ghrelin physiologically increases food intake and stimulates adipogenesis, gastrointestinal motility and gastric acid secretion, and has other hormonal and cardiovascular functions. Ghrelin blood concentration is reduced in massive obesity, non-alcoholic steatohepatitis, polycystic ovary syndrome, acromegaly, hypogonadism, ageing, short bowel syndrome and rheumatoid arthritis; and increased in primary or secondary anorexia, starvation, chronic liver disease and celiac disease. Cerebral and peritoneal ghrelin administration (rats) and systemic administration (rats and healthy volunteers, cancer patients or patients on peritoneal dialysis) promotes food consumption and increases adiposity, of utmost importance in the treatment of patients with anorexia.

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

    PubMed

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

    2008-11-01

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

  6. Long-term suppression of methamphetamine-induced c-Fos expression in rat striatum by the injection of c-fos antisense oligodeoxynucleotides absorbed in water-absorbent polymer.

    PubMed

    Semba, Jun'ichi; Wakuta, Maki; Suhara, Tetsuya

    2004-10-01

    The use of water-absorbent polymer (WAP) as a hydrogel carrier for the slow delivery of antisense oligodeoxynucleotides (ODN) in the brain, was recently developed. In this experiment, 15-mer phosphorothioate ODN, complementary to c-fos gene absorbed in WAP, was injected in the rat striatum. The expression of c-Fos-immunoreactivity induced by methamphetamine (6 mg/kg, intraperitoneally) around the injection site was suppressed until 5 days after injection. Using this method, it was observed that unilateral injection with c-fos antisense ODN into the rat striatum caused robust ipsilateral rotations after methamphetamine challenge 4 days post injection. This method is simple, and the biological and behavioral effects of antisense ODN in WAP can be maintained for several days even after a single injection into the brain.

  7. 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

  8. 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

  9. A Fear-Inducing Odor Alters PER2 and c-Fos Expression in Brain Regions Involved in Fear Memory

    PubMed Central

    Pantazopoulos, Harry; Dolatshad, Hamid; Davis, Fred C.

    2011-01-01

    Evidence demonstrates that rodents learn to associate a foot shock with time of day, indicating the formation of a fear related time-stamp memory, even in the absence of a functioning SCN. In addition, mice acquire and retain fear memory better during the early day compared to the early night. This type of memory may be regulated by circadian pacemakers outside of the SCN. As a first step in testing the hypothesis that clock genes are involved in the formation of a time-stamp fear memory, we exposed one group of mice to fox feces derived odor (TMT) at ZT 0 and one group at ZT 12 for 4 successive days. A separate group with no exposure to TMT was also included as a control. Animals were sacrificed one day after the last exposure to TMT, and PER2 and c-Fos protein were quantified in the SCN, amygdala, hippocampus, and piriform cortex. Exposure to TMT had a strong effect at ZT 0, decreasing PER2 expression at this time point in most regions except the SCN, and reversing the normal rhythm of PER2 expression in the amygdala and piriform cortex. These changes were accompanied by increased c-Fos expression at ZT0. In contrast, exposure to TMT at ZT 12 abolished the rhythm of PER2 expression in the amygdala. In addition, increased c-Fos expression at ZT 12 was only detected in the central nucleus of the amygdala in the TMT12 group. TMT exposure at either time point did not affect PER2 or c-Fos in the SCN, indicating that under a light-dark cycle, the SCN rhythm is stable in the presence of repeated exposure to a fear-inducing stimulus. Taken together, these results indicate that entrainment to a fear-inducing stimulus leads to changes in PER2 and c-Fos expression that are detected 24 hours following the last exposure to TMT, indicating entrainment of endogenous oscillators in these regions. The observed effects on PER2 expression and c-Fos were stronger during the early day than during the early night, possibly to prepare appropriate systems at ZT 0 to respond to a fear-inducing

  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

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

    2015-01-01

    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. 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

  12. Neutralizing circulating ghrelin by expressing a growth hormone secretagogue receptor-based protein protects against high-fat diet-induced obesity in mice.

    PubMed

    Gagnon, J; Zhu, L; Anini, Y; Wang, Q

    2015-09-01

    Ghrelin is a stomach-derived peptide hormone that stimulates appetite and promotes adiposity through binding to the growth hormone secretagogue receptor (GHS-R1a). Administration of ghrelin in rodents increases weight gain due to stimulating food intake and reducing fat utilization. Therefore, reducing circulating ghrelin levels holds the potential to reduce weight gain. We developed a GHS-R1a-fusion constructs of a decoy protein containing the ligand-binding domains of the ghrelin receptor. Intramuscular injection of the GHSR/Fc plasmid decreased circulating levels of acylated-ghrelin. When challenged with the high fat diet, treated mice displayed reduced weight gain compared with controls, which was associated with reduced fat accumulation in the peritoneum but not lean mass. Quantitative PCR with reverse transcription showed increased PPARγ and hormone sensitive lipase transcripts levels in adipose tissue of treated animals, illustrating a preference for increased fat utilization. Intra-peritoneal glucose tolerance and insulin tolerance tests showed improved glucose clearance and insulin sensitivity in GHSR/Fc treated animals. We suggest that in vivo expression of the GHSR-based fusion protein prevents diet-induced weight gain, altering adipose gene expression and improving glucose tolerance. These findings, while confirming the role of ghrelin in peripheral energy metabolism, suggest that a strategy involving neutralization of the circulation ghrelin by intramuscular injection of the GHSR1/Fc fusion construct may find clinical application in the treatment of obesity.

  13. Reduction of Cocaine-Induced Locomotor Effects by Enriched Environment Is Associated with Cell-Specific Accumulation of ΔFosB in Striatal and Cortical Subregions.

    PubMed

    Lafragette, Audrey; Bardo, Michael T; Lardeux, Virginie; Solinas, Marcello; Thiriet, Nathalie

    2016-12-08

    Early exposure to enriched environments has been shown to decrease the locomotor effects induced by repeated injections of cocaine and modify basal and cocaine-induced total protein levels of the transcription factor ΔFosB in the whole striatum of mice. In this study, we aimed at characterizing whether the profile of ΔFosB accumulation induced by enriched environments and cocaine would be similar or different in terms of brain areas and cell type. We used mice expressing the eGFP protein in D1 receptor positive (D1R(+)) neurons to determine whether Δ FosB induced by enriched environment or cocaine injections (5×15 mg/kg) would occur in selective subpopulations of neurons in several subregions of the striatum and prefrontal cortex. We found that: (1) exposure to enriched environment reduces cocaine-induced locomotor activation, confirming our previous findings; (2) exposure to enriched environment by itself increases the accumulation of Δ FosB mostly in D1R(-) cells in the shell part of the nucleus accumbens and dorsal striatum, whereas in the nucleus accumbens core, Δ FosB accumulates in both D1R(+) and D1R(-) neurons; (3) in standard environment mice, cocaine induces accumulation of Δ FosB selectively in D1R(+) cells in the nucleus accumbens, dorsal striatum, and infralimbic cortex; and (4) the effects of enriched environments and cocaine on accumulation of Δ FosB were reciprocally blocked by their combination. Altogether, these results suggest that the enriched environment-induced reduction in behavioral effects of cocaine might result from 2 distinct effects on ΔFosB in striatal medium-sized spiny neurons belonging to the direct and indirect pathways. © The Author 2016. Published by Oxford University Press on behalf of CINP.

  14. 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. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  15. Ghrelin protects human umbilical vein endothelial cells against advanced glycation end products-induced apoptosis via NO/cGMP signaling

    PubMed Central

    Li, Pengjie; Liu, Ying; Xiang, Ying; Lin, Miao; Gao, Jinling

    2015-01-01

    Objectives: The aim of this study was to investigate the intracellular mechanism involved in the anti-apoptotic effect of ghrelin on human umbilical vein endothelial cells (HUVECs). Methods: HUVECs were pretreated with ghrelin before exposure to 200 μg/ml advanced glycation end products (AGEs)-BSA for 48 h. Cell viability and apoptosis were determined by MTT assay and Annexin V/PI staining. Intracellular cGMP levels evaluation and cGMP analogs were employed to explore possible mechanisms. Results: The inhibitory effect on AGEs induced HUVECs apoptosis could be exerted by ghrelin and co-incubation with growth hormone secretagogue receptor (GHSR)-1a antagonist [D-Lys3]-GHRP-6 abolished this inhibition. Decreased cGMP level in AGEs induced HUVECs apoptosis was restored by ghrelin pretreatment and abolished by [D-Lys3]-GHRP-6 co-incubation. cGMP analogs (8 Br-cGMP and DB-cGMP) pretreatment also exhibited inhibitory effect on AGEs induced HUVECs apoptosis. Conclusions: Our results demonstrated that ghrelin produces a protective effect on HUVECs through GHS-R1a and cGMP/NO signaling pathway mediates the effect of ghrelin. These observations suggest a novel intracellular mechanism in the process of AGEs induced HUVECs apoptosis. PMID:26629013

  16. Ghrelin inhibits AngII -induced expression of TNF-α, IL-8, MCP-1 in human umbilical vein endothelial cells

    PubMed Central

    Deng, Bin; Fang, Fang; Yang, Tianlu; Yu, Zaixin; Zhang, Bin; Xie, Xiumei

    2015-01-01

    Aim: Ghrelin, a gastric peptide, is involved in several metabolic and cardiovascular processes. Emerging evidence indicates the potential involvement of ghrelin in low-grade inflammatory diseases such as atherosclerosis and hypertension. Cytokine-induced inflammation is critical in these pathological states. The growth hormone secretagogue receptor (GHSR) has been identified in blood vessels, so we predict that ghrelin might inhibit proinflammatory responses in human umbilical vein endothelial cells (HUVECs). The aim of this study is to examine the effect of ghrelin on angiotension II (AngII)-induced expression of TNF-α, MCP-1, IL-8 in HUVECs. Method: HUVECs were pretreated with ghrelin, with or without the specific antagonist of GHSR [D-Lys3]-GHRP-6, the selective inhibitor of nuclear factor-kappaB (NF-κB) PDTC, and the selective inhibitor of extracellular signal-regulated kinase (ERK1/2) PD98059. The cells were finally treated with AngII. The expression of TNF-α, MCP-1, IL-8 was examined by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). The activity of ERK1/2 and NF-κB was analyzed by Western blot. Result: our study showed that ghrelin inhibited AngII -induced expression of IL-8, TNF-α and MCP-1 in the HUVECs via GHSR pathway in concentration- and time-dependent manners. We also found that ghrelin inhibited AngII -induced activation of ERK1/2 and NF-κB. Conclusions: these results suggest that Ghrelin may play novel antiinflammatory and immunoregulatory roles in HUVECs. PMID:25785032

  17. Capsaicin-Sensitive Sensory Nerves Are Necessary for the Protective Effect of Ghrelin in Cerulein-Induced Acute Pancreatitis in Rats

    PubMed Central

    Bonior, Joanna; Warzecha, Zygmunt; Ceranowicz, Piotr; Gajdosz, Ryszard; Pierzchalski, Piotr; Kot, Michalina; Leja-Szpak, Anna; Nawrot-Porąbka, Katarzyna; Link-Lenczowski, Paweł; Olszanecki, Rafał; Bartuś, Krzysztof; Trąbka, Rafał; Kuśnierz-Cabala, Beata; Dembiński, Artur; Jaworek, Jolanta

    2017-01-01

    Ghrelin was shown to exhibit protective and therapeutic effect in the gut. Aim of the study was to investigate the role of sensory nerves (SN) in the protective effect of ghrelin in acute pancreatitis (AP). Studies were performed on male Wistar rats or isolated pancreatic acinar cells. After capsaicin deactivation of sensory nerves (CDSN) or treatment with saline, rats were pretreated intraperitoneally with ghrelin or saline. In those rats, AP was induced by cerulein or pancreases were used for isolation of pancreatic acinar cells. Pancreatic acinar cells were incubated in cerulein-free or cerulein containing solution. In rats with intact SN, pretreatment with ghrelin led to a reversal of the cerulein-induced increase in pancreatic weight, plasma activity of lipase and plasma concentration of tumor necrosis factor-α (TNF-α). These effects were associated with an increase in plasma interleukin-4 concentration and reduction in histological signs of pancreatic damage. CDSN tended to increase the severity of AP and abolished the protective effect of ghrelin. Exposure of pancreatic acinar cells to cerulein led to increase in cellular expression of mRNA for TNF-α and cellular synthesis of this cytokine. Pretreatment with ghrelin reduced this alteration, but this effect was only observed in acinar cells obtained from rats with intact SN. Moreover, CDSN inhibited the cerulein- and ghrelin-induced increase in gene expression and synthesis of heat shock protein 70 (HSP70) in those cells. Ghrelin exhibits the protective effect in cerulein-induced AP on the organ and pancreatic acinar cell level. Sensory nerves ablation abolishes this effect. PMID:28665321

  18. Retrieval of morphine-associated context induces cFos in dentate gyrus neurons.

    PubMed

    Rivera, Phillip D; Raghavan, Ramya K; Yun, Sanghee; Latchney, Sarah E; McGovern, Mary-Katherin; García, Emily F; Birnbaum, Shari G; Eisch, Amelia J

    2015-04-01

    Addiction has been proposed to emerge from associations between the drug and the reward-associated contexts. This associative learning has a cellular correlate, as there are more cFos+ neurons in the hippocampal dentate gyrus (DG) after psychostimulant conditioned place preference (CPP) versus saline controls. However, it is unknown whether morphine CPP leads to a similar DG activation, or whether DG activation is due to locomotion, handling, pharmacological effects, or-as data from contextual fear learning suggests-exposure to the drug-associated context. To explore this, we employed an unbiased, counterbalanced, and shortened CPP design that led to place preference and more DG cFos+ cells. Next, mice underwent morphine CPP but were then sequestered into the morphine-paired (conditioned stimulus+ [CS+]) or saline-paired (CS-) context on test day. Morphine-paired mice sequestered to CS+ had ∼30% more DG cFos+ cells than saline-paired mice. Furthermore, Bregma analysis revealed morphine-paired mice had more cFos+ cells in CS+ compared to CS- controls. Notably, there was no significant difference in DG cFos+ cell number after handling alone or after receiving morphine in home cage. Thus, retrieval of morphine-associated context is accompanied by activation of hippocampal DG granule cell neurons.

  19. TGF beta induces a sustained c-fos expression associated with stimulation or inhibition of cell growth in EL2 or NIH 3T3 fibroblasts.

    PubMed

    Liboi, E; Di Francesco, P; Gallinari, P; Testa, U; Rossi, G B; Peschle, C

    1988-02-29

    We have previously indicated that epidermal growth factor (EGF) plays a fundamental role in the proliferation control of EL2 rat fibroblast line. It is shown here that transforming growth factor beta (TGF beta) stimulates both DNA synthesis and proliferation of EL2 cells, while exerting an inhibitory effect on the growth of murine NIH-3T3 fibroblasts. We also report the effect of TGF beta and EGF on c-fos expression in EL2 cells, as compared to that of TGF beta in NIH-3T3 fibroblasts. In EL2 cells EGF induces a transient c-fos expression at both mRNA and protein level, as previously observed in NIH-3T3 fibroblasts treated with platelet-derived or fibroblast growth factor (PDGF, FGF). Conversely, TGF beta induces in EL2 cells a sustained expression of fos mRNA and protein, which are still detectable at least 24 and 7 hr after treatment respectively. In NIH-3T3 fibroblasts TGF beta causes a sustained fos RNA expression, which is not associated, however, with detectable fos protein. We conclude that in fibroblasts stimulated by mitogens c-fos expression may be differentially modulated, depending of the growth factor and the cell line. This is seemingly due to differential regulation of fos gene expression, not only at the transcriptional and/or post-transcriptional level (transient or sustained fos RNA induction by EGF or TGF beta in EL2 cells), but also at the translational level (fos protein(s) induction by TGF beta in EL2 but not NIH-3T3 fibroblasts, possibly related to the stimulatory vs inhibitory effect of this factor on the growth of the former vs the latter line).

  20. 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

  1. Social experience induces sex-specific fos expression in the amygdala of the juvenile rat.

    PubMed

    Weathington, Jill M; Strahan, J Alex; Cooke, Bradley M

    2012-07-01

    To compare the response of the medial amygdala and central amygdala to juvenile social subjugation (JSS), we used unbiased stereology to quantify the immediate early gene product Fos in prepubertal rats after aggressive or benign social encounters or handling. We estimated the overall number of neurons and the proportion of Fos immunoreactive neurons in the posterodorsal (MePD) and posteroventral medial amygdala (MePV) and the central amygdala (CeA). Experience elicited Fos in a sex- and hemisphere-dependent manner in the MePD. The left MePD was selective for JSS in both sexes, but the right MePD showed a specific Fos response to JSS in males only. In the MePV, irrespective of hemisphere or sex, JSS elicited the greatest amount of Fos, benign social experience elicited an intermediate level, and handling the least. None of the experiential conditions elicited significant levels of Fos in the CeA. We found a previously unreported sex difference in the number of CeA neurons (M>F) that was highly significant and a strong trend toward a sex difference (M>F) in the MePD. These data show that the posterior MeA subnuclei are more responsive to JSS than to benign social interaction, that sex interacts with hemispheric laterality to determine the response of the MePD to JSS and that the MePV responds to social experience and JSS. Taken together, these findings support the hypothesis that juvenile rats process JSS in a sex-specific manner.

  2. Excitatory amino acid receptor antagonists and electroacupuncture synergetically inhibit carrageenan-induced behavioral hyperalgesia and spinal fos expression in rats.

    PubMed

    Zhang, Yu-Qiu; Ji, Guang-Chen; Wu, Gen-Cheng; Zhao, Zhi-Qi

    2002-10-01

    The interaction between electroacupuncture and an N-methyl-D-aspartic acid (NMDA) receptor antagonist, (DL-2-amino-5-phosphonopentanoic acid; AP5), or an (+/-)-alpha-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid/kainite (AMPA/KA) receptor antagonist, (6,7-dinitroquinoxaline-2,3 (1H,4H); DNQX) administered intrathecally on carrageenan-induced thermal hyperalgesia and spinal c-Fos expression was investigated. The latency of paw withdrawal (PWL) from a thermal stimulus was used as a measure of hyperalgesia in awake rats. Intrathecal (i.t.) injection of 1 and 10 nmol AP5, but not DNQX, markedly increased the PWL of the carrageenan-injected paw. At a dose of 100 nmol, either AP5 or DNQX significantly increased the PWL of carrageenan-injected paw, with AP5 being more potent. The PWLs of the non-injected and normal saline (NS)-injected paws were not detectably affected by the administration of NMDA or AMPA/KA receptor antagonists at the doses tested. Unilateral electroacupuncture stimulation of the 'Zu-San-Li' (St 36) and 'Kun-Lun' (UB 60) acupuncture points (60 and 2 Hz alternately, 1-2-3 mA) contralateral to the carrageenan-injected paw significantly elevated the PWLs of carrageenan- and NS-injected paws. Although neither i.t. injection of 0.1 nmol AP5 nor 1 nmol DNQX alone had an effect on the PWL of the carrageenan- and NS-injected paws, both significantly potentiated electroacupuncture-induced analgesia in carrageenan-injected rats, especially 0.1 nmol AP5. Fos expression evoked by intraplantar (i.pl.) injection of carrageenan was examined in the spinal cord with immunohistochemical methods. Three hours after i.pl. injection of carrageenan, the number of Fos-like immunoreactive (Fos-LI) neurons was significantly increased in all the layers of the ipsilateral spinal cord at L(4-5), with the highest density in laminae I-II and V-VI. Intrathecally pre-administered AP5 (10 nmol) or DNQX (100 nmol) significantly reduced the total number of carrageenan-induced Fos

  3. AP-1/Fos-TGase2 Axis Mediates Wounding-induced Plasmodium falciparum Killing in Anopheles gambiae*

    PubMed Central

    Nsango, Sandrine E.; Pompon, Julien; Xie, Ting; Rademacher, Annika; Fraiture, Malou; Thoma, Martine; Awono-Ambene, Parfait H.; Moyou, Roger S.; Morlais, Isabelle; Levashina, Elena A.

    2013-01-01

    Anopheline mosquitoes are the only vectors of human malaria worldwide. It is now widely accepted that mosquito immune responses play a crucial role in restricting Plasmodium development within the vector; therefore, further dissection of the molecular mechanisms underlying these processes should inform new vector control strategies urgently needed to roll back the disease. Here, using genome-wide transcriptional profiling, bioinformatics, and functional gene analysis, we identify a new axis of mosquito resistance to monoclonal Plasmodium falciparum infections that includes the AP-1 transcription factor Fos and the transglutaminase 2 (TGase2), a cross-linking enzyme with known roles in wound responses. We demonstrate that Fos regulates induction of TGase2 expression after wounding but does not affect expression of the components of the well characterized complement-like system. Silencing of Fos or of TGase2 aborts the wounding-induced mosquito killing of P. falciparum. These results reveal multiple signaling pathways that are required for efficient Plasmodium killing in Anopheles gambiae. PMID:23592781

  4. 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.

  5. Effects of striatal ΔFosB overexpression and ketamine on social defeat stress-induced anhedonia in mice

    PubMed Central

    Donahue, Rachel J.; Muschamp, John W.; Russo, Scott J.; Nestler, Eric J.; Carlezon, William A.

    2014-01-01

    Background Chronic social defeat stress (CSDS) produces persistent behavioral adaptations in mice. In many behavioral assays, it can be difficult to determine if these adaptations reflect core signs of depression. We designed studies to characterize the effects of CSDS on sensitivity to reward, since anhedonia (reduced sensitivity to reward) is a defining characteristic of depressive disorders in humans. We also examined the effects of striatal ΔFosB overexpression or the N-methyl-D-aspartate antagonist ketamine, both of which promote resilience, on CSDS-induced alterations in reward function and social interaction. Methods We used intracranial self-stimulation (ICSS) to quantify CSDS-induced changes in reward function. Mice were implanted with lateral hypothalamic (LH) electrodes and ICSS thresholds were measured following each of 10 daily CSDS sessions, and during a 5-day recovery period. We also examined if acute administration of ketamine (2.5–20 mg/kg, intraperitoneal) reverses CSDS-induced effects on reward or, in separate mice, social interaction. Results CSDS increased ICSS thresholds, indicating decreases in the rewarding impact of LH stimulation (anhedonia). This effect was attenuated in mice overexpressing ΔFosB in striatum, consistent with pro-resilient actions of this transcription factor. High but not low doses of ketamine administered after completion of the CSDS regimen attenuated social avoidance in defeated mice, although this effect was transient. Ketamine did not block CSDS-induced anhedonia in the ICSS test. Conclusions Our findings demonstrate that CSDS triggers persistent anhedonia, and confirm that ΔFosB overexpression produces stress resilience. They also indicate that acute ketamine fails to attenuate CSDS-induced anhedonia despite reducing other depression-related behavioral abnormalities. PMID:24495460

  6. 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. © The Author(s) 2016.

  7. 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

  8. 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.

  9. The pregnancy-induced increase in baseline circulating growth hormone in rats is not induced by ghrelin.

    PubMed

    El-Kasti, M M; Christian, H C; Huerta-Ocampo, I; Stolbrink, M; Gill, S; Houston, P A; Davies, J S; Chilcott, J; Hill, N; Matthews, D R; Carter, D A; Wells, T

    2008-03-01

    The elevation in baseline circulating growth hormone (GH) that occurs in pregnant rats is thought to arise from increased pituitary GH secretion, but the underlying mechanism remains unclear. Distribution, Fourier and algorithmic analyses confirmed that the pregnancy-induced increase in circulating GH in 3-week pregnant rats was due to a 13-fold increase in baseline circulating GH (P < 0.01), without any significant alteration in the parameters of episodic secretion. Electron microscopy revealed that pregnancy resulted in a reduction in the proportion of mammosomatotrophs (P < 0.01) and an increase in type II lactotrophs (P < 0.05), without any significant change in the somatotroph population. However, the density of the secretory granules in somatotrophs from 3-week pregnant rats was reduced (P < 0.05), and their distribution markedly polarised; the granules being grouped nearest the vasculature. Pituitary GH content was not increased, but steady-state GH mRNA levels declined progressively during pregnancy (P < 0.05). In situ hybridisation revealed that pregnancy was accompanied by a suppression of GH-releasing hormone mRNA expression in the arcuate nuclei (P < 0.05) and enhanced somatostatin mRNA expression in the periventricular nuclei (P < 0.05), an expression pattern normally associated with increased GH feedback. Although gastric ghrelin mRNA expression was elevated by 50% in 3-week pregnant rats (P < 0.01), circulating ghrelin, GH-secretagogue receptor mRNA expression and the GH response to a bolus i.v. injection of exogenous ghrelin were all largely unaffected during pregnancy. Although trace amounts of 'pituitary' GH could be detected in the placenta with radioimmunoassay, significant GH-immunoreactivity could not be observed by immunohistochemistry, indicating that rat placenta itself does not produce 'pituitary' GH. Although not excluding the possibility that the pregnancy-associated elevation in baseline circulating GH could arise from alternative extra

  10. Treatment with either obestatin or ghrelin attenuates mesenteric ischemia-reperfusion-induced oxidative injury of the ileum and the remote organ lung.

    PubMed

    Şen, Leyla Semiha; Karakoyun, Berna; Yeğen, Cumhur; Akkiprik, Mustafa; Yüksel, Meral; Ercan, Feriha; Özer, Ayşe; Yeğen, Berrak Ç

    2015-09-01

    To evaluate the effects of exogenous ghrelin or obestatin on intestinal injury and accompanying pulmonary injury, intestinal ischemia-reperfusion (I/R) was induced in rats by obstructing the superior mesenteric artery for 60min, whereas laparotomy was performed in the sham group. At the beginning of the 90-min reperfusion period, the rats were injected with obestatin (100μg/kg), ghrelin (10ng/kg), or saline intravenously (iv). At the end of reperfusion, the blood, ileum, and lung samples were taken for the histological and biochemical assays. In the saline-treated I/R group, the increased serum interleukin (IL)-1β level, high damage scores, and elevated tissue malondialdehyde level and collagen content in both tissues were significantly reduced by obestatin or ghrelin. Increased ileal myeloperoxidase activity of the saline-treated I/R group was reduced by treatment with obestatin or ghrelin, whereas increased pulmonary myeloperoxidase activity was reduced with administration of obestatin. Increased DNA fragmentation in the ileum of the saline-treated I/R group was reduced by both peptides. Elevated luminol-lucigenin chemiluminescence levels and nuclear factor kappa B (NF-κB) messenger RNA (mRNA) expression in the ileum of the saline-treated-I/R group were significantly decreased by obestatin or ghrelin treatment. I/R-induced depletion of the antioxidant glutathione in both ileal and pulmonary tissues was prevented with either obestatin or ghrelin treatment. Administration of either obestatin or ghrelin exerts similar protective effects against I/R-induced ileal and pulmonary injury, thus warranting further investigation for their possible use against ischemic intestinal injury.

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

    PubMed

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

    2002-10-01

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

  12. Caloric Restriction Protects against Lactacystin-Induced Degeneration of Dopamine Neurons Independent of the Ghrelin Receptor.

    PubMed

    Coppens, Jessica; Bentea, Eduard; Bayliss, Jacqueline A; Demuyser, Thomas; Walrave, Laura; Albertini, Giulia; Van Liefferinge, Joeri; Deneyer, Lauren; Aourz, Najat; Van Eeckhaut, Ann; Portelli, Jeanelle; Andrews, Zane B; Massie, Ann; De Bundel, Dimitri; Smolders, Ilse

    2017-03-04

    Parkinson's disease (PD) is a neurodegenerative disorder, characterized by a loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNc). Caloric restriction (CR) has been shown to exert ghrelin-dependent neuroprotective effects in the 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine (MPTP)-based animal model for PD. We here investigated whether CR is neuroprotective in the lactacystin (LAC) mouse model for PD, in which proteasome disruption leads to the destruction of the DA neurons of the SNc, and whether this effect is mediated via the ghrelin receptor. Adult male ghrelin receptor wildtype (WT) and knockout (KO) mice were maintained on an ad libitum (AL) diet or on a 30% CR regimen. After 3 weeks, LAC was injected unilaterally into the SNc, and the degree of DA neuron degeneration was evaluated 1 week later. In AL mice, LAC injection significanty reduced the number of DA neurons and striatal DA concentrations. CR protected against DA neuron degeneration following LAC injection. However, no differences were observed between ghrelin receptor WT and KO mice. These results indicate that CR can protect the nigral DA neurons from toxicity related to proteasome disruption; however, the ghrelin receptor is not involved in this effect.

  13. Ghrelin and GHRP-6-induced ACTH and cortisol release in thyrotoxicosis.

    PubMed

    Nascif, Sergio Oliva; Molica, Patrícia; Correa-Silva, Silvia Regina; Silva, Marcos Roberto; Lengyel, Ana-Maria Judith

    2009-01-01

    Thyrotoxicosis might alter the hypothalamic-pituitary-adrenal (HPA) axis. We evaluated the effects of ghrelin and GHRP-6 on the HPA axis in 20 hyperthyroid patients and in 9 controls. Mean basal cortisol (microg/dl) and ACTH (pg/ml) levels were higher in hyperthyroidism (cortisol: 10.7 +/- 0.7; ACTH: 21.5 +/- 2.9) compared to controls (cortisol: 8.1 +/- 0.7; ACTH: 13.5 +/- 1.8). In thyrotoxicosis Delta AUC cortisol values (microg/dl.90 min) after ghrelin (484 +/- 80) and GHRP-6 (115 +/- 63) were similar to controls (ghrelin: 524 +/- 107; GHRP-6: 192 +/- 73). A significant increase in Delta AUC ACTH (pg/ml x 90 min) after ghrelin was observed in thyrotoxicosis (4,189 +/- 1,202) compared to controls (1,499 +/- 338). Delta AUC ACTH values after GHRP-6 were also higher, although not significantly (patients: 927 +/- 330; controls: 539 +/- 237). In summary, our results suggest that ghrelin-mediated pathways of ACTH release might be activated by thyroid hormone excess, but adrenocortical reserve is maintained.

  14. Caloric Restriction Protects against Lactacystin-Induced Degeneration of Dopamine Neurons Independent of the Ghrelin Receptor

    PubMed Central

    Coppens, Jessica; Bentea, Eduard; Bayliss, Jacqueline A.; Demuyser, Thomas; Walrave, Laura; Albertini, Giulia; Van Liefferinge, Joeri; Deneyer, Lauren; Aourz, Najat; Van Eeckhaut, Ann; Portelli, Jeanelle; Andrews, Zane B.; Massie, Ann; De Bundel, Dimitri; Smolders, Ilse

    2017-01-01

    Parkinson’s disease (PD) is a neurodegenerative disorder, characterized by a loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNc). Caloric restriction (CR) has been shown to exert ghrelin-dependent neuroprotective effects in the 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine (MPTP)-based animal model for PD. We here investigated whether CR is neuroprotective in the lactacystin (LAC) mouse model for PD, in which proteasome disruption leads to the destruction of the DA neurons of the SNc, and whether this effect is mediated via the ghrelin receptor. Adult male ghrelin receptor wildtype (WT) and knockout (KO) mice were maintained on an ad libitum (AL) diet or on a 30% CR regimen. After 3 weeks, LAC was injected unilaterally into the SNc, and the degree of DA neuron degeneration was evaluated 1 week later. In AL mice, LAC injection significanty reduced the number of DA neurons and striatal DA concentrations. CR protected against DA neuron degeneration following LAC injection. However, no differences were observed between ghrelin receptor WT and KO mice. These results indicate that CR can protect the nigral DA neurons from toxicity related to proteasome disruption; however, the ghrelin receptor is not involved in this effect. PMID:28273852

  15. 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

  16. Biostimulation and nursing modify mating-induced c-FOS immunoreactivity in the female rabbit forebrain.

    PubMed

    González-Mariscal, Gabriela; García Dalmán, Cipatli; Jiménez, Angeles

    2015-05-22

    Mating in rabbits lasts only 3-5s but profoundly changes the female׳s physiology and behavior (e.g., inhibition of scent-marking and ambulation, changes in EEG, and release of GnRH). The behavioral responsiveness to copulation is reduced in lactating rabbits, relative to estrous does, but is enhanced after suppressing a single nursing bout ("biostimulation"). Little is known about the mechanisms mediating the differential responsiveness to mating among estrous, lactating, and biostimulated rabbits. To begin addressing this issue we quantified the number of c-FOS-immunoreactive (IR) cells in the preoptic area (POA), dorsomedial hypothalamus (DMH), ventromedial hypothalamus (VMH), infundibular nucleus (INF), paraventricular nucleus (PVN), supraoptic nucleus (SON), and lateral septum (LS) in mated and unmated does from the above three reproductive conditions. Mating increased c-FOS-IR cells in the POA and PVN relative to unmated estrous does. Biostimulation increased c-FOS-IR cells in the PVN, relative to lactating does, regardless of mating. Lactation reduced the responsiveness of the LS and INF to copulation but increased it in the DMH. No differences were found in the VMH. a) copulation activates forebrain nuclei that regulate scent-marking (POA), ovulation (INF), and post-coital oxytocin release (PVN); b) lactation and suppression of one nursing bout modulate the magnitude of such changes. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. 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.

