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Bradfield LA, Becchi S, Kendig MD. Striatal Acetylcholine and Dopamine Interactions Produce Situation-appropriate Action Selection. Curr Neuropharmacol 2023; 22:CN-EPUB-134437. [PMID: 37702238 PMCID: PMC11097990 DOI: 10.2174/1570159x21666230912093041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/20/2023] [Accepted: 03/29/2023] [Indexed: 09/14/2023] Open
Abstract
Individuals often learn how to perform new actions for particular outcomes against a complex background of existing action-outcome associations. As such, this new knowledge can interfere or even compete with existing knowledge, such that individuals must use internal and external cues to determine which action is appropriate to the current situation. The question thus remains as to how this problem is solved at a neural level. Research over the last decade or so has begun to determine how the brain achieves situation-appropriate action selection. Several converging lines of evidence suggest that it is achieved through the complex interactions of acetylcholine and dopamine within the striatum in a manner that relies on glutamatergic inputs from the cortex and thalamus. Here we briefly review this evidence, then relate it to several very recent findings to provide new, speculative insights regarding the precise nature of striatal acetylcholine/dopamine interaction dynamics and their relation to situation- appropriate action selection.
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Affiliation(s)
- Laura A. Bradfield
- School of Life Sciences, Faculty of Science, University of Technology Sydney, New South Wales 2007, Australia
| | - Serena Becchi
- Decision Neuroscience Laboratory, School of Psychology, University of New South Wales Sydney, Sydney, NSW 2052, Australia
| | - Michael D. Kendig
- School of Life Sciences, Faculty of Science, University of Technology Sydney, New South Wales 2007, Australia
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Gladding JM, Lingawi NW, Leung BK, Kendig MD, Chieng BC, Laurent V. High fat diet allows food-predictive stimuli to energize action performance in the absence of hunger, without distorting insulin signaling on accumbal cholinergic interneurons. Appetite 2023:106769. [PMID: 37399905 DOI: 10.1016/j.appet.2023.106769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/29/2023] [Accepted: 06/30/2023] [Indexed: 07/05/2023]
Abstract
Obesity can disrupt how food-predictive stimuli control action performance and selection. These two forms of control recruit cholinergic interneurons (CIN) located in the nucleus accumbens core (NAcC) and shell (NAcS), respectively. Given that obesity is associated with insulin resistance in this region, we examined whether interfering with CIN insulin signaling disrupts how food-predictive stimuli control actions. To interfere with insulin signaling we used a high-fat diet (HFD) or genetic excision of insulin receptor (InsR) from cholinergic cells. HFD left intact the capacity of food-predictive stimuli to energize performance of an action earning food when mice were tested hungry. However, it allowed this energizing effect to persist when the mice were tested sated. This persistence was linked to NAcC CIN activity but was not associated with distorted CIN insulin signaling. Accordingly, InsR excision had no effect on how food-predicting stimuli control action performance. Next, we found that neither HFD nor InsR excision altered the capacity of food-predictive stimuli to guide action selection. Yet, this capacity was associated with changes in NAcS CIN activity. These results indicate that insulin signaling on accumbal CIN does not modulate how food-predictive stimuli control action performance and selection. However, they show that HFD allows food-predictive stimuli to energize performance of an action earning food in the absence of hunger.
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Affiliation(s)
- Joanne M Gladding
- Decision Neuroscience Laboratory, School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Nura W Lingawi
- Decision Neuroscience Laboratory, School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Beatrice K Leung
- Decision Neuroscience Laboratory, School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Michael D Kendig
- Brain & Behaviour Group, School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Billy C Chieng
- Decision Neuroscience Laboratory, School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Vincent Laurent
- Decision Neuroscience Laboratory, School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia.
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Gladding JM, Bradfield LA, Kendig MD. Diet and obesity effects on cue-driven food-seeking: insights from studies of Pavlovian-instrumental transfer in rodents and humans. Front Behav Neurosci 2023; 17:1199887. [PMID: 37424751 PMCID: PMC10325859 DOI: 10.3389/fnbeh.2023.1199887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 06/06/2023] [Indexed: 07/11/2023] Open
Abstract
Our modern environment is said to be obesogenic, promoting the consumption of calorically dense foods and reducing energy expenditure. One factor thought to drive excess energy intake is the abundance of cues signaling the availability of highly palatable foods. Indeed, these cues exert powerful influences over food-related decision-making. Although obesity is associated with changes to several cognitive domains, the specific role of cues in producing this shift and on decision-making more generally, remains poorly understood. Here we review the literature examining how obesity and palatable diets affect the ability of Pavlovian cues to influence instrumental food-seeking behaviors by examining rodent and human studies incorporating Pavlovian-instrumental transfer (PIT) protocols. There are two types of PIT: (a) general PIT that tests whether cues can energize actions elicited in the pursuit of food generally, and (b) specific PIT which tests whether cues can elicit an action that earns a specific food outcome when faced with a choice. Both types of PIT have been shown to be vulnerable to alterations as a result of changes to diet and obesity. However, effects appear to be driven less by increases in body fat and more by palatable diet exposure per se. We discuss the limitations and implications of the current findings. The challenges for future research are to uncover the mechanisms underlying these alterations to PIT, which appear unrelated to excess weight itself, and to better model the complex determinants of food choice in humans.
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Kendig MD, Leigh S, Hasebe K, Kaakoush NO, Westbrook RF, Morris MJ. Obesogenic Diet Cycling Produces Graded Effects on Cognition and Microbiota Composition in Rats. Mol Nutr Food Res 2023; 67:e2200809. [PMID: 37083181 PMCID: PMC10909530 DOI: 10.1002/mnfr.202200809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 02/20/2023] [Indexed: 04/22/2023]
Abstract
SCOPE The effects of diet cycling on cognition and fecal microbiota are not well understood. METHOD AND RESULTS Adult male Sprague-Dawley rats were cycled between a high-fat, high-sugar "cafeteria" diet (Caf) and regular chow. The impairment in place recognition memory produced by 16 days of Caf diet was reduced by switching to chow for 11 but not 4 days. Next, rats received 16 days of Caf diet in 2, 4, 8, or 16-day cycles, each separated by 4-day chow cycles. Place recognition memory declined from baseline in all groups and was impaired in the 16- versus 2-day group. Finally, rats received 24 days of Caf diet continuously or in 3-day cycles separated by 2- or 4-day chow cycles. Any Caf diet access impaired cognition and increased adiposity relative to controls, without altering hippocampal gene expression. Place recognition and adiposity were the strongest predictors of global microbiota composition. Overall, diets with higher Caf > chow ratios produced greater spatial memory impairments and larger shifts in gut microbiota species richness and beta diversity. CONCLUSION Results suggest that diet-induced cognitive deficits worsen in proportion to unhealthy diet exposure, and that shifting to a healthy chow for at least a week is required for recovery under the conditions tested here.
