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Díaz-Urbina D, Medina-Reyes EI, López-Alonso VE, Delgado-Buenrostro NL, Mancilla Díaz JM, Pedraza-Chaverri J, Chirino YI. Food-grade titanium dioxide (E171) differentially affects satiation in mice fed a regular or a high fat diet. Food Chem Toxicol 2023; 173:113610. [PMID: 36657699 DOI: 10.1016/j.fct.2023.113610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 12/17/2022] [Accepted: 01/09/2023] [Indexed: 01/18/2023]
Abstract
Food-grade titanium dioxide (E171) is a widely used food additive and the toxicity after oral consumption is still under research, although it has been already banned in some countries. The consumption of this additive occurs mainly through ultra-processed food products which also contain high amounts of fat. High fat diets (HFD) impair the physiological system controlling satiation and satiety, which are responsible for control of food intake and energy status. The impact of E171 on animal behavior has been poorly explored and here we hypothesize that E171 could worsen the effects on feeding behavior induced by HFD. Therefore, we aimed to evaluate the effects of E171 on the feeding pattern and the behavioral satiety sequence (BSS) of mice fed with a regular diet (RD) or a HFD after 1 and 16 weeks of exposure. The results showed that RD + E171 increased food intake and feeding time, but the prototypical structure of the BSS pattern (feeding→ grooming-activity → resting), was preserved. Conversely, food consumption was not altered in HFD + E171, but the BSS pattern was disrupted as the animals prolonged resting time and spent less time being active. Our findings suggest that E171 delayed the onset of satiation in mice fed with RD but induced the opposite effect in mice fed with HFD.
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Affiliation(s)
- Daniel Díaz-Urbina
- Laboratorio de Neurobiología de la Alimentación, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios No. 1, Tlalnepantla de Baz, CP 54090, Estado de México, Mexico.
| | - Estefany I Medina-Reyes
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México, Av. Universidad 3000 C.U., Coyoacán, 04510, Ciudad de México, CDMX, Mexico.
| | - Verónica E López-Alonso
- Laboratorio de Neurobiología de la Alimentación, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios No. 1, Tlalnepantla de Baz, CP 54090, Estado de México, Mexico
| | - Norma Laura Delgado-Buenrostro
- Laboratorio de Carcinogénesis y Toxicología. Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios No. 1, Tlalnepantla de Baz, CP 54090, Estado de México, Mexico
| | - Juan M Mancilla Díaz
- Laboratorio de Neurobiología de la Alimentación, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios No. 1, Tlalnepantla de Baz, CP 54090, Estado de México, Mexico
| | - José Pedraza-Chaverri
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México, Av. Universidad 3000 C.U., Coyoacán, 04510, Ciudad de México, CDMX, Mexico
| | - Yolanda I Chirino
- Laboratorio de Carcinogénesis y Toxicología. Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Av. de los Barrios No. 1, Tlalnepantla de Baz, CP 54090, Estado de México, Mexico
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2
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Eliason NL, Martin L, Low MJ, Sharpe AL. Melanocortin receptor agonist melanotan-II microinjected in the nucleus accumbens decreases appetitive and consumptive responding for food. Neuropeptides 2022; 96:102289. [PMID: 36155088 PMCID: PMC10152796 DOI: 10.1016/j.npep.2022.102289] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 08/20/2022] [Accepted: 09/13/2022] [Indexed: 01/23/2023]
Abstract
RATIONALE Obesity is a major health problem worldwide. An understanding of the factors that drive feeding behaviors is key to the development of pharmaceuticals to decrease appetite and consumption. Proopiomelanocortin (POMC), the melanocortin peptide precursor, is essential in the regulation of body weight and ingestive behaviors. Deletion of POMC or impairment of melanocortin signaling in the brain results in hyperphagic obesity. Neurons in the hypothalamic arcuate nucleus produce POMC and project to many areas including the nucleus accumbens (NAcc), which is well established in the rewarding and reinforcing effects of both food and drugs of abuse. OBJECTIVE These studies sought to determine the role of melanocortins in the NAcc on consumption of and motivation to obtain access to standard rodent chow. METHODS Male, C57BL/6J mice were microinjected bilaterally into the NAcc (100 nl/side) with the melanocortin receptor 3/4 agonist melanotan-II (MT-II; 0.1, 0.3, and 1 nmol), and ingestive behaviors were examined in both home cage and operant food self-administration experiments. In addition, the ability of MT-II in the NAcc to produce aversive properties or affect metabolic rate were tested. RESULTS MT-II injected into the NAcc significantly decreased consumption in both home cage and operant paradigms, and furthermore decreased appetitive responding to gain access to food. There was no development of conditioned taste avoidance or change in metabolic parameters following anorexic doses of MT-II. CONCLUSIONS MT-II in the NAcc decreased both the motivation to eat and the amount of food consumed without inducing an aversive state or affecting metabolic rate, suggesting a role for melanocortin signaling in the NAcc that is selective for appetite and satiety without affecting metabolism or producing an aversive state.
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Affiliation(s)
- Nicole L Eliason
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America
| | - Lynne Martin
- Department of Pharmaceutical Sciences, Feik College of Pharmacy, University of the Incarnate Word, San Antonio, TX, United States of America
| | - Malcolm J Low
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - Amanda L Sharpe
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America; Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America.