  18. 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.

  19. 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.

  20. Differential involvement of 3', 5'-cyclic adenosine monophosphate-dependent protein kinase in regulation of Fos and tyrosine hydroxylase expression in the heart after naloxone induced morphine withdrawal.

    PubMed

    Almela, Pilar; Cerezo, Manuela; González-Cuello, A; Milanés, M Victoria; Laorden, M Luisa

    2007-01-01

    We previously demonstrated that morphine withdrawal induced hyperactivity of the heart by the activation of noradrenergic pathways innervating the left and right ventricle, as evaluated by noradrenaline (NA) turnover and Fos expression. We investigated whether cAMP-dependent protein kinase (PKA) plays a role in this process by estimating changes in PKA immunoreactivity and the influence of inhibitor of PKA on Fos protein expression, tyrosine hydroxylase (TH) immunoreactivity levels and NA turnover in the left and right ventricle. Dependence on morphine was induced by a 7-day s.c. implantation of morphine pellets. Morphine withdrawal was precipitated on day 8 by an injection of naloxone (5 mg/kg). When opioid withdrawal was precipitated, an increase in PKA immunoreactivity and phospho-CREB (cyclic AMP response element protein) levels were observed in the heart. Moreover, morphine withdrawal induces Fos expression, an enhancement of NA turnover and an increase in the total TH levels. When the selective PKA inhibitor HA-1004 was infused, concomitantly with morphine pellets, it diminished the increase in NA turnover and the total TH levels observed in morphine-withdrawn rats. However, this inhibitor neither modifies the morphine withdrawal induced Fos expression nor the increase of nonphosphorylated TH levels. The present findings indicate that an up-regulated PKA-dependent transduction pathway might contribute to the activation of the cardiac catecholaminergic neurons in response to morphine withdrawal and suggest that Fos is not a target of PKA at heart levels.

  1. Delta 9-tetrahydrocannabinol suppresses vomiting behavior and Fos expression in both acute and delayed phases of cisplatin-induced emesis in the least shrew.

    PubMed

    Ray, Andrew P; Griggs, Lisa; Darmani, Nissar A

    2009-01-03

    Cisplatin chemotherapy frequently causes severe vomiting in two temporally separated clusters of bouts dubbed the acute and delayed phases. Cannabinoids can inhibit the acute phase, albeit through a poorly understood mechanism. We examined the substrates of cannabinoid-mediated inhibition of both the emetic phases via immunolabeling for serotonin, Substance P, cannabinoid receptors 1 and 2 (CB(1), CB(2)), and the neuronal activation marker Fos in the least shrew (Cryptotis parva). Shrews were injected with cisplatin (10mg/kg i.p.), and one of vehicle, Delta(9)-THC, or both Delta(9)-THC and the CB(1) receptor antagonist SR141716A (2mg/kg i.p.), and monitored for vomiting. Delta(9)-THC-pretreatment caused concurrent decreases in the number of shrews expressing vomiting and Fos-immunoreactivity (Fos-IR), effects which were blocked by SR141716A-pretreatment. Acute phase vomiting induced Fos-IR in the solitary tract nucleus (NTS), dorsal motor nucleus of the vagus (DMNX), and area postrema (AP), whereas in the delayed phase Fos-IR was not induced in the AP at all, and was induced at lower levels in the other nuclei when compared to the acute phase. CB(1) receptor-IR in the NTS was dense, punctate labeling indicative of presynaptic elements, which surrounded Fos-expressing NTS neurons. CB(2) receptor-IR was not found in neuronal elements, but in vascular-appearing structures. All areas correlated with serotonin- and Substance P-IR. These results support published acute phase data in other species, and are the first describing Fos-IR following delayed phase emesis. The data suggest overlapping but separate mechanisms are invoked for each phase, which are sensitive to antiemetic effects of Delta(9)-THC mediated by CB(1) receptors.

  2. Role of hormonal axis, growth hormone - IGF-1, in the therapeutic effect of ghrelin in the course of cerulein-induced acute pancreatitis.

    PubMed

    Ceranowicz, D; Warzecha, Z; Dembinski, A; Ceranowicz, P; Cieszkowski, J; Kusnierz-Cabala, B; Tomaszewska, R; Kuwahara, A; Kato, I

    2010-10-01

    Ghrelin is a ligand for growth hormone secretagogue receptor and stimulates release of growth hormone (GH). Recent studies have shown that treatment with ghrelin exhibits protective and therapeutic effect in the course of experimental pancreatitis. The aim of present study was to examine the role of GH and insulin-like growth factor-1 (IGF-1) in these effects. Acute pancreatitis was induced by cerulein. Study was performed on pituitary-intact hypophysectomized rats. Ghrelin was administered twice a day at the dose of 8 nmol/kg/dose. IGF-1 was given twice a day at the dose of 20 nmol/kg/dose. The severity of acute pancreatitis was assessed 0 h or 1, 2, 3, 5 and 10 days after the last dose of cerulein. Administration of cerulein led to the development of acute edematous pancreatitis. In pituitary-intact rats, treatment with ghrelin reduced biochemical indexes of the severity of acute pancreatitis and morphological signs of pancreatic damage, leading to faster regeneration of the pancreas reduction in serum concentration of pro-inflammatory interleukin-1β and decrease in serum activity of amylase and lipase. These effects were accompanied with an improvement of pancreatic blood flow and an increase in pancreatic DNA synthesis. Hypophysectomy delayed the healing of the pancreas and abolished the therapeutic effect of ghrelin. In hypophysectomized rats with pancreatitis, treatment with IGF-1 exhibits therapeutic effect similar to that observed in ghrelin-treated rats with the intact pituitary. We conclude that therapeutic effect of ghrelin in cerulein-induced pancreatitis is indirect and depends on the release of GH and IGF-1.

  3. Aging effects on exercise-induced alternations in plasma acylated ghrelin and leptin in male rats.

    PubMed

    Hsu, Ya-Wen; Pan, Yi-Ju; Cho, Yu-Min; Liou, Tsan-Hon; Chou, Pesus; Wang, Paulus S

    2011-05-01

    Ghrelin and exercise have been known to stimulate the release of growth hormone which is related to the glucose metabolism. However, the age effects of exercise on ghrelin in energy consumption remain unclear. Young (3 month old) and middle-aged (12 month old) Sprague-Dawley male rats were overnight fasted, and then randomly partitioned into exercise and control groups. Exercise groups swam for 20 min in 25°C water. Rats immersed in 25°C water for 20 min were used as control animals. All blood samples were collected before and 10, 20, 30, and 60 min after initiation of exercise via the right jugular vein. Our results indicated that the swimming regimen decreased the secretion of acylated ghrelin and insulin, but increased the secretion of leptin, lactate, and glucose. In addition, exercise significantly amplified the inverse correlation between leptin and acylated ghrelin (r < -0.6) in middle-age group. Both the above findings were not emphasized in related articles before. Moreover, the time courses of these changes were slightly different in young and middle-aged rats. In basal metabolic characteristics, body weight and the plasma lactate, glucose, insulin, and leptin are higher in middle-age group than that in young group. In conclusion, compared with young rats, middle-aged rats have higher basal body weight, plasma glucose, insulin, and leptin, but age had no effect on the level of plasma acylated ghrelin. A 20-min exercise regimen decreased acylated ghrelin and increased leptin with inverse correlation between them which was strengthened during exercise, but were not influenced by age.

  4. UV-induced DNA damage is an intermediate step in UV-induced expression of human immunodeficiency virus type 1, collagenase, c-fos, and metallothionein

    SciTech Connect

    Stein, B.; Rahmsdorf, H.J.; Steffen, A.; Litfin, M.; Herrlich, P. )

    1989-11-01

    UV irradiation of human and murine cells enhances the transcription of several genes. Here we report on the primary target of relevant UV absorption, on pathways leading to gene activation, and on the elements receiving the UV-induced signal in the human immunodeficiency virus type 1 (HIV-1) long terminal repeat, in the gene coding for collagenase, and in the cellular oncogene fos. In order to induce the expression of genes, UV radiation needs to be absorbed by DNA and to cause DNA damage of the kind that cannot be repaired by cells from patients with xeroderma pigmentosum group A. UV-induced activation of the three genes is mediated by the major enhancer elements (located between nucleotide positions -105 and -79 of HIV-1, between positions -72 and -65 of the collagenase gene, and between positions -320 and -299 of fos). These elements share no apparent sequence motif and bind different trans-acting proteins; a member of the NF kappa B family binds to the HIV-1 enhancer, the heterodimer of Jun and Fos (AP-1) binds to the collagenase enhancer, and the serum response factors p67 and p62 bind to fos. DNA-binding activities of the factors recognizing the HIV-1 and collagenase enhancers are augmented in extracts from UV-treated cells. The increase in activity is due to posttranslational modification. While AP-1 resides in the nucleus and must be modulated there, NF kappa B is activated in the cytoplasm, indicating the existence of a cytoplasmic signal transduction pathway triggered by UV-induced DNA damage. In addition to activation, new synthesis of AP-1 is induced by UV radiation.

  5. Effects of electroacupuncture on ethanol-induced impairments of spatial learning and memory and Fos expression in the hippocampus in rats.

    PubMed

    Lu, Bin; Ma, Zhao; Cheng, Fei; Zhao, Yan; Zhang, Xin; Mao, Huijuan; Shen, Xueyong; Liu, Sheng

    2014-07-25

    It is well established that alcohol impairs spatial learning and memory. Here, we investigated the effects of electroacupuncture (EA) at ST36 or nonacupoint on ethanol-induced learning and memory impairment and the expression of Fos in the hippocampus. Ethanol (5g/kg) was administered intragastrically once a day for 5 consecutive days; 2Hz EA was administered immediately after ethanol exposure. After a 2-day ethanol abstinence, for 6 consecutive days, the rats were submitted to Morris water maze training. Probe trials were performed on 1 day after the final training session. We also applied immunohistochemistry to detect Fos-positive nuclei in the hippocampus. We found that 5-day ethanol exposure markedly decreased spatial learning and memory abilities in the Morris water maze task as indicated by escape latency and time in the target quadrant. EA treatment shortened the time of reaching platform and increased times traveled in the target quadrant (P<0.05). Animals administered with ethanol emitted significantly fewer Fos expression in the hippocampal CA1 area. EA increased Fos expression in the hippocampal CA1 area. Significant correlations were obtained between Fos protein expression in CA1 and time in the target quadrant. Altogether, these results suggest that EA protects against ethanol-induced impairments of spatial learning and memory, which may be involved in the hippocampal CA1 area. EA treatment may provide a novel nonpharmacological strategy for ethanol-induced learning and memory impairment.

  6. The effects of DL-AP5 and glutamate on ghrelin-induced feeding behavior in 3-h food-deprived broiler cockerels.

    PubMed

    Taati, Majid; Nayebzadeh, Hassan; Zendehdel, Morteza

    2011-06-01

    This study was designed to examine the effects of intracerebroventricular injection of DL-AP5 (N-methyl-D-aspartate (NMDA) receptor antagonist) and glutamate on ghrelin-induced feeding behavior in 3-h food-deprived (FD3) broiler cockerels. At first, guide cannula was surgically implanted in the right lateral ventricle of chickens. In experiment 1, birds were intracerebroventricularly injected with 0, 2.5, 5, and 10 nmol of DL-AP5. In experiment 2, chickens received 5 nmol DL-AP5 prior to the injection of 0.6 nmol ghrelin. In experiment 3, birds were administered with 0.6 nmol ghrelin after 300 nmol glutamate, and the cumulative feed intake was determined at 3-h postinjection. The results of this study showed that the intracerebroventricular injection of DL-AP5 increased food consumption in FD3 broiler cockerels (P ≤ 0.05), and this increase occurs in a dose-dependent manner. Moreover, the decreased food intake induced with the intracerebroventricular injection of ghrelin was additively enhanced by pretreatment with glutamate, and this effect was attenuated by DL-AP5 administration(P ≤ 0.05).These results suggest that there is an interaction between ghrelin and glutamatergic system (through NMDA receptor) on food intake in broiler cockerels.

  7. c-Fos expression in the paternal mouse brain induced by communicative interaction with maternal mates.

    PubMed

    Zhong, Jing; Liang, Mingkun; Akther, Shirin; Higashida, Chiharu; Tsuji, Takahiro; Higashida, Haruhiro

    2014-09-11

    Appropriate parental care by fathers greatly facilitates health in human family life. Much less is known from animal studies regarding the factors and neural circuitry that affect paternal behavior compared with those affecting maternal behavior. We recently reported that ICR mouse sires displayed maternal-like retrieval behavior when they were separated from pups and caged with their mates (co-housing) because the sires receive communicative interactions via ultrasonic and pheromone signals from the dams. We investigated the brain structures involved in regulating this activity by quantifying c-Fos-immunoreactive cells as neuronal activation markers in the neural pathway of male parental behavior. c-Fos expression in the medial preoptic area (mPOA) was significantly higher in sires that exhibited retrieval behavior (retrievers) than those with no such behavior (non-retrievers). Identical increased expression was found in the mPOA region in the retrievers stimulated by ultrasonic vocalizations or pheromones from their mates. Such increases in expression were not observed in the ventral tegmental area (VTA), nucleus accumbens (NAcc) or ventral palladium (VP). On the following day that we identified the families of the retrievers or non-retrievers, c-Fos expression in neuronal subsets in the mPOA, VTA, NAcc and VP was much higher in the retriever sires when they isolated together with their mates in new cages. This difference was not observed in the singly isolated retriever sires in new cages. The non-retriever sires did not display expression changes in the four brain regions that were assessed. The mPOA neurons appeared to be activated by direct communicative interactions with mate dams, including ultrasonic vocalizations and pheromones. The mPOA-VTA-NAcc-VP neural circuit appears to be involved in paternal retrieval behavior.

  8. Cytisine modulates chronic voluntary ethanol consumption and ethanol-induced striatal up-regulation of ΔFosB in mice.

    PubMed

    Sajja, Ravi Kiran; Rahman, Shafiqur

    2013-06-01

    Chronic administration of ethanol induces persistent accumulation of ΔFosB, an important transcription factor, in the midbrain dopamine system. This process underlies the progression to addiction. Previously, we have shown that cytisine, a neuronal nicotinic acetylcholine receptor (nAChR) partial agonist, reduces various ethanol-drinking behaviors and ethanol-induced striatal dopamine function. However, the effects of cytisine on chronic ethanol drinking and ethanol-induced up-regulation of striatal ΔFosB are not known. Therefore, we examined the effects of cytisine on chronic voluntary ethanol consumption and associated striatal ΔFosB up-regulation in C57BL/6J mice using behavioral and biochemical methods. Following the chronic voluntary consumption of 15% (v/v) ethanol under a 24-h two-bottle choice intermittent access (IA; 3 sessions/week) or continuous access (CA; 24 h/d and 7 d/week) paradigm, mice received repeated intraperitoneal injections of saline or cytisine (0.5 or 3.0 mg/kg). Ethanol and water intake were monitored for 24 h post-treatment. Pretreatment with cytisine (0.5 or 1.5 mg/kg) significantly reduced ethanol consumption and preference in both paradigms at 2 h and 24 h post-treatment. The ΔFosB levels in the ventral and dorsal striatum were determined by Western blotting 18-24 h after the last point of ethanol access. In addition, cytisine (0.5 mg/kg) significantly attenuated up-regulation of ΔFosB in the ventral and dorsal striatum following chronic ethanol consumption in IA and CA paradigms. The results indicate that cytisine modulates chronic voluntary ethanol consumption and reduces ethanol-induced up-regulation of striatal ΔFosB. Further, the data suggest a critical role of nAChRs in chronic ethanol-induced neurochemical adaptations associated with ethanol addiction.

  9. Ghrelin promotes thymopoiesis during aging

    PubMed Central

    Dixit, Vishwa Deep; Yang, Hyunwon; Sun, Yuxiang; Weeraratna, Ashani T.; Youm, Yun-Hee; Smith, Roy G.; Taub, Dennis D.

    2007-01-01

    The decline in adaptive immunity, T lymphocyte output, and the contraction of the TCR repertoire with age is largely attributable to thymic involution. The loss of thymic function with age may be due to diminished numbers of progenitors and the loss of critical cytokines and hormones from the thymic microenvironment. We have previously demonstrated that the orexigenic hormone ghrelin is expressed by immune cells and regulates T cell activation and inflammation. Here we report that ghrelin and ghrelin receptor expression within the thymus diminished with progressive aging. Infusion of ghrelin into 14-month-old mice significantly improved the age-associated changes in thymic architecture and thymocyte numbers, increasing recent thymic emigrants and improving TCR diversity of peripheral T cell subsets. Ghrelin-induced thymopoiesis during aging was associated with enhanced early thymocyte progenitors and bone marrow–derived Lin–Sca1+cKit+ cells, while ghrelin- and growth hormone secretagogue receptor–deficient (GHS-R–deficient) mice displayed enhanced age-associated thymic involution. Leptin also enhanced thymopoiesis in aged but not young mice. Our findings demonstrate what we believe to be a novel role for ghrelin and its receptor in thymic biology and suggest a possible therapeutic benefit of harnessing this pathway in the reconstitution of thymic function in immunocompromised subjects. PMID:17823656

  10. 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

  11. 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. Copyright 2002 Elsevier Science B.V.

  12. The role of ghrelin in reward-based eating

    PubMed Central

    Perelló, Mario; Zigman, Jeffrey M.

    2012-01-01

    The peptide hormone ghrelin acts in the central nervous system as a potent orexigenic signal. Not only is ghrelin recognized as playing an important role in feeding circuits traditionally thought of as affecting body weight homeostasis, but an accumulating number of scientific studies now have identified ghrelin as being a key regulator of reward-based, hedonic eating behaviors. In the current article, we review ghrelin’s orexigenic actions, the evidence linking ghrelin to food reward behavior, potential mechanisms by which ghrelin mediates reward-based eating behavior, and those studies suggesting an obligatory role for ghrelin in the changed eating behaviors induced by stress. PMID:22458951

  13. Medial prefrontal cortex neuronal activation and synaptic alterations after stress-induced reinstatement of palatable food seeking: a study using c-fos-GFP transgenic female rats.

    PubMed

    Cifani, Carlo; Koya, Eisuke; Navarre, Brittany M; Calu, Donna J; Baumann, Michael H; Marchant, Nathan J; Liu, Qing-Rong; Khuc, Thi; Pickel, James; Lupica, Carl R; Shaham, Yavin; Hope, Bruce T

    2012-06-20

    Relapse to maladaptive eating habits during dieting is often provoked by stress and there is evidence for a role of ovarian hormones in stress responses and feeding. We studied the role of these hormones in stress-induced reinstatement of food seeking and medial prefrontal cortex (mPFC) neuronal activation in c-fos-GFP transgenic female rats, which express GFP in strongly activated neurons. Food-restricted ovariectomized or sham-operated c-fos-GFP rats were trained to lever-press for palatable food pellets. Subsequently, lever-pressing was extinguished and reinstatement of food seeking and mPFC neuronal activation was assessed after injections of the pharmacological stressor yohimbine (0.5-2 mg/kg) or pellet priming (1-4 noncontingent pellets). Estrous cycle effects on reinstatement were also assessed in wild-type rats. Yohimbine- and pellet-priming-induced reinstatement was associated with Fos and GFP induction in mPFC; both reinstatement and neuronal activation were minimally affected by ovarian hormones in both c-fos-GFP and wild-type rats. c-fos-GFP transgenic rats were then used to assess glutamatergic synaptic alterations within activated GFP-positive and nonactivated GFP-negative mPFC neurons following yohimbine-induced reinstatement of food seeking. This reinstatement was associated with reduced AMPA receptor/NMDA receptor current ratios and increased paired-pulse facilitation in activated GFP-positive but not GFP-negative neurons. While ovarian hormones do not appear to play a role in stress-induced relapse of food seeking in our rat model, this reinstatement was associated with unique synaptic alterations in strongly activated mPFC neurons. Our paper introduces the c-fos-GFP transgenic rat as a new tool to study unique synaptic changes in activated neurons during behavior.

  14. 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. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. 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 Central

    Carroll, Marilyn E.; Meisel, Robert L.

    2013-01-01

    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 that 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 either 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. PMID:22613730

  16. Unacylated ghrelin promotes adipogenesis in rodent bone marrow via ghrelin O-acyl transferase and GHS-R1a activity: evidence for target cell-induced acylation

    PubMed Central

    Hopkins, Anna L.; Nelson, Timothy A. S.; Guschina, Irina A.; Parsons, Lydia C.; Lewis, Charlotte L.; Brown, Richard C.; Christian, Helen C.; Davies, Jeffrey S.; Wells, Timothy

    2017-01-01

    Despite being unable to activate the cognate ghrelin receptor (GHS-R), unacylated ghrelin (UAG) possesses a unique activity spectrum that includes promoting bone marrow adipogenesis. Since a receptor mediating this action has not been identified, we re-appraised the potential interaction of UAG with GHS-R in the regulation of bone marrow adiposity. Surprisingly, the adipogenic effects of intra-bone marrow (ibm)-infused acylated ghrelin (AG) and UAG were abolished in male GHS-R-null mice. Gas chromatography showed that isolated tibial marrow adipocytes contain the medium-chain fatty acids utilised in the acylation of UAG, including octanoic acid. Additionally, immunohistochemistry and immunogold electron microscopy revealed that tibial marrow adipocytes show prominent expression of the UAG-activating enzyme ghrelin O-acyl transferase (GOAT), which is located in the membranes of lipid trafficking vesicles and in the plasma membrane. Finally, the adipogenic effect of ibm-infused UAG was completely abolished in GOAT-KO mice. Thus, the adipogenic action of exogenous UAG in tibial marrow is dependent upon acylation by GOAT and activation of GHS-R. This suggests that UAG is subject to target cell-mediated activation – a novel mechanism for manipulating hormone activity. PMID:28361877

  17. 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.

  18. 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.

  19. 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

    2013-08-09

    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. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  20. Role of aquaporin-7 in ghrelin- and GLP-1-induced improvement of pancreatic β-cell function after sleeve gastrectomy in obese rats.

    PubMed

    Méndez-Giménez, L; Becerril, S; Camões, S P; da Silva, I V; Rodrigues, C; Moncada, R; Valentí, V; Catalán, V; Gómez-Ambrosi, J; Miranda, J P; Soveral, G; Frühbeck, G; Rodríguez, A

    2017-09-01

    Glycerol is a key metabolite for lipid accumulation in insulin-sensitive tissues as well as for pancreatic insulin secretion. We examined the role of aquaporin-7 (AQP7), the main glycerol channel in β-cells, and AQP12, an aquaporin related to pancreatic damage, in the improvement of pancreatic function and steatosis after sleeve gastrectomy in diet-induced obese rats. Male Wistar obese rats (n=125) were subjected to surgical (sham operation and sleeve gastrectomy) or dietary (pair-fed to the amount of food eaten by sleeve-gastrectomized animals) interventions. The tissue distribution and expression of AQPs in the rat pancreas were analyzed by real-time PCR, western blotting and immunohistochemistry. The effect of ghrelin isoforms and glucagon-like peptide 1 (GLP-1) on insulin secretion, triacylglycerol (TG) accumulation and AQP expression was determined in vitro in RIN-m5F β-cells. Sleeve gastrectomy reduced pancreatic β-cell apoptosis, steatosis and insulin secretion. Lower ghrelin and higher GLP-1 concentrations were also found after bariatric surgery. Acylated and desacyl ghrelin increased TG content, whereas GLP-1 increased insulin release in RIN-m5F β-cells. Sleeve gastrectomy was associated with an upregulation of AQP7 together with a normalization of the increased AQP12 levels in the rat pancreas. Interestingly, ghrelin and GLP-1 repressed AQP7 and AQP12 expression in RIN-m5F β-cells. AQP7 protein was negatively correlated with intracellular lipid accumulation in acylated ghrelin-treated cells and with insulin release in GLP-1-stimulated β-cells. AQP7 upregulation in β-cells after sleeve gastrectomy contributes, in part, to the improvement of pancreatic steatosis and insulin secretion by increasing intracellular glycerol used for insulin release triggered by GLP-1 rather than for ghrelin-induced TG biosynthesis.

  1. Chronic ghrelin treatment reduced photophobia and anxiety-like behaviors in nitroglycerin- induced migraine: role of pituitary adenylate cyclase-activating polypeptide.

    PubMed

    Farajdokht, Fereshteh; Babri, Shirin; Karimi, Pouran; Alipour, Mohammad Reza; Bughchechi, Ramin; Mohaddes, Gisou

    2017-03-01

    Chronic migraine is a debilitating disorder that has a significant impact on patients and society. Nearly all migraineurs frequently reported light sensitivity during a headache attack. Pituitary adenylate cyclase-activating polypeptide (PACAP) plays an important role in the activation of trigeminal system and migraine pain. To identify the effect of chronic ghrelin treatment on endogenous PACAP and associated symptoms of migraine, an experimental chronic migraine model was induced by intermittent intraperitoneal (i.p) injection of nitroglycerin (NTG). Photophobia and anxiety-like behaviors were determined in the modified elevated plus maze on days 2, 4, 6, 8, and 10 and in the light/dark box on days 3, 5, 7, 9, and 11. Blood levels of PACAP and cortisol were assessed by enzyme-linked immunosorbent (ELISA) kits. Chronic injection of NTG evoked photophobia and anxiety-like behaviors and treatment with ghrelin (150 μg/kg) for 11 days effectively attenuated photophobia and anxiety-like behaviors in the both paradigms. We further found that NTG increased the blood levels of PACAP and cortisol, which was significantly reduced by ghrelin treatment. Additionally, staining with Hematoxylin and Eosin (H&E) revealed that ghrelin reduced NTG-induced increase in the number of satellite glial cells in the trigeminal ganglion. Furthermore, for the first time we showed that repeated administrations of NTG increased white blood cell (WBC) counts and mean platelet volume (MPV), and decreased platelet counts. These results indicated that ghrelin decreased migraine associated symptoms possibly through attenuating endogenous PACAP and cortisol levels. Therefore, ghrelin may hold therapeutic potentialities in managing the chronic migraine.

  2. TGF alpha and v-fos cooperation in transgenic mouse epidermis induces aberrant keratinocyte differentiation and stable, autonomous papillomas.

    PubMed

    Wang, X J; Greenhalgh, D A; Lu, X R; Bickenbach, J R; Roop, D R

    1995-01-19

    To assess the synergistic effect of growth and transcription factor deregulation on carcinogenesis in vivo, mating experiments were performed between transgenic mice expressing human TGF alpha or v-fos exclusively in the epidermis by means of a human keratin K1-based targeting vector (HK1.fos, HK1.TGF alpha and HK1.fos/alpha). While HK1.TGF alpha mice exhibited mild epidermal hyperplasia resulting in a wrinkled appearance, this hyperplasia was significantly increased in HK1.fos/alpha mice which also exhibited a novel opalescent and peeling skin phenotype. HK1.fos/alpha keratinocyte differentiation was considerably deregulated with cornified cells appearing in the granular layer, granular cells in the spinous layer and a sixfold increase in BrdU labeling over normal. In addition, hyperplastic HK1.fos/alpha epidermis exhibited aberrant loricrin, filaggrin and novel K13 expression associated with v-fos expression. Unlike adult HK1.TGF alpha controls, hyperplasia persisted in HK1.fos/alpha adults which also rapidly developed autonomous squamous cell papillomas. These results demonstrate that v-fos and TGF alpha over-expression can cooperate to reprogram keratinocyte differentiation and elicit the early stages of neoplasia. Moreover, TGF alpha over-expression appeared to play an early, initiating role in HK1.fos/alpha papilloma etiology, and a promotion role in the accelerated appearance of v-fos wound-associated preneoplastic phenotypes. However, the stable persistence of HK1.fos/alpha papillomas for up to 12 months, suggests that additional events are required for malignant conversion.

  3. 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

  4. TMJ inflammation increases Fos expression in the nucleus raphe magnus induced by subsequent formalin injection of the masseter or hindpaw of rats.

    PubMed

    Oh, Sang-Hoon; Imbe, Hiroki; Iwai-Liao, Yasutomo

    2006-08-01

    The study was designed to examine the effect of persistent temporomandibular joint (TMJ) inflammation on neuronal activation in the descending pain modulatory system in response to noxious stimulus. Formalin was injected into the left masseter muscle or hindpaw of rats 10 days after injection of the left TMJ with saline or complete Freund's adjuvant (CFA). The results showed that 10-day persistent TMJ inflammation (induced by CFA) alone did not induce a significant increase in Fos-like immunoreactive (Fos-LI) neurons in the rostral ventromedial medulla (RVM) or locus coeruleus (LC), but that formalin injection of the masseter muscle or hindpaw induced a significant increase in Fos-LI neurons in the RVM and LC of rats with and without TMJ inflammation (P < 0.05). However, persistent TMJ inflammation significantly increased Fos-LI neurons in the nucleus raphe magnus (NRM) induced by subsequent formalin injection of the masseter muscle and hindpaw (70.2% increase and 53.8% increase, respectively, over the control TMJ-saline-injected rats; P < 0.05). The results suggest that persistent TMJ inflammation increases neuronal activity, in particularly in the NRM, by the plastic change of the descending pain modulatory system after ipsilateral application of a noxious stimulus to either orofacial area or a spatially remote body area.

  5. Characterization of the transduction pathway involved in c-fos and c-jun expression induced by Aggregatibacter actinomycetemcomitans lipopolysaccharides in human gingival fibroblasts.

    PubMed

    Gutiérrez-Venegas, Gloria; Castillo-Alemán, Ramiro

    2008-11-01

    Periodontal disease is an inflammatory disease caused by infection with oral bacteria that results in tooth exfoliation. Lipopolysaccharides (LPS) are a major component of the outer membrane of Gram-negative microorganisms and are involved in the inflammatory response. c-fos and c-jun are involved in pathological conditions such as inflammatory disorders. Inflammatory signaling cascades leading to c-fos activation in human gingival fibroblasts (HGFs) are not well characterized. Thus, we have investigated the kinase pathways involved in c-fos and c-jun activation induced by LPS in human gingival fibroblasts. LPS promoted a dose- and time-dependent increase in c-fos transcription. Phosphoinositide-phospholipase C inhibitor (U-73122), protein kinase A inhibitor (H89), MEK1 inhibitor (PD 98,059), p38 inhibitor (SB203580), and tyrosine kinase inhibitors (genistein and herbimycin) attenuated the LPS effect, while the PI-3 K inhibitor (Wortmannin) had no effect on LPS-induced c-fos transcription. Protein kinase C inhibitors (Ro 31-8220, calphostin C, staurosporine, and chelerythrine chloride) also inhibited LPS-induced c-fos transcription. However, long-term treatment (24 -h) with the PKC activator tetradecanoyl phorbol-13-acetate (PMA) had no significant effect on LPS-induced transcription in HGFs. We also found an increase in c-jun expression in HGF stimulated with LPS. In addition, experiments using pharmacological inhibitors of individual mitogen-activated protein kinases (MAPK) and of protein kinase C (PKC) revealed that p38, ERK 1/2, and PKC are involved in LPS-induced c-jun expression. Our results indicate that LPS-induced c-fos and c-jun expressions are mediated by two different signaling pathways: one through phosphoinositide-phospholipase C via an upstream protein tyrosine kinase, which activates PKC isoforms that are insensitive to phorbol stress, and the second through activation of protein kinase A (PKA). Both kinases regulate the phosphorylation of the

  6. Heterodimers of the transcriptional factors NFATc3 and FosB mediate tissue factor expression for 15(S)-hydroxyeicosatetraenoic acid-induced monocyte trafficking.

    PubMed

    Kotla, Sivareddy; Singh, Nikhlesh K; Kirchhofer, Daniel; Rao, Gadiparthi N

    2017-09-08

    Tissue factor (TF) is expressed in vascular and nonvascular tissues and functions in several pathways, including embryonic development, inflammation, and cell migration. Many risk factors for atherosclerosis, including hypertension, diabetes, obesity, and smoking, increase TF expression. To better understand the TF-related mechanisms in atherosclerosis, here we investigated the role of 12/15-lipoxygenase (12/15-LOX) in TF expression. 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE), the major product of human 15-LOXs 1 and 2, induced TF expression and activity in a time-dependent manner in the human monocytic cell line THP1. Moreover, TF suppression with neutralizing antibodies blocked 15(S)-HETE-induced monocyte migration. We also found that NADPH- and xanthine oxidase-dependent reactive oxygen species (ROS) production, calcium/calmodulin-dependent protein kinase IV (CaMKIV) activation, and interactions between nuclear factor of activated T cells 3 (NFATc3) and FosB proto-oncogene, AP-1 transcription factor subunit (FosB) are involved in 15(S)-HETE-induced TF expression. Interestingly, NFATc3 first induced the expression of its interaction partner FosB before forming the heterodimeric NFATc3-FosB transcription factor complex, which bound the proximal AP-1 site in the TF gene promoter and activated TF expression. We also observed that macrophages from 12/15-LOX(-/-) mice exhibit diminished migratory response to monocyte chemotactic protein 1 (MCP-1) and lipopolysaccharide compared with WT mouse macrophages. Similarly, compared with WT macrophages, monocytes from 12/15-LOX(-/-) mice displayed diminished trafficking, which was rescued by prior treatment with 12(S)-HETE, in a peritonitis model. These observations indicate that 15(S)-HETE-induced monocyte/macrophage migration and trafficking require ROS-mediated CaMKIV activation leading to formation of NFATc3 and FosB heterodimer, which binds and activates the TF promoter. © 2017 by The American Society for

  7. Transcutaneous electrical nerve stimulation on Yongquan acupoint reduces CFA-induced thermal hyperalgesia of rats via down-regulation of ERK2 phosphorylation and c-Fos expression.