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Affiliation(s)
- Michael D. Kendig
- School of Medical SciencesUNSW SydneySydneyNSW2052Australia
- School of Life SciencesUniversity of TechnologyUltimoNSW2007Australia
| | - Sarah‐Jane Leigh
- School of Medical SciencesUNSW SydneySydneyNSW2052Australia
- APC MicrobiomeUniversity of CorkCorkT12 K8AFIreland
| | - Kyoko Hasebe
- School of Medical SciencesUNSW SydneySydneyNSW2052Australia
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Kendig MD, Chow JYL, Martire SI, Rooney KB, Boakes RA. Switching from Sugar- to Artificially-Sweetened Beverages: A 12-Week Trial. Nutrients 2023; 15:2191. [PMID: 37432352 DOI: 10.3390/nu15092191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 07/12/2023] Open
Abstract
BACKGROUND Consumption of sugar-sweetened beverages (SSBs) forms the primary source of added sugar intake and can increase the risk of metabolic disease. Evidence from studies in humans and rodents also indicates that consumption of SSBs can impair performance on cognitive tests, but that removing SSB access can ameliorate these effects. METHODS The present study used an unblinded 3-group parallel design to assess the effects of a 12-week intervention in which young healthy adults (mean age = 22.85, SD = 3.89; mean BMI: 23.2, SD = 3.6) who regularly consumed SSBs were instructed to replace SSB intake with artificially-sweetened beverages (n = 28) or water (n = 25), or (c) to continue SSB intake (n = 27). RESULTS No significant group differences were observed in short-term verbal memory on the Logical Memory test or the ratio of waist circumference to height (primary outcomes), nor in secondary measures of effect, impulsivity, adiposity, or glucose tolerance. One notable change was a significant reduction in liking for strong sucrose solutions in participants who switched to water. Switching from SSBs to 'diet' drinks or water had no detectable impact on cognitive or metabolic health over the relatively short time frame studied here. This study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12615001004550; Universal Trial Number: U1111-1170-4543).
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Affiliation(s)
- Michael D Kendig
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Julie Y L Chow
- School of Psychology, UNSW Sydney, Sydney, NSW 2052, Australia
- School of Psychology, University of Sydney, Sydney, NSW 2006, Australia
| | - Sarah I Martire
- School of Psychology, University of Sydney, Sydney, NSW 2006, Australia
| | - Kieron B Rooney
- Discipline of Exercise and Sport Science, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia
| | - Robert A Boakes
- School of Psychology, University of Sydney, Sydney, NSW 2006, Australia
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Kang JWM, Keay KA, Kendig MD, Corbit LH, Mor D. Serotonin and Dopamine Show Different Response Profiles to Acute Stress in the Nucleus Accumbens and Medial Prefrontal Cortex of Rats with Neuropathic Pain. Neurochem Res 2023; 48:2265-2280. [PMID: 36941432 PMCID: PMC10182167 DOI: 10.1007/s11064-023-03906-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 02/23/2023] [Accepted: 03/03/2023] [Indexed: 03/23/2023]
Abstract
The ability to adaptively guide behaviour requires the integration of external information with internal motivational factors. Decision-making capabilities can be impaired by acute stress and is often exacerbated by chronic pain. Chronic neuropathic pain patients often present with cognitive dysfunction, including impaired decision-making. The mechanisms underlying these changes are not well understood but may include altered monoaminergic transmission in the brain. In this study we investigated the relationships between dopamine, serotonin, and their metabolites in key brain regions that regulate motivated behaviour and decision-making. The neurochemical profiles of the medial prefrontal cortex, orbital prefrontal cortex, and nucleus accumbens were analysed using HPLC in rats that received a chronic constriction injury (CCI) of the right sciatic nerve and an acute stress (15-min restraint), prior to an outcome devaluation task. CCI alone significantly decreased dopamine but not serotonin concentrations in the medial prefrontal cortex. By contrast, restraint stress acutely increased dopamine in the medial prefrontal cortex, and the nucleus accumbens; and increased serotonin in the medial prefrontal cortex 2 h later. The sustained dopaminergic and serotonergic responses to acute stress highlight the importance of an animal's ability to mount an effective coping response. In addition, these data suggest that the impact of nerve injury and acute stress on outcome-devaluation occurs independently of dopaminergic and serotonergic transmission in the medial prefrontal cortex, orbital prefrontal cortex and nucleus accumbens of rats.
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Affiliation(s)
- James W M Kang
- School of Medical Sciences [Neuroscience], The University of Sydney, Sydney, NSW, 2006, Australia.
