A functional role for central glucagon-like peptide-1 receptors in lithium chloride-induced anorexia

1999 ◽  
Vol 277 (5) ◽  
pp. R1537-R1540 ◽  
Author(s):  
Linda Rinaman
Keyword(s):  
Food Intake ◽  
Receptor Antagonist ◽  
Lithium Chloride ◽  
Neural Pathways ◽  
Sprague Dawley ◽  
Receptor Signalling ◽  
Sprague Dawley Rats ◽  
Licl Treatment ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

The present study sought to determine whether central glucagon-like peptide-1 (GLP-1)-receptor signalling contributes to the anorexigenic effects of systemically administered lithium chloride (LiCl). Male Sprague-Dawley rats with chronic intracerebroventricular (ICV) cannulas were acclimated to a feeding schedule that included daily 30-min access to palatable mash. In the first experiment, ICV infusion of a GLP-1-receptor antagonist [exendin-4-(3—39)] significantly attenuated (10 μg dose) or completely blocked (20 μg dose) the inhibition of food intake produced by subsequent ICV infusion of GLP-1-(7—36) amide (5 μg). In the second experiment, rats were infused with 0, 10, or 20 μg of the GLP-1-receptor antagonist ICV, followed by injection of 0.15 M LiCl (50 mg/kg ip) or the same volume of 0.15 M NaCl. The ability of LiCl treatment to suppress food intake was significantly attenuated in rats that were pretreated with the GLP-1-receptor antagonist. These results support the view that central mechanisms underlying LiCl-induced anorexia include a prominent role for endogenous GLP-1 neural pathways.

scholarly journals The Effects of Mutual Interaction of Orexin-A and Glucagon-Like Peptide-1 on Reflex Swallowing Induced by SLN Afferents in Rats

2020 ◽  
Vol 21 (12) ◽  
pp. 4422
Author(s):  
Motoi Kobashi ◽  
Yuichi Shimatani ◽  
Masako Fujita ◽  
Yoshihiro Mitoh ◽  
Ryusuke Yoshida ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Nucleus Tractus Solitarius ◽  
Superior Laryngeal Nerve ◽  
Mutual Interaction ◽  
Sprague Dawley ◽  
Orexin A ◽  
Medial Nucleus ◽  
Sprague Dawley Rats ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

(1) Background: Our previous studies revealed that orexin-A, an appetite-increasing peptide, suppressed reflex swallowing via the commissural part of the nucleus tractus solitarius (cNTS), and that glucagon-like peptide-1 (GLP-1), an appetite-reducing peptide, also suppressed reflex swallowing via the medial nucleus of the NTS (mNTS). In this study, we examined the mutual interaction between orexin-A and GLP-1 in reflex swallowing. (2) Methods: Sprague–Dawley rats under urethane–chloralose anesthesia were used. Swallowing was induced by electrical stimulation of the superior laryngeal nerve (SLN) and was identified by the electromyographic (EMG) signals obtained from the mylohyoid muscle. (3) Results: The injection of GLP-1 (20 pmol) into the mNTS reduced the swallowing frequency and extended the latency of the first swallow. These suppressive effects of GLP-1 were not observed after the fourth ventricular administration of orexin-A. After the injection of an orexin-1 receptor antagonist (SB334867) into the cNTS, an ineffective dose of GLP-1 (6 pmol) into the mNTS suppressed reflex swallowing. Similarly, the suppressive effects of orexin-A (1 nmol) were not observed after the injection of GLP-1 (6 pmol) into the mNTS. After the administration of a GLP-1 receptor antagonist (exendin-4(5-39)), an ineffective dose of orexin-A (0.3 nmol) suppressed reflex swallowing. (4) Conclusions: The presence of reciprocal inhibitory connections between GLP-1 receptive neurons and orexin-A receptive neurons in the NTS was strongly suggested.

scholarly journals GLP-1 receptor signaling contributes to anorexigenic effect of centrally administered oxytocin in rats

2002 ◽  
Vol 283 (1) ◽  
pp. R99-R106 ◽  
Author(s):  
Linda Rinaman ◽  
Elizabeth E. Rothe
Keyword(s):  
Food Intake ◽  
Receptor Antagonist ◽  
Male Rats ◽  
Neural Systems ◽  
Neural Pathways ◽  
Receptor Signaling ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Access To Food ◽  
Anorexigenic Effect