    PubMed

    Yang, Lin; Yang, Lianxue; Gao, Xiulai

    2010-07-01

    Activation of extracellular signal-regulated kinase-1/2 (ERK1/2) and its involvement in regulating gene expression in spinal dorsal horn, cortical and subcortical neurons by peripheral noxious stimulation contribute to pain hypersensitivity. Transcutaneous electrical nerve stimulation (TENS) is a treatment used in physiotherapy practice to promote analgesia in acute and chronic inflammatory conditions. In this study, a total number of 114 rats were used for three experiments. Effects of complete Freund's adjuvant (CFA)-induced inflammatory pain hypersensitivity and TENS analgesia on ERK1/2 phosphorylation and c-Fos protein expression were examined by using behavioral test, Western blot, and immunostaining methods. We found that CFA injection caused an area of localized swelling, erythema, hypersensitivity to thermal stimuli, the decreased response time of hind paw licking (HPL), as well as upregulation of c-Fos protein expression and ERK2 phosphorylation in the ipsilateral spinal dorsal horn and the contralateral primary somatosensory area of cortex and the amygdala of rats. TENS on Yongquan acupoint for 20 min produced obvious analgesic effects as demonstrated with increased HPL to thermal stimuli of CFA-treated rats. In addition, TENS application suppressed the CFA-induced ERK2 activation and c-Fos protein expression. These results suggest that down-regulation of ERK2 phosphorylation and c-Fos expression were involved in TENS inhibition on CFA-induced thermal hyperalgesia of rats.

  8. Activation of MAPK/c-Fos induced responses in oral epithelial cells is specific to Candida albicans and Candida dubliniensis hyphae.

    PubMed

    Moyes, David L; Murciano, Celia; Runglall, Manohursingh; Kohli, Arinder; Islam, Ayesha; Naglik, Julian R

    2012-02-01

    Oral epithelial cells detect the human pathogenic fungus Candida albicans via NF-κB and a bi-phasic mitogen-activated protein kinase (MAPK) signaling response. However, discrimination between C. albicans yeast and hyphal forms is mediated only by the MAPK pathway, which constitutes activation of the MAPK phosphatase MKP1 and the c-Fos transcription factor and is targeted against the hyphal form. Given that C. albicans is not the only Candida species capable of filamentation or causing mucosal infections, we sought to determine whether this MAPK/MKP1/c-Fos mediated response mechanism was activated by other pathogenic Candida species, including C. dubliniensis, C. tropicalis, C. parapsilosis, C. glabrata and C. krusei. Although all Candida species activated the NF-κB signaling pathway, only C. albicans and C. dubliniensis were capable of inducing MKP1 and c-Fos activation, which directly correlated with hypha formation. However, only C. albicans strongly induced cytokine production (G-CSF, GM-CSF, IL-6 and IL-1α) and cell damage. Candida dubliniensis, C. tropicalis and C. parapsilosis were also capable of inducing IL-1α and this correlated with mild cell damage and was dependent upon fungal burdens. Our data demonstrate that activation of the MAPK/MKP1/c-Fos pathway in oral epithelial cells is specific to C. dubliniensis and C. albicans hyphae.

  9. Myeloid-Specific Fos-Related Antigen-1 Regulates Cigarette Smoke–Induced Lung Inflammation, Not Emphysema, in Mice

    PubMed Central

    Vaz, Michelle; Rajasekaran, Subbiah; Potteti, Haranatha R.

    2015-01-01

    Heightened lung inflammation is a cardinal feature of chronic obstructive pulmonary disease (COPD). Cigarette smoke (CS)-induced macrophage recruitment and activation, accompanied by abnormal secretion of a number of inflammatory cytokines and matrix metalloproteinases, play a major role in the pathophysiology of COPD. The Fos-related antigen-1 (Fra-1) transcription factor differentially regulates several cellular processes that are implicated in COPD, such as inflammation and immune responses, cell proliferation and death, and extracellular remodeling. Although CS stimulates Fra-1 expression in the lung, the precise role of this transcription factor in the regulation of CS-induced lung inflammation in vivo is poorly understood. Here, we report that myeloid-specific Fra-1 signaling is important for CS-induced lung macrophagic inflammatory response. In response to chronic CS exposure, mice with Fra-1 specifically deleted in myeloid cells showed reduced levels of CS-induced lung macrophagic inflammation, accompanied by decreased expression levels of proinflammatory cytokines compared with their wild-type counterparts. Consistent with this result, bone marrow–derived Fra-1–null macrophages treated with CS showed decreased levels of proinflammatory mediators and matrix metalloproteinases. Interestingly, deletion of Fra-1 in myeloid cells did not affect the severity of emphysema. We propose that Fra-1 plays a key role in promoting chronic CS-induced lung macrophagic inflammation in vivo, and that targeting this transcription factor may be useful in dampening persistent lung inflammation in patients with COPD. PMID:25489966

  10. 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.

  11. Metabolic and Cardiovascular Effects of Ghrelin

    PubMed Central

    Tesauro, Manfredi; Schinzari, Francesca; Caramanti, Miriam; Lauro, Renato; Cardillo, Carmine

    2010-01-01

    Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, is synthesized as a preprohormone and then proteolytically processed to yield a 28-amino acid peptide. This peptide was originally reported to induce growth hormone release; large evidence, however, has indicated many other physiological activities of ghrelin, including regulation of food intake and energy balance, as well as of lipid and glucose metabolism. Ghrelin receptors have been detected in the hypothalamus and the pituitary, but also in the cardiovascular system, where ghrelin exerts beneficial hemodynamic activities. Ghrelin administration acutely improves endothelial dysfunction by increasing nitric oxide bioavailability and normalizes the altered balance between endothelin-1 and nitric oxide within the vasculature of patients with metabolic syndrome. Other cardiovascular effects of ghrelin include improvement of left ventricular contractility and cardiac output, as well as reduction of arterial pressure and systemic vascular resistance. In addition, antinflammatory and antiapoptotic actions of ghrelin have been reported both in vivo and in vitro. This review summarizes the most recent findings on the metabolic and cardiovascular effects of ghrelin through GH-dependent and -independent mechanisms and the possible role of ghrelin as a therapeutic molecule for treating cardiovascular diseases. PMID:20798901

  12. Ghrelin and motilin in the gastrointestinal system.

    PubMed

    Chen, Chih-Yen; Tsai, Chang-Youh

    2012-01-01

    Human ghrelin and human motilin, belonging to the ghrelin/motilin-related peptide family, share 36% amino acid sequence identity, while the human ghrelin receptor exhibits a remarkable 50% overall identity with the human motilin receptor. In addition to their structural resemblance, ghrelin and motilin are the only two mammalian hormones known to decrease in the postprandial period. Ghrelin and motilin participate in initiating the migrating motor complex in the stomach, and stimulate gastrointestinal motility, accelerate gastric emptying, and induce "gastric hunger". In addition to modulating the release of growth hormone and gut motility, ghrelin plays a crucial role in the secretion and protection of the stomach and colon. Ghrelin mimetics and motilin agonists are currently being developed to reverse gastrointestinal hypomotility disorders. With additional appetite-enhancing, adiposity-promoting, and anti-inflammatory effects, ghrelin and rikkunshito (a traditional Japanese herb enhancing acyl ghrelin signaling) are superior to motilin in the treatment of cancer-related anorexia and cachexia, post-chemotherapy symptoms, rheumatological diseases, age-related frailty, as well as post-operative, septic, and post-burn gut ileus.

  13. Amphetamine and cocaine induce drug-specific activation of the c-fos gene in striosome-matrix compartments and limbic subdivisions of the striatum.

    PubMed Central

    Graybiel, A M; Moratalla, R; Robertson, H A

    1990-01-01

    Amphetamine and cocaine are stimulant drugs that act on central monoaminergic neurons to produce both acute psychomotor activation and long-lasting behavioral effects including addiction and psychosis. Here we report that single doses of these drugs induce rapid expression of the nuclear proto-oncogene c-fos in the forebrain and particularly in the striatum, an extrapyramidal structure implicated in addiction and in long-term drug-induced changes in motor function. The two drugs induce strikingly different patterns of c-fos expression in the striosome-matrix compartments and limbic subdivisions of the striatum, and their effects are pharmacologically distinct, although both are sensitive to dopamine receptor blockade. We propose that differential activation of immediate-early genes by psychostimulants may be an early step in drug-specific molecular cascades contributing to acute and long-lasting psychostimulant-induced changes in behavior. Images PMID:2118661

  14. Central administration of pan-somatostatin agonist ODT8-SST prevents abdominal surgery-induced inhibition of circulating ghrelin, food intake and gastric emptying in rats.

    PubMed

    Stengel, A; Goebel-Stengel, M; Wang, L; Luckey, A; Hu, E; Rivier, J; Taché, Y

    2011-07-01

      Activation of brain somatostatin receptors (sst(1-5) ) with the stable pan-sst(1-5) somatostatin agonist, ODT8-SST blocks acute stress and central corticotropin-releasing factor (CRF)-mediated activation of endocrine and adrenal sympathetic responses. Brain CRF signaling is involved in delaying gastric emptying (GE) immediately post surgery. We investigated whether activation of brain sst signaling pathways modulates surgical stress-induced inhibition of gastric emptying and food intake. Fasted rats were injected intracisternally (i.c.) with somatostatin agonists and underwent laparotomy and 1-min cecal palpation. Gastric emptying of a non-nutrient solution and circulating acyl and desacyl ghrelin levels were assessed 50min post surgery. Food intake was monitored for 24 h. The abdominal surgery-induced inhibition of GE (65%), food intake (73% at 2h) and plasma acyl ghrelin levels (67%) was completely prevented by ODT8-SST (1μg per rat, i.c.). The selective sst(5) agonist, BIM-23052 prevented surgery-induced delayed GE, whereas selective sst(1) , sst(2) , or sst(4) agonists had no effect. However, the selective sst(2) agonist, S-346-011 (1μg per rat, i.c.) counteracted the abdominal surgery-induced inhibition of acyl ghrelin and food intake but not the delayed GE. The ghrelin receptor antagonist, [D-Lys(3) ]-GHRP-6 (0.93mg kg(-1) , intraperitoneal, i.p.) blocked i.p. ghrelin-induced increased GE, while not influencing i.c. ODT8-SST-induced prevention of delayed GE and reduced food intake after surgery. ODT8-SST acts in the brain to prevent surgery-induced delayed GE likely via activating sst(5) . ODT8-SST and the sst(2) agonist prevent the abdominal surgery-induced decrease in food intake and plasma acyl ghrelin indicating dissociation between brain somatostatin signaling involved in preventing surgery-induced suppression of GE and feeding response. © 2011 Blackwell Publishing Ltd.

  15. Central administration of pansomatostatin agonist ODT8-SST prevents abdominal surgery-induced inhibition of circulating ghrelin, food intake and gastric emptying in rats

    PubMed Central

    STENGEL, A.; GOEBEL-STENGEL, M.; WANG, L.; LUCKEY, A.; HU, E.; RIVIER, J.; TACHÉ, Y.

    2011-01-01

    Background Activation of brain somatostatin receptors (sst1-5) with the stable pan-sst1-5 somatostatin agonist, ODT8-SST blocks acute stress and central corticotropin-releasing factor (CRF)-mediated activation of endocrine adrenal sympathetic responses. Brain CRF signaling is involved in delaying gastric emptying (GE) immediately post surgery. We investigated whether activation of brain sst signaling pathways modulates surgical stress-induced inhibition of gastric emptying and food intake. Methods Fasted rats were injected intracisternally (i.c.) with somatostatin agonists and underwent laparotomy and 1-min cecal palpation. GE of a non-nutrient solution and circulating acyl and desacyl ghrelin levels were assessed 50 min post surgery. Food intake was monitored for 24h. Key results The abdominal surgery-induced inhibition of GE (65%), food intake (73% at 2h) and plasma acyl ghrelin levels (67%) was completely prevented by ODT8-SST (1μg/rat, i.c.). The selective sst5 agonist, BIM-23052 prevented surgery-induced delayed GE, whereas selective sst1, sst2 or sst4 agonists had no effect. However, the selective sst2 agonist, S-346-011 (1μg/rat, i.c.) counteracted the abdominal surgery-induced inhibition of acyl ghrelin and food intake but not the delayed GE. The ghrelin receptor antagonist, [D-Lys3]-GHRP-6 (0.93 mg/kg, intraperitoneal, i.p.) blocked i.p. ghrelin-induced increased GE, while not influencing i.c. ODT8-SST-induced prevention of delayed GE and reduced food intake after surgery. Conclusions & Inferences ODT8-SST acts in the brain to prevent surgery-induced delayed GE likely via activating sst5. ODT8-SST and the sst2 agonist prevent the abdominal surgery-induced decrease in food intake and plasma acyl ghrelin indicating dissociation between brain somatostatin signaling involved in preventing surgery-induced suppression of GE and feeding response. PMID:21569179

  16. Cold ambient temperature reverses abdominal surgery-induced delayed gastric emptying and decreased plasma ghrelin levels in rats.

    PubMed

    Stengel, Andreas; Goebel, Miriam; Luckey, Andrew; Yuan, Pu-Qing; Wang, Lixin; Taché, Yvette

    2010-12-01

    We investigated whether acute cold-induced vagal activation through brainstem thyrotropin-releasing hormone (TRH) signaling influences abdominal surgery-induced delayed gastric emptying (GE) in fasted rats. Laparotomy and cecal palpation or sham (short anesthesia alone) was performed 10 min before or 30 min after cold exposure (4-6°C) lasting 90 min. Non-nutrient GE was assessed during 70-90 min of cold exposure. Control groups remained at room temperature (RT). The stable TRH analog, RX-77368 (50 ng/rat) was injected intracisternally immediately before surgery and GE monitored 30-50 min postsurgery in rats maintained at RT. Plasma acyl (AG) and total ghrelin levels were assessed using the new RAPID blood processing method and radioimmunoassays. Desacyl ghrelin (DAG) was derived from total minus AG. In rats maintained at RT, abdominal surgery decreased GE by 60% compared to sham. Cold before or after surgery or RX-77368 normalized the delayed GE. In non-fasted rats, cold exposure increased plasma AG and DAG levels at 2 h (2.4- and 2.7-times, respectively) and 4 h (2.2- and 2.0-times, respectively) compared to values in rats maintained at RT. In fasted rats, abdominal surgery decreased AG and DAG levels by 2.4- and 2.1-times, respectively, at 90 min. Cold for 90 min after surgery normalized AG and DAG levels to those observed in sham-treated animals kept at RT. These data indicate that endogenous (cold exposure) and exogenous (TRH analog) activation of medullary TRH vagal signaling prevent abdominal surgery-induced delayed GE. The restoration of circulating AG levels inhibited by abdominal surgery may contribute to alleviate postoperative gastric ileus. Published by Elsevier Inc.

  17. 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. Copyright 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. Ghrelin and obestatin: different role in fetal lung development?

    PubMed

    Nunes, Susana; Nogueira-Silva, Cristina; Dias, Emanuel; Moura, Rute S; Correia-Pinto, Jorge

    2008-12-01

    Ghrelin and obestatin are two proteins that originate from post-translational processing of the preproghrelin peptide. Various authors claim an opposed role of ghrelin and obestatin in several systems. Preproghrelin mRNA is significantly expressed in airway epithelium throughout lung development, predominantly during the earliest stages. The aim of this study was to evaluate the role of ghrelin and obestatin in fetal lung development in vitro. Immunohistochemistry studies were performed at different gestational ages in order to clarify the expression pattern of ghrelin, GHS-R1a, obestatin and GPR39 during fetal lung development. Fetal rat lung explants were harvested at 13.5 days post-conception (dpc) and cultured during 4 days with increasing doses of total ghrelin, acylated ghrelin, desacyl-ghrelin, ghrelin antagonist (D-Lys(3)-GHRP-6) or obestatin. Immunohistochemistry studies demonstrated that ghrelin, GHS-R1a, obestatin and GPR39 proteins were expressed in primitive rat lung epithelium throughout all studied gestational ages. Total and acylated ghrelin supplementation significantly increased the total number of peripheral airway buds, whereas desacyl-ghrelin induced no effect. Moreover, GHS-R1a antagonist significantly decreased lung branching. Finally, obestatin supplementation induced no significant effect in the measured parameters. The present study showed that ghrelin has a positive effect in fetal lung development through its GHS-R1a receptor, whereas obestatin has no effect on lung branching.

  19. Androgen receptors and estrogen receptors are colocalized in male rat hypothalamic and limbic neurons that express Fos immunoreactivity induced by mating.

    PubMed

    Gréco, B; Edwards, D A; Michael, R P; Clancy, A N

    1998-01-01

    Conversion of testosterone into estradiol is important for male rat sexual behavior, and both steroids probably contribute to mating. The distributions of neurons containing androgen receptors (AR) and estrogen receptors (ER) overlap, and many AR-immunoreactive (AR-ir) neurons express Fos immunoreactivity (Fos-ir) induced by mating. Because mating-induced Fos-ir in the male rat occurs mainly in AR-ir neurons, and because both steroids are important for mating, we hypothesized that (i) AR-ir and ER-ir are colocalized and that (ii) some of these neurons are activated during mating. We examined, in adjacent sections from the medial preoptic area (MPN) through the central tegmental field (CTF), the expression of ER-ir in: (i) AR-ir-containing neurons, and (ii) Fos-ir-expressive neurons. PG21 anti-AR, OA-11-824 anti-c-fos, H222 or 1D5 anti-ER primary antibodies were visualized, respectively, with cyanine-conjugated, fluorescein- or cyanine-conjugated, and fluorescein-conjugated secondary antibodies in male rats which were killed 1 h after ejaculating with a receptive female. In MPN, bed nucleus of the stria terminalis (BNST), and medial amygdala (MEA), 80-90% of ER-ir labeling occurred in AR-ir-positive neurons but only about 30% of AR-ir neurons were ER-ir-positive. No ER-ir was found in the CTF. This suggests the presence of three types of brain neurons sensitive to gonadal steroid hormones: neurons sensitive to androgens only, neurons sensitive to both androgens and estrogens, and neurons sensitive to estrogens only. About 50% of ER-ir labeling occurred in cells expressing mating-induced Fos-ir but only about 30% of Fos-ir neurons were ER-ir-positive. These findings suggest that, in the MPN, at least two different neuronal populations are activated during mating: the first contains AR-ir only and the second contains AR-ir and ER-ir. In the BNST and MEA, at least three hormonally sensitive populations are activated during mating: the two described above plus a third

  20. [Immunohistochemical detection of transcription factors CREB and c-Fos activation in the land snail nervous system induced by pentylenetetrazole].

    PubMed

    Efimova, O I; Ierusalimskiĭ, V N; Anokhin, K V; Balaban, P M

    2006-01-01

    Phosphorylation of transcription factor CREB and expression of immediate early gene c-fos play a key role in molecular mechanisms of long-term neuronal plasticity in the vertebrate brain. Here, we have defined the procedure of immunohistochemical detection of pCREB and c-Fos in the nervous system of the land snail Helix lucorum (Pulmonata: Stylommatophora) and have shown its activation after the convulsant pentylenetetrazole injection. Baseline pCREB1 and c-Fos levels in the intact snail nervous system appeared to be low. In contrast, injection of pentylenetetrazole (600 mg/kg) produced a rapid induction of CREB phosphorylation and c-Fos expression in a wide range of neurons including a number of identified cells. Double immunofluorescence for pCREB and c-Fos showed that c-Fos was always colocalized with pCREB-immunoreactivity, although the latter had a broader pattern. The results suggest that transcription factors CREB and c-Fos can be used as molecular markers for mapping long-term neuronal plasticity in molluscan nervous system.

  1. Role of thalamic nuclei in the modulation of Fos expression within the cerebral cortex during hypertonic saline-induced muscle nociception.

    PubMed

    Xiao, Y; Lei, J; Ye, G; Xu, H; You, H-J

    2015-09-24

    It has been proposed that thalamic mediodorsal (MD) and ventromedial (VM) nuclei form thalamic 'nociceptive discriminators' in discrimination of nociceptive afferents, and specifically govern endogenous descending facilitation and inhibition. The present study conducted in rats was to explore the role of thalamic MD and VM nuclei in modulation of cerebral neuronal activities by means of detection of spatiotemporal variations of Fos expression within the cerebral cortex. Following a unilateral intramuscular injection of 5.8% saline into the gastrocnemius muscle, Fos expression within the bilateral, different areas of the cerebral cortex except S2 was significantly increased (P<0.05). Particularly, the increases in Fos expression within the cingulate cortex and the insular cortex occurred at 0.5h, 4h and reached the peak level at 4h, 16h, respectively. Electrolytic lesion of the contralateral thalamic MD and VM nuclei significantly blocked the 5.8% saline intramuscularly induced increases in Fos expression within the bilateral cingulate and insular cortices, respectively. Additionally, the 5.8% saline-induced Fos expression in the cingulate cortex and the insular cortex were dose-dependently attenuated by microinjection of μ-opioid antagonist β-funaltrexamine hydrochloride into the thalamic MD and VM nuclei. It is suggested that (1) the neural circuits of 'thalamic MD nucleus - cingulate cortex' and 'thalamic VM nucleus - insular cortex' form two distinct pathways in the endogenous control of nociception, (2) mirror or contralateral pain is hypothesized to be related to cross-talk of neuronal activities within the bilateral cerebral cortices modulated by μ-opioid receptors within the thalamic MD and VM nuclei.

  2. Neurogenic Effects of Ghrelin on the Hippocampus.

    PubMed

    Kim, Chanyang; Kim, Sehee; Park, Seungjoon

    2017-03-08

    Mammalian neurogenesis continues throughout adulthood in the subventricular zone of the lateral ventricle and in the subgranular zone of the dentate gyrus in the hippocampus. It is well known that hippocampal neurogenesis is essential in mediating hippocampus-dependent learning and memory. Ghrelin, a peptide hormone mainly synthesized in the stomach, has been shown to play a major role in the regulation of energy metabolism. A plethora of evidence indicates that ghrelin can also exert important effects on neurogenesis in the hippocampus of the adult brain. The aim of this review is to discuss the current role of ghrelin on the in vivo and in vitro regulation of neurogenesis in the adult hippocampus. We will also discuss the possible role of ghrelin in dietary restriction-induced hippocampal neurogenesis and the link between ghrelin-induced hippocampal neurogenesis and cognitive functions.

  3. Neurogenic Effects of Ghrelin on the Hippocampus

    PubMed Central

    Kim, Chanyang; Kim, Sehee; Park, Seungjoon

    2017-01-01

    Mammalian neurogenesis continues throughout adulthood in the subventricular zone of the lateral ventricle and in the subgranular zone of the dentate gyrus in the hippocampus. It is well known that hippocampal neurogenesis is essential in mediating hippocampus-dependent learning and memory. Ghrelin, a peptide hormone mainly synthesized in the stomach, has been shown to play a major role in the regulation of energy metabolism. A plethora of evidence indicates that ghrelin can also exert important effects on neurogenesis in the hippocampus of the adult brain. The aim of this review is to discuss the current role of ghrelin on the in vivo and in vitro regulation of neurogenesis in the adult hippocampus. We will also discuss the possible role of ghrelin in dietary restriction-induced hippocampal neurogenesis and the link between ghrelin-induced hippocampal neurogenesis and cognitive functions. PMID:28282857

  4. Induced Ablation of Ghrelin Cells in Adult Mice Does Not Decrease Food Intake, Body Weight, or Response to High Fat Diet

    PubMed Central

    McFarlane, Matthew R.; Brown, Michael S.; Goldstein, Joseph L.; Zhao, Tong-Jin

    2014-01-01

    SUMMARY Injection of the peptide hormone ghrelin stimulates food intake in mice and humans. However, mice born without ghrelin demonstrate no significant loss of appetite. This paradox suggests either that compensation develops in mice born without ghrelin or that ghrelin is not essential for appetite control. To distinguish these possibilities, we generated transgenic mice (Ghrl-DTR) that express the diphtheria toxin receptor in ghrelin-secreting cells. Injection of diphtheria toxin in adulthood ablated ghrelin cells and reduced plasma ghrelin by 80-95%. Ghrelin cell-ablated mice exhibited no loss of appetite or body weight and no resistance to a high fat diet. To stimulate food intake in mice by ghrelin injection, we had to raise plasma levels many-fold above normal. Like germline ghrelin-deficient mice, the ghrelin cell-ablated mice developed profound hypoglycemia when subjected to prolonged calorie restriction, confirming that ghrelin acts to maintain blood glucose under famine conditions. PMID:24836560

  5. 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

  6. Kisspeptin Stimulates Growth Hormone Release by Utilizing Neuropeptide Y Pathways and Is Dependent on the Presence of Ghrelin in the Ewe.

    PubMed

    Foradori, Chad D; Whitlock, Brian K; Daniel, Jay A; Zimmerman, Arthur D; Jones, Melaney A; Read, Casey C; Steele, Barbara P; Smith, Jeremy T; Clarke, Iain J; Elsasser, Theodore H; Keisler, Duane H; Sartin, James L

    2017-10-01

    Although kisspeptin is the primary stimulator of gonadotropin-releasing hormone secretion and therefore the hypothalamic-pituitary-gonadal axis, recent findings suggest kisspeptin can also regulate additional neuroendocrine processes including release of growth hormone (GH). Here we show that central delivery of kisspeptin causes a robust rise in plasma GH in fasted but not fed sheep. Kisspeptin-induced GH secretion was similar in animals fasted for 24 hours and those fasted for 72 hours, suggesting that the factors involved in kisspeptin-induced GH secretion are responsive to loss of food availability and not the result of severe negative energy balance. Pretreatment with the neuropeptide Y (NPY) Y1 receptor antagonist, BIBO 3304, blocked the effects of kisspeptin-induced GH release, implicating NPY as an intermediary. Kisspeptin treatment induced c-Fos in NPY and GH-releasing hormone (GHRH) cells of the arcuate nucleus. The same kisspeptin treatment resulted in a reduction in c-Fos in somatostatin (SS) cells in the periventricular nucleus. Finally, blockade of systemic ghrelin release or antagonism of the ghrelin receptor eliminated or reduced the ability of kisspeptin to induce GH release, suggesting the presence of ghrelin is required for kisspeptin-induced GH release in fasted animals. Our findings support the hypothesis that during short-term fasting, systemic ghrelin concentrations and NPY expression in the arcuate nucleus rise. This permits kisspeptin activation of NPY cells. In turn, NPY stimulates GHRH cells and inhibits SS cells, resulting in GH release. We propose a mechanism by which kisspeptin conveys reproductive and hormone status onto the somatotropic axis, resulting in alterations in GH release. Copyright © 2017 Endocrine Society.

  7. 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.

  8. Nalfurafine prevents 5'-guanidinonaltrindole- and compound 48/80-induced spinal c-fos expression and attenuates 5'-guanidinonaltrindole-elicited scratching behavior in mice.

    PubMed

    Inan, S; Dun, N J; Cowan, A

    2009-09-29

    The aims of the present study were to establish if nalfurafine, a kappa opioid agonist, inhibits compulsive scratching in mice elicited by the s.c. administration (behind the neck) of 5'-guanidinonaltrindole (GNTI), a kappa opioid antagonist; to assess if nalfurafine prevents c-fos expression provoked by GNTI or compound 48/80, two chemically diverse pruritogens; and to distinguish on the basis of neuroanatomy, those neurons in the brainstem activated by either GNTI-induced itch or formalin-induced pain (both compounds given s.c. to the right cheek). Pretreatment of mice with nalfurafine (0.001-0.03 mg/kg s.c.) attenuated GNTI (0.3 mg/kg)-evoked scratching dose-dependently. A standard antiscratch dose of nalfurafine (0.02 mg/kg) had no marked effect on the spontaneous locomotion of mice. Tolerance did not develop to the antiscratch activity of nalfurafine. Both GNTI and compound 48/80 provoked c-fos expression on the lateral side of the superficial layer of the dorsal horn of the cervical spinal cord and pretreating mice with nalfurafine inhibited c-fos expression induced by both pruritogens. In contrast to formalin, GNTI did not induce c-fos expression in the trigeminal nucleus suggesting that pain and itch sensations are projected differently along the sensory trigeminal pathway. Our data indicate that the kappa opioid system is involved, at least in part, in the pathogenesis of itch; and that nalfurafine attenuates excessive scratching and prevents scratch-induced neuronal activity at the spinal level. On the basis of our results, nalfurafine holds promise as a potentially useful antipruritic in human conditions involving itch.

  9. c-fos is induced in the hippocampus during consolidation of sexual imprinting in the zebra finch (Taeniopygia guttata).

    PubMed

    Sadananda, Monika; Bischof, Hans-Joachim

    2004-01-01

    c-fos was used to mark regions of enhanced neuronal activity during sexual imprinting, an early learning process by which information about the prospective sexual partner is acquired and consolidated. In the present study, we demonstrate that the hippocampus, already known for its specialized spatial memory capacities in navigating pigeons and in food-storing birds, depicts a selective differential c-fos induction in a situation shown to lead to sexual imprinting, that is, exposing previously isolated male birds to a female for 1 h. c-fos induction is lateralized, the left hippocampus showing more c-fos activity than the right. Our results would indicate a role for the hippocampus in the consolidation process of imprinting, probably in the transfer of information to the other telencephalic areas that show alterations in synaptic connectivity as a result of consolidation of sexual imprinting.

  10. Effect of NMDA receptor antagonist MK-801 on light-induced Fos expression in the suprachiasmatic nuclei and on melatonin production in the Syrian hamster.

    PubMed

    Vuillez, P; Jacob, N; Teclemariam-Mesbah, R; Van Rossum, A; Vivien-Roels, B; Pévet, P

    1998-09-01

    In mammals, circadian rhythms generated by the suprachiasmatic nuclei (SCN) are daily synchronized by a light-dark cycle. Photic information is transmitted to the SCN mainly through the direct retinohypothalamic tract, the neurotransmitters involved being excitatory amino acids. It is also commonly accepted that photoperiodic information coming from the retina via the SCN is transduced by the pineal into a nocturnal signal, i.e. melatonin production. Light exposure at night induces (1) an inhibition of melatonin synthesis and (2) an expression of c-fos in numerous cells of SCN. To determine the role of the NMDA receptor in these effects, we treated Syrian hamsters with ip injections of MK-801, a noncompetitive NMDA receptor antagonist. Several subpopulations of light-sensitive cells in the SCN are affected by MK-801. According to previous studies, MK-801 inhibits light-induced Fos immunoreactivity mainly in the most ventral part of the SCN. However, we observed that numerous other cells are still activated by light. When light is applied in the middle of the night, MK-801 pretreatment does not reduce Fos-ir in the dorsal SCN. At the beginning of the night, labeled cells in this part of the nucleus appear even more numerous after MK-801. We also found that MK-801 fails to reduce the light-induced inhibition of melatonin synthesis. Moreover, in control animals, which received no light stimulation, ip injection of MK-801 induces by itself a dose-dependent inhibition of melatonin production.

  11. Carbon dioxide in carbonated beverages induces ghrelin release and increased food consumption in male rats: Implications on the onset of obesity.

    PubMed

    Eweis, Dureen Samandar; Abed, Fida; Stiban, Johnny

    The dangerous health risks associated with obesity makes it a very serious public health issue. Numerous studies verified a correlation between the increase in obesity and the parallel increase in soft drink consumption among world populations. The effects of one main component in soft drinks namely the carbon dioxide gas has not been studied thoroughly in any previous research. Male rats were subjected to different categories of drinks and evaluated for over a year. Stomach ex vivo experiments were undertaken to evaluate the amount of ghrelin upon different beverage treatments. Moreover, 20 male students were tested for their ghrelin levels after ingestion of different beverages. Here, we show that rats consuming gaseous beverages over a period of around 1 year gain weight at a faster rate than controls on regular degassed carbonated beverage or tap water. This is due to elevated levels of the hunger hormone ghrelin and thus greater food intake in rats drinking carbonated drinks compared to control rats. Moreover, an increase in liver lipid accumulation of rats treated with gaseous drinks is shown opposed to control rats treated with degassed beverage or tap water. In a parallel study, the levels of ghrelin hormone were increased in 20 healthy human males upon drinking carbonated beverages compared to controls. These results implicate a major role for carbon dioxide gas in soft drinks in inducing weight gain and the onset of obesity via ghrelin release and stimulation of the hunger response in male mammals. Copyright © 2017 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.