| | - Kevin A Keay
- School of Medical Sciences [Neuroscience], The University of Sydney, Sydney, NSW, 2006, Australia
| | - Michael D Kendig
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Laura H Corbit
- Department of Psychology, The University of Toronto, Toronto, ON, M5S 3G3, Canada
| | - David Mor
- School of Medical Sciences [Neuroscience], The University of Sydney, Sydney, NSW, 2006, Australia
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Kendig MD, Hasebe K, Tajaddini A, Kaakoush NO, Westbrook RF, Morris MJ. The Benefits of Switching to a Healthy Diet on Metabolic, Cognitive, and Gut Microbiome Parameters Are Preserved in Adult Rat Offspring of Mothers Fed a High-Fat, High-Sugar Diet. Mol Nutr Food Res 2023; 67:e2200318. [PMID: 36271770 PMCID: PMC10909468 DOI: 10.1002/mnfr.202200318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 09/05/2022] [Indexed: 01/19/2023]
Abstract
SCOPE Maternal obesity increases the risk of health complications in children, highlighting the need for effective interventions. A rat model of maternal obesity to examine whether a diet switch intervention could reverse the adverse effects of an unhealthy postweaning diet is used. METHODS AND RESULTS Male and female offspring born to dams fed standard chow or a high-fat, high-sugar "cafeteria" (Caf) diet are weaned onto chow or Caf diets until 22 weeks of age, when Caf-fed groups are switched to chow for 5 weeks. Adiposity, gut microbiota composition, and place recognition memory are assessed before and after the switch. Body weight and adiposity fall in switched groups but remain significantly higher than chow-fed controls. Nonetheless, the diet switch improves a deficit in place recognition memory observed in Caf-fed groups, increases gut microbiota species richness, and alters β diversity. Modeling indicate that adiposity most strongly predicts gut microbiota composition before and after the switch. CONCLUSION Maternal obesity does not alter the effects of switching diet on metabolic, microbial, or cognitive measures. Thus, a healthy diet intervention lead to major shifts in body weight, adiposity, place recognition memory, and gut microbiota composition, with beneficial effects preserved in offspring born to obese dams.
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Affiliation(s)
- Michael D. Kendig
- Department of PharmacologySchool of Medical SciencesUNSW SydneyNSW2052Australia
- School of Life SciencesUniversity of Technology SydneyNSW2007Australia
| | - Kyoko Hasebe
- Department of PharmacologySchool of Medical SciencesUNSW SydneyNSW2052Australia
| | - Aynaz Tajaddini
- Department of PharmacologySchool of Medical SciencesUNSW SydneyNSW2052Australia
| | | | | | - Margaret J. Morris
- Department of PharmacologySchool of Medical SciencesUNSW SydneyNSW2052Australia
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Kendig MD, Bradfield LA. Association learning: Dopamine and the formation of backward associations. Curr Biol 2022; 32:R769-R771. [PMID: 35882194 DOI: 10.1016/j.cub.2022.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The activity of dopamine neurons is critical for the ability to learn and update cue-reward associations. New work in rats shows that dopamine transients are also critical for the formation of backward associations in which the reward precedes the neutral stimulus.
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Affiliation(s)
- Michael D Kendig
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Laura A Bradfield
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, Australia.
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Hasebe K, Kendig MD, Kaakoush NO, Tajaddini A, Westbrook RF, Morris MJ. The influence of maternal unhealthy diet on maturation of offspring gut microbiota in rat. Anim Microbiome 2022; 4:31. [PMID: 35551670 PMCID: PMC9102338 DOI: 10.1186/s42523-022-00185-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 04/27/2022] [Indexed: 12/04/2022] Open
Abstract
Background Despite well-known effects of diet on gut microbiota diversity, relatively little is known about how maternal diet quality shapes the longitudinal maturation of gut microbiota in offspring. To investigate, we fed female rats standard chow (Chow) or a western-style, high-choice cafeteria diet (Caf) prior to and during mating, gestation and lactation. At weaning (3 weeks), male and female offspring were either maintained on their mother’s diet (ChowChow, CafCaf groups) or switched to the other diet (ChowCaf, CafChow). Fecal microbial composition was assessed in dams and longitudinally in offspring at 3, 7 and 14 weeks of age. Results The effect of maternal diet on maturation of offspring gut microbiota was assessed by α- and β-diversities, Deseq2/LEfSe, and SourceTracker analyses. Weanling gut microbiota composition was characterised by reduced α- and β-diversity profiles that clustered away from dams and older siblings. After weaning, offspring gut microbiota came to resemble an adult-like gut microbiota, with increased α-diversity and reduced dissimilarity of β-diversity. Similarly, Deseq2/LEfSe analyses found fewer numbers of altered operational taxonomic units (OTUs) between groups from weaning to adulthood. SourceTracker analyses indicated a greater overall contribution of Caf mothers’ microbial community (up to 20%) to that of their offspring than the contribution of Chow mothers (up to 8%). Groups maintained on the maternal diet (ChowChow, CafCaf), versus those switched to the other diet (ChowCaf, CafChow) post-weaning significantly differed from each other at 14 weeks (Permutational Multivariate Analysis of Variance), indicating interactive effects of maternal and post-weaning diet on offspring gut microbiota maturation. Nevertheless, this developmental trajectory was unaffected by sex and appeared consistent between ChowChow, CafCaf, ChowCaf and CafChow groups. Conclusions Introducing solid food at weaning triggered the maturation of offspring gut microbiota to an adult-like profile in rats, in line with previous human studies. Postweaning Caf diet exposure had the largest impact on offspring gut microbiota, but this was modulated by maternal diet history. An unhealthy maternal Caf diet did not alter the developmental trajectory of offspring gut microbiota towards an adult-like profile, insofar as it did not prevent the age-associated increase in α-diversity and reduction in β-diversity dissimilarity. Supplementary Information The online version contains supplementary material available at 10.1186/s42523-022-00185-w.
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Affiliation(s)
- Kyoko Hasebe
- School of Medical Sciences, Faculty of Medicine and Health, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Michael D Kendig
- School of Medical Sciences, Faculty of Medicine and Health, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Nadeem O Kaakoush
- School of Medical Sciences, Faculty of Medicine and Health, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Aynaz Tajaddini
- School of Medical Sciences, Faculty of Medicine and Health, UNSW Sydney, Sydney, NSW, 2052, Australia
| | | | - Margaret J Morris
- School of Medical Sciences, Faculty of Medicine and Health, UNSW Sydney, Sydney, NSW, 2052, Australia.