The present study examined possible interactions between central glucagon-like peptide-1 (GLP-1) and oxytocin (OT) neural systems by determining whether blockade of GLP-1 receptors attenuates OT-induced anorexia and vice versa. Male rats were acclimated to daily 4-h food access. In the first experiment, rats were infused centrally with GLP-1 receptor antagonist or vehicle, followed by an anorexigenic dose of synthetic OT. Access to food began 20 min later. Cumulative food intake was measured every 30 min for 4 h. In the second experiment, rats were infused with OT receptor blocker or vehicle, followed by synthetic GLP-1 [(7–36) amide]. Subsequent food intake was monitored as before. The anorexigenic effect of OT was eliminated in rats pretreated with the GLP-1 receptor antagonist. Conversely, GLP-1-induced anorexia was not affected by blockade of OT receptors. In a separate immunocytochemical study, OT-positive terminals were found closely apposed to GLP-1-positive perikarya, and central infusion of OT activated c-Fos expression in GLP-1 neurons. These findings implicate endogenous GLP-1 receptor signaling as an important downstream mediator of anorexia in rats after activation of central OT neural pathways.

scholarly journals Central infusion of glucagon-like peptide-1-(7–36) amide (GLP-1) receptor antagonist attenuates lithium chloride-induced c-Fos induction in rat brainstem

1998 ◽  
Vol 801 (1-2) ◽  
pp. 164-170 ◽  
Author(s):  
Todd E Thiele ◽  
Randy J Seeley ◽  
David D'Alessio ◽  
John Eng ◽  
Ilene L Bernstein ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Lithium Chloride ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Rat Brainstem

Glucagon-like peptide-1 response to whey protein is less diminished by dipeptidyl peptidase-4 in comparison with responses to dextrin, a lipid and casein in rats

2020 ◽  
pp. 1-10 ◽  
Author(s):  
Yuki Shimizu ◽  
Hiroshi Hara ◽  
Tohru Hira
Keyword(s):  
Whey Protein ◽  
Dipeptidyl Peptidase ◽  
Dietary Proteins ◽  
Sprague Dawley ◽  
Dipeptidyl Peptidase 4 ◽  
Sprague Dawley Rats ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

Abstract Although glucose is the best-known nutrient to stimulate glucagon-like peptide-1 (GLP-1) secretion, dietary peptides also potently stimulate GLP-1 secretion. Certain peptide fragments derived from dietary proteins possess dipeptidyl peptidase-4 (DPP-4) inhibitory activity in vitro. Hence, we hypothesised that dietary peptides protect GLP-1 from degradation through attenuating DPP-4 activity in vivo. Here, we compared GLP-1 responses with dietary proteins, a carbohydrate and a lipid (Intralipos) in rats having or not having plasma DPP-4 activity. Plasma GLP-1 concentrations clearly increased by oral administration of whey protein (2–4 g/kg), but not by that of dextrin (2–4 g/kg), in control rats (untreated Sprague–Dawley rats and F344/Jcl rats), having DPP-4 activity. In contrast, dextrin administration increased the plasma GLP-1 concentrations as the whey protein administration did, in rats having reduced or no DPP-4 activity (a DPP-4 inhibitor, sitagliptin-treated Sprague–Dawley rats or DPP-4-deficient F344/DuCrl/Crlj rats). DPP-4 inhibition by sitagliptin treatment also enhanced GLP-1 response to Intralipos, and casein, but the treatment did not further enhance GLP-1 response to whey protein. Intestinal GLP-1 content and gastric emptying rate were not associated with differences in GLP-1 responses to test nutrients. The luminal contents from rats administered whey protein decreased DPP-4 activity in vitro. These results suggest that GLP-1 released by dextrin, Intralipos and casein was immediately degraded by DPP-4, while GLP-1 released by whey protein was less degraded. Our study provides novel in vivo evidence supporting the hypothesis that dietary peptides not only stimulate GLP-1 secretion but also inhibit DPP-4 activity to potentiate GLP-1 response.

Glucagon-like peptide (GLP-1) is involved in the central modulation of fecal output in rats

2000 ◽  
Vol 278 (6) ◽  
pp. G924-G929 ◽  
Author(s):  
M. Ali Gülpinar ◽  
Ayhan Bozkurt ◽  
Tamer Coşkun ◽  
Nefise B. Ulusoy ◽  
Berrak Ç. Yeǧen
Keyword(s):  
Receptor Antagonist ◽  
Restraint Stress ◽  
Colonic Motility ◽  
Sprague Dawley ◽  
Fecal Output ◽  
Sprague Dawley Rats ◽  
Ketamine Anesthesia ◽  
Stereotaxic Instrument ◽  
Glucagon Like Peptide