  12. Synergistic effect of melatonin and ghrelin in preventing cisplatin-induced ovarian damage via regulation of FOXO3a phosphorylation and binding to the p27(Kip1) promoter in primordial follicles.

    PubMed

    Jang, Hoon; Na, Younghwa; Hong, Kwonho; Lee, Sangho; Moon, Sohyeon; Cho, Minha; Park, Miseon; Lee, Ok-Hee; Chang, Eun Mi; Lee, Dong Ryul; Ko, Jung Jae; Lee, Woo Sik; Choi, Youngsok

    2017-10-01

    Premature ovarian failure during chemotherapy is a serious problem for young women with cancer. To preserve the fertility of these patients, approaches to prevent chemotherapy-induced ovarian failure are needed. In a previous study, we reported that melatonin treatment prevents the depletion of the dormant follicle pool via repression of the simultaneous activation of dormant primordial follicles by cisplatin. However, melatonin's protective effect was only partial and thus insufficient. In this study, we found that the hormone ghrelin enhances the protective effect of melatonin against cisplatin-induced ovarian failure in mouse model. Co-administration of melatonin and ghrelin more effectively prevented cisplatin-induced follicle disruption. Simultaneous treatment with melatonin and ghrelin almost restored the number of primordial follicles and the corpus luteum in cisplatin-treated ovaries, compared with single administration. We found melatonin and ghrelin receptors on the cell membrane of premature oocytes of primordial follicles. In addition, melatonin and ghrelin co-administration inhibited the cisplatin-induced phosphorylation of PTEN and FOXO3a that induces cytoplasmic translocation of FOXO3a. Inhibition of FOXO3a phosphorylation by melatonin and ghrelin increased the binding affinity of FOXO3a for the p27(Kip1) promoter in primordial follicles. Co-administration of melatonin and ghrelin in cisplatin-treated ovaries restored the expression of p27(Kip1) , which is critical for retention of the dormant status of primordial follicles. In conclusion, these findings suggest that melatonin and ghrelin co-administration is suitable for use as a fertoprotective adjuvant therapy during cisplatin chemotherapy in young female cancer patients. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Long-term ethanol self-administration induces ΔFosB in male and female adolescent, but not in adult, Wistar rats.

    PubMed

    Wille-Bille, Aranza; de Olmos, Soledad; Marengo, Leonardo; Chiner, Florencia; Pautassi, Ricardo Marcos

    2017-03-06

    Early-onset ethanol consumption predicts later development of alcohol use disorders. Age-related differences in reactivity to ethanol's effects may underlie this effect. Adolescent rats are more sensitive and less sensitive than adults to the appetitive and aversive behavioral effects of ethanol, respectively, and more sensitive to the neurotoxic effects of experimenter-administered binge doses of ethanol. However, less is known about age-related differences in the neural consequences of self-administered ethanol. ΔFosB is a transcription factor that accumulates after chronic drug exposure and serves as a molecular marker of neural plasticity associated with the transition to addiction. We analyzed the impact of chronic (18 two-bottle choice intake sessions spread across 42days, session length: 18h) ethanol [or only vehicle (control group)] self-administration during adolescence or adulthood on the induction of ΔFosB in several brain areas, anxiety-like behavior, and ethanol-induced locomotor activity and conditioned place preference (CPP) in Wistar rats. Adolescent rats exhibited a progressive escalation of ethanol intake and preference, whereas adult rats exhibited a stable pattern of ingestion. Few behavioral differences in the open field or light-dark test were observed after the intake test. Furthermore, ethanol self-administration did not promote the expression of ethanol-induced CPP. There were, however, large age-related differences in the neural consequences of ethanol drinking: a significantly greater number of ethanol-induced ΔFosB-positive cells was found in adolescents vs. adults in the prelimbic cortex, dorsolateral striatum, nucleus accumbens core and shell, and central amygdala nucleus capsular and basolateral amygdala, with sex-related differences found at central amygdala. This greater ethanol-induced ΔFosB induction may represent yet another age-related difference in the sensitivity to ethanol that may put adolescents at higher risk for

  14. Exercise training does not enhance hypothalamic responsiveness to leptin or ghrelin in male mice.

    PubMed

    Borg, M L; Andrews, Z B; Watt, M J

    2014-02-01

    The detection of hormone and nutrient signals by the hypothalamus is blunted in obesity and contributes to dysregulated energy homeostasis. We investigated whether aerobic exercise training would improve long-term hypothalamic sensitivity to both leptin and ghrelin, independent of acute exercise-induced signalling. Male C57Bl/6J mice were fed either a chow or high-fat diet for 6 weeks, then remained sedentary on their respective diet, or completed 6 weeks of treadmill exercise training with a progressive increase in exercise volume and intensity. Food intake and hypothalamic signalling were assessed in mice injected with leptin or ghrelin at least 24 h after the last exercise bout. Exercise training reduced body mass, increased daily food intake and improved glucose tolerance. Intraperitoneal leptin administration reduced food intake in lean and obese mice, and this was not enhanced after exercise training. Leptin-mediated activation of phosphorylated signal transducer and activator of transcription 3 in the arcuate nucleus and ventromedial nucleus of the hypothalamus was not enhanced with exercise training. Ghrelin increased food intake and c-Fos positive neurones in the hypothalamus in lean and obese mice, and these physiological and molecular responses were not enhanced with exercise training. This suggests that the previously reported exercise effects on sensitising hypothalamic signalling and food intake responses may be limited to the period immediately after an exercise bout, and are not a result of stable structural or molecular changes that occur with exercise training. © 2014 British Society for Neuroendocrinology.

  15. Thapsigargin induces rapid, transient growth inhibition and c-fos expression followed by sustained growth stimulation in mouse keratinocyte cultures.

    PubMed

    Harmon, C S; Ducote, J; Xiong, Y

    1996-08-01

    Although the sesquiterpene lactone thapsigargin has been shown to possess hyperplastic and tumor-promoting activities when applied topically to mouse skin in vivo, the cellular mechanism(s) which underlie these effects are unclear. We show here that thapsigargin treatment of Primary mouse epidermal keratinocytes increased intracellular free Ca2+ concentration (Cai) in a concentration-dependent manner. Thapsigargin induced a rapid, transient elevation in keratinocyte Cai, in part due to the release of Ca2+ from intracellular stores. This response was followed by a sustained elevation in Ca2+, resulting entirely from calcium influx. Thapsigargin elicited a biphasic effect on keratinocyte DNA synthesis: a rapid inhibitory effect (50-60% inhibition at 4-8 h), followed by a very marked and sustained elevation. Prolonged treatment of keratinocytes with thapsigargin at relatively high concentrations resulted in cytotoxicity (inhibition of neutral red uptake). The rapid antiproliferative effect of thapsigargin was not associated with cytotoxicity, as determined by either neutral red uptake or by trypan blue exclusion, and was not blocked by pretreatment with Ro 31-7349, a selective inhibitor of protein kinase C. The rapid antiproliferative effect of thapsigargin was associated with rapid, transient activation of keratinocyte c-fos expression and rapid inhibition of total protein synthesis. Taken together, these findings raise the possibility that the hyperplastic and tumor-promoting activities of thapsigargin on epidermis in vivo result from direct keratinocyte growth stimulation as a consequence of a prolonged elevation in levels of Cai.

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. Comparison of ΔFosB immunoreactivity induced by vagal nerve stimulation with that caused by pharmacologically diverse antidepressants.

    PubMed

    Furmaga, Havan; Sadhu, Mohona; Frazer, Alan

    2012-05-01

    Vagal nerve stimulation (VNS) has been approved for treatment of refractory depression. However, there have been few, if any, studies directly comparing the effects produced by VNS in animals with those caused by antidepressants, particularly using clinically relevant stimulation parameters in nonanesthetized animals. In this study, ΔFosB immunohistochemistry was used to evaluate different brain regions activated by long-term administration of VNS. Effects of VNS were compared with those caused by sertraline or desipramine (DMI). Double-labeling of ΔFosB and serotonin was used to determine whether serotonergic neurons in the dorsal raphe nucleus (DRN) were activated by long-term VNS. VNS significantly increased ΔFosB staining in the nucleus tractus solitarius (NTS), parabrachial nucleus (PBN), locus ceruleus (LC), and DRN, as well as in many cortical and limbic areas of brain including those involved in mood and cognition. Most, but not all, of these effects were seen also upon long-term treatments of rats with sertraline or DMI. Some areas where VNS increased ΔFosB (e.g., the NTS, PBN, LC, and peripeduncular nucleus) were not affected significantly by either drug. Sertraline was similar to VNS in causing an increase in the DRN whereas DMI did not. Double-labeling of the DRN with ΔFosB and an antibody for serotonin revealed that only a small percentage of ΔFosB staining in the DRN colocalized with serotonergic neurons. The effects of VNS were somewhat more widespread than those caused by the antidepressants. The increases in ΔFosB produced by VNS were either equivalent to and/or more robust than those seen with antidepressants.

  1. Current and potential roles of ghrelin in clinical practice.

    PubMed

    Angelidis, G; Valotassiou, V; Georgoulias, P

    2010-12-01

    Ghrelin is a novel GH-releasing peptide, which has been identified as an endogenous ligand for GH-secretagogue receptor. Ghrelin is mainly secreted by the stomach and plays a critical role in a variety of physiological processes including endocrine, metabolic, cardiovascular, immunological, and other actions. Ghrelin stimulates food intake via hypothalamic neurons and causes a positive energy balance and body weight gain by decreasing fat utilization and promoting adiposity. Given the multiple effects of ghrelin, its potential clinical applications have been evaluated in various conditions. Preliminary trials have shown that it may prove valuable in the management of disease-induced cachexia. Ghrelin may improve the wasting syndrome through GH-dependent or GH-independent effects. Moreover, ghrelin may play a role in the management of disorders of gut motility and obesity. Finally, other potential clinical applications of ghrelin include the treatment of patients with diabetes mellitus, infections, rheumatological diseases or GH deficiency and the diagnosis of this hormonal disorder.

  2. 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

  3. Obesity Impairs the Action of the Neuroendocrine Ghrelin System.

    PubMed

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. 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.

  5. Acupuncture attenuates repeated nicotine-induced behavioral sensitization and c-Fos expression in the nucleus accumbens and striatum of the rat.

    PubMed

    Chae, Younbyoung; Yang, Chae Ha; Kwon, Young Kyu; Kim, Mi Ryeo; Pyun, Kwang-Ho; Hahm, Dae-Hyun; Lee, Hye-Jung; Shim, Insop

    2004-03-25

    Repeated injections of nicotine can produce behavioral sensitization, as evidenced by an enhanced locomotor response to a subsequent injection of the drug. Behavioral sensitization has been suggested as a model for studying drug addiction. Acupuncture as a therapeutic intervention is widely used for treatment for many functional disorders, such as substance abuse and mental dysfunction. We examined the effect of acupuncture on nicotine-induced behavioral locomotor activity and c-fos expression in the nucleus accumbens and striatum utilizing the immunocytochemical detection of the Fos protein. The rats were given repeated daily nicotine injections (0.4 mg/kg s.c., twice daily for 7 days) followed by one challenging injection on the 4th day after the last daily injection. Acupuncture at zusanli (ST36), but not control, significantly attenuated expected increase in nicotine-induced locomotor activity and Fos-like-immunoreactivity in the nucleus accumebns and striatum to subsequent nicotine challenge. These findings suggest that acupuncture has a therapeutic effect on nicotine addiction, possibly by modulating postsynaptic neuronal activity in the nucleus accumbens and the striatum.

  6. Alteration of c-Fos mRNA in the accessory lobe of crayfish is associated with a conditioned-cocaine induced reward.

    PubMed

    Nathaniel, Thomas I; Panksepp, Jaak; Huber, Robert

    2012-03-01

    The major molecular and anatomical substrates of drug related reward in mammals have received considerable attention. In contrast, molecular mechanisms and specific neuroanatomical targets of drug associated reward in invertebrate models of drug addiction have gone largely unexplored. With a modular nervous system amenable to molecular techniques, crayfish offer a novel system for simultaneously exploring molecular mechanism and neuroanatomical targets of cocaine-induced reward in an invertebrate system. We aimed to determine whether novelty in a cocaine-paired stimulus is accompanied by changes in c-Fos mRNA in the accessory lobe of crayfish. The first set of experiments revealed that cocaine-conditioned animals demonstrated reward in a drug-paired compartment in contrast to saline-conditioned animals. Following the expression of reward, we designed a second set of experiments to determine context-specificity of the cocaine-conditioned novelty effect in altering c-Fos mRNA expression in the accessory lobe of cocaine treated crayfish. This is the first report that characterized context-specific alteration of c-Fos mRNA expression in the accessory lobe of crayfish during drug-induced reward. Copyright © 2011 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

  7. 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. Copyright © 2016. Published by Elsevier Ireland Ltd.

  8. Translational research of ghrelin.

    PubMed

    Ueno, Hiroaki; Shiiya, Tomomi; Nakazato, Masamitsu

    2010-07-01

    Gastrointestinal peptides play important roles regulating feeding and energy homeostasis. Most gastrointestinal peptides including glucagon like peptide-1, peptide YY, amylin, and oxytomodulin are anorectic, and only ghrelin is an orexigenic peptide. Ghrelin increases appetite, modulates energy balance, suppresses inflammation, and enhances growth hormone secretion. Given its diversity of functions, ghrelin is expected be an effective therapy for lean patients with cachexia caused by chronic heart failure, chronic respiratory disease, anorexia nervosa, functional dyspepsia, and cancer. Clinical trials have demonstrated that ghrelin effectively increases lean body mass and activity in cachectic patients. Ghrelin interrupts the vicious cycle of the cachectic paradigm through its orexigenic, anabolic, and anti-inflammatory effects, and ghrelin administration may improve the quality of life of cachectic patients. We discuss the significant roles of ghrelin in the pathophysiology of cachectic diseases and the possible clinical applications of ghrelin.

  9. Changes in ghrelin, CCK, GLP-1, and peroxisome proliferator-activated receptors in a hypoxia-induced anorexia rat model.

    PubMed

    Duraisamy, Arul Joseph; Bayen, Susovan; Saini, Supriya; Sharma, Alpesh Kumar; Vats, Praveen; Singh, Shashi Bala

    2015-01-01

    A high-altitude environment causes appetite loss in unacclimatised humans, leading to weight reduction. Ghrelin, cholecystokinin (CCK), and glucagon like peptide-1 (GLP-1), are gut hormones involved in the regulation of food intake and energy metabolism. The liver is an important site of metabolic regulation, and together with the gut it plays a role in food intake regulation. This study intends to study the time-dependent changes occurring in plasma gut hormones, PPARα, PPARδ, and PGC1α, in the stomach and liver during hypoxia. Male Sprague Dawley rats were exposed to hypobaric hypoxia in a decompression chamber at 7620 m for different durations up to seven days. Hypoxia increased circulating ghrelin from the third day onwards while CCK and GLP-1 decreased immediately. An increase in ghrelin, ghrelin receptor protein levels, and GOAT mRNA levels in the stomach was observed. Stomach cholecystokinin receptor (CCKAR), PPARα, and PPARδ decreased. Liver CCKAR decreased during the first day of hypoxia and returned to normal levels from the third day onwards. PPARα and PGC1α expression increased while PPARδ protein levels reduced in the liver on third day. Hypoxia alters the expression of ghrelin and ghrelin receptor in the stomach, CCKAR in the liver, and PPAR and its cofactors, which might be possible role players in the contribution of gut and liver to anorexia at high altitude.

  10. Hypovolemic hemorrhage induces Fos expression in the rat hypothalamus: Evidence for involvement of the lateral hypothalamus in the decompensatory phase of hemorrhage.

    PubMed

    Göktalay, G; Millington, W R

    2016-05-13

    This study tested the hypothesis that the hypothalamus participates in the decompensatory phase of hemorrhage by measuring Fos immunoreactivity and by inhibiting neuronal activity in selected hypothalamic nuclei with lidocaine or cobalt chloride. Previously, we reported that inactivation of the arcuate nucleus inhibited, but did not fully prevent, the fall in arterial pressure evoked by hypotensive hemorrhage. Here, we report that hemorrhage (2.2 ml/100g body weight over 20 min) induced Fos expression in a high percentage of cells in the paraventricular, supraoptic and arcuate nuclei of the hypothalamus as shown previously. Lower densities of Fos immunoreactive cells were also found in the medial preoptic area (mPOA), anterior hypothalamus, lateral hypothalamus (LH), dorsomedial hypothalamus, ventromedial hypothalamus (VMH) and posterior hypothalamus. Bilateral injection of lidocaine (2%; 0.1 μl or 0.3 μl) or cobalt chloride (5mM; 0.3 μl) into the tuberal portion of the LH immediately before hemorrhage was initiated reduced the magnitude of hemorrhagic hypotension and bradycardia significantly. Lidocaine injection into the VMH also attenuated the fall in arterial pressure and heart rate evoked by hemorrhage although inactivation of the mPOA or rostral LH was ineffective. These findings indicate that hemorrhage activates neurons throughout much of the hypothalamus and that a relatively broad area of the hypothalamus, extending from the arcuate nucleus laterally through the caudal VMH and tuberal LH, plays an important role in the decompensatory phase of hemorrhage.

  11. Identification of Neural Networks That Contribute to Motion Sickness through Principal Components Analysis of Fos Labeling Induced by Galvanic Vestibular Stimulation

    PubMed Central

    Balaban, Carey D.; Ogburn, Sarah W.; Warshafsky, Susan G.; Ahmed, Abdul; Yates, Bill J.

    2014-01-01

    Motion sickness is a complex condition that includes both overt signs (e.g., vomiting) and more covert symptoms (e.g., anxiety and foreboding). The neural pathways that mediate these signs and symptoms are yet to identified. This study mapped the distribution of c-fos protein (Fos)-like immunoreactivity elicited during a galvanic vestibular stimulation paradigm that is known to induce motion sickness in felines. A principal components analysis was used to identify networks of neurons activated during this stimulus paradigm from functional correlations between Fos labeling in different nuclei. This analysis identified five principal components (neural networks) that accounted for greater than 95% of the variance in Fos labeling. Two of the components were correlated with the severity of motion sickness symptoms, and likely participated in generating the overt signs of the condition. One of these networks included neurons in locus coeruleus, medial, inferior and lateral vestibular nuclei, lateral nucleus tractus solitarius, medial parabrachial nucleus and periaqueductal gray. The second included neurons in the superior vestibular nucleus, precerebellar nuclei, periaqueductal gray, and parabrachial nuclei, with weaker associations of raphe nuclei. Three additional components (networks) were also identified that were not correlated with the severity of motion sickness symptoms. These networks likely mediated the covert aspects of motion sickness, such as affective components. The identification of five statistically independent component networks associated with the development of motion sickness provides an opportunity to consider, in network activation dimensions, the complex progression of signs and symptoms that are precipitated in provocative environments. Similar methodology can be used to parse the neural networks that mediate other complex responses to environmental stimuli. PMID:24466215

  12. Inhibitory Effect of Oleic Acid on Octanoylated Ghrelin Production.

    PubMed

    Oiso, Shigeru; Nobe, Miyuki; Iwasaki, Syuhei; Nii, Wakana; Goto, Natsumi; Seki, Yukari; Nakajima, Kensuke; Nakamura, Kazuo; Kariyazono, Hiroko

    2015-01-01

    Ghrelin is a growth hormone-releasing peptide that also displays orexigenic activity. Since serine-3 acylation with octanoylate (octanoylation) is essential for the orexigenic activity of ghrelin, suppression of octanoylation could lead to amelioration or prevention of obesity. To enable the exploration of inhibitors of octanoylated ghrelin production, we developed a cell-based assay system using AGS-GHRL8 cells, in which octanoylated ghrelin concentration increases in the presence of octanoic acid. Using this assay system, we investigated whether fatty acids contained in foods or oils, such as acetic acid, stearic acid, oleic acid, linoleic acid, and α-linolenic acid, have inhibitory effects on octanoylated ghrelin production. Acetic acid did not suppress the increase in octanoylated ghrelin production in AGS-GHRL8 cells, which was induced by the addition of octanoic acid. However, stearic acid, oleic acid, linoleic acid, and α-linolenic acid significantly suppressed octanoylated ghrelin production, with the effect of oleic acid being the strongest. Additionally, oleic acid decreased the serum concentration of octanoylated ghrelin in mice. The serum concentration of des-acyl ghrelin (without acyl modification) was also decreased, but the decrease was smaller than that of octanoylated ghrelin. Decreased octanoylated ghrelin production likely resulted from post-translational ghrelin processing, as there were no significant differences in gene expression in the stomach between oleic acid-treated mice and controls. These results suggest that oleic acid is a potential inhibitor of octanoylated ghrelin production and that our assay system is a valuable tool for screening compounds with suppressive effects on octanoylated ghrelin production.

  13. 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.

  14. Cue-Induced Food Seeking After Punishment Is Associated With Increased Fos Expression in the Lateral Hypothalamus and Basolateral and Medial Amygdala.

    PubMed

    Campbell, Erin J; Barker, David J; Nasser, Helen M; Kaganovsky, Konstantin; Dayas, Christopher V; Marchant, Nathan J

    2017-02-20

    In humans, relapse to unhealthy eating habits following dieting is a significant impediment to obesity treatment. Food-associated cues are one of the main triggers of relapse to unhealthy eating during self-imposed abstinence. Here we report a behavioral method examining cue-induced relapse to food seeking following punishment-induced suppression of food taking. We trained male rats to lever press for food pellets that were delivered after a 10-s conditional stimulus (CS) (appetitive). Following training, 25% of reinforced lever presses resulted in the presentation of a compound stimulus consisting of a novel CS (aversive) and the appetitive CS followed by a pellet and footshock. After punishment-imposed abstinence, we tested the rats in an extinction test where lever pressing resulted in the presentation of either the appetitive or aversive CS. We then compared activity of lateral hypothalamus (LH) and associated extrahypothalamic regions following this test. We also assessed Fos expression in LH orexin and GABA neurons. We found that cue-induced relapse of food seeking on test was higher in rats tested with the appetitive CS compared to the aversive CS. Relapse induced by the appetitive CS was associated with increased Fos expression in LH, caudal basolateral amygdala (BLA), and medial amygdala (MeA). This relapse was also associated with increased Fos expression in LH orexin and VGAT-expressing neurons. These data show that relapse to food seeking can be induced by food-associated cues after punishment-imposed abstinence, and this relapse is associated with increased activity in LH, caudal BLA, and MeA. (PsycINFO Database Record

  15. Ifenprodil Attenuates Methamphetamine-Induced Behavioral Sensitization and Activation of Ras-ERK-∆FosB Pathway in the Caudate Putamen.

    PubMed

    Li, Lu; Liu, Xinshe; Qiao, Chuchu; Chen, Gang; Li, Tao

    2016-10-01

    Addiction is a debilitating, chronic psychiatric disorder that is difficult to cure completely owing to the high rate of relapse. Behavioral sensitization is considered to may underlie behavioral changes, such as relapse, caused by chronic abuse of psychomotor stimulants. Thus, its animal models have been widely used to explore the etiology of addiction. Recently, increasing evidence has demonstrated that N-methyl-D-aspartate receptors (NMDARs) play an important role in addiction to psychomotor stimulants. However, the role of GluN2B-containing receptors and their downstream signaling pathway(s) in behavioral sensitization induced by methamphetamine (METH) have not been investigated yet. In this study, we used different doses of ifenprodil (2.5, 5, 10 mg/kg), a selective antagonist of the GluN2B subunit, to investigate the role of GluN2B-containing NMDARs in METH-induced behavioral sensitization. We then examined changes in the levels of Ras, phosphorylated extracellular signal-regulated kinase (pERK)/ERK, and ∆FosB in the caudate putamen (CPu) by western blot. We found that 2.5 or 10 mg/kg ifenprodil significantly attenuated METH-induced behavioral sensitization, whereas the mice treated with a moderate dose of ifenprodil (5 mg/kg) displayed no significant changes. Further results of western blot experiments showed that repeated administration of METH caused the increases in the levels of Ras, pERK/ERK and ∆FosB in the CPu, and these changes were inhibited by only the 2.5 mg/kg dose of ifenprodil. In conclusion, these results demonstrated that 2.5 mg/kg ifenprodil could attenuate METH-induced behavioral sensitization. Moreover, GluN2B-containing NMDARs and their downstream Ras-ERK-∆FosB signaling pathway in the CPu might be involved in METH-induced behavioral sensitization.

  16. Effect of ghrelin receptor antagonist on meal patterns in cholecystokinin type 1 receptor null mice.

    PubMed

    Lee, Jennifer; Martin, Elizabeth; Paulino, Gabriel; de Lartigue, Guillaume; Raybould, Helen E

    2011-05-03

    Vagal afferent neurons (VAN) express the cholecystokinin (CCK) type 1 receptor (CCK₁R) and, as predicted by the role of CCK in inducing satiation, CCK₁R⁻/⁻ mice ingest larger and longer meals. However, after a short fast, CCK₁R⁻/⁻ mice ingesting high fat (HF) diets initiate feeding earlier than wild-type mice. We hypothesized that the increased drive to eat in CCK₁R⁻/⁻ mice eating HF diet is mediated by ghrelin, a gut peptide that stimulates food intake. The decrease in time to first meal, and the increase in meal size and duration in CCK₁R⁻/⁻ compared to wild-type mice ingesting high fat (HF) diet were reversed by administration of GHSR1a antagonist D-(Lys3)-GHRP-6 (p<0.05). Administration of the GHSR1a antagonist significantly increased expression of the neuropeptide cocaine and amphetamine-regulated transcript (CART) in VAN of HF-fed CCK₁R⁻/⁻ but not wild-type mice. Administration of the GHSR1a antagonist decreased neuronal activity measured by immunoreactivity for fos protein in the nucleus of the solitary tract (NTS) and the arcuate nucleus of both HF-fed wild-type and CCK₁R⁻/⁻ mice. The data show that hyperphagia in CCK₁R⁻/⁻ mice ingesting HF diet is reversed by blockade of the ghrelin receptor, suggesting that in the absence of the CCK₁R, there is an increased ghrelin-dependent drive to feed. The site of action of ghrelin receptors is unclear, but may involve an increase in expression of CART peptide in VAN in HF-fed CCK₁R⁻/⁻ mice.

  17. Ghrelin Attenuates Intestinal Barrier Dysfunction Following Intracerebral Hemorrhage in Mice

    PubMed Central

    Cheng, Yijun; Wei, Yongxu; Yang, Wenlei; Cai, Yu; Chen, Bin; Yang, Guoyuan; Shang, Hanbing; Zhao, Weiguo

    2016-01-01

    Intestinal barrier dysfunction remains a critical problem in patients with intracerebral hemorrhage (ICH) and is associated with poor prognosis. Ghrelin, a brain-gut peptide, has been shown to exert protection in animal models of gastrointestinal injury. However, the effect of ghrelin on intestinal barrier dysfunction post-ICH and its possible underlying mechanisms are still unknown. This study was designed to investigate whether ghrelin administration attenuates intestinal barrier dysfunction in experimental ICH using an intrastriatal autologous blood infusion mouse model. Our data showed that treatment with ghrelin markedly attenuated intestinal mucosal injury at both histomorphometric and ultrastructural levels post-ICH. Ghrelin reduced ICH-induced intestinal permeability according to fluorescein isothiocyanate conjugated-dextran (FITC-D) and Evans blue extravasation assays. Concomitantly, the intestinal tight junction-related protein markers, Zonula occludens-1 (ZO-1) and claudin-5 were upregulated by ghrelin post-ICH. Additionally, ghrelin reduced intestinal intercellular adhesion molecule-1 (ICAM-1) expression at the mRNA and protein levels following ICH. Furthermore, ghrelin suppressed the translocation of intestinal endotoxin post-ICH. These changes were accompanied by improved survival rates and an attenuation of body weight loss post-ICH. In conclusion, our results suggest that ghrelin reduced intestinal barrier dysfunction, thereby reducing mortality and weight loss, indicating that ghrelin is a potential therapeutic agent in ICH-induced intestinal barrier dysfunction therapy. PMID:27929421

  18. Beta-adrenoceptor Activation by Norepinephrine Enhances Lipopolysaccharide-induced Matrix Metalloproteinase-9 Expression Through the ERK/JNK-c-Fos Pathway in Human THP-1 Cells

    PubMed Central

    Yin, Xiang; Zhou, Linli; Han, Fei; Han, Jie; Zhang, Yuanyuan; Sun, Zewei; Zhao, Wenting; Wang, Zhen

    2017-01-01

    Aim: Atherosclerosis is a chronic inflammatory disease, which leads to thrombosis and acute coronary syndrome. Matrix metalloproteinase-9 (MMP-9) is involved in the stability of the extracellular matrix (ECM) and atherosclerosis plaque. Until now, it is established that lipopolysaccharide (LPS) and norepinephrine (NE) are associated with the pathological process of atherosclerosis. However, the combined effect of LPS and NE on MMP-9 is unclear. We investigated the combined effect of LPS and NE on MMP-9 expression in human monocytes and the mechanism involved in the process. Methods: THP-1 cells were cultured and treated with LPS and/or NE. MMP-9 and TIMP-1 gene and protein expression were detected by real time PCR and ELISA, respectively. MMP-9 activity was detected by gelatin zymography. Adrenoceptor antagonists and MAPKs inhibitors were used to clarify the mechanism. Pathway-related proteins were detected by Western blot. Results: We found that NE enhances LPS-induced MMP-9 and TIMP-1 expression as well as MMP-9 activity in THP-1 cells. This effect is reversed by the beta (β)-adrenoceptor antagonist propranolol, extracellular signal-regulated kinases (ERK) inhibitor U0126, and c-Jun N-terminal kinase (JNK) inhibitor SP600125. NE enhances LPS-induced ERK/JNK phosphorylation. NE up-regulates LPS-induced c-Fos expression, which is counteracted by propranolol, U0126, and SP600125. Furthermore, c-Fos silence reverses the effect of NE on MMP-9 activity. Conclusions: Our results suggest that NE enhances LPS-induced MMP-9 expression through β-adrenergic receptor and downstream ERK/JNK-c-Fos pathway. This study may help us to understand the combined effect and mechanism of NE/LPS on MMP-9 expression. PMID:27237101

  19. Hypothalamic κ-Opioid Receptor Modulates the Orexigenic Effect of Ghrelin

    PubMed Central

    Romero-Picó, Amparo; Vázquez, Maria J; González-Touceda, David; Folgueira, Cintia; Skibicka, Karolina P; Alvarez-Crespo, Mayte; Van Gestel, Margriet A; Velásquez, Douglas A; Schwarzer, Christoph; Herzog, Herbert; López, Miguel; Adan, Roger A; Dickson, Suzanne L; Diéguez, Carlos; Nogueiras, Rubén

    2013-01-01

    The opioid system is well recognized as an important regulator of appetite and energy balance. We now hypothesized that the hypothalamic opioid system might modulate the orexigenic effect of ghrelin. Using pharmacological and gene silencing approaches, we demonstrate that ghrelin utilizes a hypothalamic κ-opioid receptor (KOR) pathway to increase food intake in rats. Pharmacological blockade of KOR decreases the acute orexigenic effect of ghrelin. Inhibition of KOR expression in the hypothalamic arcuate nucleus is sufficient to blunt ghrelin-induced food intake. By contrast, the specific inhibition of KOR expression in the ventral tegmental area does not affect central ghrelin-induced feeding. This new pathway is independent of ghrelin-induced AMP-activated protein kinase activation, but modulates the levels of the transcription factors and orexigenic neuropeptides triggered by ghrelin to finally stimulate feeding. Our novel data implicate hypothalamic KOR signaling in the orexigenic action of ghrelin. PMID:23348063

  20. Effect of resveratrol on c-fos expression of rat trigeminal spinal nucleus caudalis and C1 dorsal horn neurons following mustard oil-induced acute inflammation.

    PubMed

    Matsumoto, Yasuhiro; Komatsu, Kyouhei; Shimazu, Yoshihito; Takehana, Shiori; Syouji, Yumiko; Kobayashi, Ayumu; Takeda, Mamoru

    2017-10-01

    The dietary constituent, resveratrol, was recently identified as a transient receptor potential ankyrin 1 (TRPA1) antagonist, voltage-dependent sodium ion (Na(+) ) channel, and cyclooxygenase-2 (COX-2) inhibitor. The aim of the present study was to investigate whether pretreatment with resveratrol attenuates acute inflammation-induced sensitization of nociceptive processing in rat spinal trigeminal nucleus caudalis (SpVc) and upper cervical (C1) dorsal horn neurons, via c-fos immunoreactivity. Mustard oil (MO), a TRPA1 channel agonist, was injected into the whisker pads of rats to induce inflammation. Pretreatment with resveratrol significantly decreased the mean thickness of inflammation-induced edema in whisker pads compared with those of untreated, inflamed rats. Ipsilateral of both the superficial and deep laminae of SpVc and C1 dorsal horn, there were significantly more c-fos-immunoreactive SpVc/C1 neurons in inflamed rats compared with naïve rats, and resveratrol pretreatment significantly decreased that number relative to untreated, inflamed rats. These results suggest that systemic administration of resveratrol attenuates acute inflammation-induced augmented nociceptive processing of trigeminal SpVc and C1 neurons. These findings support resveratrol as a potential therapeutic agent for use in alternative, complementary medicine to attenuate, or even prevent, acute trigeminal inflammatory pain. © 2017 Eur J Oral Sci.