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Hossain MJ, Kendig MD, Letton ME, Morris MJ, Arnold R. Peripheral Neuropathy Phenotyping in Rat Models of Type 2 Diabetes Mellitus: Evaluating Uptake of the Neurodiab Guidelines and Identifying Future Directions. Diabetes Metab J 2022; 46:198-221. [PMID: 35385634 PMCID: PMC8987683 DOI: 10.4093/dmj.2021.0347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/25/2022] [Indexed: 11/08/2022] Open
Abstract
Diabetic peripheral neuropathy (DPN) affects over half of type 2 diabetes mellitus (T2DM) patients, with an urgent need for effective pharmacotherapies. While many rat and mouse models of T2DM exist, the phenotyping of DPN has been challenging with inconsistencies across laboratories. To better characterize DPN in rodents, a consensus guideline was published in 2014 to accelerate the translation of preclinical findings. Here we review DPN phenotyping in rat models of T2DM against the 'Neurodiab' criteria to identify uptake of the guidelines and discuss how DPN phenotypes differ between models and according to diabetes duration and sex. A search of PubMed, Scopus and Web of Science databases identified 125 studies, categorised as either diet and/or chemically induced models or transgenic/spontaneous models of T2DM. The use of diet and chemically induced T2DM models has exceeded that of transgenic models in recent years, and the introduction of the Neurodiab guidelines has not appreciably increased the number of studies assessing all key DPN endpoints. Combined high-fat diet and low dose streptozotocin rat models are the most frequently used and well characterised. Overall, we recommend adherence to Neurodiab guidelines for creating better animal models of DPN to accelerate translation and drug development.
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Affiliation(s)
- Md Jakir Hossain
- Department of Pharmacology, School of Medical Sciences, University of New South Wales (UNSW) Sydney, Sydney, Australia
| | - Michael D. Kendig
- Department of Pharmacology, School of Medical Sciences, University of New South Wales (UNSW) Sydney, Sydney, Australia
| | - Meg E. Letton
- Department of Exercise Physiology, School of Medical Sciences, University of New South Wales (UNSW) Sydney, Sydney, Australia
| | - Margaret J. Morris
- Department of Pharmacology, School of Medical Sciences, University of New South Wales (UNSW) Sydney, Sydney, Australia
| | - Ria Arnold
- Department of Pharmacology, School of Medical Sciences, University of New South Wales (UNSW) Sydney, Sydney, Australia
- Department of Exercise Physiology, School of Medical Sciences, University of New South Wales (UNSW) Sydney, Sydney, Australia
- Department of Exercise and Rehabilitation, School of Medical, Indigenous and Health Science, University of Wollongong, Wollongong, Australia
- Corresponding author: Ria Arnold https://orcid.org/0000-0002-7469-6587 Department of Exercise Physiology, School of Health Sciences, UNSW Sydney, Sydney, NSW 2052, Australia E-mail:
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Kendig MD, Hasebe K, McCague R, Lee F, Leigh SJ, Arnold R, Morris MJ. Adolescent exposure to a solid high-fat, high-sugar ‘cafeteria’ diet leads to more pronounced changes in metabolic measures and gut microbiome composition than liquid sugar in female rats. Appetite 2022; 172:105973. [DOI: 10.1016/j.appet.2022.105973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 02/08/2022] [Accepted: 02/12/2022] [Indexed: 11/02/2022]
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Tajaddini A, Kendig MD, Prates KV, Westbrook RF, Morris MJ. Male Rat Offspring Are More Impacted by Maternal Obesity Induced by Cafeteria Diet than Females-Additive Effect of Postweaning Diet. Int J Mol Sci 2022; 23:ijms23031442. [PMID: 35163366 PMCID: PMC8835941 DOI: 10.3390/ijms23031442] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/25/2022] [Accepted: 01/26/2022] [Indexed: 01/07/2023] Open
Abstract
Maternal obesity increases the risk of health complications in offspring, but whether these effects are exacerbated by offspring exposure to unhealthy diets warrants further investigation. Female Sprague-Dawley rats were fed either standard chow (n = 15) or ‘cafeteria’ (Caf, n = 21) diets across pre-pregnancy, gestation, and lactation. Male and female offspring were weaned onto chow or Caf diet (2–3/sex/litter), forming four groups; behavioural and metabolic parameters were assessed. At weaning, offspring from Caf dams were smaller and lighter, but had more retroperitoneal (RP) fat, with a larger effect in males. Maternal Caf diet significantly increased relative expression of ACACA and Fasn in male and female weanling liver, but not CPT-1, SREBP and PGC1; PPARα was increased in males from Caf dams. Maternal obesity enhanced the impact of postweaning Caf exposure on adult body weight, RP fat, liver mass, and plasma leptin in males but not females. Offspring from Caf dams appeared to exhibit reduced anxiety-like behaviour on the elevated plus maze. Hepatic CPT-1 expression was reduced only in adult males from Caf fed dams. Post weaning Caf diet consumption did not alter liver gene expression in the adult offspring. Maternal obesity exacerbated the obesogenic phenotype produced by postweaning Caf diet in male, but not female offspring. Thus, the impact of maternal obesity on adiposity and liver gene expression appeared more marked in males. Our data underline the sex-specific detrimental effects of maternal obesity on offspring.
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Affiliation(s)
- Aynaz Tajaddini
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia; (A.T.); (M.D.K.); (K.V.P.)
| | - Michael D. Kendig
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia; (A.T.); (M.D.K.); (K.V.P.)
| | - Kelly V. Prates
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia; (A.T.); (M.D.K.); (K.V.P.)
| | | | - Margaret J. Morris
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia; (A.T.); (M.D.K.); (K.V.P.)
- Correspondence:
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Fam J, Clemens KJ, Westbrook RF, Morris MJ, Kendig MD. Chronic exposure to cafeteria-style diet in rats alters sweet taste preference and reduces motivation for, but not 'liking' of sucrose. Appetite 2022; 168:105742. [PMID: 34634373 DOI: 10.1016/j.appet.2021.105742] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 10/07/2021] [Accepted: 10/07/2021] [Indexed: 12/27/2022]
Abstract
Obesity is associated with changes to taste perception and brain reward circuitry. It is important to understand how these effects alter the preference for palatable foods and drinks, given that these are widely consumed, and leading risk factors for obesity. This study examined the effects of diet-induced obesity on sweet taste preference by analysing the microstructure of licking for sugar solutions and assessing pERK expression in the nucleus accumbens shell and insula. Adult male Sprague-Dawley rats were fed standard chow (Control; n = 16) or a varied, palatable cafeteria diet (Caf; n = 16) for 12 weeks. Two-choice preference tests between 2%, 8% and 32% sucrose solutions were conducted at baseline and in weeks 11-12 of the diet. Rats in the Caf group trebled energy intake and doubled weight gain relative to controls. In tests held under water restriction after 11 weeks of diet, the Control group reliably preferred higher sucrose concentrations (i.e., 32% > 8% > 2%). Relative to controls, the Caf group showed a stronger preference for 32% vs. 2% sucrose, lower preference for 32% vs. 8% sucrose, and were indifferent to 8% vs. 2% sucrose. Testing without water restriction increased preference for higher sucrose concentrations in both groups. Chronic Caf diet increased the latency to lick, decreased total licks and reduced alternations between spouts, but did not alter lick cluster size, a measure of hedonic appraisal, on any test. Following a final exposure to a novel sucrose concentration, neuronal activity (pERK) in the insula and nucleus accumbens shell was significantly reduced in the Caf group. Results indicate that differences in 'liking' do not underlie obesity-induced changes to sweet taste preference.