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Gabriel MO, Nikou M, Akinola OB, Pollak DD, Sideromenos S. Western diet-induced fear memory impairment is attenuated by 6-shogaol in C57BL/6N mice. Behav Brain Res 2019; 380:112419. [PMID: 31816337 DOI: 10.1016/j.bbr.2019.112419] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/18/2019] [Accepted: 12/05/2019] [Indexed: 01/23/2023]
Abstract
Dementia is a progressive cognitive diminution impeding with normal daily activities that is constantly on the increase. Currently, the estimated prevalence is 50 million affected people worldwide, a figure expected to triple within the next 30 years. While the pathophysiology of the different types of dementia is complex, likely involving the interplay between multiple genetic and environmental factors, strong evidence points towards an important link between diet and cognitive health. Here we examined the consequences of high-fat, high-sugar Western diet (HFSD)-induced obesity on cognitive performance in the fear conditioning task in mice and explored a possible beneficial effect of 6-shogaol (6S), an active constituent of ginger, in this model. Chronic exposure to HFSD significantly enhanced body weight gain in C57BL/6N mice and this effect was prevented by treatment with 6S. HFSD + vehicle-treated mice presented with a selective deficit in cued fear memory, which was not observed in HFSD + 6S-treated animals. The findings of this study provide first evidence for a beneficial effect of 6S on HFSD-induced obesity and emotional memory deficit in mice.
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Affiliation(s)
- Michael O Gabriel
- Department of Anatomy, Faculty of Basic Medical Sciences, College of Medical Sciences, Edo University Iyamho, Edo State, Nigeria; Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Austria
| | - Maria Nikou
- Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Austria
| | - Oluwole B Akinola
- Department of Anatomy, Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin, Ilorin, Nigeria
| | - Daniela D Pollak
- Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Austria
| | - Spyridon Sideromenos
- Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Austria.
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Chapelot D, Charlot K. Physiology of energy homeostasis: Models, actors, challenges and the glucoadipostatic loop. Metabolism 2019; 92:11-25. [PMID: 30500561 DOI: 10.1016/j.metabol.2018.11.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/25/2018] [Accepted: 11/19/2018] [Indexed: 12/16/2022]
Abstract
The aim of this review is to discuss the physiology of energy homeostasis (EH), which is a debated concept. Thus, we will see that the set-point theory is highly challenged and that other models integrating an anticipative component, such as energy allostasis, seem more relevant to experimental reports and life preservation. Moreover, the current obesity epidemic suggests that EH is poorly efficient in the modern human dietary environment. Non-homeostatic phenomena linked to hedonism and reward seem to profoundly impair EH. In this review, the apparent failed homeostatic responses to energy challenges such as exercise, cafeteria diet, overfeeding and diet-induced weight loss, as well as their putative determinants, are analyzed to highlight the mechanisms of EH. Then, the hormonal, neuronal, and metabolic factors of energy intake or energy expenditure are briefly presented. Last, this review focuses on the contributions of two of the most pivotal and often overlooked determinants of EH: the availability of endogenous energy and the pattern of energy intake. A glucoadipostatic loop model is finally proposed to link energy stored in adipose tissue to EH through changes in eating behavior via leptin and sympathetic nervous system activity.
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Affiliation(s)
- Didier Chapelot
- Université Paris 13, Centre de Recherche en Epidémiologie et Statistique, Equipe de Recherche en Epidémiologie Nutritionnelle (EREN), Inserm (U1153), Inra (U1125), Cnam, Bobigny, France.
| | - Keyne Charlot
- Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, Département Environnements Opérationnels, Brétigny-sur-Orge, France
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Thompson EE, Jagielo-Miller JE, Vemuri VK, Makriyannis A, McLaughlin PJ. CB1 antagonism produces behaviors more consistent with satiety than reduced reward value in food-maintained responding in rats. J Psychopharmacol 2016; 30:482-91. [PMID: 27005309 PMCID: PMC5531753 DOI: 10.1177/0269881116639287] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cannabinoid CB1 antagonists are widely known to reduce motivation for food, but it is not known whether they induce satiety or reduce reward value of food. It may therefore be necessary to compare effects of altered satiety and reward food value in the same appetitive task, and determine whether CB1 antagonism produces a behavior pattern similar to either, both, or neither. A fine-grained analysis of fixed-ratio 10 (FR10) responding for palatable food initially included number and duration of, and between, all lever presses and food tray entries in order to differentiate the pattern of suppression of prefeeding from that caused by reducing the reward value of the pellets with quinine. Discriminant function analysis then determined that these manipulations were best differentiated by effects on tray entries, pellet retrieval latencies, and time of the first response. At 0.5 mg/kg, AM 6527 produced similar effects to reducing reward value, but at 1.0 and 4.0 mg/kg, effects were more similar to those when animals were satiated. We conclude that AM 6527 both reduced reward value and enhanced satiety, but as dose increased, effects on satiety became much more prominent. These findings contribute to knowledge about the behavioral processes affected by CB1 antagonism.