  1. 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

  2. The Prokinetic Face of Ghrelin

    PubMed Central

    Sallam, Hanaa S.; Chen, Jiande D. Z.

    2010-01-01

    This review evaluated published data regarding the effects of ghrelin on GI motility using the PubMed database for English articles from 1999 to September 2009. Our strategy was to combine all available information from previous literature, in order to provide a complete structured review on the prokinetic properties of exogenous ghrelin and its potential use for treatment of various GI dysmotility ailments. We classified the literature into two major groups, depending on whether studies were done in health or in disease. We sub-classified the studies into stomach, small intestinal and colon studies, and broke them down further into studies done in vitro, in vivo (animals) and in humans. Further more, the reviewed studies were presented in a chronological order to guide the readers across the scientific advances in the field. The review shows evidences that ghrelin and its (receptor) agonists possess a strong prokinetic potential to serve in the treatment of diabetic, neurogenic or idiopathic gastroparesis and possibly, chemotherapy-associated dyspepsia, postoperative, septic or post-burn ileus, opiate-induced bowel dysfunction and chronic idiopathic constipation. Further research is necessary to close the gap in knowledge about the effect of ghrelin on the human intestines in health and disease. PMID:20721347

  3. 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. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

  4. The role of CD4-dependent signaling in interleukin-16 induced c-Fos expression and facilitation of neurite outgrowth in cerebellar granule neurons.

    PubMed

    Fenster, Catherine P; Chisnell, Hope K; Fry, Carl R; Fenster, Steven D

    2010-11-26

    Neuronal interleukin 16 (NIL-16) is the larger neural-specific splice variant of the interleukin-16 (IL16) gene and shows restricted expression to post-mitotic neurons of the mammalian hippocampus and cerebellum. Although the N-terminus of NIL-16 is unique to the neuronal variant, the C-terminus is identical to pro-IL-16, the IL-16 precursor expressed primarily in T-cells. IL-16 was originally described as a proinflammatory cytokine and has diverse immunoregulatory effects which involve signaling through CD4. NIL-16-expressing neurons can secrete IL-16 and may express CD4; moreover, treatment of cultured cerebellar granule neurons (CGCs) with IL-16 increases the expression of c-Fos, an immediate-early gene which transcriptionally regulates genes directing survival, proliferation, and growth. Taken together, we hypothesize that IL-16 functions as a neuroregulatory cytokine which signals through neuronal CD4 receptors. In this study, we investigated the role of CD4 in IL-16-induced c-Fos expression in CGCs, as well as the effects of IL-16 on neuronal survival and growth. We detected components involved in IL-16-signaling in lymphocytes, including CD4 and the associated tyrosine kinase p56(lck), in CGCs using qRT-PCR and immunoblotting. We also show that IL-16 induces c-Fos expression in wild-type CGCs, but not CD4-deficient CGCs or following inhibition of p56(lck). Finally, treatment of CGCs with IL-16 enhanced neurite outgrowth, an effect also observed in CD4-deficient CGCs. Taken together, our results indicate that IL-16-signaling affects neuronal gene expression and growth through CD4-dependent and independent pathways. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  5. 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

  6. Inhibition of osteoclast differentiation and bone resorption by rotenone, through down-regulation of RANKL-induced c-Fos and NFATc1 expression.

    PubMed

    Kwak, Han Bok; Lee, Byeong Ki; Oh, Jaemin; Yeon, Jeong-Tae; Choi, Sik-Won; Cho, Hae Joong; Lee, Myeung Su; Kim, Jeong-Joong; Bae, Ji-Myung; Kim, Seong Hwan; Kim, Hun Soo

    2010-03-01

    Osteoclasts are responsible for bone erosion in diseases as diverse as osteoporosis, periodontitis, and rheumatoid arthritis. Natural plant-derived products have received recent attention as potential therapeutic and preventative drugs in human disease. The effect of rotenone in RANKL-induced osteoclast differentiation was examined in this study. Rotenone 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, TRAP, and OSCAR in RANKL-treated BMMs was inhibited by rotenone treatment. Rotenone strongly inhibited p38 and ERK phosphorylation and I-kappaB degradation in RANKL-stimulated BMMs, and did not inhibit JNK phosphorylation. Further, RANKL-induced c-Fos and NFATc1 protein expression was suppressed by rotenone. Rotenone additionally inhibited the bone resorptive activity of differentiated osteoclasts. A lipopolysaccharide (LPS)-induced bone erosion study was also performed to assess the effects of rotenone in vivo. Mice treated with rotenone demonstrated marked attenuation of bone erosion based on Micro CT and histologic analysis of femurs. These results collectively suggested that rotenone demonstrated inhibitory effects on osteoclast differentiation in vitro and suppressed inflammatory bone loss in vivo. Rotenone may therefore serve as a useful drug in the prevention of bone loss.

  7. c-fos and HSP70 gene expression in rat brains in high gravitation-induced cerebral ischemia.

    PubMed

    Son, M; Shahed, A R; Werchan, P M; Lee, J C

    1995-11-17

    Previous studies have shown that brief exposures of rodents to high gravitational forces (+Gz) in a specifically designed centrifuge cause global cerebral ischemia. In the present study, the effect of +Gz exposure to +22.5Gz for 15 to 60 s on c-fos and HSP70 gene expression was examined. Northern and RT-PCR analyses to total RNA isolated from brains of rats in different post-exposure times revealed a significant, time-dependent increase in the c-fos mRNA level which returned to near normal by 180 min. The HSP70 mRNA level was increased two-fold at 30 min post exposure, and remained elevated until 180 min. The transient stimulation of c-fos and HSP70 gene expression should serve as useful biomarkers for hypergravic stress on the brain. The present results should aid in design of future experiments in our understanding of the pathophysiology of the high +Gz challenges.

  8. Imipramine-induced c-Fos expression in the medial prefrontal cortex is decreased in the ACTH-treated rats.

    PubMed

    Li, Bingjin; Suemaru, Katsuya; Kitamura, Yoshihisa; Gomita, Yutaka; Araki, Hiroaki; Cui, Ranji

    2013-11-01

    Previous studies have shown that the antidepressive-like effect of tricyclic antidepressants is blocked by repeated treatments with adrenocorticotropic hormone (ACTH). However, little is known about the neuroanatomy underlying the mechanism of the imipramine treatment-resistant depression model. In the present study, first experimental evidence showed no significant difference of the serum imipramine concentrations between the saline and ACTH-treated rats. In further study, imipramine produced significant increases in the c-Fos expression in the medial prefrontal cortex (mPFC), the dentate gyrus of the hippocampus (DGH), and the central nucleus of the amygdala (CeA), in rats repeatedly treated with saline. The imipramine-increased c-Fos immunoreactivity was suppressed in the mPFC of rats repeatedly treated with ACTH. However, there was no significant difference in c-Fos expression in the DGH and CeA between ACTH- and saline-treated rats. These results suggest that the mPFC is maybe involved in effects of the imipramine in the ACTH-treated rats.

  9. Ghrelin in central neurons.

    PubMed

    Ferrini, F; Salio, C; Lossi, L; Merighi, A

    2009-03-01

    Ghrelin, an orexigenic peptide synthesized by endocrine cells of the gastric mucosa, is released in the bloodstream in response to a negative energetic status. Since discovery, the hypothalamus was identified as the main source of ghrelin in the CNS, and effects of the peptide have been mainly observed in this area of the brain. In recent years, an increasing number of studies have reported ghrelin synthesis and effects in specific populations of neurons also outside the hypothalamus. Thus, ghrelin activity has been described in midbrain, hindbrain, hippocampus, and spinal cord. The spectrum of functions and biological effects produced by the peptide on central neurons is remarkably wide and complex. It ranges from modulation of membrane excitability, to control of neurotransmitter release, neuronal gene expression, and neuronal survival and proliferation. There is not at present a general consensus concerning the source of ghrelin acting on central neurons. Whereas it is widely accepted that the hypothalamus represents the most important endogenous source of the hormone in CNS, the existence of extra-hypothalamic ghrelin-synthesizing neurons is still controversial. In addition, circulating ghrelin can theoretically be another natural ligand for central ghrelin receptors. This paper gives an overview on the distribution of ghrelin and its receptor across the CNS and critically analyses the data available so far as regarding the effects of ghrelin on central neurotransmission.

  10. Ghrelin in Central Neurons

    PubMed Central

    Ferrini, F; Salio, C; Lossi, L; Merighi, A

    2009-01-01

    Ghrelin, an orexigenic peptide synthesized by endocrine cells of the gastric mucosa, is released in the bloodstream in response to a negative energetic status. Since discovery, the hypothalamus was identified as the main source of ghrelin in the CNS, and effects of the peptide have been mainly observed in this area of the brain. In recent years, an increasing number of studies have reported ghrelin synthesis and effects in specific populations of neurons also outside the hypothalamus. Thus, ghrelin activity has been described in midbrain, hindbrain, hippocampus, and spinal cord. The spectrum of functions and biological effects produced by the peptide on central neurons is remarkably wide and complex. It ranges from modulation of membrane excitability, to control of neurotransmitter release, neuronal gene expression, and neuronal survival and proliferation. There is not at present a general consensus concerning the source of ghrelin acting on central neurons. Whereas it is widely accepted that the hypothalamus represents the most important endogenous source of the hormone in CNS, the existence of extra-hypothalamic ghrelin-synthesizing neurons is still controversial. In addition, circulating ghrelin can theoretically be another natural ligand for central ghrelin receptors. This paper gives an overview on the distribution of ghrelin and its receptor across the CNS and critically analyses the data available so far as regarding the effects of ghrelin on central neurotransmission. PMID:19721816

  11. Administration of exogenous acylated ghrelin or rikkunshito, an endogenous ghrelin enhancer, improves the decrease in postprandial gastric motility in an acute restraint stress mouse model

    PubMed Central

    Nahata, M; Saegusa, Y; Sadakane, C; Yamada, C; Nakagawa, K; Okubo, N; Ohnishi, S; Hattori, T; Sakamoto, N; Takeda, H

    2014-01-01

    Background Physical or psychological stress causes functional disorders in the upper gastrointestinal tract. This study aims to elucidate the ameliorating effect of exogenous acylated ghrelin or rikkunshito, a Kampo medicine which acts as a ghrelin enhancer, on gastric dysfunction during acute restraint stress in mice. Methods Fasted and postprandial motor function of the gastric antrum was wirelessly measured using a strain gauge force transducer and solid gastric emptying was detected in mice exposed to restraint stress. Plasma corticosterone and ghrelin levels were also measured. To clarify the role of ghrelin on gastrointestinal dysfunction in mice exposed to stress, exogenous acylated ghrelin or rikkunshito was administered, then the mice were subjected to restraint stress. Key Results Mice exposed to restraint stress for 60 min exhibited delayed gastric emptying and increased plasma corticosterone levels. Gastric motility was decreased in mice exposed to restraint stress in both fasting and postprandial states. Restraint stress did not cause any change in plasma acylated ghrelin levels, but it significantly increased the plasma des-acyl ghrelin levels. Administration of acylated ghrelin or rikkunshito improved the restraint stress-induced delayed gastric emptying and decreased antral motility. Ameliorating effects of rikkunshito on stress-induced gastric dysfunction were abolished by simultaneous administration of a ghrelin receptor antagonist. Conclusions & Inferences Plasma acylated/des-acyl ghrelin imbalance was observed in acute restraint stress. Supplementation of exogenous acylated ghrelin or enhancement of endogenous ghrelin signaling may be useful in the treatment of decreased gastric function caused by stress. PMID:24684160

  12. Ghrelin, reward and motivation.

    PubMed

    Menzies, John R W; Skibicka, Karolina P; Leng, Gareth; Dickson, Suzanne L

    2013-01-01

    Almost all circulating gut peptides contribute to the control of food intake by signalling satiety. One important exception is ghrelin, the only orexigenic peptide hormone thus far described. Ghrelin secretion increases before meals and behavioural and electrophysiological evidence shows that ghrelin acts in the hypothalamus via homeostatic pathways to signal hunger and increase food intake and adiposity. These findings strongly suggest that ghrelin is a dynamically regulated peripheral hunger signal. However, ghrelin also interacts with the brain reward pathways to increase food intake, alter food preference and enhance food reward. Here we discuss ghrelin's role as an endocrine gut-brain reward signal in relation to homeostatic and hedonic feeding control. Copyright © 2013 S. Karger AG, Basel.

  13. Expression of c-fos mRNA in the Basal Ganglia Associated with Contingent Tolerance to Amphetamine-Induced Hypophagia

    PubMed Central

    Bachand, Kimberlee D.; Guthrie, Kathleen M.; Wolgin, David L.

    2009-01-01

    Tolerance to the hypophagic effect of psychostimulants is contingent on having access to food while intoxicated. Rats given chronic injections of such drugs with access to food learn to suppress stereotyped movements, which interfere with feeding. In contrast, controls given the drug after food access do not learn to suppress stereotypy and, therefore, do not become tolerant. To determine the role of the basal ganglia in this phenomenon, we used in situ hybridization to measure the expression of c-fos mRNA, a marker for neural activation, in the brains of tolerant and nontolerant rats. Rats given chronic amphetamine injections prior to food access learned to suppress stereotyped movements, whereas yoked controls given the drug after feeding did not. Following an acute injection of amphetamine, both of these groups had higher levels of c-fos mRNA than saline-treated controls throughout the striatum, in the nucleus accumbens core, the ventral pallidum and layers V–VI of the motor cortex. In contrast, tolerant rats, which had learned to suppress stereotypy, had higher levels of c-fos mRNA than both amphetamine- and saline-treated controls in the entopeduncular nucleus, globus pallidus, subthalamic nucleus, pedunculopontine nucleus, nucleus accumbens shell, olfactory tubercle, somatosensory cortex, and layers II–IV of motor cortex. These data suggest that the learned suppression of amphetamine-induced stereotypy involves the activation of dorsal striatal pathways previously implicated in response selection as well as the ventral striatum, long implicated in appetitive motivation and reinforcement. PMID:19084559

  14. Parthenolide is the component of tanacetum parthenium that inhibits nitroglycerin-induced Fos activation: studies in an animal model of migraine.

    PubMed

    Tassorelli, C; Greco, R; Morazzoni, P; Riva, A; Sandrini, G; Nappi, G

    2005-08-01

    Tanacetum parthenium (TP) is a member of the Asteracee family long used empirically as a herbal remedy for migraine. So far, however, clinical trials have failed to prove consistently the effectiveness of TP extracts in preventing migraine attacks, probably as a consequence of the uncertainty as regards the active principle. In this study, the biological effects of different TP extracts and purified parthenolide were tested in an animal model of migraine based on the quantification of neuronal activation induced by nitroglycerin. The extract enriched in parthenolide significantly reduced nitroglycerin-induced Fos expression in the nucleus trigeminalis caudalis. Purified parthenolide inhibited nitroglycerin-induced neuronal activation in additional brain nuclei and, significantly, the activity of nuclear factor-kappaB. These findings strongly suggest that parthenolide is the component responsible for the biological activity of TP as regards its antimigraine effect and provide important information for future controlled clinical trials.

  15. Distribution of ghrelin-producing cells in stomach and the effects of ghrelin administration in the house musk shrew (Suncus murinus).

    PubMed

    Li, Jun; Yi, Shuang-Qin; Terayama, Hayato; Naito, Munekazu; Hirai, Shuichi; Qu, Ning; Wang, Heng-Xiao; Yi, Nozomi; Ozaki, Noriyuki; Itoh, Masahiro

    2010-01-01

    To investigate the distribution of ghrelin, an important appetite regulatory factor related to obesity, in the stomach of Suncus murinus, and attempted to elucidate the ghrelin-mediated regulatory effect in this animal. The stomachs of Suncus murinus were divided into 5 sections, cardia, fundus, greater curvature, lesser curvature, and pylorus, for investigating the ghrelin-producing cells by immunohistochemistry and Western blotting. Then Suncus murinus were randomized into two groups with ghrelin intraperitoneal injection (ghrelin-ip group) and saline intraperitoneal injection (control group), respectively. The effects of food intake and body weight were measured, and furthermore, the distribution of ghrelin in stomach was also investigated by immunohistochemistry and Western blotting. The immunolocalization and protein levels of ghrelin differed significantly in different regions of the stomach of Suncus murinus. Furthermore, ghrelin administration did not change the rate of food intake, but resulted in an increase in body weight compared with the control group. In this study, we elucidated the distribution of ghrelin-producing cells in the stomach of Suncus murinus in detail for the first time. Ghrelin intraperitoneal administration was found to induce an increase in body weight without changing food intake in this species. Our study implied ghrelin showed a different regulatory function in Suncus murinus from other species. It is considered that ghrelin may be associated with obesity-resistance phenomenon in Suncus murinus.

  16. 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.

  17. c-Fos protein expression is increased in cholinergic neurons of the rodent basal forebrain during spontaneous and induced wakefulness

    PubMed Central

    McKenna, J. T.; Cordeira, J. W.; Jeffrey, B. A.; Ward, C. P.; Winston, S.; McCarley, R. W.; Strecker, R. E.

    2009-01-01

    It has been proposed that cholinergic neurons of the basal forebrain (BF) may play a role in vigilance state control. Since not all vigilance states have been studied, we evaluated cholinergic neuronal activation levels across spontaneously occurring states of vigilance, as well as during sleep deprivation and recovery sleep following sleep deprivation. Sleep deprivation was performed for two hours at the beginning of the light (inactive) period, by means of gentle sensory stimulation. In the rodent BF, we used immunohistochemical detection of the c-Fos protein as a marker for activation combined with labeling for choline acetyl-transferase (ChAT) as a marker for cholinergic neurons. We found c-Fos activation in BF cholinergic neurons was highest in the group undergoing sleep deprivation (12.9% of cholinergic neurons), while the spontaneous wakefulness group showed a significant increase (9.2%), compared to labeling in the spontaneous sleep group (1.8%) and sleep deprivation recovery group (0.8%). A subpopulation of cholinergic neurons expressed c-Fos during spontaneous wakefulness, when possible confounds of the sleep deprivation procedure were minimized (e.g., stress and sensory stimulation). Double-labeling in the sleep deprivation treatment group was significantly elevated in select subnuclei of the BF (medial septum/vertical limb of the diagonal band, horizontal limb of the diagonal band, and the magnocellular preoptic nucleus), when compared to spontaneous wakefulness. These findings support and provide additional confirming data of previous reports that cholinergic neurons of BF play a role in vigilance state regulation by promoting wakefulness. PMID:19716862

  18. Novel cues reinstate cocaine-seeking behavior and induce Fos protein expression as effectively as conditioned cues.

    PubMed

    Bastle, Ryan M; Kufahl, Peter R; Turk, Mari N; Weber, Suzanne M; Pentkowski, Nathan S; Thiel, Kenneth J; Neisewander, Janet L

    2012-08-01

    Cue reinstatement of extinguished cocaine-seeking behavior is a widely used model of cue-elicited craving in abstinent human addicts. This study examined Fos protein expression in response to cocaine cues or to novel cues as a control for activation produced by test novelty. Rats were trained to self-administer cocaine paired with either a light or a tone cue, or received yoked saline and cue presentations, and then underwent daily extinction training. They were then tested for reinstatement of extinguished cocaine-seeking behavior elicited by response-contingent presentations of either the cocaine-paired cue or a novel cue (that is, tone for those trained with a light or vice versa). Surprisingly, conditioned and novel cues both reinstated responding and increased Fos similarly in most brain regions. Exceptions included the anterior cingulate, which was sensitive to test cue modality in saline controls and the dorsomedial caudate-putamen, where Fos was correlated with responding in the novel, but not conditioned, cue groups. In subsequent experiments, we observed a similar pattern of reinstatement in rats trained and tested for sucrose-seeking behavior, whereas rats trained and tested with the cues only reinstated to a novel, and not a familiar, light or tone. The results suggest that novel cues reinstate responding to a similar extent as conditioned cues regardless of whether animals have a reinforcement history with cocaine or sucrose, and that both types of cues activate similar brain circuits. Several explanations as to why converging processes may drive drug and novel cue reinforcement and seeking behavior are discussed.

  19. Characterization of adult ghrelin and ghrelin receptor knockout mice under positive and negative energy balance.

    PubMed

    Sun, Yuxiang; Butte, Nancy F; Garcia, Jose M; Smith, Roy G

    2008-02-01

    Ghrelin and the ghrelin receptor (GH secretagogue receptor, GHS-R), are believed to have important roles in energy homeostasis. We describe results from the first studies to be conducted in congenic (N10) adult ghrelin(-/-) and Ghsr(-/-) mice under conditions of both positive (high-fat diet) and negative (caloric restriction) energy balance. In contrast to results from young N2 mutant mice, changes in body weight and energy expenditure are not clearly distinguishable across genotypes. Although respiratory quotient was lower in mice fed a high-fat diet, no differences were evident between littermate wild-type and null genotypes. With normal chow, a modest decrease trend in respiratory quotient was detected in ghrelin(-/-) mice but not in Ghsr(-/-) mice. Under caloric restriction, the weight loss of ghrelin(-/-) and Ghsr(-/-) mice was identical to wild-type littermates, but blood glucose levels were significantly lower. We conclude that adult congenic ghrelin(-/-) and Ghsr(-/-) mice are not resistant to diet-induced obesity but under conditions of negative energy balance show impairment in maintaining glucose homeostasis. These results support our hypothesis that the primary metabolic function of ghrelin in adult mice is to modulate glucose sensing and insulin sensitivity, rather than directly regulate energy intake and energy expenditure.

  20. Ghrelin and appetite control in humans--potential application in the treatment of obesity.

    PubMed

    Patterson, Michael; Bloom, Stephen R; Gardiner, James V

    2011-11-01

    Ghrelin is a peptide hormone secreted into circulation from the stomach. It has been postulated to act as a signal of hunger. Ghrelin administration acutely increases energy intake in lean and obese humans and chronically induces weight gain and adiposity in rodents. Circulating ghrelin levels are elevated by fasting and suppressed following a meal. Inhibiting ghrelin signaling therefore appears an attractive target for anti-obesity therapies. A number of different approaches to inhibiting the ghrelin system to treat obesity have been explored. Despite this, over a decade after its discovery, no ghrelin based anti-obesity therapies are close to reaching the market. This article discusses the role of ghrelin in appetite control in humans, examines different approaches to inhibiting the ghrelin system and assesses their potential as anti-obesity therapies.

  1. 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

    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/m(2)) at 4-5 weeks postpartum and 20 never-pregnant controls (BMI = 24.0 ± 3.1 kg/m(2)). 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.

  2. 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

  3. Taste aversion learning induced c-fos expression in the nucleus of the solitary tract after spontaneous flavor intake: role of the inter-stimulus interval.

    PubMed

    Mediavilla, Cristina; Bernal, Antonio; Puerto, Amadeo

    2007-09-01

    Taste aversion learning (TAL) can be induced by associating a flavor intake with the immediate or delayed (30 min) intragastric administration of a noxious substance, e.g., hypertonic NaCl. The objective of this study was to analyze the induction of c-Fos immunoreactivity in the intermediate nucleus of the solitary nucleus (iNST) after acquisition of a contiguous or delayed TAL, offering the flavor for voluntary consumption in both cases. The behavioral results obtained indicate that, although the learning was established under both experimental conditions, an increase in c-Fos induction was only produced in the group that learned by means of a non-delayed TAL. Immunohistochemical analyses revealed the participation of different brain structures in these two TAL modalities. Thus, the nucleus of the solitary tract may be involved in the TAL procedure in which voluntary flavor intake and intragastric administration of the noxious visceral stimulus are contiguous but not in delayed TAL, which would depend on other anatomical circuits that do not include the iNST.

  4. Clinical application of ghrelin.

    PubMed

    Strasser, Florian

    2012-01-01

    Ghrelin as a human natural hormone is involved in fundamental regulatory processes of eating and energy balance. Ghrelin signals the nutrient availability from the gastrointestinal tract to the central nervous system, up-regulates food intake and lowers energy expenditure mainly through hypothalamic mediators acting both centrally and peripherally including the gastrointestinal tract (motility, epithelium), promotes both neuro-endocrine and inflammatory signals to increase skeletal muscle growth and decrease protein breakdown, and increases lipolysis while body fat utilization is reduced. Ghrelin does more to exert its probably sentinel role around "human energy": it influences through mainly extra-hypothalamic actions the hedonic and incentive value of food, mood and anxiety, sleep-wake regulation, learning and memory, and neurogenesis. Recently numerous ghrelin gene-derived peptides were discovered, demonstrating the complexity within the ghrelin/ghrelin receptor axis. For clinical applications, not only the natural ghrelin and its slice variants, but also several modified or artificial molecules acting at ghrelin-associated receptors were and are developed. Current clinical applications are limited to clinical studies, focusing mainly on cachexia in chronic heart failure, COPD, cancer, endstage- renal-disease or cystic fibrosis, but also on frailty in elderly, gastrointestinal motility (e.g., gastroparesis, functional dyspepsia, postoperative ileus), after curative gastrectomy, anorexia nervosa, growth hormone deficient patients, alcohol craving, sleep-wake regulation (e.g. major depression), or sympathetic nervous activity in obesity. The results of completed, preliminary studies support the clinical potential of ghrelin, ghrelin gene-derived peptides, and artificial analogues, suggesting that larger clinical trials are demanded to move ghrelin towards an available and reimbursed pharmaceutical intervention.

  5. β1-Adrenergic receptor deficiency in ghrelin-expressing cells causes hypoglycemia in susceptible individuals

    PubMed Central

    Mani, Bharath K.; Osborne-Lawrence, Sherri; Vijayaraghavan, Prasanna; Hepler, Chelsea; Zigman, Jeffrey M.

    2016-01-01

    Ghrelin is an orexigenic gastric peptide hormone secreted when caloric intake is limited. Ghrelin also regulates blood glucose, as emphasized by the hypoglycemia that is induced by caloric restriction in mouse models of deficient ghrelin signaling. Here, we hypothesized that activation of β1-adrenergic receptors (β1ARs) localized to ghrelin cells is required for caloric restriction–associated ghrelin release and the ensuing protective glucoregulatory response. In mice lacking the β1AR specifically in ghrelin-expressing cells, ghrelin secretion was markedly blunted, resulting in profound hypoglycemia and prevalent mortality upon severe caloric restriction. Replacement of ghrelin blocked the effects of caloric restriction in β1AR-deficient mice. We also determined that treating calorically restricted juvenile WT mice with beta blockers led to reduced plasma ghrelin and hypoglycemia, the latter of which is similar to the life-threatening, fasting-induced hypoglycemia observed in infants treated with beta blockers. These findings highlight the critical functions of ghrelin in preventing hypoglycemia and promoting survival during severe caloric restriction and the requirement for ghrelin cell–expressed β1ARs in these processes. Moreover, these results indicate a potential role for ghrelin in mediating beta blocker–associated hypoglycemia in susceptible individuals, such as young children. PMID:27548523

  6. Induction of deltaFosB in reward-related brain structures after chronic stress.

    PubMed

    Perrotti, Linda I; Hadeishi, Yuki; Ulery, Paula G; Barrot, Michel; Monteggia, Lisa; Duman, Ronald S; Nestler, Eric J

    2004-11-24

    Acute and chronic stress differentially regulate immediate-early gene (IEG) expression in the brain. Although acute stress induces c-Fos and FosB, repeated exposure to stress desensitizes the c-Fos response, but FosB-like immunoreactivity remains high. Several other treatments differentially regulate IEG expression in a similar manner after acute versus chronic exposure. The form of FosB that persists after these chronic treatments has been identified as DeltaFosB, a splice variant of the fosB gene. This study was designed to determine whether the FosB form induced after chronic stress is also DeltaFosB and to map the brain regions and identify the cell populations that exhibit this effect. Western blotting, using an antibody that recognizes all Fos family members, revealed that acute restraint stress caused robust induction of c-Fos and full-length FosB, as well as a small induction of DeltaFosB, in the frontal cortex (fCTX) and nucleus accumbens (NAc). The induction of c-Fos (and to some extent full-length FosB) was desensitized after 10 d of restraint stress, at which point levels of DeltaFosB were high. A similar pattern was observed after chronic unpredictable stress. By use of immunohistochemistry, we found that chronic restraint stress induced DeltaFosB expression predominantly in the fCTX, NAc, and basolateral amygdala, with lower levels of induction seen elsewhere. These findings establish that chronic stress induces DeltaFosB in several discrete regions of the brain. Such induction could contribute to the long-term effects of stress on the brain.

  7. Serotonin receptors are involved in the spinal mediation of descending facilitation of surgical incision-induced increase of Fos-like immunoreactivity in rats

    PubMed Central

    2010-01-01

    Background Descending pronociceptive pathways may be implicated in states of persistent pain. Paw skin incision is a well-established postoperative pain model that causes behavioral nociceptive responses and enhanced excitability of spinal dorsal horn neurons. The number of spinal c-Fos positive neurons of rats treated intrathecally with serotonin, noradrenaline or acetylcholine antagonists where evaluated to study the descending pathways activated by a surgical paw incision. Results The number of c-Fos positive neurons in laminae I/II ipsilateral, lamina V bilateral to the incised paw, and in lamina X significantly increased after the incision. These changes: remained unchanged in phenoxybenzamine-treated rats; were increased in the contralateral lamina V of atropine-treated rats; were inhibited in the ipsilateral lamina I/II by 5-HT1/2B/2C (methysergide), 5-HT2A (ketanserin) or 5-HT1/2A/2C/5/6/7 (methiothepin) receptors antagonists, in the ipsilateral lamina V by methysergide or methiothepin, in the contralateral lamina V by all the serotonergic antagonists and in the lamina X by LY 278,584, ketanserin or methiothepin. Conclusions We conclude: (1) muscarinic cholinergic mechanisms reduce incision-induced response of spinal neurons inputs from the contralateral paw; (2) 5-HT1/2A/2C/3 receptors-mediate mechanisms increase the activity of descending pathways that facilitates the response of spinal neurons to noxious inputs from the contralateral paw; (3) 5-HT1/2A/2C and 5-HT1/2C receptors increases the descending facilitation mechanisms induced by incision in the ipsilateral paw; (4) 5-HT2A/3 receptors contribute to descending pronociceptive pathways conveyed by lamina X spinal neurons; (5) α-adrenergic receptors are unlikely to participate in the incision-induced facilitation of the spinal neurons. PMID:20331882

  8. Ghrelin and the short- and long-term regulation of appetite and body weight.

    PubMed

    Cummings, David E

    2006-08-30

    Ghrelin, an acylated upper gastrointestinal peptide, is the only known orexigenic hormone. Considerable evidence implicates ghrelin in mealtime hunger and meal initiation. Circulating levels decrease with feeding and increase before meals, achieving concentrations sufficient to stimulate hunger and food intake. Preprandial ghrelin surges occur before every meal on various fixed feeding schedules and also among individuals initiating meals voluntarily without time- or food-related cues. Ghrelin injections stimulate food intake rapidly and transiently, primarily by increasing appetitive feeding behaviors and the number of meals. Preprandial ghrelin surges are probably triggered by sympathetic nervous output. Postprandial suppression is not mediated by nutrients in the stomach or duodenum, where most ghrelin is produced. Rather, it results from post-ingestive increases in lower intestinal osmolarity (information probably relayed to the foregut via enteric nervous signaling), as well as from insulin surges. Consequently, ingested lipids suppress ghrelin poorly compared with other macronutrients. Beyond a probable role in meal initiation, ghrelin also fulfills established criteria for an adiposity-related hormone involved in long-term body-weight regulation. Ghrelin levels circulate in relation to energy stores and manifest compensatory changes in response to body-weight alterations. Ghrelin crosses the blood-brain barrier and stimulates food intake by acting on several classical body-weight regulatory centers, including the hypothalamus, hindbrain, and mesolimbic reward system. Chronic ghrelin administration increases body weight via diverse, concerted actions on food intake, energy expenditure, and fuel utilization. Congenital ablation of the ghrelin or ghrelin-receptor gene causes resistance to diet-induced obesity, and pharmacologic ghrelin blockade reduces food intake and body weight. Ghrelin levels are high in Prader-Willi syndrome and low after gastric bypass

  9. 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.