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Affiliation(s)
- Justine Fam
- School of Psychology, UNSW Sydney, NSW, 2052, Australia
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Kendig MD, Leigh SJ, Morris MJ. Unravelling the impacts of western-style diets on brain, gut microbiota and cognition. Neurosci Biobehav Rev 2021; 128:233-243. [PMID: 34153343 DOI: 10.1016/j.neubiorev.2021.05.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 03/23/2021] [Accepted: 05/24/2021] [Indexed: 02/06/2023]
Abstract
The steady rise in the prevalence of obesity has been fostered by modern environments that reduce energy expenditure and encourage consumption of 'western'-style diets high in fat and sugar. Obesity has been consistently associated with impairments in executive function and episodic memory, while emerging evidence indicates that high-fat, high-sugar diets can impair aspects of cognition within days, even when provided intermittently. Here we review the detrimental effects of diet and obesity on cognition and the role of inflammatory and circulating factors, compromised blood-brain barrier integrity and gut microbiome changes. We next evaluate evidence for changing risk profiles across life stages (adolescence and ageing) and other populations at risk (e.g. through maternal obesity). Finally, interventions to ameliorate diet-induced cognitive deficits are discussed, including dietary shifts, exercise, and the emerging field of microbiome-targeted therapies. With evidence that poor diet and obesity impair cognition via multiple mechanisms across the human lifespan, the challenge for future research is to identify effective interventions, in addition to diet and exercise, to prevent and ameliorate adverse effects.
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15
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Kendig MD, Martire SI, Boakes RA, Rooney KB. Comparable metabolic effects of isocaloric sucrose and glucose solutions in rats. Physiol Behav 2021; 229:113239. [PMID: 33152355 DOI: 10.1016/j.physbeh.2020.113239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/30/2020] [Accepted: 11/01/2020] [Indexed: 10/23/2022]
Abstract
Much of the global increase in sugar intake is attributable to rising consumption of sugar-sweetened beverages (SSBs). Because people compensate poorly for liquid calories, SSB consumption increases total energy intake, raising the risk of harmful metabolic effects in addition to possible effects of sugars per se. Glucose and fructose, the constituent sugars in sucrose, can exert distinct effects on metabolism and also differ in their satiating properties, suggesting that compensation for the calories in these sugars may also vary. In light of claims that the fructose within sucrose is particularly harmful, the present study compared the effects of giving rats access to either a sucrose or an isoenergetic glucose solution. Adult male rats were fed standard chow and water supplemented with 95 ml of 10% glucose (Glucose group; n = 10), 9% sucrose solution (Sucrose group; n = 10) or water only (Control group; n = 10) daily for 7 weeks. Sugar-fed groups had higher total energy intakes than the Control group, but the extent of this incomplete compensation did not vary between Sucrose and Glucose groups. In a short-term compensation test, sugar groups were less sensitive to the effects of a sweet pre-meal, with no differences between the Glucose and Sucrose groups. Relative to water, both sugars reduced insulin sensitivity after 4 weeks on the diets and elevated fat mass at 7 weeks. Results suggest that sucrose and glucose induce comparable metabolic impairments and alter the homeostatic regulation of food intake even under conditions where daily access is capped.
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Affiliation(s)
- Michael D Kendig
- School of Psychology, University of Sydney, NSW, 2006, Australia.
| | - Sarah I Martire
- School of Psychology, University of Sydney, NSW, 2006, Australia.
| | - Robert A Boakes
- School of Psychology, University of Sydney, NSW, 2006, Australia.
| | - Kieron B Rooney
- Faculty of Medicine and Healthy, University of Sydney, NSW, 2006, Australia.
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16
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Hossain MJ, Kendig MD, Wild BM, Issar T, Krishnan AV, Morris MJ, Arnold R. Evidence of Altered Peripheral Nerve Function in a Rodent Model of Diet-Induced Prediabetes. Biomedicines 2020; 8:biomedicines8090313. [PMID: 32872256 PMCID: PMC7555926 DOI: 10.3390/biomedicines8090313] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/26/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022] Open
Abstract
Peripheral neuropathy (PN) is a debilitating complication of diabetes that affects >50% of patients. Recent evidence suggests that obesity and metabolic disease, which often precede diabetes diagnosis, may influence PN onset and severity. We examined this in a translationally relevant model of prediabetes induced by a cafeteria (CAF) diet in Sprague–Dawley rats (n = 15 CAF versus n = 15 control). Neuropathy phenotyping included nerve conduction, tactile sensitivity, intraepidermal nerve fiber density (IENFD) and nerve excitability testing, an in vivo measure of ion channel function and membrane potential. Metabolic phenotyping included body composition, blood glucose and lipids, plasma hormones and inflammatory cytokines. After 13 weeks diet, CAF-fed rats demonstrated prediabetes with significantly elevated fasting blood glucose, insulin and impaired glucose tolerance as well as obesity and dyslipidemia. Nerve conduction, tactile sensitivity and IENFD did not differ; however, superexcitability was significantly increased in CAF-fed rats. Mathematical modeling demonstrated this was consistent with a reduction in sodium–potassium pump current. Moreover, superexcitability correlated positively with insulin resistance and adiposity, and negatively with fasting high-density lipoprotein cholesterol. In conclusion, prediabetic rats over-consuming processed, palatable foods demonstrated altered nerve function that preceded overt PN. This work provides a relevant model for pathophysiological investigation of diabetic complications.