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Affiliation(s)
- Emily E Thompson
- Department of Psychology, Edinboro University of Pennsylvania, Edinboro, PA, USA
| | | | - V Kiran Vemuri
- Center for Drug Discovery, Northeastern University, Boston, MA, USA
| | | | - Peter J McLaughlin
- Department of Psychology, Edinboro University of Pennsylvania, Edinboro, PA, USA
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Wright FL, Rodgers RJ. Behavioural profile of exendin-4/naltrexone dose combinations in male rats during tests of palatable food consumption. Psychopharmacology (Berl) 2014; 231:3729-44. [PMID: 24682505 DOI: 10.1007/s00213-014-3507-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 02/12/2014] [Indexed: 12/25/2022]
Abstract
RATIONALE The glucagon-like peptide 1 receptor (GLP-1R) agonist exendin-4 potently suppresses food intake in animals and humans. However, little is known about the behavioural specificity of this effect either when administered alone or when co-administered with another anorectic agent. OBJECTIVES The present study characterises the effects of exendin-4, both alone and in combination with naltrexone, on behaviours displayed by male rats during tests with palatable mash. METHODS Experiment 1 examined the dose-response effects of exendin-4 (0.025-2.5 μg/kg, IP), while experiment 2 profiled the effects of low-dose combinations of the peptide (0.025 and 0.25 μg/kg) and naltrexone (0.1 mg/kg). RESULTS In experiment 1, exendin-4 dose dependently suppressed food intake as well as the frequency and rate of eating. However, these effects were accompanied by dose-dependent reductions in all active behaviours and, at 2.5 μg/kg, a large increase in resting and disruption of the behavioural satiety sequence (BSS). In experiment 2, while exendin-4 (0.25 μg/kg) and naltrexone each produced a significant reduction in intake and feeding behaviour (plus an acceleration in the BSS), co-treatment failed to produce stronger effects than those seen in response to either compound alone. CONCLUSION Similarities between the behavioural signature of exendin-4 and that previously reported for the emetic agent lithium chloride would suggest that exendin-4 anorexia is related to the aversive effects of the peptide. Furthermore, as low-dose combinations of the peptide with naltrexone failed to produce an additive/synergistic anorectic effect, this particular co-treatment strategy would not appear to have therapeutic significance.
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Affiliation(s)
- F L Wright
- Behavioural Neuroscience Laboratory, Institute of Psychological Sciences, University of Leeds, Leeds, LS2 9JT, UK, England
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Oleoylethanolamide: a novel potential pharmacological alternative to cannabinoid antagonists for the control of appetite. BIOMED RESEARCH INTERNATIONAL 2014; 2014:203425. [PMID: 24800213 PMCID: PMC3996326 DOI: 10.1155/2014/203425] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 02/18/2014] [Accepted: 03/05/2014] [Indexed: 01/05/2023]
Abstract
The initial pharmaceutical interest for the endocannabinoid system as a target for antiobesity therapies has been restricted by the severe adverse effects of the CB1 antagonist rimonabant. This study points at oleoylethanolamide (OEA), a monounsaturated analogue, and functional antagonist of anandamide, as a potential and safer antiobesity alternative to CB1 antagonism. Mice treated with equal doses (5 or 10 mg/kg, i.p.) of OEA or rimonabant were analyzed for the progressive expression of spontaneous behaviors (eating, grooming, rearing, locomotion, and resting) occurring during the development of satiety, according to the paradigm called behavioral satiety sequence (BSS). Both drugs reduced food (wet mash) intake to a similar extent. OEA treatment decreased eating activity within the first 30 min and caused a temporary increase of resting time that was not accompanied by any decline of horizontal, vertical and total motor activity. Besides decreasing eating activity, rimonabant caused a marked increase of the time spent grooming and decreased horizontal motor activity, alterations that might be indicative of aversive nonmotivational effects on feeding. These results support the idea that OEA suppresses appetite by stimulating satiety and that its profile of action might be predictive of safer effects in humans as a novel antiobesity treatment.
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8
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Wright FL, Rodgers RJ. On the behavioural specificity of hypophagia induced in male rats by mCPP, naltrexone, and their combination. Psychopharmacology (Berl) 2014; 231:787-800. [PMID: 24114428 DOI: 10.1007/s00213-013-3295-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 09/16/2013] [Indexed: 12/11/2022]
Abstract
RATIONALE Serotonergic (5-hydroxytryptamine, 5-HT) and opioidergic mechanisms are intimately involved in appetite regulation. OBJECTIVES In view of recent evidence of positive anorectic interactions between opioid and various non-opioid substrates, our aim was to assess the behavioural specificity of anorectic responses to the opioid receptor antagonist naltrexone, the 5-HT2C/1B receptor agonist mCPP and their combination. METHODS Behavioural profiling techniques, including the behavioural satiety sequence (BSS), were used to examine acute drug effects in non-deprived male rats tested with palatable mash. Experiment 1 characterised the dose-response profile of mCPP (0.1-3.0 mg/kg), while experiment 2 assessed the effects of combined treatment with a sub-anorectic dose of mCPP (0.1 mg/kg) and one of two low doses of naltrexone (0.1 and 1.0 mg/kg). RESULTS Experiment 1 confirmed the dose-dependent anorectic efficacy of mCPP, with robust effects on intake and feeding-related measures observed at 3.0 mg/kg. However, that dose was also associated with other behavioural alterations including increased grooming, reductions in locomotion and sniffing, and disruption of the BSS. In experiment 2, naltrexone dose-dependently reduced food intake and time spent feeding, effects accompanied by a behaviourally selective acceleration in the BSS. However, the addition of 0.1 mg/kg mCPP did not significantly alter the behavioural changes observed in response to either dose of naltrexone given alone. CONCLUSIONS In contrast to recently reported positive anorectic interactions involving low-dose combinations of opioid receptor antagonists or mCPP with cannabinoid CB1 receptor antagonists, present results would not appear to provide any support for potentially clinically relevant anorectic interactions between opioid and 5-HT2C/1B receptor mechanisms.