In addition to its insulinotropic action, exogenously administered glucagon-like peptide (GLP-1) inhibits gastropancreatic motility and secretion via central pathways. The aims of the present study were to evaluate the effects of exogenous GLP-1-(7–36) amide on fecal output and to investigate the role of endogenous GLP-1 on stress-induced colonic activity. With the use of a stereotaxic instrument, adult male Sprague-Dawley rats weighing 200–250 g were fitted with stainless steel cerebroventricular guide cannulas under ketamine anesthesia. A group of rats were placed in Bollman-type cages to induce restraint stress. Fecal output monitored for 2 h was increased significantly by intracerebroventricular GLP-1 to 500, 1,000, and 3,000 pmol/rat ( P < 0.05–0.01), whereas intraperitoneal GLP-1 had no effect. Intracerebroventricular administration of the GLP-1 receptor antagonist exendin-(9–39) (10 nmol/rat) reversed the increases induced by GLP-1 (500 pmol/rat; P < 0.01). Similar results were also observed with the injection of corticotropin-releasing factor receptor antagonist astressin (10 μg/rat icv). The significant increase in fecal pellet output induced by restraint stress was also decreased by both intracerebroventricular exendin (10 nmol/rat) and astressin (10 μg/rat; P < 0.01–0.001). These results suggest that GLP-1 participates in the central, but not peripheral, regulation of colonic motility via its own receptor and that GLP-1 is likely to be a candidate brain-gut peptide that acts as a physiological modulator of stress-induced colonic motility.

scholarly journals Potential modulation of plasma ghrelin and glucagon-like peptide-1 by anorexigenic cannabinoid compounds, SR141716A (rimonabant) and oleoylethanolamide

2004 ◽  
Vol 92 (5) ◽  
pp. 757-761 ◽  
Author(s):  
Patrice D. Cani ◽  
Maite Lasa Montoya ◽  
Audrey M. Neyrinck ◽  
Nathalie M. Delzenne ◽  
Didier M. Lambert
Keyword(s):  
Gastrointestinal Tract ◽  
Food Intake ◽  
Receptor Antagonist ◽  
Food Consumption ◽  
Cannabinoid Receptor ◽  
Short Term ◽  
Cannabinoid Compounds ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Fasted Rats

The CB1 cannabinoid receptor antagonist, N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methylpyrazole-3-carboxamide (rimonabant; SR141716A), and oleoylethanolamide (OEA) are known to reduce food consumption, by, at least partially, a peripheral regulation of feeding. The effects of systemic SR141716A or OEA (5 mg/kg) administrations on food consumption in 24 h food-deprived and fed rats were investigated. In fasted rats, SR141716A and OEA produced an inhibition in food intake measurable the first 20 min following injection. The increase in ghrelin levels observed in the vehicle-injected rats was abolished in animals receiving OEA and significantly reduced with SR141716A. Neither OEA nor SR141716A modified glucagon-like peptide-1 (7–36) amide portal levels 20 min after the administration. In fed rats, plasma ghrelin levels of SR141716A- and OEA-treated rats were 35% lower as compared with those of the vehicle-injected rats. These results show an influence of cannabinoid agents on circulating ghrelin levels and suggest that their short-term action on appetite seems to be in accordance with the control of secretion of gastrointestinal orexigenic peptides, mainly expressed in the upper part of the gastrointestinal tract.

scholarly journals Nutrient-specific feeding and endocrine effects of jejunal infusions in obese animals

2014 ◽  
Vol 306 (6) ◽  
pp. R420-R428 ◽  
Author(s):  
Megan J. Dailey ◽  
Alexander A. Moghadam ◽  
Timothy H. Moran
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Casein Hydrolysate ◽  
Sprague Dawley ◽  
High Fat ◽  
Laboratory Rats ◽  
Sprague Dawley Rats ◽  
Intestinal Infusion ◽  
Glucagon Like Peptide 1 ◽  
Infusion Period

Intestinal nutrient infusions result in variable decreases in food intake and body weight based on the nutrient type and the specific intestinal infusion site. We previously found that intrajejunal infusions of a fatty acid and glucose, but not casein hydrolysate, decreases food intake and body weight in lean chow-fed laboratory rats. To test whether obese, high fat-fed animals would show similar decreases in food intake and body weight in response to intrajejunal infusions of the same nutrients, equal kilocalorie loads of these nutrients (11.4 kcal) or vehicle were infused into the jejunum of obese, high fat-fed male Sprague-Dawley rats over 7 h/day for 5 consecutive days. Food intake was continuously monitored, and body weight was measured daily. After the infusion on the final day, rats were killed and plasma was collected. Similar to lean chow-fed rats, intrajejunal infusions of linoleic acid (LA) and glucose (Glu), but not casein hydrolysate (Cas), suppressed food intake with no compensatory increase in food intake after the infusion period. In contrast to lean chow-fed rats, only the LA, and not the Glu or Cas, produced decreases in body weight in the obese high fat-fed rat. There also were no differences in plasma glucagon-like peptide-1 levels in any of the nutrient infusion groups compared with saline infusion. These results suggest that there is a differential response to the same nutrients in lean vs. obese animals.