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Affiliation(s)
- Md Jakir Hossain
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Michael D. Kendig
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Brandon M. Wild
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Tushar Issar
- Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW 2052, Australia; (T.I.); (A.V.K.)
| | - Arun V. Krishnan
- Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW 2052, Australia; (T.I.); (A.V.K.)
| | - Margaret J. Morris
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Ria Arnold
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
- Correspondence: ; Tel.: +61-293858709
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17
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Kendig MD, Morris MJ, Samaras K. Mendacity: The Tendency to Lie or Deceive. A Cautionary Tale in Obesity Research, Stigma, and Headlining. Front Endocrinol (Lausanne) 2020; 11:598713. [PMID: 33505356 PMCID: PMC7829183 DOI: 10.3389/fendo.2020.598713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 12/04/2020] [Indexed: 11/15/2022] Open
Affiliation(s)
- Michael D. Kendig
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Margaret J. Morris
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Katherine Samaras
- Diabetes and Metabolism, Healthy Ageing Theme, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
- Department of Endocrinology, St Vincent’s Hospital, Darlinghurst, NSW, Australia
- St Vincent’s Clinical School, St Vincent’s Hospital, Darlinghurst, NSW, Australia
- *Correspondence: Katherine Samaras,
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18
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Leigh SJ, Kendig MD, Morris MJ. Palatable Western-style Cafeteria Diet as a Reliable Method for Modeling Diet-induced Obesity in Rodents. J Vis Exp 2019. [PMID: 31736485 DOI: 10.3791/60262] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Obesity is rapidly increasing in incidence in developed and developing countries and is known to induce or exacerbate many diseases. The health burden of obesity and its comorbid conditions highlight the need for better understanding of its pathogenesis, yet ethical constraints limit studies in humans. To this end externally valid models of obesity in laboratory animals are essential for the understanding of being overweight and obesity. While many species have been used to model the range of changes that accompany obesity in humans, rodents are most commonly used. Our laboratory has developed a western-style cafeteria diet that consistently leads to considerable weight gain and markers of metabolic disease in rodents. The diet exposes rodents to a variety of highly palatable foods to induce hyperphagia, modeling the modern western food environment. This diet rapidly induces weight gain and body fat accumulation in rats allowing for the study of effects of overeating and obesity. While the cafeteria diet may not provide the same control over macronutrient and micronutrient profile as purified high-fat or high-fat, high-sugar diets, the cafeteria diet typically induces a more severe metabolic phenotype than that observed with purified diets and is more in line with metabolic disturbances observed in the overweight and obese human population.
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Affiliation(s)
- Sarah-Jane Leigh
- Department of Pharmacology, School of Medical Sciences, UNSW Sydney
| | - Michael D Kendig
- Department of Pharmacology, School of Medical Sciences, UNSW Sydney
| | - Margaret J Morris
- Department of Pharmacology, School of Medical Sciences, UNSW Sydney;
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Deng F, Li Y, Hossain MJ, Kendig MD, Arnold R, Goldys EM, Morris MJ, Liu G. Polymer brush based fluorescent immunosensor for direct monitoring of interleukin-1β in rat blood. Analyst 2019; 144:5682-5690. [PMID: 31418433 DOI: 10.1039/c9an01300h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A sandwich immunosensor was successfully developed for monitoring of interleukin-1β (IL-1β) in rat whole blood. The substrate stainless steel (SS) was first coated with a polydopamine layer and subsequently grafted with poly(ethylene glycol) methacrylate brushes, onto which a sandwich immunosensor was modified for detection of IL-1β. The device has been successfully applied for monitoring of IL-1β with a limit of detection of 4.7 pg mL-1, and a linear detection range of 12.5-200 pg mL-1. Good specificity and selectivity for monitoring of IL-1β in rat macrophage secretion were achieved. Furthermore, this device was validated by detection of IL-1β in rat whole blood samples with greater concentrations observed in obese rats compared to control, and strong positive correlation between concentrations of IL-1β and blood glucose. These results suggest this device is feasible for direct detection of target analytes in biological samples.
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Affiliation(s)
- Fei Deng
- Graduate School of Biomedical Engineering, ARC Centre of Excellence in Nanoscale Biophotonics, Faculty of Engineering, UNSW Sydney, NSW 2052, Australia. and Australian Centre for NanoMedicine, UNSW Sydney, NSW 2052, Australia
| | - Yi Li
- Graduate School of Biomedical Engineering, ARC Centre of Excellence in Nanoscale Biophotonics, Faculty of Engineering, UNSW Sydney, NSW 2052, Australia. and Australian Centre for NanoMedicine, UNSW Sydney, NSW 2052, Australia
| | | | | | - Ria Arnold
- School of Medical Sciences, UNSW Sydney, NSW 2052, Australia
| | - Ewa M Goldys
- Graduate School of Biomedical Engineering, ARC Centre of Excellence in Nanoscale Biophotonics, Faculty of Engineering, UNSW Sydney, NSW 2052, Australia. and Australian Centre for NanoMedicine, UNSW Sydney, NSW 2052, Australia
| | | | - Guozhen Liu
- Graduate School of Biomedical Engineering, ARC Centre of Excellence in Nanoscale Biophotonics, Faculty of Engineering, UNSW Sydney, NSW 2052, Australia. and Australian Centre for NanoMedicine, UNSW Sydney, NSW 2052, Australia
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Gemikonakli G, Keay KA, Kendig MD, Kang JWM, Corbit LH, Mor D. Altered monoamine levels in the dorsal striatum of the rat are associated with alterations in behavioural selection and motivation following peripheral nerve injury and acute stress. Eur J Neurosci 2019; 50:2786-2800. [PMID: 31325375 DOI: 10.1111/ejn.14518] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 07/05/2019] [Accepted: 07/15/2019] [Indexed: 12/21/2022]
Abstract
Chronic neuropathic pain and psychological stress interact to compromise goal-directed control over behaviour following mild psychological stress. The dorsomedial (DMS) and dorsolateral (DLS) striatum in the rat are crucial for the expression of goal-directed and habitual behaviours, respectively. This study investigated whether changes in monoamine levels in the DMS and DLS following nerve injury and psychological stress reflect these behavioural differences. Neuropathic pain was induced by a chronic constriction injury (CCI) of the sciatic nerve in Sprague-Dawley rats. Acute stress was induced using a 15-min restraint. Behavioural flexibility was assessed using the outcome devaluation paradigm. Noradrenaline, serotonin, dopamine and associated metabolites were measured bilaterally from the DLS and DMS. In uninjured rats, restraint increased dopaminergic markers in the left and serotonergic markers in the right of both the DMS and DLS, indicating a possible left hemisphere-mediated dominance. CCI led to a slightly different lateralised effect, with a larger effect in the DMS than in the DLS. Individual differences in behavioural flexibility following CCI negatively correlated with dopaminergic markers in the right DLS, but positively correlated with these markers in the left DMS. A combination of CCI and restraint reduced behavioural flexibility, which was associated with the loss of the left/DMS dominance. These data suggest that behavioural flexibility following psychological stress or pain is associated with a left hemisphere dominance within the dorsal striatum. The loss of behavioural flexibility following the combined stressors is then associated with a transition from left to right, and DMS to DLS dominance.