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Affiliation(s)
- F L Wright
- Behavioural Neuroscience Laboratory, Institute of Psychological Sciences, University of Leeds, Leeds, LS2 9JT, UK
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Spudeit WA, Sulzbach NS, Bittencourt MDA, Duarte AMC, Liang H, Lino-de-Oliveira C, Marino-Neto J. The behavioral satiety sequence in pigeons (Columba livia). Description and development of a method for quantitative analysis. Physiol Behav 2013; 122:62-71. [DOI: 10.1016/j.physbeh.2013.08.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 08/30/2013] [Indexed: 11/15/2022]
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10
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Mul JD, Spruijt BM, Brakkee JH, Adan RAH. Melanocortin MC(4) receptor-mediated feeding and grooming in rodents. Eur J Pharmacol 2013; 719:192-201. [PMID: 23872405 DOI: 10.1016/j.ejphar.2013.04.060] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 03/27/2013] [Accepted: 04/03/2013] [Indexed: 02/04/2023]
Abstract
Decades ago it was recognized that the pharmacological profile of melanocortin ligands that stimulated grooming behavior in rats was strikingly similar to that of Xenopus laevis melanophore pigment dispersion. After cloning of the melanocortin MC1 receptor, expressed in melanocytes, and the melanocortin MC4 receptor, expressed mainly in brain, the pharmacological profiles of these receptors appeared to be very similar and it was demonstrated that these receptors mediate melanocortin-induced pigmentation and grooming respectively. Grooming is a low priority behavior that is concerned with care of body surface. Activation of central melanocortin MC4 receptors is also associated with meal termination, and continued postprandial stimulation of melanocortin MC4 receptors may stimulate natural postprandial grooming behavior as part of the behavioral satiety sequence. Indeed, melanocortins fail to suppress food intake or induce grooming behavior in melanocortin MC4 receptor-deficient rats. This review will focus on how melanocortins affect grooming behavior through the melanocortin MC4 receptor, and how melanocortin MC4 receptors mediate feeding behavior. This review also illustrates how melanocortins were the most likely candidates to mediate grooming and feeding based on the natural behaviors they induced.
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Affiliation(s)
- Joram D Mul
- Metabolic Diseases Institute, University of Cincinnati, 2170 East Galbraith Road, 45237 Cincinnati, Ohio, USA.
| | - Berry M Spruijt
- Department of Biology, Faculty of Beta Sciences, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Jan H Brakkee
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
| | - Roger A H Adan
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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Acute behavioural effects of bupropion and naltrexone, alone and in combination, in non-deprived male rats presented with palatable mash. Psychopharmacology (Berl) 2013; 228:291-307. [PMID: 23455599 DOI: 10.1007/s00213-013-3036-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 02/11/2013] [Indexed: 01/28/2023]
Abstract
RATIONALE In appetite research, drugs frequently progress to clinical trials on the basis of outcome (reduced food intake/body weight gain) with insufficient attention to process (behavioural analysis). Although bupropion and naltrexone (alone and in combination) reduce food consumption in rodents and humans, their effects on behaviour during feeding tests have not been thoroughly investigated. OBJECTIVES This study aimed to assess the behavioural specificity of anorectic responses to bupropion, naltrexone and their combination. METHODS Video analysis was employed to characterise the behavioural effects of acute systemic treatment with bupropion (10.0-40.0 mg/kg), naltrexone (0.1-3.0 mg/kg) and combined bupropion (20 mg/kg) plus naltrexone (0.1-1.0 mg/kg) in non-deprived male rats exposed for 1 h to palatable mash. Particular attention was paid to the behavioural satiety sequence (BSS). RESULTS In experiment 1, the anorectic response to 40 mg/kg bupropion was associated with significant psychomotor stimulation and a complete disruption of the BSS. In experiment 2, the anorectic response to 3 mg/kg naltrexone was associated with an accelerated but otherwise normal BSS. In experiment 3, the co-administration of 20 mg/kg bupropion and naltrexone (0.1 and 1.0 mg/kg) not only produced an additive anorectic profile (including a reduced rate of eating), but the addition of the opioid receptor antagonist also concurrently attenuated the psychomotor stimulant response to the atypical antidepressant. CONCLUSIONS Low-dose co-treatment with naltrexone and bupropion produces a stronger suppression of appetite than that seen with either agent alone and has the additional advantage of reducing some of the unwanted effects of bupropion.
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Wright TM, Fone KC, Langley‐Evans SC, Voigt JW. Exposure to maternal consumption of cafeteria diet during the lactation period programmes feeding behaviour in the rat. Int J Dev Neurosci 2011; 29:785-93. [DOI: 10.1016/j.ijdevneu.2011.09.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 09/29/2011] [Accepted: 09/30/2011] [Indexed: 12/19/2022] Open
Affiliation(s)
- Thomas M. Wright
- School of Veterinary Medicine and ScienceUniversity of NottinghamSuttonBoningtonLoughboroughLE12 5RDUnited Kingdom
| | - Kevin C.F. Fone
- School of Biomedical SciencesQueen's Medical CentreUniversity of Nottingham, SuttonBoningtonLoughboroughLE12 5RDUnited Kingdom
| | - Simon C. Langley‐Evans
- School of BiosciencesUniversity of Nottingham, SuttonBoningtonLoughboroughLE12 5RDUnited Kingdom
| | - Jörg‐Peter W. Voigt
- School of Veterinary Medicine and ScienceUniversity of NottinghamSuttonBoningtonLoughboroughLE12 5RDUnited Kingdom
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Oliveira LDS, Souza SLD, Manhães-De-Castro R. Behavioral satiety sequence: an experimental model for studying feeding behavior. REV NUTR 2011. [DOI: 10.1590/s1415-52732011000400010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Feeding behavior is controlled by interactions between psychobiological and physiological systems. In rats, there is a sequence in the feeding behavior that is characterized by similar movements at the beginning and end of a meal, known as the behavioral satiety sequence. In the sequence, eating is followed by grooming and other activities, and ends with resting. The objective of this systematic review is to evaluate the use of the behavioral satiety sequence as an experimental model for the study of feeding behavior. A systematic search of the electronic databases MedLine, Lilacs, SciELO, Cochrane Library and PubMed was done from November 2007 to January 2008, using combinations of the keywords "behavioral," "satiety" and "sequence". Ninety articles were found and, of these, fifteen articles were selected for the review. The studies demonstrated the efficacy of using behavioral satiety sequence to evaluate the effects of some types of manipulations on feeding behavior. With this study method it was also possible to observe different factors that can interfere with feeding behavior, such as sedation, malaise or intake inhibition, by increasing satiety. Behavioral satiety sequence offers solid tools for gaining a better understanding of how treatment can influence feeding behavior.