  10. Reduction in circulating ghrelin concentration after maturation does not affect food intake.

    PubMed

    Ariyasu, Hiroyuki; Yamada, Go; Iwakura, Hiroshi; Matsumura, Sigenobu; Inoue, Kazuo; Kangawa, Kenji; Nakao, Kazuwa; Akamizu, Takashi

    2014-01-01

    Ghrelin has a potent orexigenic effect and induces adiposity when administered exogenously. Since plasma ghrelin levels rise before meals, ghrelin was thought to play a crucial role in the regulation of appetite. In contrast, mice deficient in the production of ghrelin or the corresponding receptor, GHS-R, do not eat less, throwing the role of ghrelin in the regulation of energy homeostasis into question. Since these mice lack ghrelin or GHS-R from the time of conception, the possibility that compensatory mechanisms may have arisen during development cannot be ruled out. In this study, we used a transgenic mouse model that expresses human diphtheria toxin (DT) receptor cDNA under the control of the ghrelin promoter (GPDTR-Tg mice). As previously reported, an injection of DT into this mouse model ablates ghrelin-secreting cells in the stomach but not in the hypothalamus, resulting in a reduction in circulating ghrelin levels. We used this model system to evaluate the physiological roles of circulating ghrelin in the regulation of food intake. Meal patterns, diurnal and nocturnal meal sizes, and cumulative food intake of DT-treated GPDTR-Tg mice were not affected, although circulating ghrelin levels markedly decreased even after fasting. These mice also displayed normal responses to starvation; however, the use of fat increased and slower weight gain when maintained on a high fat diet was observed. Together, these data suggest that circulating ghrelin does not play a crucial role in feeding behavior, but rather is involved in maintaining body weight.

  11. Effects of ghrelin in energy balance and body weight homeostasis.

    PubMed

    Mihalache, Laura; Gherasim, Andreea; Niță, Otilia; Ungureanu, Maria Christina; Pădureanu, Sergiu Serghei; Gavril, Radu Sebastian; Arhire, Lidia Iuliana

    2016-02-01

    Ghrelin is a gut peptide composed of 28 amino acids mostly secreted in the gastric fundus mucosa. It was isolated and described in 1999 by Kojima et al. and only three years later its specific receptor, GHSR1a, was also identified. Ghrelin, the endogenous ligand for the GH secretagogue receptor, is the only peripheral orexigenic hormone that activates the receptors to be found especially in the appetite center (hypothalamus and pituitary gland). Ghrelin is present in human plasma in two forms: an inactive form known as deacylated ghrelin, and an active form called acylated ghrelin synthesized under the action of ghrelin O-acyltransferase enzyme (GOAT). The literature even mentions an extremely complex ghrelin/GOAT/GHSR system involved in the regulation of human energy, metabolism and adaptation of energy homeostasis to environmental changes. In humans, there is a preprandial rise and a postprandial fall in plasma ghrelin levels, which strongly suggest that the peptide plays a physiological role in meal initiation and may be employed in determining the amount and quality of ingested food. Besides the stimulation of food intake, ghrelin determines a decrease in energy expenditure and promotes the storage of fatty acids in adipocytes. Thus, in the human body ghrelin induces a positive energy balance, an increased adiposity gain, as well as an increase in caloric storage, seen as an adaptive mechanism to caloric restriction conditions. In the current world context, when we are witnessing an increasing availability of food and a reduction of energy expenditure to a minimum level, these mechanisms have become pathogenic. As a consequence, the hypothesis that ghrelin is involved in the current obesity epidemic has been embraced by many scholars and researchers.

  12. Continuous antagonism of the ghrelin receptor results in early induction of salt-sensitive hypertension.

    PubMed

    Sato, Takahiro; Nakashima, Yoshiki; Nakamura, Yuki; Ida, Takanori; Kojima, Masayasu

    2011-02-01

    Ghrelin is a hormone that mediates a variety of physiological roles, such as stimulating appetite, initiating food intake, and modulating energy metabolism. Although it has been reported that a bolus injection of ghrelin decreases blood pressure, the effect of continuous ghrelin administration on vasoregulation has yet to be determined. We examined the longitudinal effect of ghrelin on vasoregulation using Dahl-Iwai salt-sensitive rats. In this model, a high-salt diet induced high blood pressure and increased ghrelin levels but reduced food intake. In salt-sensitive hypertension, cumulative food intake decreased, while both ghrelin messenger RNA levels and plasma ghrelin content increased. Continuous administration of a ghrelin receptor agonist, growth hormone releasing peptide-6 (GHRP-6), for 2 weeks by mini-osmotic pump did not change blood pressure values although the cumulative food intake recovered. In contrast, continuous administration of a ghrelin receptor antagonist, [D-Lys³]-GHRP-6, induced early elevations in blood pressure without changes in heart rate. Quantitative RT-PCR revealed high expression levels of genes involved in the catecholamine biosynthetic pathway, tyrosine hydroxylase and dopamine-β-hydroxylase, after continuous [D-Lys³]-GHRP-6 administration. These results indicate that continuous antagonism of the ghrelin receptor results in early induction of salt-sensitive hypertension in this animal model and suggests that increases in autonomic nervous activity induced by ghrelin receptor antagonism are responsible, as indicated by the high expression levels of genes in the catecholamine biosynthetic pathway.

  13. Anxiolytic-Like Effects of Increased Ghrelin Receptor Signaling in the Amygdala

    PubMed Central

    Jensen, Morten; Ratner, Cecilia; Rudenko, Olga; Christiansen, Søren H.; Skov, Louise J.; Hundahl, Cecilie; Woldbye, David P.D.

    2016-01-01

    Background: Besides the well-known effects of ghrelin on adiposity and food intake regulation, the ghrelin system has been shown to regulate aspects of behavior including anxiety and stress. However, the effect of virus-mediated overexpression of the ghrelin receptor in the amygdala has not previously been addressed directly. Methods: First, we examined the acute effect of peripheral ghrelin administration on anxiety- and depression-like behavior using the open field, elevated plus maze, forced swim, and tail suspension tests. Next, we examined the effect of peripheral ghrelin administration and ghrelin receptor deficiency on stress in a familiar and social environment using the Intellicage system. Importantly, we also used a novel approach to study ghrelin receptor signaling in the brain by overexpressing the ghrelin receptor in the amygdala. We examined the effect of ghrelin receptor overexpression on anxiety-related behavior before and after acute stress and measured the modulation of serotonin receptor expression. Results: We found that ghrelin caused an anxiolytic-like effect in both the open field and elevated plus maze tests. Additionally, it attenuated air-puff–induced stress in the social environment, while the opposite was shown in ghrelin receptor deficient mice. Finally, we found that overexpression of the ghrelin receptor in the basolateral division of the amygdala caused an anxiolytic-like effect and decreased the 5HT1a receptor expression. Conclusions: Ghrelin administration and overexpression of the ghrelin receptor in the amygdala induces anxiolytic-like behavior. Since the ghrelin receptor has high constitutive activity, ligand-independent signaling in vivo may be important for the observed anxiolytic-like effects. The anxiolytic effects seem to be mediated independently from the HPA axis, potentially engaging the central serotonin system. PMID:26578081

  14. Effects of ghrelin on anorexia in tumor-bearing mice with eicosanoid-related cachexia.

    PubMed

    Wang, Wenhua; Andersson, Marianne; Iresjö, Britt-Marie; Lönnroth, Christina; Lundholm, Kent

    2006-06-01

    Ghrelin is a novel brain-gut peptide that stimulates food intake and may secondarily increase body weight via a growth hormone secretagogue receptor (GHS-R). Tumor-bearing mice (MCG101), characterized by anorexia, fat loss and muscle wasting due to increased concentration of PGE2 and proinflammatory cytokines (IL-1beta, IL-6, TNF-alpha), were provided ghrelin i.p. at a low (20 microg/day) and high dose (40 microg/day) to examine the ability of ghrelin to counteract tumor-induced anorexia. Immunohistochemical staining and Western blot analyses were used to identify GHS-R expression in the brain as well as its relationship to NPY expression in hypothalamic neurons. GHS-R mRNA in hypothalamus and ghrelin mRNA in gastric fundus were quantified by RT-PCR. Body composition was determined by carcass extractions. GHS-R expression in hypothalamus and plasma ghrelin levels were significantly increased in freely-fed tumor-bearing mice, while gastric fundus expression of ghrelin was unaltered compared to non-tumor-bearing mice (controls). Ghrelin treatment increased food intake, body weight and whole body fat at both low and high doses of ghrelin in normal controls, while tumor-bearing mice showed improved intake and body composition at the high dose of ghrelin only. Exogenous ghrelin normalized the GHS-R expression in hypothalamus from tumor-bearing mice without alterations in the gastric fundus expression of ghrelin. Tumor growth was not altered by exogenous ghrelin. Our results indicate that MCG 101-bearing mice became ghrelin resistant despite upregulation of hypothalamic GHS-R expression, which confirms similar indirect observations in cancer patients. Thus, other factors downstream of the ghrelin-GHS-R system appear to be more important than ghrelin to explain cancer-induced anorexia.

  15. 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.

  16. 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.

  17. L-DOPA-induced dyskinesia in adult rats with a unilateral 6-OHDA lesion of dopamine neurons is paralleled by increased c-fos gene expression in the subthalamic nucleus.

    PubMed

    Soghomonian, Jean-Jacques

    2006-05-01

    Levodopa (L-DOPA), the metabolic precursor of dopamine, is widely used as a pharmacological agent for the symptomatic treatment of Parkinson's disease. However, long-term L-DOPA use results in abnormal involuntary movements such as dyskinesias. There is evidence that abnormal cell signaling in the basal ganglia is involved in L-DOPA-induced dyskinesia. The subthalamic nucleus (STN) plays a key role in the circuitry of the basal ganglia and in the pathophysiology of Parkinson's disease. However, the contribution of the STN to L-DOPA-induced dyskinesias remains unclear. The objective of this work was to study the effects of acute or chronic systemic administration of L-DOPA to adult rats with a unilateral 6-hydroxydopamine (6-OHDA) lesion of dopamine neurons on c-fos expression in the STN and test the hypothesis that these effects correlate with L-DOPA-induced dyskinesias. c-fos mRNA expression was measured in the STN by in situ hybridization histochemistry at the single cell level. Our results confirm earlier evidence that the chronic administration of L-DOPA to rats with a unilateral 6-OHDA lesion increases c-fos expression in the STN. We also report that c-fos expression can be increased following an acute injection of L-DOPA to 6-OHDA-lesioned rats but not following a chronic injection of L-DOPA to sham-operated, unlesioned rats. Finally, we provide evidence that the occurrence and severity of dyskinesia is correlated with c-fos mRNA levels in the ipsilateral STN. These results suggest that altered cell signaling in the STN is involved in some of the behavioral effects induced by systemic L-DOPA administration.

  18. The effect of ghrelin on cell proliferation in small intestinal IEC-6 cells.

    PubMed

    Yu, Huafang; Xu, Guoxiong; Fan, Xiaoming

    2013-04-01

    Recent evidence demonstrates that ghrelin, a short orexigenic peptide from the stomach, has dual effects on cell proliferation in different cell types via autocrine and/or paracrine mechanisms. The aim of this study is to investigate the proliferative role of ghrelin in intestinal epithelial IEC-6 cells and explore underlying mechanism. RT-PCR was used for the detection of growth hormone secretagogue receptor 1a. Cell proliferation was measured using Cell Counting Kit-8. Protein expression of ERK 1/2 and Akt was examined using western blotting. Inhibitors of mitogen activated protein kinases kinase and phosphatidylinositol 3-kinase were used to evaluate the role of these signalling pathways in ghrelin-induced proliferation of IEC-6 cells. Growth hormone secretagogue receptor 1a mRNA was present in IEC-6 cells. Ghrelin and des-acyl ghrelin increased IEC-6 cell proliferation in a dose- and time-dependent manner. Ghrelin and des-acyl ghrelin activated ERK1/2, but not Akt. U0126, a specific inhibitor of mitogen activated protein kinases kinase, blocked ghrelin- and des-acyl ghrelin-induced ERK1/2 phosphorylation and cell proliferation in IEC-6 cells. Ghrelin and des-acyl ghrelin stimulate the proliferation of IEC-6 cells via the ERK1/2 pathway. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  19. 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. © 2014 Society for Endocrinology.

  20. 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

  1. An Integrative Review on Role and Mechanisms of Ghrelin in Stress, Anxiety and Depression.

    PubMed

    Bali, Anjana; Jaggi, Amteshwar Singh

    2016-01-01

    Ghrelin is orexigenic hormone primarily synthesized by endocrine X/A-like cells of gastric oxyntic mucosa to stimulate appetite and food intake along with regulation of growth hormone and insulin secretion; glucose and lipid metabolism; gastrointestinal motility; blood pressure, heart rate and neurogenesis. Furthermore, peripherally (after crossing the blood brain barrier) as well as centrally synthesized ghrelin (in the hypothalamus) regulates diverse functions of central nervous system including stress-associated behavioral functions. Exposure to stress alters the ghrelin levels and alteration in ghrelin levels significantly affects neuro-endocrinological parameters; metabolism-related physiology, behavior and mood. Studies have shown both anxiolytic and anxiogenic role of ghrelin suggesting its dual role in modulating anxiety-related behavior. However, it is proposed that increase in ghrelin levels during stress condition is an endogenous stress coping behavior and increased ghrelin levels may be required to prevent excessive anxiety. In preclinical and clinical studies, an elevation in ghrelin levels during depression has been correlated with their antidepressant activities. Ghrelin-induced modulation of stress and associated conditions has been linked to alteration in hypothalamic-pituitary-adrenal (HPA) axis; autonomic nervous system (mainly sympathetic nervous system and serotonergic neurotransmission. A reciprocal relationship has been reported between corticotropin-releasing hormone (CRH) and ghrelin as ghrelin increases the release of CRH, ACTH and corticosteroids; while CRH decreases the expression of ghrelin. Similarly, ghrelin increases the serotonin turnover and in turn, serotonin controls ghrelin signaling to modulate anxiety-related behavior. The present review discusses the dual role of ghrelin in stress and related behavioral disorders along with possible mechanisms.

  2. New ghrelin agonist, HM01 alleviates constipation and L-dopa-delayed gastric emptying in 6-hydroxydopamine rat model of Parkinson’s disease

    PubMed Central

    Karasawa, H.; Pietra, C.; Giuliano, C.; Garcia-Rubio, S.; Xu, X.; Yakabi, S.; Taché, Y.; Wang, L.

    2015-01-01

    Background Constipation and L-dopa-induced gastric dysmotility are common gastrointestinal (GI) symptoms in Parkinson’s disease (PD). We investigate the novel ghrelin agonist, HM01 influence on GI motor dysfunctions in 6-hydroxydopamine (6-OHDA) rats. Methods HM01 pharmacological profiles were determined in vitro and in vivo in rats. We assessed changes in fecal output and water content, and gastric emptying (GE) in 6-OHDA rats treated or not with orogastric (og) HM01 and L-dopa/carbidopa (LD/CD, 20/2 mg kg−1). Fos immunoreactivity (ir) cells in specific brain and lumbosacral spinal cord were quantified. Key results HM01 displayed a high binding affinity to ghrelin receptor (Ki: 1.42 ± 0.36 nM), 4.3±1.0 h half-life and high brain/plasma ratio. 6-OHDA rats had reduced daily fecal output (22%) and water intake (23%) compared to controls. HM01 (3 and 10 mg kg−1) similarly reversed the decreased 4-h fecal weight and water content in 6-OHDA rats. Basal GE was not modified in 6-OHDA rats, however, LD/CD (once or daily for 8 days) delayed GE in 6-OHDA and control rats that was prevented by HM01 (3 mg kg−1 acute or daily before LD/CD). HM01 increased Fos-ir cell number in the area postrema, arcuate nucleus, nucleus tractus solitarius and lumbosacral intermediolateral column of 6-OHDA rats where 6-OHDA had a lowering effect compared to controls. Conclusions & Inferences 6-OHDA rats display constipation- and adipsia-like features of PD and L-dopa-inhibited GE. The new orally active ghrelin agonist, HM01 crosses the blood brain barrier and alleviates these alterations suggesting a potential benefit for PD with GI disorders. PMID:25327342

  3. Regulatory neuropeptides (ghrelin, obestatin and nesfatin-1) levels in serum and reproductive tissues of female and male rats with fructose-induced metabolic syndrome.

    PubMed

    Catak, Zekiye; Aydin, Suleyman; Sahin, Ibrahim; Kuloglu, Tuncay; Aksoy, Aziz; Dagli, Adile Ferda

    2014-06-01

    Although, the exact mechanisms underlying the development of the metabolic syndrome (MetS) are not still completely understood, obesity, circulated peptide hormone levels and their interaction with genetic factors are considered largely responsible. The purpose of this study is to explore how the levels of ghrelin, obestatin (OBS) and NUCB2/nesfatin-1 (NES)/NUCB2 change in serum and the reproductive tissues of female and male rats with fructose-induced metabolic syndrome, and whether the levels of each hormone is correlated with the hormones involved with fertility. Experiments were conducted on 5-week-old Sprague-Dawley male and female rats assigned to either a control group or a MetS group. Controls were fed standard rat food and water ad libitum, while the MetS group was fed standard food with 10% (v/v) fructose solution added to their drinking water for 12 weeks with a 12/12h photoperiod circle. Then, all animals were sacrificed after a one night fast. Peptides levels in the serum and reproductive tissues of rats were studied using the ELISA method while the immunoreactivity of reproductive system peptide hormones were shown by immunohistochemical staining method. Furthermore, the other biochemical parameters were measured using Konelab-60 equipment and infertility hormones were measured with Immulite2000. Fasting serum insulin, glucose, triglyceride, alanine aminotransferase (ALT), gamma glutamyl transpeptidase (GGT), low-density lipoprotein cholesterol (LDL-C), and total cholesterol (TC) levels were statistically significantly higher, and the amount of high density lipoprotein cholesterol (HDL-C) was significantly lower, in the MetS groups. Serum and tissue supernatant NES levels were significantly higher in the rats with MetS than the control group. Ghrelin, OBS and NES were expressed in the cytoplasm, concentrated around the apical parts of the epithelial cells in the reproductive tissues of the rats. The amounts of ghrelin were lower in the reproductive

  4. Ghrelin and autophagy.

    PubMed

    Ezquerro, Silvia; Frühbeck, Gema; Rodríguez, Amaia

    2017-09-01

    A compromised autophagy is associated with the onset of obesity, type 2 diabetes, nonalcoholic fatty liver disease, cardiovascular and neurodegenerative diseases. Our aim is to review the potential role of ghrelin, a gut hormone involved in energy homeostasis, in the regulation of autophagy. In the recent years, it has been demonstrated that autophagy constitutes an important mechanism by which ghrelin exerts a plethora of central and peripheral actions. Ghrelin enhances autophagy through the activation of AMP-activated protein kinase in different target organs to regulate lipid and glucose metabolism, the remodeling and protection of small intestine mucosa, protection against cardiac ischemia as well as higher brain functions such as learning and memory consolidation. Nonetheless, in inflammatory states, such as acute hepatitis, liver fibrosis or adipose tissue inflammation, ghrelin acts as an anti-inflammatory factor reducing the autophagic flux to prevent further cell injury. Interestingly, several cardiometabolic disorders, including obesity, type 2 diabetes, nonalcoholic fatty liver disease or chronic heart failure are accompanied by low ghrelin levels in addition to altered autophagy. Ghrelin represents an attractive target for development of therapeutics for prevention or treatment of metabolic, cardiac or neuronal disorders, in which autophagy is impaired.

  5. Immunohistochemical detection of the activation of CREB and c-Fos transcription factors in the nervous system of the terrestrial snail induced by pentylenetetrazole.

    PubMed

    Efimova, O I; Ierusalimskii, V N; Anokhin, K V; Balaban, P M

    2007-11-01

    Phosphorylation of CREB transcription factor and expression of the immediate early gene c-fos in the brains of vertebrates play a key role in the molecular genetic mechanisms of long-term neuronal plasticity. The present study identifies the conditions for immunohistochemical detection of pCREB and c-Fos in the nervous system of the mollusk Helix lucorum (Pulmonata: Stylommatophora); activation of these transcription factors was demonstrated after administration of the convulsive agent pentylenetetrazole. Basal pCREB and c-Fos levels in the central nervous system of intact animals were low. Injection of pentylenetetrazole at a dose of 600 mg/kg evoked characteristic stereotypical motor responses, along with sharp reductions in the phosphorylation of CREB1 and expression of the immediate early gene c-fos, this also occurring in identified neurons. Double immunofluorescent labeling of pCREB and c-Fos showed that expression of c-Fos transcription factor was seen only in pCREB-immunoreactive neurons. These data provide evidence that activation of pCREB and c-Fos transcription factors can be used as molecular markers for mapping the processes of neuronal plasticity in the nervous systems of mollusks.

  6. CB1 Cannabinoid Agonist (WIN55,212-2) Within the Basolateral Amygdala Induced Sensitization to Morphine and Increased the Level of μ-Opioid Receptor and c-fos in the Nucleus Accumbens.

    PubMed

    Molaei, Marzieh; Fatahi, Zahra; Zaringhalam, Jalal; Haghparast, Abbas

    2016-04-01

    The basolateral amygdala (BLA) is rich of CB1 cannabinoid receptors (CB1R) and has reciprocal connections with the nucleus accumbens (NAc) which is involved in opioid sensitization. In this study, effects of intra-BLA administration of CB1R agonist on sensitization to antinociceptive effect of morphine and changes in the levels of μ-opioid receptor (MOR), p-CREB, and c-fos in the NAc were investigated. Animals received intra-BLA microinjection of CB1R agonist (WIN55,212-2) once daily for 3 days consecutively (sensitization period). After 5 days free of drug, tail-flick test was performed before and after the administration of an ineffective dose of morphine. Afterward, the levels of MOR, p-CREB, and c-fos proteins were measured in the NAc by Western blot analysis. The results indicated that intra-BLA injection of WIN55,212-2 during sensitization period resulted in the induction of antinociceptive responses by ineffective dose of morphine and caused a significant increase in the MOR and c-fos levels but not p-CREB/CREB ratio in the NAc. These finding revealed that CB1 receptor agonist in the BLA induces development of morphine sensitization and increases expression of MOR in the NAc. It seems that c-fos is one of the important factors involved in the induction of sensitization to antinociceptive effect of morphine.

  7. 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.

  8. Intracerebroventricular injection of ghrelin decreases wheel running activity in rats.

    PubMed

    Miyatake, Yumiko; Shiuchi, Tetsuya; Mawatari, Kazuaki; Toda, Satomi; Taniguchi, Yasuko; Futami, Akari; Sato, Fukiko; Kuroda, Masashi; Sebe, Mayu; Tsutsumi, Rie; Harada, Nagakatsu; Minokoshi, Yasuhiko; Kitamura, Tadahiro; Gotoh, Koro; Ueno, Masaki; Nakaya, Yutaka; Sakaue, Hiroshi

    2017-01-01

    There is an increasing interest in elucidating the molecular mechanisms by which voluntary exercise is regulated. In this study, we examined how the central nervous system regulates exercise. We used SPORTS rats, which were established in our laboratory as a highly voluntary murine exercise model. SPORTS rats showed lower levels of serum ghrelin compared with those of the parental line of Wistar rats. Intracerebroventricular and intraperitoneal injection of ghrelin decreased wheel-running activity in SPORTS rats. In addition, daily injection of the ghrelin inhibitor JMV3002 into the lateral ventricles of Wistar rats increased wheel-running activity. Co-administration of obestatin inhibited ghrelin-induced increases in food intake but did not inhibit ghrelin-induced suppression of voluntary exercise in rats. Growth hormone secretagogue receptor (GHSR) in the hypothalamus and hippocampus of SPORTS rats was not difference that in control rats. We created an arcuate nucleus destruction model by administering monosodium glutamate (MSG) to neonatal SPORTS rats. Injection of ghrelin into MSG-treated rats decreased voluntary exercise but did not increase food intake, suggesting that wheel-running activity is not controlled by the arcuate nucleus neurons that regulate feeding. These results provide new insights into the mechanism by which ghrelin regulates voluntary activity independent of arcuate nucleus neurons.

  9. 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

  10. FosB Null Mutant Mice Show Enhanced Methamphetamine Neurotoxicity: Potential Involvement of FosB in Intracellular Feedback Signaling and Astroglial Function

    PubMed Central

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

    2010-01-01

    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

  11. 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.

  12. Reduced anticipatory locomotor responses to scheduled meals in ghrelin receptor deficient mice.

    PubMed

    Blum, I D; Patterson, Z; Khazall, R; Lamont, E W; Sleeman, M W; Horvath, T L; Abizaid, A

    2009-12-01

    Ghrelin, an orexigenic hormone produced by the stomach, is secreted in anticipation of scheduled meals and in correlation with anticipatory locomotor activity. We hypothesized that ghrelin is directly implicated in stimulating locomotor activity in anticipation of scheduled meals. To test this hypothesis, we observed 24 h patterns of locomotor activity in mice with targeted mutations of the ghrelin receptor gene (GHSR KO) and wild-type littermates, all given access to food for 4 h daily for 14 days. While wild type (WT) and GHSR KO mice produced increases in anticipatory locomotor activity, anticipatory locomotor activity in GHSR KO mice was attenuated (P<0.05). These behavioral measures correlated with attenuated levels of Fos immunoreactivity in a number of hypothalamic nuclei from GHSR KO placed on the same restricted feeding schedule for 7 days and sacrificed at ZT4. Interestingly, seven daily i.p. ghrelin injections mimicked hypothalamic Fos expression patterns to those seen in mice under restricted feeding schedules. These data suggest that ghrelin acts in the hypothalamus to augment locomotor activity in anticipation of scheduled meals.

  13. Reduced Anticipatory Locomotor Responses to Scheduled Meals in Ghrelin Receptor Deficient Mice

    PubMed Central

    Blum, Ian D.; Patterson, Zack; Khazall, Rim; Lamont, Elaine Waddington; Sleeman, Mark W.; Horvath, Tamas L.; Abizaid, Alfonso

    2009-01-01

    Ghrelin, an orexigenic hormone produced by the stomach, is secreted in anticipation of scheduled meals and in correlation with anticipatory locomotor activity. We hypothesized that ghrelin is directly implicated in stimulating locomotor activity in anticipation of scheduled meals. To test this hypothesis, we observed 24 hr patterns of locomotor activity in mice with targeted mutations of the ghrelin receptor gene (GHSR KO) and wild-type littermates, all given access to food for four hours daily for 14 days. While WT and GHSR KO mice produced increases in anticipatory locomotor activity, anticipatory locomotor activity in GHSR KO mice was attenuated (p.< 0.05). These behavioral measures correlated with attenuated levels of Fos immunoreactivity in a number of hypothalamic nuclei from GHSR KO placed on the same restricted feeding schedule for seven days and sacrificed at ZT4. Interestingly, seven daily intraperitoeneal ghrelin injections mimicked hypothalamic Fos expression patterns to those seen in mice under restricted feeding schedules. These data suggest that ghrelin acts in the hypothalamus to augment locomotor activity in anticipation of scheduled meals. PMID:19666088

  14. Postprandial inhibition of gastric ghrelin secretion by long-chain fatty acid through GPR120 in isolated gastric ghrelin cells and mice

    PubMed Central

    Lu, Xinping; Zhao, Xilin; Feng, Jianying; Liou, Alice P.; Anthony, Shari; Pechhold, Susanne; Sun, Yuxiang; Lu, Huiyan

    2012-01-01

    Ghrelin is a gastric peptide hormone that controls appetite and energy homeostasis. Plasma ghrelin levels rise before a meal and fall quickly thereafter. Elucidation of the regulation of ghrelin secretion has been hampered by the difficulty of directly interrogating ghrelin cells diffusely scattered within the complex gastric mucosa. Therefore, we generated transgenic mice with ghrelin cell expression of green fluorescent protein (GFP) to enable characterization of ghrelin secretion in a pure population of isolated gastric ghrelin-expressing GFP (Ghr-GFP) cells. Using quantitative RT-PCR and immunofluorescence staining, we detected a high level of expression of the long-chain fatty acid (LCFA) receptor GPR120, while the other LCFA receptor, GPR40, was undetectable. In short-term-cultured pure Ghr-GFP cells, the LCFAs docosadienoic acid, linolenic acid, and palmitoleic acid significantly suppressed ghrelin secretion. The physiological mechanism of LCFA inhibition on ghrelin secretion was studied in mice. Serum ghrelin levels were transiently suppressed after gastric gavage of LCFA-rich lipid in mice with pylorus ligation, indicating that the ghrelin cell may directly sense increased gastric LCFA derived from ingested intraluminal lipids. Meal-induced increase in gastric mucosal LCFA was assessed by measuring the transcripts of markers for tissue uptake of LCFA, lipoprotein lipase (LPL), fatty acid translocase (CD36), glycosylphosphatidylinositol-anchored HDL-binding protein 1, and nuclear fatty acid receptor peroxisome proliferator-activated receptor-γ. Quantitative RT-PCR studies indicate significantly increased mRNA levels of lipoprotein lipase, glycosylphosphatidylinositol-anchored HDL-binding protein 1, and peroxisome proliferator-activated receptor-γ in postprandial gastric mucosa. These results suggest that meal-related increases in gastric mucosal LCFA interact with GPR120 on ghrelin cells to inhibit ghrelin secretion. PMID:22678998

  15. 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.

  16. Arachidonic acid induces Fas and FasL upregulation in human leukemia U937 cells via Ca2+/ROS-mediated suppression of ERK/c-Fos pathway and activation of p38 MAPK/ATF-2 pathway.

    PubMed

    Liu, Wen-Hsin; Chang, Long-Sen

    2009-12-15

    Arachidonic acid (AA)-induced apoptotic death of human leukemia U937 cells was characteristic of increase in intracellular Ca(2+) concentration ([Ca(2+)]i), ROS generation, ERK inactivation, p38 MPAK activation, degradation of procaspase-8 and production of truncated Bid (tBid). Moreover, AA treatment upregulated Fas/FasL protein expression and transcription of Fas/FasL mRNA. Downregulation of FADD blocked AA-induced procaspase-8 degradation and rescued viability of AA-treated cells. BAPTA-AM (Ca(2+) chelator) pretreatment abolished AA-induced ROS generation, while N-acetylcysteine (NAC, ROS scavenger) was unable to alter AA-elicited [Ca(2+)]i increase. Pretreatment with BAPTA-AM or NAC abrogated p38 MAPK activation and restored ERK activation. Suppression of p38 MAPK or transfection of constitutively active MEK1 abolished AA-induced Fas and FasL upregulation. AA treatment repressed ERK-mediated c-Fos phosphorylation but evoked p38 MAPK-mediated ATF-2 phosphorylation. Knockdown of c-Fos and ATF-2 by siRNA reflected that c-Fos counteracted the effect of ATF-2 on Fas/FasL upregulation. Taken together, our data indicate that Fas/FasL upregulation in AA-treated U937 cells is elicited by Ca(2+)/ROS-mediated suppression of ERK/c-Fos pathway and activation of p38 MAPK/ATF-2, and suggest that autocrine Fas-mediated apoptotoic mechanism is involved in AA-induced cell death.

  17. Ghrelin-Reactive Immunoglobulins in Conditions of Altered Appetite and Energy Balance

    PubMed Central

    Fetissov, Sergueï O.; Lucas, Nicolas; Legrand, Romain

    2017-01-01

    Part of circulating ghrelin is bound to immunoglobulins (Ig) protecting it from degradation and preserving its functional activity. This review summarizes the data on ghrelin- and desacyl-ghrelin-reactive IgG in conditions of altered appetite and energy balance. Plasma levels and affinity kinetics of such IgG were compared in patients with obesity and anorexia nervosa (AN) and in animal models of obesity including ob/ob mice, high-fat diet-induced obese mice, and obese Zucker rats as well as in mice after chronic food restriction and activity-based anorexia and in rats with methotrexate-induced anorexia. We show that plasmatic IgG in both obese humans and animals are characterized by increased affinity for ghrelin. In contrast, patients with AN and anorectic rodents all show lower affinity of ghrelin- and desacyl-ghrelin-reactive IgG, respectively, the changes which were not observed in non-anorectic, chronically starved mice. We also show that affinity of ghrelin-reactive IgG correlate with plasma levels of ghrelin. These data point to common mechanisms underlying modifications of affinity kinetics properties of ghrelin-reactive IgG during chronic alterations of energy balance in humans and rodents and support a functional role of such autoantibodies in ghrelin-mediated regulation of appetite. PMID:28191004

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

    PubMed

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

    2017-01-01

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

  19. FOS Target Acquisition Test

    NASA Astrophysics Data System (ADS)

    Koratkar, Anuradha

    1994-01-01

    FOS onboard target acquisition software capabilities will be verified by this test -- point source binary, point source firmware, point source peak-up, wfpc2 assisted realtime, point source peak-down, taled assisted binary, taled assisted firmware, and nth star binary modes. The primary modes are tested 3 times to determine repeatability. This test is the only test that will verify mode-to-mode acquisition offsets. This test has to be conducted for both the RED and BLUE detectors.