Central glucagon-like peptide 1 receptor-induced anorexia requires glucose metabolism-mediated suppression of AMPK and is impaired by central fructose

2013 ◽  
Vol 304 (7) ◽  
pp. E677-E685 ◽  
Author(s):  
Melissa A. Burmeister ◽  
Jennifer Ayala ◽  
Daniel J. Drucker ◽  
Julio E. Ayala
Keyword(s):  
Food Intake ◽  
Glucose Metabolism ◽  
Dependent Manner ◽  
Anorectic Effect ◽  
Dependent Inhibition ◽  
Glycolytic Inhibitor ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Amp Activated Protein Kinase ◽  
Mediated Reduction

Glucagon-like peptide-1 (GLP-1) suppresses food intake via activation of a central (i.e., brain) GLP-1 receptor (GLP-1R). Central AMP-activated protein kinase (AMPK) is a nutrient-sensitive regulator of food intake that is inhibited by anorectic signals. The anorectic effect elicited by hindbrain GLP-1R activation is attenuated by the AMPK stimulator AICAR. This suggests that central GLP-1R activation suppresses food intake via inhibition of central AMPK. The present studies examined the mechanism(s) by which central GLP-1R activation inhibits AMPK. Supporting previous findings, AICAR attenuated the anorectic effect elicited by intracerebroventricular (icv) administration of the GLP-1R agonist exendin-4 (Ex-4). We demonstrate that Ex-4 stimulates glycolysis and suppresses AMPK phosphorylation in a glucose-dependent manner in hypothalamic GT1-7 cells. This suggests that inhibition of AMPK and food intake by Ex-4 requires central glucose metabolism. Supporting this, the glycolytic inhibitor 2-deoxyglucose (2-DG) attenuated the anorectic effect of Ex-4. However, icv glucose did not enhance the suppression of food intake by Ex-4. AICAR had no effect on Ex-4-mediated reduction in locomotor activity. We also tested whether other carbohydrates affect the anorectic response to Ex-4. Intracerebroventricular pretreatment with the sucrose metabolite fructose, an AMPK activator, attenuated the anorectic effect of Ex-4. This potentially explains the increased food intake observed in sucrose-fed mice. In summary, we propose a model whereby activation of the central GLP-1R reduces food intake via glucose metabolism-dependent inhibition of central AMPK. We also suggest that fructose stimulates food intake by impairing central GLP-1R action. This has significant implications given the correlation between sugar consumption and obesity.

scholarly journals Hindbrain glucagon-like peptide-1 neurons track intake volume and contribute to injection stress-induced hypophagia in meal-entrained rats

2016 ◽  
Vol 310 (10) ◽  
pp. R906-R916 ◽  
Author(s):  
Alison D. Kreisler ◽  
Linda Rinaman
Keyword(s):  
Food Intake ◽  
Potential Role ◽  
Liquid Diet ◽  
Neural Activation ◽  
Intracerebroventricular Injection ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Diet Intake ◽  
Published Research ◽  
Diet Type

Published research supports a role for central glucagon-like peptide 1 (GLP-1) signaling in suppressing food intake in rodent species. However, it is unclear whether GLP-1 neurons track food intake and contribute to satiety, and/or whether GLP-1 signaling contributes to stress-induced hypophagia. To examine whether GLP-1 neurons track intake volume, rats were trained to consume liquid diet (LD) for 1 h daily until baseline intake stabilized. On test day, schedule-fed rats consumed unrestricted or limited volumes of LD or unrestricted volumes of diluted (calorically matched to LD) or undiluted Ensure. Rats were perfused after the test meal, and brains processed for immunolocalization of cFos and GLP-1. The large majority of GLP-1 neurons expressed cFos in rats that consumed satiating volumes, regardless of diet type, with GLP-1 activation proportional to intake volume. Since GLP-1 signaling may limit intake only when such large proportions of GLP-1 neurons are activated, a second experiment examined the effect of central GLP-1 receptor (R) antagonism on 2 h intake in schedule-fed rats. Compared with baseline, intracerebroventricular vehicle (saline) suppressed Ensure intake by ∼11%. Conversely, intracerebroventricular injection of vehicle containing GLP-1R antagonist increased intake by ∼14% compared with baseline, partly due to larger second meals. We conclude that GLP-1 neural activation effectively tracks liquid diet intake, that intracerebroventricular injection suppresses intake, and that central GLP-1 signaling contributes to this hypophagic effect. GLP-1 signaling also may contribute to satiety after large volumes have been consumed, but this potential role is difficult to separate from a role in the hypophagic response to intracerebroventricular injection.

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