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Pulman K, Somerville E, Clifton P. Intra-accumbens baclofen, but not muscimol, mimics the effects of food withdrawal on feeding behaviour. Pharmacol Biochem Behav 2010; 97:156-62. [DOI: 10.1016/j.pbb.2010.05.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Revised: 04/16/2010] [Accepted: 05/29/2010] [Indexed: 11/24/2022]
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Behavioural satiety sequence (BSS): Separating wheat from chaff in the behavioural pharmacology of appetite. Pharmacol Biochem Behav 2010; 97:3-14. [DOI: 10.1016/j.pbb.2010.03.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 02/15/2010] [Accepted: 03/02/2010] [Indexed: 11/18/2022]
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Tallett AJ, Blundell JE, Rodgers RJ. Effects of acute low-dose combined treatment with rimonabant and sibutramine on appetite and weight gain in rats. Pharmacol Biochem Behav 2009; 97:92-100. [PMID: 20026165 DOI: 10.1016/j.pbb.2009.12.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 10/16/2009] [Accepted: 12/14/2009] [Indexed: 12/13/2022]
Abstract
In view of its potential advantages, drug polytherapy is currently attracting significant interest in the field of obesity research. In this context, concurrent manipulation of serotonergic and cannabinoid pathways in rodents has been found to reduce food and fluid intake in both an additive or synergistic manner. To further assess the value of this polytherapeutic approach, the current study examined the acute effects of low-dose combinations of the cannabinoid CB1 receptor antagonist/inverse agonist rimonabant (0.5 mg/kg) and the dual serotonin- and noradrenaline-reuptake inhibitor sibutramine (0.125 and 0.25 mg/kg) in male rats. Ethological analysis was used to generate comprehensive behavioural profiles, including the behavioural satiety sequence (BSS). Findings confirmed that, although neither drug given alone significantly altered food intake, feeding behaviour or weight gain, rimonabant per se tended to reduce consumption and time spent feeding while significantly increasing scratching and grooming responses. However, none of these effects of the CB1 receptor antagonist/inverse agonist was significantly altered by the presence of either dose of sibutramine. In striking contrast to recent reports of acute low-dose interactions (enhanced appetite suppression and reduced side-effects) between rimonabant and naloxone, present results would not appear to support the clinical potential of rimonabant/sibutramine polytherapy for obesity.
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Affiliation(s)
- A J Tallett
- Institute of Psychological Sciences, University of Leeds, Leeds, UK
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Dose–response effects of PEGylated cholecystokinin on the behavioral satiety sequence. Physiol Behav 2009; 98:198-204. [DOI: 10.1016/j.physbeh.2009.05.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 04/02/2009] [Accepted: 05/19/2009] [Indexed: 11/21/2022]
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Disruption of the behavioral satiety sequence by simmondsin. Appetite 2009; 52:703-710. [DOI: 10.1016/j.appet.2009.03.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 01/15/2009] [Accepted: 03/19/2009] [Indexed: 11/19/2022]
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Night and day: diurnal differences in the behavioural satiety sequence in male rats. Physiol Behav 2009; 97:125-30. [PMID: 19419667 DOI: 10.1016/j.physbeh.2009.01.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 01/20/2009] [Accepted: 01/27/2009] [Indexed: 11/20/2022]
Abstract
The behavioural satiety sequence (BSS) is an important method for assessing the selectivity of treatment (physiological, pharmacological and/or genetic) effects on food intake in rodents. The concept describes the natural progression from feeding to resting, with the transition between the two a useful biomarker of behavioural satiety. Although treatments can accelerate (anorexigenics) or delay (orexigenics) this transition without disrupting behavioural structure, the detection of such changes depends upon the timing of the transition under control conditions. Fasting and presatiation are known to affect this timing. However, recent observations in our laboratory have suggested that phase of testing (light or dark) might also be an important consideration. The present study therefore directly compared food intake and the BSS in thoroughly habituated male rats maintained either on a normal light cycle and tested during the light phase or on a reversed light cycle and tested during the dark phase. The results show that phase of testing had relatively little impact on food intake or diverse measures of ingestive and non-ingestive behaviour. Although modest differences were detected in locomotion, grooming and scratching (higher in dark phase), by far the largest difference concerned resting behaviour which had both a later onset and a much lower peak level during dark phase testing. Importantly, these behavioural differences delayed the transition between eating and resting. The potential contribution of diurnal differences in rate of eating is discussed as are the implications of these findings for future studies on the neurobiology of feeding behaviour.
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Tallett A, Blundell J, Rodgers R. Effects of acute low-dose combined treatment with naloxone and AM 251 on food intake, feeding behaviour and weight gain in rats. Pharmacol Biochem Behav 2009; 91:358-66. [DOI: 10.1016/j.pbb.2008.08.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 08/04/2008] [Accepted: 08/06/2008] [Indexed: 01/08/2023]
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21
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A robust automated system elucidates mouse home cage behavioral structure. Proc Natl Acad Sci U S A 2008; 105:20575-82. [PMID: 19106295 DOI: 10.1073/pnas.0809053106] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Patterns of behavior exhibited by mice in their home cages reflect the function and interaction of numerous behavioral and physiological systems. Detailed assessment of these patterns thus has the potential to provide a powerful tool for understanding basic aspects of behavioral regulation and their perturbation by disease processes. However, the capacity to identify and examine these patterns in terms of their discrete levels of organization across diverse behaviors has been difficult to achieve and automate. Here, we describe an automated approach for the quantitative characterization of fundamental behavioral elements and their patterns in the freely behaving mouse. We demonstrate the utility of this approach by identifying unique features of home cage behavioral structure and changes in distinct levels of behavioral organization in mice with single gene mutations altering energy balance. The robust, automated, reproducible quantification of mouse home cage behavioral structure detailed here should have wide applicability for the study of mammalian physiology, behavior, and disease.