  20. Ghrelin improves vascular autophagy in rats with vascular calcification.

    PubMed

    Xu, Mingming; Liu, Lin; Song, Chenfang; Chen, Wei; Gui, Shuyan

    2017-06-15

    This study aimed to investigate whether ghrelin ameliorated vascular calcification (VC) through improving autophagy. VC model was induced by nicotine plus vitamin D3 in rats and β-glycerophosphate in vascular smooth muscle cell (VSMC). Calcium deposition was detected by von Kossa staining or alizarin red S staining. ALP activity was also detected. Western blot was used to assess the protein expression. Ghrelin treatment attenuated the elevation of calcium deposition and ALP activity in VC model both in vivo and in vitro. Interesting, the protein levels of autophagy markers, LC3 and beclin1 were significantly upregulated by ghrelin in VC model. An autophagy inhibitor, 3-methyladenine blocks the ameliorative effect of ghrelin on VC. Furthermore, protein expressions of phosphate-AMPK were increased by ghrelin treatment both in calcified aorta and VSMC. The effect of ghrelin on autophagy induction and VC attenuation was prevented by AMPK inhibitor, compound C. Our results suggested that ghrelin improved autophagy through AMPK activation, which was resulted in VC amelioration. These data maybe throw light on prevention and therapy of VC. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Ghrelin and its therapeutic potential for cachectic patients.

    PubMed

    Ashitani, Jun-ichi; Matsumoto, Nobuhiro; Nakazato, Masamitsu

    2009-10-01

    The discovery of ghrelin has resulted in the development of approaches to appetite, enabling a better understanding of the mechanisms regulating appetite through molecular analyses. Ghrelin is a 28-amino acid peptide that was isolated from the stomach only a decade ago, and has recently been investigated as a potential therapeutic endogenous agent. This peptide increases appetite, adjusts energy balance, suppresses inflammation, and enhances the release of growth hormone from the pituitary gland. Although many bioactive substances such as peptide YY, leptin, adiponectin and obestatin are involved in appetite control, ghrelin is the only known peptide to signal starvation information from a peripheral organ to the central nervous system, contributing to an increase in appetite. Clinical trials have revealed the effectiveness of ghrelin in increasing lean body mass and activity in cachectic patients. As shown in clinical research on humans and basic research using animal models, cachexia often occurs in response to excess release of proinflammatory cytokines and induces further appetite loss, which aggravates the physiological status of underlying diseases. Ghrelin functions as a protector against the vicious cycle of the cachectic paradigm through orexigenic, anabolic and anti-inflammatory effects, so administration of ghrelin may be able to improve quality of life in cachectic patients. We show here a significant role of ghrelin in the pathophysiology of cachectic diseases and the possibility of clinical applications.

  2. Microinjection of the SH2 domain of the 85-kilodalton subunit of phosphatidylinositol 3-kinase inhibits insulin-induced DNA synthesis and c-fos expression.

    PubMed Central

    Jhun, B H; Rose, D W; Seely, B L; Rameh, L; Cantley, L; Saltiel, A R; Olefsky, J M

    1994-01-01

    We have investigated the functional role of the SH2 domain of the 85-kDa subunit (p85) of the phosphatidylinositol 3-kinase in the insulin signal transduction pathway. Microinjection of a bacterial fusion protein containing the N-terminal SH2 domain of p85 inhibited insulin- and other growth factor-induced DNA synthesis by 90% and c-fos protein expression by 80% in insulin-responsive rat fibroblasts. The specificity of the fusion protein was examined by in vitro precipitation experiments, which showed that the SH2 domain of p85 can independently associate with both insulin receptor substrate 1 and the insulin receptor itself in the absence of detectable binding to other phosphoproteins. The microinjection results were confirmed through the use of an affinity-purified antibody directed against p85, which gave the same phenotype. Additional studies were carried out in another cell line expressing mutant insulin receptors which lack the cytoplasmic tyrosine residues with which p85 interacts. Microinjection of the SH2 domain fusion protein also inhibited insulin signaling in these cells, suggesting that association of p85 with insulin receptor substrate 1 is a key element in insulin-mediated cell cycle progression. In addition, coinjection of purified p21ras protein with the p85 fusion protein or the antibody restored DNA synthesis, suggesting that ras function is either downstream or independent of p85 SH2 domain interaction. Images PMID:7935461

  3. Regional c-Fos and FosB/ΔFosB expression associated with chronic methamphetamine self-administration and methamphetamine-seeking behavior in rats.

    PubMed

    Cornish, J L; Hunt, G E; Robins, L; McGregor, I S

    2012-03-29

    The regional expression of the transcription factors c-Fos and FosB/ΔFosB was examined in rats given acute exposure to intravenous methamphetamine (METH) or repeated intravenous METH self-administration. One group of rats self-administered METH via lever pressing in 2 h sessions every day for 3 weeks and on a final test day received self-administered METH as usual. A second group with the same METH self-administration history received saline infusions on the test day, to induce drug-seeking behavior. Other rats were trained with infusions of intravenous saline that were yoked to the passive delivery of METH in the other two groups. On test day, half of these yoked rats received passive METH infusions for the first time, whereas the others received saline as usual. The results showed that acute METH produced a characteristic signature of Fos expression with elevations in striatal, cortical, and extended amygdala regions. Importantly, rats with a 3-week history of METH self-administration displayed similar regional Fos expression to rats receiving METH for the first time. Rats seeking, but not receiving, METH on the test day had augmented Fos in the lateral hypothalamus, septum, and vertical limb of the diagonal band of Broca, suggesting a primary role for these regions in METH-seeking behavior. Both acute and chronic METH activated orexin-positive cells in the perifornical area of the hypothalamus. FosB/ΔFosB was elevated in the lateral hypothalamus, posterior ventral tegmental area, central amygdala, and dorsal raphe of all the rats with a history of METH self-administration. This occurred regardless of whether they received METH on test day, suggesting presence of the long-lived FosB isoform, ΔFosB. Overall, these results show persistent upregulated regional brain Fos and FosB/ΔFosB expression with chronic METH self-administration and indicate a role for the lateral hypothalamus and lateral septum in METH-seeking behavior.

  4. Neonatal overfeeding disrupts pituitary ghrelin signalling in female rats long-term; Implications for the stress response

    PubMed Central

    Ziko, Ilvana; Spencer, Sarah J.

    2017-01-01

    The hypothalamic-pituitary-adrenal (HPA) axis responses to psychological stress are exacerbated in adult female but not male rats made obese due to overfeeding in early life. Ghrelin, traditionally known for its role in energy homeostasis, has been recently recognised for its role in coordinating the HPA responses to stress, particularly by acting directly at the anterior pituitary where the growth hormone secretagogue receptor (GHSR), the receptor for acyl ghrelin, is abundantly expressed. We therefore hypothesised that neonatal overfeeding in female rats would compromise pituitary responsiveness to ghrelin, contributing to a hyperactive central stress responsiveness. Unlike in males where hypothalamic ghrelin signalling is compromised by neonatal overfeeding, there was no effect of early life diet on circulating ghrelin or hypothalamic ghrelin signalling in females, indicating hypothalamic feeding and metabolic ghrelin circuitry remains intact. However, neonatal overfeeding did lead to long-term alterations in the pituitary ghrelin system. The neonatally overfed females had increased neonatal and reduced adult expression of GHSR and ghrelin-O-acyl transferase (GOAT) in the pituitary as well as reduced pituitary responsiveness to exogenous acyl ghrelin-induced adrenocorticotropic hormone (ACTH) release in vitro. These data suggest that neonatal overfeeding dysregulates pituitary ghrelin signalling long-term in females, potentially accounting for the hyper-responsive HPA axis in these animals. These findings have implications for how females may respond to stress throughout life, suggesting the way ghrelin modifies the stress response at the level of the pituitary may be less efficient in the neonatally overfed. PMID:28282447

  5. Scheduled feeding results in adipogenesis and increased acylated ghrelin.

    PubMed

    Verbaeys, I; Tolle, V; Swennen, Q; Zizzari, P; Buyse, J; Epelbaum, J; Cokelaere, M

    2011-06-01

    Ghrelin, known to stimulate adipogenesis, displays an endogenous secretory rhythmicity closely related to meal patterns. Therefore, a chronic imposed feeding schedule might induce modified ghrelin levels and consequently adiposity. Growing Wistar rats were schedule-fed by imposing a particular fixed feeding schedule of 3 meals/day without caloric restriction compared with total daily control intake. After 14 days, their body composition was measured by DEXA and compared with ad libitum-fed controls and to rats daily intraperitoneal injection with ghrelin. Feeding patterns, circadian activity, and pulsatile acylated ghrelin variations were monitored. After 14 days, rats on the imposed feeding schedule displayed, despite an equal daily calorie intake, a slower growth rate compared with ad libitum-fed controls. Moreover, schedule-fed rats exhibiting a feeding pattern with intermittent fasting periods had a higher fat/lean ratio compared with ad libitum-fed controls. Interestingly, ghrelin-treated rats also showed an increase in fat mass, but the fat/lean ratio was not significantly increased compared with controls. In the schedule-fed rats, spontaneous activity and acylated ghrelin levels were increased and associated with the scheduled meals, indicating anticipatory effects. Our results suggest that scheduled feeding, associated with intermittent fasting periods, even without nutrient/calorie restriction on a daily basis, results in adipogenesis. This repartitioning effect is associated with increased endogenous acylated ghrelin levels. This schedule-fed model points out the delicate role of meal frequency in adipogenesis and provides an investigative tool to clarify any effects of endogenous ghrelin without the need for ghrelin administration.

  6. Expression and Possible Immune-regulatory Function of Ghrelin in Oral Epithelium

    PubMed Central

    Ohta, K.; Laborde, N.J.; Kajiya, M.; Shin, J.; Zhu, T.; Thondukolam, A.K.; Min, C.; Kamata, N.; Karimbux, N.Y.; Stashenko, P.; Kawai, T.

    2011-01-01

    Originally found in stomach mucosa, ghrelin is a peptide appetite hormone that has been implicated as an immuno-modulatory factor. Ghrelin has also been found in salivary glands and saliva; however, its expression patterns and biological properties in the oral cavity remain unclear. Therefore, we investigated the expression patterns of ghrelin in saliva, gingival crevicular fluid (GCF), and gingival tissue, as well as its in vitro effects on IL-8 production by TNF-α or LPS-stimulated oral epithelial cells. In the clinical samples obtained from 12 healthy volunteers, the concentration of ghrelin in GCF remarkably exceeded that detected in saliva. The expression of ghrelin mRNAs and growth hormone secretagogue (GHS) receptors could be detected in human oral epithelial cells. Immunohistochemical analysis revealed the expression of ghrelin in gingival epithelium, as well as in fibroblasts in the lamina propria. Ghrelin increased intracellular calcium mobilization and cAMP levels in oral epithelial cells, suggesting that ghrelin acts on epithelial cells to induce cell signaling. Furthermore, synthetic ghrelin inhibited the production of IL-8 from TNF-α or LPS-stimulated oral epithelial cells. These results indicate that ghrelin produced in the oral cavity appears to play a regulatory role in innate immune responses to inflammatory infection. PMID:21865591

  7. Determination of ghrelin immunoreactivity in the rat stomach after fasting and refeeding.

    PubMed

    Sönmez, Mehmet Fatih; Ozan, Enver

    2007-01-01

    Ghrelin is a recently discovered hormone secreted by cells of the stomach. The aim of this study was to investigate fasting and refeeding induced alterations on ghrelin immunolabelling of cells of the stomach. Thirty-six adult male Wistar rats were used in this study. Rats were divided into six groups. Group I: control group; Group II: rats fasted for 7 days; Group III: rats fed for 1 day after 7 days of fasting; Group IV: rats fed for 3 days after 7 days of fasting; Group V: rats fed for 5 days after 7 days of fasting; Group VI: rats fed for 7 days after 7 days of fasting. At the end of the experiment, rats were sacrificed and stomach tissues were processed for imunohistochemistry to localize ghrelin. Ghrelin-immunopositive cells were detected only in the mucosal lining of the stomach. After fasting for 7 days, the number of ghrelin-immunopositive cells increased significantly compared to the control rats. Following refeeding, the number of ghrelin-immunoreactive cells was reduced to a level comparable to the controls. Therefore, fasting and refeeding after fasting were observed to result in changes in ghrelin immunoreactivity in the cells of the stomach. We conclude that ghrelin is highly expressed in the stomach and that fasting increases the expression of ghrelin in the stomach, but this expression decreases after refeeding. Our results indicate that regulation of ghrelin is a process probably involved in the long-term control of nutritional states.

  8. Mediation of oxidative stress in hypothalamic ghrelin-associated appetite control in rats treated with phenylpropanolamine.

    PubMed

    Yu, C-H; Chu, S-C; Chen, P-N; Hsieh, Y-S; Kuo, D-Y

    2017-04-01

    Phenylpropanolamine (PPA)-induced appetite control is associated with oxidative stress in the hypothalamus. This study explored whether hypothalamic antioxidants participated in hypothalamic ghrelin system-associated appetite control in PPA-treated rats. Rats were given PPA daily for 4 days, and changes in food intake and the expression of neuropeptide Y (NPY), the cocaine- and amphetamine-regulated transcript (CART), superoxide dismutase, catalase, ghrelin, acyl ghrelin (AG), ghrelin O-acyltransferase (GOAT) and the ghrelin receptor (GHSR1a) were examined and compared. Results showed that both food intake and the expression of NPY and ghrelin/AG/GOAT/GHSR1a decreased in response to PPA treatment with maximum decrease on Day 2 of the treatment. In contrast, the expression of antioxidants and CART increased, with the maximum increase on Day 2, with the expression opposite to that of NPY and ghrelin. A cerebral infusion of either a GHSR1a antagonist or reactive oxygen species scavenger modulated feeding behavior and NPY, CART, antioxidants and ghrelin system expression, showing the involvement of ghrelin signaling and oxidative stress in regulating PPA-mediated appetite control. We suggest that hypothalamic ghrelin signaling system, with the help of antioxidants, may participate in NPY/CART-mediated appetite control in PPA-treated rats.

  9. 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.

  10. Ghrelin and Eating Disorders

    PubMed Central

    Atalayer, Deniz; Gibson, Charlisa; Konopacka, Alexandra; Geliebter, Allan

    2012-01-01

    There is growing evidence supporting a multifactorial etiology that includes genetic, neurochemical, and physiological components for eating disorders above and beyond the more conventional theories based on psychological and sociocultural factors. Ghrelin is one of the key gut signals associated with appetite, and the only known circulating hormone that triggers a positive energy balance by stimulating food intake. This review summarizes recent findings and several conflicting reports on ghrelin in eating disorders. Understanding these findings and inconsistencies may help in developing new methods to prevent and treat patients with these disorders. PMID:22960103

  11. A rat model of childhood diet-induced obesity: Roux-en-Y gastric bypass induced changes in metabolic parameters and gastric peptide ghrelin.

    PubMed

    Aprahamian, Charles J; Tekant, Gonça; Chen, Min; Yagmurlu, Ayden; Yang, Ying-Kui; Loux, Tara; Harmon, Carroll M

    2007-07-01

    Childhood morbid obesity is reaching epidemic proportions. Roux-en-Y gastric bypass (RYGB) results in many metabolic alterations, including changes in glucose and lipid metabolism, and changes in levels of the gastric hormone, ghrelin. As more children are undergoing RYGB, an animal model would be beneficial to further study RYGB and its subsequent metabolic effects. DIO Sprague Dawley rats underwent RYGB, sham jejunojejunostomy (SH), or no operation (HFC) after 6 weeks of high-fat diet. Non-obese rats fed standard chow (SC) were a final control group. Animals were post-operatively fed standard chow for 7 days before sacrifice. At sacrifice, venous blood and gastric mucosa was collected for metabolic parameters and ghrelin determination. RYGB rats weighed less than SH and HFC (361 +/- 8.8 vs. 437 +/- 9.3 and 443 +/- 6.2 g, P < 0.05). Compared to HFC, RYGB animals had decreased plasma glucose (292 +/- 23 vs. 141 +/- 10 mg/dL), cholesterol (80 +/- 12 vs. 45 +/- 5 mg/dL), triglycerides (138 +/- 37 vs. 52 +/- 7 mg/dL), HDL (43 +/- 5 vs. 20 +/- 3 mg/dL), and free fatty acids (0.72 +/- 0.14 vs. 0.23 +/- 0.02 mEq/L), all P < 0.05. Plasma ghrelin increased in RYGB rats compared to SC and HFC (116.22 +/- 32.27 vs. 31.60 +/- 2.66 and 31.75 +/- 0.75 pg/mL, P < 0.05). In a rat model of RYGB, we demonstrated improved metabolic parameters and increased plasma and gastric mRNA ghrelin levels. The rat model for RYBG appears to be a reasonable model for future study of the cellular and molecular regulatory pathways of obesity and its surgical treatment.

  12. Obestatin, a peptide encoded by the ghrelin gene, opposes ghrelin's effects on food intake.

    PubMed

    Zhang, Jian V; Ren, Pei-Gen; Avsian-Kretchmer, Orna; Luo, Ching-Wei; Rauch, Rami; Klein, Cynthia; Hsueh, Aaron J W

    2005-11-11

    Ghrelin, a circulating appetite-inducing hormone, is derived from a prohormone by posttranslational processing. On the basis of the bioinformatic prediction that another peptide also derived from proghrelin exists, we isolated a hormone from rat stomach and named it obestatin-a contraction of obese, from the Latin "obedere," meaning to devour, and "statin," denoting suppression. Contrary to the appetite-stimulating effects of ghrelin, treatment of rats with obestatin suppressed food intake, inhibited jejunal contraction, and decreased body-weight gain. Obestatin bound to the orphan G protein-coupled receptor GPR39. Thus, two peptide hormones with opposing action in weight regulation are derived from the same ghrelin gene. After differential modification, these hormones activate distinct receptors.

  13. 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. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. 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.

  15. Calcium signals activated by ghrelin and D-Lys(3)-GHRP-6 ghrelin antagonist in developing dorsal root ganglion glial cells.

    PubMed

    Erriquez, Jessica; Bernascone, Silvia; Ciarletta, Monica; Filigheddu, Nicoletta; Graziani, Andrea; Distasi, Carla

    2009-09-01

    Ghrelin is a hormone regulating energy homeostasis via interaction with its receptor, GHSR-1a. Ghrelin activities in dorsal root ganglia (DRG) cells are unknown. Herein we show that ghrelin induces a change of cytosolic calcium concentration in both glia and neurons of embryonic chick DRG. Both RT-PCR and binding studies performed with fluorescent ghrelin in the presence of either unlabeled ghrelin or GHSR-1a antagonist D-Lys(3)-GHRP-6, indicate that DRG cells express GHSR-1a. In glial cells the response is characterized by a rapid transient rise in [Ca(2+)](i) followed by a long lasting rise. The calcium elevation is dependent on calcium release from thapsigargin-sensitive intracellular stores and on activation of two distinct Ca(2+) entry pathways, a receptor activated calcium entry and a store operated calcium entry. Surprisingly, D-Lys(3)-GHRP-6 exerts several activities in the absence of exogenous ghrelin: (i) it activates calcium release from thapsigargin-sensitive intracellular stores and calcium entry via voltage-operated channels in non-neuronal cells; (ii) it inhibits calcium oscillations in non-neuronal cells exhibiting spontaneous Ca(2+) activity and iii) it promotes apoptosis of DRG cells, both neurons and glia. In summary, we provide the first evidence for ghrelin activity in DRG, and we also demonstrate that the widely used D-Lys(3)-GHRP-6 ghrelin antagonist features ghrelin independent activities.

  16. Ghrelin and peptide YY in youth: are there race-related differences?

    PubMed

    Bacha, Fida; Arslanian, Silva A

    2006-08-01

    Obesity prevalence is higher in African-American (AA) vs. American white (AW) youth. Ghrelin is a "hunger" peptide that is high preprandially and decreases postprandially, and peptide YY (PYY) is a "satiety" hormone increasing after meals. Impaired regulation of ghrelin/PYY may be conducive to obesity. We hypothesized that racial differences in childhood obesity could partly be explained by differences in ghrelin/PYY dynamics. We investigated: 1) ghrelin suppression/PYY elevation in response to an oral glucose tolerance test (OGTT) in AA vs. AW, and 2) the relationship of ghrelin and PYY dynamics to insulin sensitivity. Thirty-three AA and 54 AW prepubertal children underwent an OGTT measuring ghrelin, PYY, glucose, and insulin. Fasting glucose to insulin ratio (G(F)/I(F)) was used to assess the relationship of insulin sensitivity to fasting and post-OGTT ghrelin and PYY levels. OGTT-induced suppression in ghrelin (Delta ghrelin) was lower in AA youth. Delta ghrelin correlated with G(F)/I(F) (r = 0.47, P < 0.001) and Delta insulin at 30 min (r = -0.47, P < 0.001). In multiple regression analysis, race (P = 0.013) and G(F)/I(F) (P = 0.004) contributed independently to the variance in Delta ghrelin (R(2) = 0.28, P < 0.001). Fasting and post-OGTT PYY levels were lower in AAs and were not related to insulin sensitivity. The lower suppression of ghrelin in AA, but not the lower PYY levels, correlates with insulinemia and insulin resistance. Less ghrelin suppression and PYY elevation after a meal in black youth could be a potential mechanism of race-related differences in hunger/satiety predisposing to risk of obesity.

  17. Evaluation and diagnostic potential of serum ghrelin in feline hypersomatotropism and diabetes mellitus.

    PubMed

    Jensen, K B; Forcada, Y; Church, D B; Niessen, S J M

    2015-01-01

    Ghrelin is a growth hormone secretagogue. It is a potent regulator of energy homeostasis. Ghrelin concentration is down-regulated in humans with hypersomatotropism (HS) and increases after successful treatment. Additionally, ghrelin secretion seems impaired in human diabetes mellitus (DM). Serum ghrelin concentration is down-regulated in cats with HS-induced DM (HSDM) compared to healthy control cats or cats with DM unrelated to HS and increases after radiotherapy. Cats with DM (n = 20) and with HSDM (n = 32), 13 of which underwent radiotherapy (RT-group); age-matched controls (n = 20). Retrospective cross-sectional study. Analytical performance of a serum total ghrelin ELISA was assessed and validated for use in cats. Differences in serum ghrelin, fructosamine, IGF-1 and insulin were evaluated. Ghrelin was significantly higher (P < .001) in control cats (mean ± SD: 12.9 ± 6.8 ng/mL) compared to HSDM- (7.9 ± 3.3 ng/mL) and DM-cats (6.7 ± 2.3 ng/mL), although not different between the HSDM- and DM-cats. After RT ghrelin increased significantly (P = .003) in HSDM-cats undergoing RT (from 6.6 ± 1.9 ng/mL to 9.0 ± 2.2 ng/mL) and the after RT ghrelin concentrations of HSDM cats were no longer significantly different from the serum ghrelin concentration of control cats. Serum IGF-1 did not significantly change in HSDM-cats after RT, despite significant decreases in fructosamine and insulin dose. Ghrelin appears suppressed in cats with DM and HSDM, although increases after RT in HSDM, suggesting possible presence of a direct or indirect negative feedback system between growth hormone and ghrelin. Serum ghrelin might therefore represent a marker of treatment effect. Copyright © 2015 by the American College of Veterinary Internal Medicine.

  18. Ghrelin and PYY levels in adolescents with severe obesity: effects of weight loss induced by long-term exercise training and modified food habits.

    PubMed

    Gueugnon, Carine; Mougin, Fabienne; Nguyen, Nhu Uyen; Bouhaddi, Malika; Nicolet-Guénat, Marie; Dumoulin, Gilles

    2012-05-01

    This study investigated (a) changes in ghrelin and peptide YY (PYY) concentrations during a weight reduction programme and (b) baseline ghrelin and PYY levels as predictors of weight loss in 32 severely obese adolescents (BMI z score = 4.1). Subjects spent an academic year in an institution for childhood obesity. Fasting ghrelin and PYY, leptin, insulin levels and insulin resistance were measured at baseline (month 0) and during the programme (months 3, 6, 9). In addition, 15 normal-weight teenagers served as reference for the baseline assessments. At baseline, obese teenagers had lower ghrelin and PYY concentrations than normal-weight adolescents (P < 0.05). Moreover, they showed significantly higher leptin, insulin levels and homeostasis model assessment (HOMA) (P < 0.0001). During the lifestyle modification, there was a significant decrease in body weight among obese teenagers, associated with an increase in ghrelin (apparent from month 6; P < 0.05), a decrease in leptin (from month 3; P < 0.05) and a decrease in insulin and HOMA (from month 3; P < 0.0001), without any significant change in PYY. Anthropometrical changes were correlated neither with baseline ghrelin levels nor with changes in ghrelin and PYY after the lifestyle modification. However, higher baseline PYY tended to correlate with greater anthropometrical changes (P < 0.1). In adolescents with severe obesity, a long-term combination of supervised aerobic exercises and a balanced diet led to weight reduction and increased ghrelin concentrations, without any change in PYY concentrations. Moreover, baseline PYY concentrations might be considered as predictors of weight loss.

  19. Function of c-Fos-like and c-Jun-like proteins on trichostatin A-induced G2/M arrest in Physarum polycephalum.

    PubMed

    Li, Xiao-Xue; Lu, Jun; Zhao, Yan-Mei; Huang, Bai-Qu

    2005-11-01

    The homologs of transcription factors c-Fos and c-Jun have been detected in slime mold Physarum polycephalum during progression of the synchronous cell cycle. Here we demonstrated that c-Fos-like and c-Jun-like proteins participated in G2/M transition by the regulation of the level of Cyclin B1 protein in P. polycephalum. The study of antibody neutralization revealed that interruption of the functions of c-Fos-like and c-Jun-like proteins resulted in G2/M transition arrest, implicating their functional roles in cell cycle control. When G2/M transition was blocked by histone deacetylase inhibitor trichostatin A, changes in c-Fos- and c-Jun-like protein levels, and hyperacetylation of c-Jun-like protein, were observed. The data suggest that in P. polycephalum, c-Fos- and c-Jun-like proteins may be the key factors in the regulation of histone acetylation-related G2/M transition, involving the coordinated expression and hyperacetylation of these proteins.

  20. 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.

  1. Ghrelin Attenuates cAMP-PKA Signaling to Evoke Insulinostatic Cascade in Islet β-Cells

    PubMed Central

    Dezaki, Katsuya; Damdindorj, Boldbaatar; Sone, Hideyuki; Dyachok, Oleg; Tengholm, Anders; Gylfe, Erik; Kurashina, Tomoyuki; Yoshida, Masashi; Kakei, Masafumi; Yada, Toshihiko

    2011-01-01

    OBJECTIVE Ghrelin reportedly restricts insulin release in islet β-cells via the Gαi2 subtype of G-proteins and thereby regulates glucose homeostasis. This study explored whether ghrelin regulates cAMP signaling and whether this regulation induces insulinostatic cascade in islet β-cells. RESEARCH DESIGN AND METHODS Insulin release was measured in rat perfused pancreas and isolated islets and cAMP production in isolated islets. Cytosolic cAMP concentrations ([cAMP]i) were monitored in mouse MIN6 cells using evanescent-wave fluorescence imaging. In rat single β-cells, cytosolic protein kinase-A activity ([PKA]i) and Ca2+ concentration ([Ca2+]i) were measured by DR-II and fura-2 microfluorometry, respectively, and whole cell currents by patch-clamp technique. RESULTS Ghrelin suppressed glucose (8.3 mmol/L)-induced insulin release in rat perfused pancreas and isolated islets, and these effects of ghrelin were blunted in the presence of cAMP analogs or adenylate cyclase inhibitor. Glucose-induced cAMP production in isolated islets was attenuated by ghrelin and enhanced by ghrelin receptor antagonist and anti-ghrelin antiserum, which counteract endogenous islet-derived ghrelin. Ghrelin inhibited the glucose-induced [cAMP]i elevation and [PKA]i activation in MIN6 and rat β-cells, respectively. Furthermore, ghrelin potentiated voltage-dependent K+ (Kv) channel currents without altering Ca2+ channel currents and attenuated glucose-induced [Ca2+]i increases in rat β-cells in a PKA-dependent manner. CONCLUSIONS Ghrelin directly interacts with islet β-cells to attenuate glucose-induced cAMP production and PKA activation, which lead to activation of Kv channels and suppression of glucose-induced [Ca2+]i increase and insulin release. PMID:21788571

  2. Islet β-cell ghrelin signaling for inhibition of insulin secretion.

    PubMed

    Dezaki, Katsuya; Yada, Toshihiko

    2012-01-01

    Ghrelin, an acylated 28-amino acid peptide, was isolated from the stomach, where circulating ghrelin is produced predominantly. In addition to its unique role in regulating growth-hormone release, mealtime hunger, lipid metabolism, and the cardiovascular system, ghrelin is involved in the regulation of glucose metabolism. Ghrelin is expressed in pancreatic islets and released into pancreatic microcirculations. Ghrelin inhibits insulin release in mice, rats, and humans. Pharmacological and genetic blockades of islet-derived ghrelin markedly augment glucose-induced insulin release. The signal transduction mechanisms of ghrelin in islet β-cells are very unique, being distinct from those utilized for growth-hormone release. Ghrelin attenuates the glucose-induced cAMP production and PKA activation, which drives activation of Kv channels and suppression of the glucose-induced [Ca(2+)](i) increase and insulin release in β-cells. Insulinostatic function of the ghrelin-GHS-R system in islets is a potential therapeutic target for type 2 diabetes. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Upregulation and nuclear translocation of testicular ghrelin protects differentiating spermatogonia from ionizing radiation injury

    PubMed Central

    Li, W; Zeng, Y; Zhao, J; Zhu, C-J; Hou, W-G; Zhang, S

    2014-01-01

    Proper control of apoptotic signaling is important for maintenance of testicular homeostasis after ionizing radiation (IR). Herein, we challenged the hypothesis that ghrelin, a pleiotropic modulator, is potentially involved in IR-induced germ cell injury. Lower body exposure to 2 Gy of IR induced a notable increase of ghrelin expression in the nuclear of differentiating spermatogonia at defined stages, with an impairment in the Leydig cells (LCs)-expressing ghrelin. Unexpectedly, inhibition of the ghrelin pathway by intraperitoneal injection of a specific GHS-R1α antagonist enhanced spermatogonia elimination by apoptosis during the early recovery following IR, and thereafter resulted in impaired male fertility, suggesting that the anti-apoptotic effects of evoked ghrelin, although transient along testicular IR injury, have a profound influence on the post-injury recovery. In addition, inhibition of ghrelin signaling resulted in a significant increase in the intratesticular testosterone (T) level at the end of 21 days after IR, which should stimulate the spermatogenic recovery from surviving spermatogonia to a certain extent during the late stage. We further demonstrated that the upregulation and nuclear trafficking of ghrelin, elaborately regulated by IR-elicited antioxidant system in spermatogonia, may act through a p53-dependent mechanism. The elicitation of ghrelin expression by IR stress, the regulation of ghrelin expression by IR-induced oxidative stress and the interaction between p53 and ghrelin signaling during IR injury were confirmed in cultured spermatogonia. Hence, our results represent the first evidence in support of a radioprotective role of ghrelin in the differentiating spermatogonia. The acutely, delicate regulation of local-produced ghrelin appears to be a fine-tune mechanism modulating the balance between testicular homeostasis and early IR injury. PMID:24853426

  4. Upregulation and nuclear translocation of testicular ghrelin protects differentiating spermatogonia from ionizing radiation injury.

    PubMed

    Li, W; Zeng, Y; Zhao, J; Zhu, C-J; Hou, W-G; Zhang, S

    2014-05-22

    Proper control of apoptotic signaling is important for maintenance of testicular homeostasis after ionizing radiation (IR). Herein, we challenged the hypothesis that ghrelin, a pleiotropic modulator, is potentially involved in IR-induced germ cell injury. Lower body exposure to 2 Gy of IR induced a notable increase of ghrelin expression in the nuclear of differentiating spermatogonia at defined stages, with an impairment in the Leydig cells (LCs)-expressing ghrelin. Unexpectedly, inhibition of the ghrelin pathway by intraperitoneal injection of a specific GHS-R1α antagonist enhanced spermatogonia elimination by apoptosis during the early recovery following IR, and thereafter resulted in impaired male fertility, suggesting that the anti-apoptotic effects of evoked ghrelin, although transient along testicular IR injury, have a profound influence on the post-injury recovery. In addition, inhibition of ghrelin signaling resulted in a significant increase in the intratesticular testosterone (T) level at the end of 21 days after IR, which should stimulate the spermatogenic recovery from surviving spermatogonia to a certain extent during the late stage. We further demonstrated that the upregulation and nuclear trafficking of ghrelin, elaborately regulated by IR-elicited antioxidant system in spermatogonia, may act through a p53-dependent mechanism. The elicitation of ghrelin expression by IR stress, the regulation of ghrelin expression by IR-induced oxidative stress and the interaction between p53 and ghrelin signaling during IR injury were confirmed in cultured spermatogonia. Hence, our results represent the first evidence in support of a radioprotective role of ghrelin in the differentiating spermatogonia. The acutely, delicate regulation of local-produced ghrelin appears to be a fine-tune mechanism modulating the balance between testicular homeostasis and early IR injury.