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Affiliation(s)
- Gizem Gemikonakli
- Discipline of Anatomy & Histology, School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Kevin A Keay
- Discipline of Anatomy & Histology, School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Michael D Kendig
- School of Psychology, The University of Sydney, Sydney, New South Wales, Australia
| | - James W M Kang
- Discipline of Anatomy & Histology, School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Laura H Corbit
- School of Psychology, The University of Sydney, Sydney, New South Wales, Australia.,Department of Psychology, The University of Toronto, Toronto, Ontario, Canada
| | - David Mor
- Discipline of Anatomy & Histology, School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
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21
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Abstract
BACKGROUND AND OBJECTIVES Consumption of salt exceeds dietary guidelines for many countries around the world, despite efforts to increase awareness of the potential cardiovascular health risks. Emerging evidence, primarily from rodent models, indicates that high salt intake may also impair aspects of cognitive function. To our knowledge, here we provide the first review of the effects of salt on cognition. To review literature on the effects of high-salt diets on cognitive measures across human and non-human animal research to generate targeted questions for future studies. METHODS AND STUDY DESIGN Non-systematic literature review of studies manipulating (in rodents) or measuring (in humans) salt intake and assessing performance on cognitive measures. RESULTS Studies in humans have focused on older populations and show mixed associations between salt intake and cognitive performance. By contrast, most rodent studies have found impairments in cognition following chronic consumption of high-salt (typically 7-8%) diets. Most report impairments in tasks assessing spatial memory with corresponding increases in hippocampal oxidative stress and inflammatory responses originating in the gut. Notably, several rodent studies reported that high-salt diets impaired cognitive function in the absence of blood pressure changes. CONCLUSIONS Contrasting results from human and animal studies emphasise the need for further studies to clarify whether salt intake affects cognition. Testing cognition in high-salt diet models that induce hypertension will increase the translatability of future studies in rodents. A challenge for research in humans is isolating the effects of salt from those of fat and sugar that tend to co-occur in 'western' diets.
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Affiliation(s)
- Michael D Kendig
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Margaret J Morris
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, Australia.
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22
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Boakes RA, Fu MX, Kendig MD, Martire SI, Rooney KB. Recovery from sucrose-induced metabolic and cognitive impairments in male rats. Obes Res Clin Pract 2019. [DOI: 10.1016/j.orcp.2018.11.127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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23
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Kendig MD, Martire SI, Boakes RA, Rooney KB. Metabolic improvement from switching to saccharin or water following chronic consumption by rats of 10% sucrose solution. Obes Res Clin Pract 2019. [DOI: 10.1016/j.orcp.2016.10.244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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24
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Kendig MD, Boakes RA, Corbit LH. Variety overcomes the specificity of cue-potentiated feeding in rats. J Exp Psychol Anim Learn Cogn 2018; 44:56-66. [PMID: 29323518 DOI: 10.1037/xan0000159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cue-potentiated feeding (CPF) describes the stimulation of food consumption by cues that have become associated with food. Determining under what Conditions CPF occurs is important to better understand how exposure to food cues contributes to overeating. CPF is typically found to be specific: cues enhance consumption only of the food they have signaled. Further, previous research has focused largely on discrete cues rather than multimodal cues such as a feeding environment. The present experiments paired a "Plus" context with highly palatable food and a "Minus" context with no food or chow in adult female rats. Experiment 1 confirmed that the Plus context enhanced consumption of the paired food (Froot Loops) but not a different food (banana bread). Experiments 2 and 3 tested whether pairing a variety of foods with the Plus context would overcome this specificity. In Experiment 2 the Plus context either contained bland chow (Chow group), 1 (Single group), or 3 palatable foods (Variety group). The test food, Froot Loops, was familiar but never paired with the Plus context. The Variety group exhibited CPF by eating more Froot Loops in the Plus than in the Minus context, while Single and Chow groups ate equivalently in the 2 contexts. Experiment 3 replicated this effect when the Minus context contained chow during training and when a novel food was tested. These findings have important implications for overeating given that modern food environments are typified by variety and that food consumption often occurs outside the home. (PsycINFO Database Record
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25
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Mor D, Kendig MD, Kang JWM, Gemikonakli G, Austin PJ, Kalman E, Corbit LH. Peripheral nerve injury impairs the ability to maintain behavioural flexibility following acute stress in the rat. Behav Brain Res 2017; 328:123-129. [PMID: 28390879 DOI: 10.1016/j.bbr.2017.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 03/28/2017] [Accepted: 04/01/2017] [Indexed: 12/13/2022]
Abstract
Chronic neuropathic pain often leads to impaired cognition and reduced behavioural flexibility. This study used a rat model to investigate if a peripheral nerve injury, with or without an additional acute psychological stress, alters behavioural flexibility and goal directed behaviour as measured by sensitivity to devaluation. Neuropathic pain was induced by a chronic constriction injury (CCI) of the sciatic nerve. CCI, sham-injury and naïve rats were trained to press two levers for two rewards. In outcome devaluation tests, one of the rewards was devalued by pre-feeding it to satiety, immediately prior to an extinction test measuring responding on the two levers. The ability to preferentially direct responding toward the action earning the currently-valued reward was taken as evidence of goal-directed behaviour. To test the impact of acute stress, rats were subjected to 15min restraint following pre-feeding and prior to the devaluation test. Neither CCI surgery nor acute stress alone altered sensitivity to devaluation, but in combination CCI and acute stress significantly reduced sensitivity to devaluation. This Study demonstrates that relatively mild stressors that are without effect in uninjured populations can markedly impair cognition under conditions of chronic pain. It further suggests that overlapping neural substrates regulated by nerve injury and/or acute stress are having a cumulative effect on behavioural flexibility.