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Mice overexpressing the 5-hydroxytryptamine transporter show no alterations in feeding behaviour and increased non-feeding responses to fenfluramine. Psychopharmacology (Berl) 2008; 200:291-300. [PMID: 18560807 DOI: 10.1007/s00213-008-1206-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Accepted: 05/14/2008] [Indexed: 11/26/2022]
Abstract
RATIONALE The 5-HT transporter (5-HTT) is implicated in the regulation of appetite. Expression of the 5-HTT varies in the human population, and this variation may determine both individual differences in feeding and abnormal feeding behaviours such as eating disorders. OBJECTIVES The effects of 5-HTT expression on feeding and satiety were examined in a transgenic mouse model of 5-HTT overexpression. MATERIALS AND METHODS We measured free-feeding food intake and observed the behavioural satiety sequence (BSS) after food deprivation in mice at baseline and after administration of the anorectic drug fenfluramine. RESULTS 5-HTT overexpressing mice were both lighter and shorter than their wildtype littermates. Despite this size difference, food intake by transgenic and wildtype mice did not differ. There was no effect of genotype on the BSS or on food intake during the test at baseline. Increasing doses of fenfluramine reduced food intake in a similar manner in both transgenic and wildtype mice. After 0.3 and 1 mg/kg fenfluramine, the temporal pattern of the BSS was the same for both groups, whereas 3 and 10 mg/kg fenfluramine disrupted the BSS. In transgenic mice, this disruption was evident at the 3 mg/kg dose, while in wildtypes, it emerged only at the 10-mg/kg dose. CONCLUSION These data suggest that overexpression of the 5-HTT does not lead to alterations in feeding or satiety in food-deprived mice but does increase the occurrence of other non-feeding behaviours in response to the 5-HT releasing agent fenfluramine.
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Tallett AJ, Blundell JE, Rodgers RJ. Endogenous opioids and cannabinoids: system interactions in the regulation of appetite, grooming and scratching. Physiol Behav 2008; 94:422-31. [PMID: 18394662 DOI: 10.1016/j.physbeh.2008.02.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 02/15/2008] [Accepted: 02/21/2008] [Indexed: 11/28/2022]
Abstract
Growing evidence suggests substantial crosstalk between endogenous opioid and cannabinoid systems in the regulation of appetite. Not only is cannabinoid-induced hyperphagia abolished by opioid receptor antagonists (and vice versa), but several laboratories have reported supra-additive anorectic responses following co-administration of opioid and CB1 receptor antagonists. In the present study, videoanalysis has been used to characterise the acute effects of sub-anorectic doses of rimonabant (0.25, 0.75 mg/kg) and naloxone (0.1 mg/kg), alone and in combination, on mash intake, ingestive and non-ingestive behaviour, and post-treatment weight gain in male rats. The results confirmed that, when administered alone, none of these treatments significantly altered mash consumption, various measures of feeding behaviour, or weight gain. Although most non-ingestive behaviours were also unaffected, 0.75 mg/kg rimonabant induced compulsive scratching and grooming. However, when naloxone was given in combination with either dose of rimonabant, both food intake and time spent feeding were significantly decreased while the behavioural satiety sequence (BSS) was accelerated. On further analysis, the co-treatment reductions in food intake and feeding behaviour were found to be of an additive rather than supra-additive nature. Intriguingly, the co-administration of naloxone also virtually abolished the compulsive scratching response to the higher dose of rimonabant. Findings are discussed in relation to current views on the molecular bases of opioid-cannabinoid system interactions and the unexpected 'dual' advantage (reduction in appetite plus attenuation of side-effect) of low-dose combinations of opioid and cannabinoid CB1 receptor antagonists.
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Affiliation(s)
- A J Tallett
- Behavioural Neuroscience Laboratory, Institute of Psychological Sciences, University of Leeds, Leeds LS29JT, UK
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Tallett AJ, Blundell JE, Rodgers RJ. Grooming, scratching and feeding: role of response competition in acute anorectic response to rimonabant in male rats. Psychopharmacology (Berl) 2007; 195:27-39. [PMID: 17639351 DOI: 10.1007/s00213-007-0880-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Accepted: 06/24/2007] [Indexed: 10/23/2022]
Abstract
RATIONALE Although the CB1 receptor antagonist/inverse agonist rimonabant acutely suppresses food intake in rodents, the behavioural specificity of this effect remains unclear. OBJECTIVES To profile the behavioural effects of rimonabant in a free-feeding context. MATERIALS AND METHODS Videoanalysis was employed to characterise the effects of acute rimonabant (1.5 and 3.0 mg/kg, IP) on the behaviour of non-deprived male rats exposed to palatable mash. Data were also collected on post-treatment weight gain, and, as prolonged appetite suppression has been found after single dosing with compounds of this series, rats were reassessed (drug-free) for food intake 7 days after initial testing. RESULTS Both doses of rimonabant not only decreased mash consumption (44-55%) but also reduced 24-h weight gain. Although videoanalysis confirmed the inhibitory effects of rimonabant on feeding behaviour, it also revealed concurrent reductions in locomotion, rearing and sniffing as well as substantial (up to tenfold) and dose-dependent increases in grooming and scratching. Timecourse analyses further revealed that rimonabant dose-dependently induced frequent episodes of atypical scratching that waned over the test but which were succeeded by prolonged and behaviourally disruptive grooming. Finally, as groups did not differ in mash consumption on retest, any prolonged anorectic effect of acute rimonabant dissipates within 7 days of treatment. CONCLUSIONS The anorectic response to rimonabant in male rats would appear to be due largely to response competition. This parsimonious conclusion is supported by the less profound (although still significant) increases in scratching and grooming observed in rats treated with a sub-anorectic dose (0.5 mg/kg) of the compound.