  5. 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…

  6. 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…

  7. Gabaergic control of anxiety-like behavior, but not food intake, induced by ghrelin in the intermediate medial mesopallium of the neonatal chick.

    PubMed

    Gastón, M S; Schiöth, H B; De Barioglio, S R; Salvatierra, N A

    2015-01-01

    Ghrelin (Grh) is an endogenous ligand of the growth hormone secretagogue receptor. In neonatal chicks, central Ghr induces anxiogenic-like behavior but strongly inhibits food intake. The intermediate medial mesopallium (IMM) of the chick forebrain has been identified to be a site of the memory formation, and the modulation of the GABAA receptors that are present here modifies the expression of behavior. Thus, the GABAergic system may constitute a central pathway for Ghr action in regulating the processes of food intake and stress-related behaviors. Therefore, we investigated if the effect of systemic administration of bicuculline (GABAA receptor antagonist) and diazepam (benzodiazepine receptor agonist) on the anxiety in an Open Field test and inhibition in food intake induced by Grh (30pmol) when injected into IMM, were mediated by GABAergic transmission. In Open Field test, bicuculline was able to block the anxiogenic-like behavior induced by Ghr, whereas diazepam did not produce it. However, the co-administration of bicuculline or diazepam plus Ghr did not show any change in food intake at 30, 60 and 120min after injection compared to Ghr alone. Our results indicate for the first time that Ghr, injected into the forebrain IMM area, induces an anxiogenic-like behavior, which was blocked by bicuculline but not diazepam, thus suggesting that Ghr plays an important role in the response pattern to acute stressor, involving the possible participation of the GABAergic system. Nevertheless, as neither drug affected the hypophagia induced by intra-IMM Ghr, this suggests that it may be mediated by different mechanisms.

  8. 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.

  9. Otolith organ or semicircular canal stimulation induces c-fos expression in unipolar brush cells and granule cells of cat and squirrel monkey.

    PubMed

    Sekerková, Gabriella; Ilijic, Ema; Mugnaini, Enrico; Baker, James F

    2005-07-01

    Immediate early gene expression in the cerebellar vermis of cats and squirrel monkeys was stimulated by prolonged whole body rotations. Continuous, earth-horizontal axis rotations that excited only otoliths or high velocity vertical axis rotations that excited only semicircular canals resulted in c-fos immunoreactive nuclei concentrated in the granular layer of lobules X and ventral IX (the nodulus and ventral uvula), which represent the medial parts of the vestibulo-cerebellum. Large clusters of labeled nuclei consisting mainly of granule cells and calretinin-positive unipolar brush cells were present in the granular layer, whereas Purkinje cell nuclei were unlabeled, and labeled basket and stellate cell nuclei were scattered in the molecular layer. In other vermal lobules there was a significant but less dense label than in the nodulus and ventral uvula. Generally, the extent of c-fos labeling of molecular layer interneurons was in relation to nuclear labeling of granular layer neurons: labeling of both basket and stellate cells accompanied nuclear labeling of neurons throughout the depth of the granular layer, whereas only stellate cells were labeled when nuclear labeling was restricted to the superficial granular layer. Yaw horizontal or roll vertical rotations each stimulated c-fos expression in the cat medial vestibulo-cerebellum to approximately the same extent. Low-velocity rotations resulted in much less c-fos expression. Similar, albeit less intense, patterns of c-fos activation were observed in monkeys. Concentrated c-fos expression in the medial vestibulo-cerebellum after exposure to a strong head velocity signal that could originate from either otolith or canal excitation suggests that granule and unipolar brush cells participate in a neuronal network for estimating head velocity, irrespective of the signal source.

  10. 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.

  11. 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

  12. Correlation of ghrelin concentration and ghrelin, ghrelin-O-acetyltransferase (GOAT) and growth hormone secretagogue receptor 1a mRNAs expression in the proventriculus and brain of the growing chicken.

    PubMed

    Kitazawa, Takio; Hiraga, Takeo; Teraoka, Hiroki; Yaosaka, Noriko; Kaiya, Hiroyuki

    2015-01-01

    To determine mechanisms for age-related decrease of GHS-R1a expression in the chicken proventriculus, changes in mRNA expression of ghrelin and ghrelin-O-acetyltransferase (GOAT) as well as ghrelin concentrations in the proventriculus and plasma were examined in growing chickens. Changes in expression levels of ghrelin, GOAT and GHS-R1a mRNAs were also examined in different brain regions (pituitary, hypothalamus, thalamus, cerebellum, cerebral cortex, olfactory bulb, midbrain and medulla oblongata). Ghrelin concentrations in the proventriculus and plasma increased with aging and reached plateaus at 30-50 days after hatching. High level of ghrelin mRNA decreased at 3 days after hatching, and it became stable at half of the initial level. Expression levels of GHS-R1a and GOAT decreased 3 or 5 days after hatching and became stable at low levels. Significant negative correlations were found between plasma ghrelin and mRNA levels of GOAT and GHS-R1a. Expression levels of ghrelin mRNA were different in the brain regions, but a significant change was not seen with aging. GHS-R1a expression was detected in all brain regions, and age-dependent changes were observed in the pituitary and cerebellum. Different from the proventriculus, the expression of GOAT in the brain increased or did not change with aging. These results suggest that decreased GHS-R1a and GOAT mRNA expression in the proventriculus is due to endogenous ghrelin-induced down-regulation. Expression levels of ghrelin, GOAT and GHS-R1a in the brain were independently regulated from that in the proventriculus, and age-related and region-dependent regulation pattern suggests a local effect of ghrelin system in chicken brain.

  13. Possible involvement of ghrelin on pain threshold in obesity.

    PubMed

    Guneli, Ensari; Gumustekin, Mukaddes; Ates, Mehmet

    2010-03-01

    hypothesis that the diminution of the susceptibility to pain in lean subjects/animals may be induced by the increase in endogenous ghrelin activity, or increased of the susceptibility to pain in obese subject/animals may be induced by the decrease in endogenous ghrelin activity.

  14. 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 Central

    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. PMID:23613773

  15. Fos is an essential component of the mammalian UV response.

    PubMed Central

    Schreiber, M; Baumann, B; Cotten, M; Angel, P; Wagner, E F

    1995-01-01

    Mouse 3T3 fibroblasts lacking c-fos were employed to demonstrate an essential function of the UV-inducible transcription factor AP-1 (Fos/Jun) in the response to the cytotoxic effects of short-wavelength ultraviolet (UVC) radiation. Clonogenic survival and proliferation of cells lacking c-fos were drastically reduced following UV irradiation. This UV hypersensitivity manifests itself primarily in increased cell death, partly by apoptosis, and prolonged recovery time from UV-induced cell cycle arrest. Co-culture with wild-type cells did not ameliorate the hypersensitivity of mutant cells. Transcriptional induction of the c-Fos target genes collagenase I, stromelysin-1 and stromelysin-2 by UV is almost absent in cells lacking c-fos which correlates with a reduced UV induction of AP-1 DNA-binding and transactivation activity. The repair of UV-induced DNA lesions was not affected, as shown by unscheduled DNA synthesis and host cell reactivation assays. These data demonstrate that c-Fos is involved in a novel protective function other than DNA repair against the harmful consequences of UVC. Images PMID:7489723

  16. Intracoronary ghrelin infusion decreases coronary blood flow in anesthetized pigs.

    PubMed

    Grossini, Elena; Molinari, Claudio; Mary, David A S G; Ghigo, Ezio; Bona, Gianni; Vacca, Giovanni

    2007-02-01

    The peptide ghrelin has been linked to the atherosclerotic process and coronary artery disease. We planned to study, for the first time, the primary effects of ghrelin on the intact coronary circulation and determine the mechanisms involved. In 24 sodium pentobarbitone-anesthetized pigs, changes in anterior descending coronary blood flow caused by intracoronary infusion of ghrelin at constant heart rate and arterial pressure were assessed using electromagnetic flowmeters. In 20 pigs, intracoronary infusion of ghrelin decreased coronary blood flow without affecting left ventricular maximum rate of change of left ventricular systolic pressure (dP/dt(max)), filling pressures of the heart or plasma levels of GH. In four pigs, this decrease was graded by step increments of infused dose of the hormone. The mechanisms of the above response were studied in the 20 pigs by repeating the experiment after coronary flow had returned to the control values observed before infusion. The ghrelin-induced coronary vasoconstriction was not affected by iv atropine (five pigs) or phentolamine (five pigs). This response was abolished by iv butoxamine (five pigs) and intracoronary N(omega)-nitro-l-arginine methyl ester (five pigs), even after reversing the increase in arterial pressure and coronary vascular resistance caused by the two blocking agents with iv infusion of papaverine. The present study showed that intracoronary infusion of ghrelin primarily caused coronary vasoconstriction. The mechanisms of this response were shown to involve the inhibition of a vasodilatory beta(2)-adrenergic receptor-mediated effect related to the release of nitric oxide.

  17. Emergence of ghrelin as a treatment for cachexia syndromes.

    PubMed

    DeBoer, Mark Daniel

    2008-09-01

    Cachexia is a constellation of symptoms that amount to body wasting in the setting of a variety of chronic illnesses, including cancer, heart failure, chronic kidney disease, and acquired immunodeficiency syndrome. Cachexia is particularly worrisome clinically because it is associated with a worsened prognosis of the underlying disease. Despite a large amount of study in this area, no single agent has been shown to have consistent efficacy in human trials. One promising class in this setting is ghrelin receptor agonists. Ghrelin binds to the growth hormone secretagogue-1a receptor in appetite-regulating centers in the brain, increasing expression of neuropeptide Y and agouti-related peptide during short-term treatment. Ghrelin has also been shown to have anti-inflammatory properties, which is significant, given that cachexia is thought to be produced at least partly by inflammation induced by the underlying disease. Animal studies have demonstrated efficacy using growth hormone secretagogue receptor agonists to treat cachexia caused by cancer, chemotherapy, and chronic kidney disease. Limited human trials using ghrelin or ghrelin receptor agonists in cancer and heart disease have shown improved appetite and body mass during treatment, although longer-term trials are needed to confirm sustained effects. Also uncertain--but an intriguing possibility--is whether the improved weight gain with ghrelin treatment might also lessen the severity of the underlying disease and improve outcomes.

  18. c-Fos expression in the parabrachial nucleus following intraoral bitter stimulation in the rat with dietary-induced zinc deficiency.

    PubMed

    Kawano, Akiyo; Honma, Shiho; Inui-Yamamoto, Chizuko; Ito, Akira; Niwa, Hitoshi; Wakisaka, Satoshi

    2017-03-15

    Zinc deficiency causes various symptoms including taste disorders. In the present study, changes in expression of c-Fos immunoreactivity in neurons of the parabrachial nucleus (PBN), one of the relay nuclei for transmission of gustatory information, after bitter stimulation to the dorsal surface of the tongue were examined in zinc-deficient rats. Experimental zinc-deficient animals were created by feeding a low-zinc diet for 4weeks, and showed the following symptoms of zinc deficiency: low body weight, low serum zinc content and behavioral changes to avoid bitter stimulation. In normal control animals, intraoral application of 1mM quinine caused increased numbers of c-Fos-immunoreactive (c-Fos-IR) neurons in the external lateral subnucleus and external medial subnucleus of the PBN (elPBN and emPBN, respectively) compared with application of distilled water. However, in the zinc-deficient animals, the numbers of c-Fos-IR neurons in the elPBN and emPBN did not differ significantly between application of quinine and distilled water. After feeding the zinc-deficient animals a normal diet for 4weeks, the symptoms of zinc deficiency recovered, and the expression of c-Fos-IR neurons following intraoral bitter stimulation became identical to that in the normal control animals. The present results indicate that dietary zinc deficiency causes alterations to neuronal activities in the gustatory neural circuit, and that these neuronal alterations can be reversed by changing to a normal diet. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Enriched environment attenuates nicotine self-administration and induces changes in ΔFosB expression in the rat prefrontal cortex and nucleus accumbens.

    PubMed

    Venebra-Muñoz, Arturo; Corona-Morales, Aleph; Santiago-García, Juan; Melgarejo-Gutiérrez, Montserrat; Caba, Mario; García-García, Fabio

    2014-06-18

    Environment enrichment conditions have important consequences on subsequent vulnerability to drugs of abuse. The present work examined whether exposure to an enriched environment (EE) decreases oral self-consumption of nicotine. Wistar rats were housed either in a standard environment (SE, four rats per standard cage) or in an EE during 60 days after weaning. EE consisted of eight animals housed in larger cages containing a variety of objects such as boxes, toys, and burrowing material that were changed three times a week. After this period, animals were exposed to nicotine for 3 weeks, where animals chose freely between water and a nicotine solution (0.006% in water). Fluid consumption was evaluated on a daily basis. ΔFosB immunohistochemistry in the prefrontal cortex and nucleus accumbens was also performed. Rats of the EE group consumed less nicotine solution (0.25±0.04 mg/kg/day) than SE rats (0.54±0.05 mg/kg/day). EE increased the number of ΔFos-immunoreactive (ΔFos-ir) cells in the nucleus accumbens core and shell and in the prefrontal cortex, compared with animals in the standard condition. However, rats exposed to nicotine in the SE showed higher ΔFos-ir cells in the nucleus accumbens core and shell than nonexposed rats. Nicotine consumption did not modify ΔFos-ir cells in these brain areas in EE animals. These results support the idea of a possible protective effect of the EE on reward sensitivity and the development of an addictive behavior to nicotine.

  20. 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

  1. 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.

  2. Plasma ghrelin, obesity, and the polycystic ovary syndrome: correlation with insulin resistance and androgen levels.

    PubMed

    Pagotto, Uberto; Gambineri, Alessandra; Vicennati, Valentina; Heiman, Mark L; Tschöp, Matthias; Pasquali, Renato

    2002-12-01

    In addition to its orexigenic properties, ghrelin has been shown to modulate the secretory pattern of pituitary hormones, and it may exert direct effects on peripheral organs such as the gonads and endocrine pancreas. To study possible interactions among ghrelin, glucose homeostasis, and the reproductive system, we investigated 10 obese women with polycystic ovary syndrome (OB-PCOS) in comparison with 10 age- and body mass index-matched obese subjects (OB). Plasma levels of insulin, glucose, androgens, and ghrelin were measured at baseline condition and after 7 months of therapy (hypocaloric diet + metformin or placebo). Plasma ghrelin levels were lower in OB-PCOS than in OB (P < 0.05). A strong negative correlation between ghrelin and androstenedione levels was found in both populations at baseline (OB-PCOS: P < 0.01; OB: P < 0.001) and after therapy (OB-PCOS: P < 0.01; OB: P < 0.05), whereas no correlation was found between ghrelin and other androgens. In both groups, the markers of insulin resistance in fasting and stimulated conditions (glucose/insulin ratio, homeostasis model insulin resistance index, homeostasis model applied to the oral glucose tolerance test) demonstrated decreased insulin sensitivity. However, a negative correlation between plasma ghrelin and all these markers was observed only in the OB-PCOS group (P < 0.05). Accordingly, a negative correlation between ghrelin variation and treatment-induced changes of the glucose/insulin ratio, HOMA-R, and HOMA(OGTT) was observed only in the OB-PCOS group (P < 0.05). In conclusion, OB-PCOS women have lower ghrelin levels than those expected based on the presence of obesity. Only in OB-PCOS, ghrelin negatively correlates with insulin sensitivity. In addition, regardless of the presence of PCOS, a marked negative correlation exists between ghrelin and androstenedione levels, suggestive of an interaction between ghrelin and steroid synthesis or action.

  3. Ghrelin Modulates Physiologic and Pathologic Retinal Angiogenesis through GHSR-1a

    PubMed Central

    Zaniolo, Karine; Sapieha, Przemyslaw; Shao, Zhuo; Stahl, Andreas; Zhu, Tang; Tremblay, Sophie; Picard, Emilie; Madaan, Ankush; Blais, Martine; Lachapelle, Pierre; Mancini, Joseph; Hardy, Pierre; Smith, Lois E. H.; Ong, Huy

    2011-01-01

    Purpose. Vascular degeneration and the ensuing abnormal vascular proliferation are central to proliferative retinopathies. Given the metabolic discordance associated with these diseases, the authors explored the role of ghrelin and its growth hormone secretagogue receptor 1a (GHSR-1a) in proliferative retinopathy. Methods. In a rat model of oxygen-induced retinopathy (OIR), the contribution of ghrelin and GHSR-1a was investigated using the stable ghrelin analogs [Dap3]-ghrelin and GHRP6 and the GSHR-1a antagonists JMV-2959 and [D-Lys3]-GHRP-6. Plasma and retinal levels of ghrelin were analyzed by ELISA, whereas retinal expression and localization of GHSR-1a were examined by immunohistochemistry and Western blot analysis. The angiogenic and vasoprotective properties of ghrelin and its receptor were further confirmed in aortic explants and in models of vaso-obliteration. Results. Ghrelin is produced locally in the retina, whereas GHSR-1a is abundantly expressed in retinal endothelial cells. Ghrelin levels decrease during the vaso-obliterative phase and rise during the proliferative phase of OIR. Intravitreal delivery of [Dap3]-ghrelin during OIR significantly reduces retinal vessel loss when administered during the hyperoxic phase. Conversely, during the neovascular phase, ghrelin promotes pathologic angiogenesis through the activation of GHSR-1a. These angiogenic effects were confirmed ex vivo in aortic explants. Conclusions. New roles were disclosed for the ghrelin-GHSR-1a pathway in the preservation of retinal vasculature during the vaso-obliterative phase of OIR and during the angiogenic phase of OIR. These findings suggest that the ghrelin-GHSR-1a pathway can exert opposing effects on retinal vasculature, depending on the phase of retinopathy, and thus holds therapeutic potential for proliferative retinopathies. PMID:21642627

  4. Obestatin partially affects ghrelin stimulation of food intake and growth hormone secretion in rodents

    PubMed Central

    Zizzari, Philippe; Longchamps, Romaine; Epelbaum, Jacques; Bluet-Pajot, Marie-Thérèse

    2007-01-01

    Administration of ghrelin, an endogenous ligand for the growth hormone secretagogue receptor 1a (GHSR 1a), induces potent stimulating effects on GH secretion and food intake. However, more than seven years after its discovery, the role of endogenous ghrelin remains elusive. Recently a second peptide, obestatin, also generated from proteolytic cleavage of preproghrelin has been identified. This peptide inhibits food intake and gastrointestinal motility but does not modify in vitro GH release from pituitary cells. In this study we have reinvestigated obestatin functions by measuring plasma ghrelin and obestatin levels in a period of spontaneous feeding in ad libitum fed and 24h-fasted mice. While fasting resulted in elevated ghrelin levels, obestatin levels were significantly reduced. Exogenous obestatin per se did not modify food intake in fasted and fed mice. However, it inhibited ghrelin orexigenic effect that were evident in fed mice only. The effects of obestatin on GH secretion were monitored in superfused pituitary explants and in freely moving rats. Obestatin was only effective in vivo to inhibit ghrelin stimulation of GH levels. Finally, the relationship between octanoylated ghrelin, obestatin and GH secretions was evaluated by iterative blood sampling every 20 minutes during 6 hours in freely moving adult male rats. The half-life of exogenous obestatin (10 μg iv) in plasma was about 22 minutes. Plasma obestatin levels exhibited an ultradian pulsatility with a frequency slightly lower than octanoylated ghrelin and GH. Ghrelin and obestatin levels were not strictly correlated. In conclusion these results show that obestatin, like ghrelin, is secreted in a pulsatile manner and that in some conditions; obestatin can modulate exogenous ghrelin action. It remains to be determined whether obestatin modulates endogenous ghrelin actions. PMID:17204551

  5. Exogenous ghrelin regulates proliferation and apoptosis in the hypotrophic gut mucosa of the rat.

    PubMed

    de Segura, Ignacio A Gómez; Vallejo-Cremades, María Teresa; Lomas, Jesús; Sánchez, Miriam F; Caballero, María Isabel; Largo, Carlota; De Miguel, Enrique

    2010-04-01

    Ghrelin is the natural endogenous ligand for growth hormone secretagogue receptors. This peptide regulates energy homeostasis and expenditure and is a potential link between gut absorptive function and growth. We hypothesized that ghrelin may induce a proliferative and antiapoptotic action promoting the recovery of the hypotrophic gut mucosa. Therefore, the aim of the study was to determine the action of exogenous ghrelin following gut mucosal hypotrophia in rats fed an elemental diet. An elemental diet provides readily absorbable simple nutrients and is usually given to patients with absorptive dysfunction. Male Wistar rats (n = 48) were fed the elemental diet for one week to induce mucosal hypotrophy and then treated for another week with systemic ghrelin and pair-fed with either a normoproteic or hyperproteic isocaloric liquid diet. Another group received a standard diet instead of the elemental diet and served as control (normotrophy). The elemental diet induced intestinal hypotrophia characterized by decreased proliferation in the ileum and increased apoptosis in jejunum and ileum. Ghrelin administration restored normal levels of proliferation in the ileum and apoptosis in the jejunum, with partial apoptosis restoration in the ileum. Ghrelin levels in plasma and fundus were increased in all groups, although the highest levels were found in rats treated with exogenous ghrelin. Ghrelin administration has a positive effect in the hypotrophic gut, regulating both proliferation and apoptosis towards a physiological balance counteracting the negative changes induced by an elemental diet in the intestines.

  6. Ghrelin directly stimulates adult hippocampal neurogenesis: implications for learning and memory.

    PubMed

    Li, Endan; Chung, Hyunju; Kim, Yumi; Kim, Dong Hyun; Ryu, Jong Hoon; Sato, Takahiro; Kojima, Masayasu; Park, Seungjoon

    2013-01-01

    Adult hippocampal neurogenesis is important in mediating hippocampal-dependent learning and memory. Exogenous ghrelin is known to stimulate progenitor cell proliferation in the dentate gyrus of adult hippocampus. The aim of this study was to investigate the role of endogenous ghrelin in regulating the in vivo proliferation and differentiation of the newly generating cells in the adult hippocampus using ghrelin knockout (GKO) mice. Targeted deletion of ghrelin gene resulted in reduced numbers of progenitor cells in the subgranular zone (SGZ) of the hippocampus, while ghrelin treatment restored progenitor cell numbers to those of wild-type controls. We also found that not only the number of bromodeoxyuridine (BrdU)-positive cells but also the fraction of immature neurons and newly generated neurons were decreased in the GKO mice, which were increased by ghrelin replacement. Additionally, in the GKO mice, we observed impairment of memory performance in Y-maze task and novel object recognition test. However, these functional deficiencies were attenuated by ghrelin administration. These results suggest that ghrelin directly induces proliferation and differentiation of adult neural progenitor cells in the SGZ. Our data suggest ghrelin may be a plausible therapeutic potential to enhance learning and memory processes.

  7. Ghrelin attenuates the growth of HO-8910 ovarian cancer cells through the ERK pathway

    PubMed Central

    Bai, R.X.; Wang, W.P.; Zhao, P.W.; Li, C.B.

    2016-01-01

    Ovarian cancer is one of the most common causes of death from gynecologic tumors and is an important public health issue. Ghrelin is a recently discovered bioactive peptide that acts as a natural endogenous ligand of the growth hormone secretagogue receptor (GHSR). Several studies have identified the protective effects of ghrelin on the mammalian reproductive system. However, little research has been done on the effects of ghrelin on ovarian cancer cells, and the underlying mechanisms of these effects. We sought to understand the potential involvement of mitogen-activated protein kinases (MAPKs) in ghrelin-mediated inhibition of growth of the ovarian line HO-8910. We applied different concentrations of ghrelin and an inhibitor of the ghrelin receptor (D-Lys3-GHRP-6) to HO-8910 cells and observed the growth rate of cells and changes in phosphorylation of the MAPKs ERK1/2, JNK and p38. We discovered that ghrelin-induced apoptosis of HO-8910 cells was though phosphorylated ERK1/2, and that this phosphorylation (as well as p90rsk phosphorylation) was mediated by the GHSR. The ERK1/2 pathway is known to play an essential part in the ghrelin-mediated apoptosis of HO-8910 cells. Hence, our study suggests that ghrelin inhibits the growth of HO-8910 cells primarily through the GHSR/ERK pathway. PMID:26840702

  8. Effect of ghrelin and metoclopramide on prolactin secretion in normal women.

    PubMed

    Messini, C I; Dafopoulos, K; Chalvatzas, N; Georgoulias, P; Anifandis, G; Messinis, I E

    2011-04-01

    Administration of ghrelin to women stimulates the secretion of PRL but the mechanism is not known. The aim of the study was to investigate the effect of the dopamine receptor blocker, metoclopramide, on ghrelin-induced PRL release. Ten healthy normally cycling women were studied in the midluteal phase of 4 menstrual cycles. A single dose of normal saline (cycle 1), ghrelin (1 μg/kg) (cycle 2), metoclopramide (20 mg) (cycle 3), and ghrelin plus metoclopramide (cycle 4) was given to the women iv. Blood samples in relation to the iv injection (time 0) were taken at -15, 0, 15, 30, 45, 60, 75, 90, and 120 min. The response of PRL and GH was assessed. Following ghrelin administration (cycles 2 and 4), plasma ghrelin and serum PRL and GH levels increased rapidly, peaking at 30 min (p<0.001). PRL was also increased after the injection of metoclopramide (p<0.001, cycle 3), but the increase was much greater than after the administration of ghrelin. The combination of ghrelin and metoclopramide stimulated PRL secretion to the same extent with metoclopramide alone. No changes in GH and PRL levels were seen after saline injection. These results demonstrate that the stimulating effect of ghrelin on PRL secretion is not additive with that of metoclopramide, although a dose range study might provide further information.

  9. 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

  10. Impairment of FOS mRNA stabilization following translation arrest in granulocytes from myelodysplastic syndrome patients.

    PubMed

    Feng, Xiaomin; Shikama, Yayoi; Shichishima, Tsutomu; Noji, Hideyoshi; Ikeda, Kazuhiko; Ogawa, Kazuei; Kimura, Hideo; Takeishi, Yasuchika; Kimura, Junko

    2013-01-01

    Although quantitative and qualitative granulocyte defects have been described in myelodysplastic syndromes (MDS), the underlying molecular basis of granulocyte dysfunction in MDS is largely unknown. We recently found that FOS mRNA elevation under translation-inhibiting stimuli was significantly smaller in granulocytes from MDS patients than in healthy individuals. The aim of this study is to clarify the cause of the impaired FOS induction in MDS. We first examined the mechanisms of FOS mRNA elevation using granulocytes from healthy donors cultured with the translation inhibitor emetine. Emetine increased both transcription and mRNA stability of FOS. p38 MAPK inhibition abolished the emetine-induced increase of FOS transcription but did not affect FOS mRNA stabilization. The binding of an AU-rich element (ARE)-binding protein HuR to FOS mRNA containing an ARE in 3'UTR was increased by emetine, and the knockdown of HuR reduced the FOS mRNA stabilizing effect of emetine. We next compared the emetine-induced transcription and mRNA stabilization of FOS between MDS patients and healthy controls. Increased rates of FOS transcription by emetine were similar in MDS and controls. In the absence of emetine, FOS mRNA decayed to nearly 17% of initial levels in 45 min in both groups. In the presence of emetine, however, 76.7±19.8% of FOS mRNA remained after 45 min in healthy controls, versus 37.9±25.5% in MDS (P<0.01). To our knowledge, this is the first report demonstrating attenuation of stress-induced FOS mRNA stabilization in MDS granulocytes.

  11. Prevention of diet-induced obesity by safflower oil: insights at the levels of PPARalpha, orexin, and ghrelin gene expression of adipocytes in mice.

    PubMed

    Zhang, Zhong; Li, Qiang; Liu, Fengchen; Sun, Yuqian; Zhang, Jinchao

    2010-03-15

    The aim of this study was to investigate the prevention of diet-induced obesity by a high safflower oil diet and adipocytic gene expression in mice. Forty 3-week-old C57BL/6 mice were randomly divided into three groups: control group (CON, 5% lard + 5% safflower oil), high lard group (LAR, 45% lard + 5% safflower oil), and high safflower oil group (SAF, 45% safflower oil + 5% lard). After 10 weeks, 10 mice of the LAR group were switched to high safflower oil diet (LAR-SAF). Ten weeks later, glucose tolerance tests were performed by intraperitoneal injection of glucose. Circulating levels of lipid and insulin were measured and white adipose tissues were taken for gene chip and reverse transcriptase-polymerase chain reaction analysis. The LAR group showed higher body weight, adiposity index, insulin, and lipids than the CON group (P<0.05). The body weight in the LAR-SAF group decreased after dietary reversal. The plasma biochemical profiles decreased in the LAR-SAF and SAF groups (P<0.05) compared with those of the LAR group. The blood glucose level of the LAR-SAF group was reduced during intraperitoneal glucose tolerance test compared with that of the LAR group. The LAR-SAF group had lower levels of Orexin and Ghrelin gene expression, whereas the level of PPARalpha gene expression was significantly enhanced compared with that of the LAR group. So, the SAF diet can alter adipocytic adiposity-related gene expression and result in effective amelioration of diet-induced obesity.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  13. Long-lasting c-fos and NGF mRNA expressions and loss of perikaryal parvalbumin immunoreactivity in the development of epileptogenesis after ethacrynic acid-induced seizure.

    PubMed

    Suzukawa, J; Omori, K; Okugawa, G; Fujiseki, Y; Heizmann, C W; Inagaki, C

    1999-07-10

    A single cerebroventricular injection of ethacrynic acid (EA), a Cl(-)-ATPase inhibitor, induces generalized tonic-clonic convulsions in mice. To clarify whether such convulsive stimulus triggers a long-lasting rearrangement of the neural circuitry culminating in seizure susceptibility, we examined molecular, cellular and behavioral changes following the EA-induced seizure. The expression of immediate early gene c-fos mRNA as an index for cellular activation increased biphasically, with an early transient increase at 60 min and a late prolonged increase on the 10th to 14th day post-EA administration, most remarkably in the hippocampus and pyriform cortex. On the 14th day post-EA seizure, subconvulsive dose of kainic acid (5-17.5 mg/kg) caused severe (stage 5) seizure in 77% of the mice, with 70% mortality. In addition, the expression of nerve growth factor (NGF) also showed biphasic increases with close spatiotemporal correlation with c-fos expression. Moreover, the number of cell somata and the density of axon fibers of parvalbumin (PARV)-positive cells, a subpopulation of GABAergic interneurons, decreased in area dentata, CA1 and CA3 on the 7th and 14th day post-EA seizure. In area dentata and CA1, the density of glutamic acid decarboxylase (GAD)-positive cells also decreased on the 14th day. Thus, the transient EA-induced seizures appear to develop seizure susceptibility by causing damage of a subpopulation of inhibitory interneurons along with increases in the expression of c-fos and NGF in limbic structures.

  14. Effect of ghrelin administration on phagocytic activity in acute cold-restraint stress exposed rats.

    PubMed

    Tümer, Cemil; Bilgin, Hakki Murat; Obay, Basra Deniz; Diken, Hüda; Taşdemir, Ezel; Sermet, Abdurrahman

    2007-02-01

    Ghrelin, an endogenous ligand for growth hormone secretagogue receptor, was identified in the rat stomach. This peptide acts through nitric oxide (NO) by expressing endothelial nitric oxide synthase (eNOS) and down regulating inducible nitric oxide synthase (iNOS) at its gastroproprotective effect against restraint stress induced damage. Recently the ghrelin receptor has also been detected in peripheral systems including immune tissue. We have investigated the possible effect of ghrelin on phagocytic activity of peritoneal macrophages in acute cold-restraint stress (ACRS) exposed rats. The rats were divided into control, stress and ghrelin groups. In ghrelin groups, single dose and three days consecutive dose of ghrelin (20 microg/kg. i.p.) were applied to rats that were exposed to ACRS for 4 h. 1 ml of saline was injected i.p. after ACRS for 3 consecutive days to the rats of the stress groups. Ghrelin administration reduced the increased phagocytic activity induced by ACRS. We conclude that ghrelin exerts an important role at macrophage phagocytic activity in ACRS exposed rats.

  15. 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

  16. The Effect of Ghrelin upon the Early Immune Response in Lean and Obese Mice during Sepsis

    PubMed Central

    Siegl, Daniel; Midura, Emily F.; Annecke, Thorsten; Conzen, Peter; Caldwell, Charles C.; Tschoep, Johannes

    2015-01-01

    Introduction It is well established that obesity-related hormones can have modulatory effects associated with the immune response. Ghrelin, a hormone mainly derived from endocrine cells of the gastric mucosa, regulates appetite, energy expenditure and body weight counteracting leptin, a hormone mainly derived from adipocytes. Additionally, receptors