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Affiliation(s)
- A J Tallett
- Behavioural Neuroscience Laboratory, Institute of Psychological Sciences, University of Leeds, Leeds, UK
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Thornton-Jones ZD, Kennett GA, Vickers SP, Clifton PG. A comparison of the effects of the CB(1) receptor antagonist SR141716A, pre-feeding and changed palatability on the microstructure of ingestive behaviour. Psychopharmacology (Berl) 2007; 193:1-9. [PMID: 17372721 DOI: 10.1007/s00213-007-0745-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Accepted: 02/12/2007] [Indexed: 02/05/2023]
Abstract
RATIONALE The cannabinoid CB(1) receptor inverse agonist SR141716A (rimonabant) is known to cause hypophagia and this study uses microstructural data to elucidate the relevant behavioural mechanisms. OBJECTIVES The aim of these studies was to determine the behavioural changes induced by SR141716A in animals consuming either a fat or carbohydrate solution. These behavioural changes were directly compared with those induced by behavioural manipulations that modify motivational state and palatability. METHODS Male hooded Lister rats drank a highly palatable fat emulsion (10% Intralipid) or a carbohydrate solution (10% sucrose) during 30-min test sessions. Microstructural analyses of licking patterns were made after either administration of SR141716A (0, 0.3, 1 and 3 mg/kg, ip) or one of the after behavioural manipulations: pre-feeding, addition of quinine to the fat solution or changes in sucrose concentration. RESULTS Intake of the fat solution was decreased after both the drug treatment and the behavioural manipulations of pre-feeding and addition of quinine. Pre-feeding and SR141716A-induced reductions were mediated via changes in bout number whereas addition of quinine caused a decrease in bout size. Although sucrose drinking was also decreased by pre-feeding, reduced sucrose concentration and SR141716A, the drug did not significantly alter the microstructure of intake. CONCLUSIONS The effects of SR141716A on consumption of Intralipid solutions are likely to reflect changes in motivational state rather than modified hedonic impact.
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Thornton-Jones ZD, Vickers SP, Clifton PG. The cannabinoid CB1 receptor antagonist SR141716A reduces appetitive and consummatory responses for food. Psychopharmacology (Berl) 2005; 179:452-60. [PMID: 15821957 DOI: 10.1007/s00213-004-2047-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2004] [Accepted: 09/21/2004] [Indexed: 10/26/2022]
Abstract
RATIONALE The CB1 receptor antagonist SR141716A reduces food intake in rats. This effect is likely to depend on modulation of reward related processes. OBJECTIVE To investigate the effects of SR141716A on responding for food under a second order instrumental task in which responding and consumption of food can be separated, and on Pavlovian responding for a stimulus predictive of food reward. METHODS Instrumental responding and pellet consumption following administration of SR141716A (0-3 mg/kg) were recorded under an FI5 min FR5(5:S) operant schedule that incorporates both a 5 min initial appetitive phase and a 25 min consummatory phase. We compared the drug-induced change in responding to that recorded following a reduction in motivational state induced by pre-feeding. In a second experiment we assessed the effects of SR141716A (0-3 mg/kg) on Pavlovian approach behaviour for a stimulus (lever) associated with food reward (CS+) and a neutral stimulus (lever) not associated with reward (CS-). RESULTS SR141716A reduced pellet consumption and instrumental responding during both the appetitive and consummatory phases of the second order schedule. Pre-feeding had a similar effect on responding during the appetitive phase, suggesting an effect on incentive motivation. SR141716A also blocked an enhancement of responding that occurred during the consummatory phase in pre-fed animals. SR141716A and pre-feeding had no effect on responding in the Pavlovian autoshaping paradigm. CONCLUSIONS SR141716A impacts on motivational processes in both the appetitive and consummatory phases of feeding behaviour.
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Affiliation(s)
- Zoë D Thornton-Jones
- Department of Psychology, John Maynard-Smith Building, University of Sussex, Brighton, Sussex, BN1 9QG, UK
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Ishii Y, Blundell JE, Halford JCG, Upton N, Porter R, Johns A, Rodgers RJ. Satiety enhancement by selective orexin-1 receptor antagonist SB-334867: influence of test context and profile comparison with CCK-8S. Behav Brain Res 2004; 160:11-24. [PMID: 15836896 DOI: 10.1016/j.bbr.2004.11.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2004] [Revised: 11/05/2004] [Accepted: 11/11/2004] [Indexed: 11/29/2022]
Abstract
Acute systemic treatment with the selective orexin-1 (OX1R) antagonist SB-334867 reduces food intake in rats, an effect associated with an acceleration in behavioural satiety and unrelated to gross behavioural disruption, alterations in palatability, or toxicity. However, as enhanced satiety is behaviourally indexed by an earlier-than-normal transition from eating to resting, and since orexin-A has been implicated in mechanisms of arousal, it remains possible that sedation contributes to the anorectic effect of acute OX1R blockade. Previous work has shown that, when treated with SB-334867 (30 mg/kg, i.p.) 30 min before a 1h test with palatable food, rats begin to show appreciable levels of resting 10-15 min earlier than under control conditions (i.e. around 20 min versus 30-35 min into the session). The present results demonstrate that a 20 min increase in the injection-test interval (i.e. 50 min) had no significant impact on the anorectic, behavioural or weight gain effects of SB-334867 in non-deprived male rats. Most importantly, this altered treatment regimen led to a temporal profile of resting virtually identical to that previously observed with the more conventional 30 min injection-test interval. Although parallel studies indicated that the OX1R antagonist accelerated the onset of resting (and suppressed most active behaviours) even in the absence of food, an equianorectic dose of the natural satiety-related signal cholescystokinin octapeptide (CCK-8S; 5 microg/kg, i.p.) also produced very similar behavioural effects regardless of the presence of food. Together with evidence that SB-334867 preserves the structural integrity of natural feeding behaviour, does not induce nausea/illness or alter taste/palatability and fails to influence EEG measures of arousal/sleep, the present findings are consistent with the view that acute OX1R antagonism selectively enhances satiety. However, unlike the immediate short-circuiting of the satiety sequence induced by CCK-8S, the slower response to SB-334867 implies a more indirect mechanism of action.
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Affiliation(s)
- Y Ishii
- Behavioural Neuroscience Laboratory, Institute of Psychological Sciences, University of Leeds, LS2 9JT, UK
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Ishii Y, Blundell JE, Halford JCG, Upton N, Porter R, Johns A, Rodgers RJ. Differential effects of the selective orexin-1 receptor antagonist SB-334867 and lithium chloride on the behavioural satiety sequence in rats. Physiol Behav 2004; 81:129-40. [PMID: 15059692 DOI: 10.1016/j.physbeh.2004.01.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2003] [Revised: 01/06/2004] [Accepted: 01/19/2004] [Indexed: 12/21/2022]
Abstract
Recent studies have shown that acute systemic administration of the selective orexin-1 receptor antagonist SB-334867 significantly reduces food intake in rats. Although this anorectic action of orexin-1 receptor blockade is associated with an acceleration in the transition from eating to resting, it is widely recognised that the behavioural indices of satiety are not dissimilar to those of illness. In this context, Experiment 1 confirmed a significant anorectic effect of 90 (but not 60) mg/kg lithium chloride (LiCl) in male rats presented with palatable mash in the home-cage environment. Experiment 2 employed a continuous monitoring technique to contrast the effects of LiCl (90 mg/kg) and SB-334867 (10 and 30 mg/kg) on food intake and behaviour during a 1-h test with palatable mash. SB-334867 dose-dependently inhibited food intake, with the higher dose producing a comparable degree of appetite suppression (approximately 40%) to that seen with LiCl. Despite equivalent anorectic action, the two compounds produced very different effects on behaviour. LiCl reduced active behaviours (locomotion, rearing, grooming and sniffing), slowed the rate of eating and disrupted the behavioural satiety sequence (BSS). In contrast, SB-334867 (30 mg/kg) decreased the duration of feeding and grooming, and modestly accelerated the transition between eating and resting. Furthermore, whereas LiCl failed to alter posttreatment bodyweight gain, SB-334867 (30 mg/kg) produced a significant weight loss in the 24-h period immediately following injection. Overall, the divergent profiles obtained with equianorectic doses of LiCl and SB-334867 provide convincing evidence for the behavioural selectivity of SB-334867-induced anorexia.
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Affiliation(s)
- Y Ishii
- Behavioural Pharmacology Laboratory, School of Psychology, University of Leeds, Leeds LS2 9JT, UK
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Ishii Y, Blundell JE, Halford JCG, Rodgers RJ. Palatability, food intake and the behavioural satiety sequence in male rats. Physiol Behav 2003; 80:37-47. [PMID: 14568306 DOI: 10.1016/s0031-9384(03)00207-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Food intake is influenced not only by nutritional status but also by diverse environmental factors. Indeed, a unique quality of food reward is its strong modulation by palatability cues, such as taste, with animals generally preferring diets that are sweet and avoiding those that are either bitter or sour. As appetite suppressants (including those currently in development) could alter food intake by modifying taste sensitivity and/or palatability, the aim of the present study was to characterise the influence of taste adulteration on the normal structure of feeding behaviour, i.e., the behavioural satiety sequence (BSS). Adult male rats were initially habituated both to the basic test diet (mash) and the test arena. Following stabilisation of basal intake, a continuous monitoring technique was used to profile behaviour in weekly 1-h sessions during which the animals were presented, in counterbalanced order, with the basic diet (control) or one of four taste-adulterated variants (0.015% quinine, 0.04% quinine, 0.2% saccharin, 0.3% saccharin). Food intake was strongly suppressed by the higher quinine concentration but was not significantly altered by any of the other additives. Behavioural analysis revealed that this anorectic-like response to 0.04% quinine-adulterated food was associated with a significant reduction in the peak feeding response, highly atypical intermittent food sampling/digging and the virtual absence of resting behaviour. Importantly, this pattern of behavioural change is readily distinguishable from those seen in response to other manipulations that reduce intake, including selective anorectics, sedatives and psychostimulants. Despite the lack of significant effect on food intake or the duration of feeding behaviour, dietary adulteration with 0.015% quinine (and, to a lesser degree, 0.3% saccharin) produced some effects on behavioural structure/time course consistent with a mild aversive response, i.e., bouts of midsession food sampling and a delay in the transition from eating to resting. Data are discussed in relation to the specific behavioural signature to quinine-induced anorexia and its potential utility in identifying appetite suppressants that may modify intake via changes in taste sensitivity and/or palatability.
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Affiliation(s)
- Y Ishii
- Behavioural Pharmacology Laboratory, School of Psychology, University of Leeds, LS2 9JT, Leeds, UK
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