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Affiliation(s)
- David Mor
- Discipline of Biomedical Sciences, School of Medical Sciences, The University of Sydney, NSW 2006, Australia.
| | - Michael D Kendig
- School of Psychology, The University of Sydney, NSW 2006, Australia
| | - James W M Kang
- Discipline of Biomedical Sciences, School of Medical Sciences, The University of Sydney, NSW 2006, Australia
| | - Gizem Gemikonakli
- Discipline of Biomedical Sciences, School of Medical Sciences, The University of Sydney, NSW 2006, Australia
| | - Paul J Austin
- Discipline of Anatomy & Histology, School of Medical Sciences, The University of Sydney, NSW 2006, Australia
| | - Eszter Kalman
- Discipline of Anatomy & Histology, School of Medical Sciences, The University of Sydney, NSW 2006, Australia
| | - Laura H Corbit
- School of Psychology, The University of Sydney, NSW 2006, Australia
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Kendig MD, Cheung AMK, Raymond JS, Corbit LH. Contexts Paired with Junk Food Impair Goal-Directed Behavior in Rats: Implications for Decision Making in Obesogenic Environments. Front Behav Neurosci 2016; 10:216. [PMID: 27877118 PMCID: PMC5099149 DOI: 10.3389/fnbeh.2016.00216] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 10/25/2016] [Indexed: 01/04/2023] Open
Abstract
The high prevalence of obesity and related metabolic diseases calls for greater understanding of the factors that drive excess energy intake. Calorie-dense palatable foods are readily available and often are paired with highly salient environmental cues. These cues can trigger food-seeking and consumption in the absence of hunger. Here we examined the effects of palatable food-paired environmental cues on control of instrumental food-seeking behavior. In Experiment 1, adult male rats received exposures to one context containing three “junk” foods (JFs context) and another containing chow (Chow context). Next, rats were food-deprived and trained to perform instrumental responses (lever-press) for two novel food rewards in a third, distinct context. Contextual influences on flexible control of food-seeking behavior were then assessed by outcome devaluation tests held in the JF, chow and training contexts. Devaluation was achieved using specific satiety and test order was counterbalanced. Rats exhibited goal-directed control over behavior when tested in the training and chow-paired contexts. Notably, performance was habitual (insensitive to devaluation) when tested in the JF context. In Experiment 2 we tested whether the impairment found in the JF context could be ameliorated by the presentation of a discrete auditory cue paired with the chow context, relative to a second cue paired with the JF context. Consistent with the results of Experiment 1, the devaluation effect was not significant when rats were tested in the JF context with the JF cue. However, presenting the chow cue increased the impact of the devaluation treatment leading to a robust devaluation effect. Further tests confirmed that performance in the chow context was goal-directed and that sensory-specific satiety in the JF context was intact. These results show that environments paired with palatable foods can impair goal-directed control over food-seeking behavior, but that this deficit was improved by a cue paired with chow. This has promising implications for assisting individuals in controlling their eating behavior in environments designed to dysregulate it.
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Affiliation(s)
- Michael D Kendig
- School of Psychology, The University of Sydney Sydney, NSW, Australia
| | | | - Joel S Raymond
- School of Psychology, The University of Sydney Sydney, NSW, Australia
| | - Laura H Corbit
- School of Psychology, The University of Sydney Sydney, NSW, Australia
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Boakes RA, Martire SI, Rooney KB, Kendig MD. Individual differences in saccharin acceptance predict rats' food intake. Physiol Behav 2016; 164:151-6. [DOI: 10.1016/j.physbeh.2016.05.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/26/2016] [Accepted: 05/28/2016] [Indexed: 01/05/2023]
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Boakes RA, Kendig MD, Martire SI, Rooney KB. Sweetening yoghurt with glucose, but not with saccharin, promotes weight gain and increased fat pad mass in rats. Appetite 2016; 105:114-28. [PMID: 27189382 DOI: 10.1016/j.appet.2016.05.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 11/16/2022]
Abstract
The claim that non-nutritive sweeteners accelerate body weight gain by disrupting sweet-calorie associations was tested in two experiments using rats. The experiments were modelled on a key study from a series of experiments reporting greater body weight gain in rats fed yoghurt sweetened with saccharin than with glucose (Swithers & Davidson, 2008). Both of the current experiments likewise compared groups fed saccharin- or glucose-sweetened yoghurt in addition to chow and water, while Experiment 1 included a third group (Control) given unsweetened yoghurt. In Experiment 1, but not in Experiment 2, rats were initially exposed to both saccharin- and glucose-sweetened yoghurts to assess their relative palatability. We also tested whether the provision of an energy-dense sweet biscuit would augment any effects of saccharin on food intake and weight gain, as seemingly predicted by Swithers and Davidson (2008). In Experiment 1 there were no differences in body weight gain or fat pad mass between the Saccharin and Control group, whereas the Glucose group was the heaviest by the final 5 weeks and at cull had the largest fat pads. Greater acceptance of saccharin predicted more weight gain over the whole experiment. Consistent with past reports, fasting blood glucose and insulin measures did not differ between the Saccharin and Control groups, but suggested some impairment of insulin sensitivity in the Glucose group. Experiment 2 found similar effects of glucose on fat mass, but not on body weight gain. In summary, adding saccharin had no detectable effects on body-weight regulation, whereas the effects of glucose on fat pad mass were consistent with previous studies reporting more harmful effects of sugars compared to non-nutritive sweeteners.
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Kendig MD, Ekayanti W, Stewart H, Boakes RA, Rooney K. Metabolic Effects of Access to Sucrose Drink in Female Rats and Transmission of Some Effects to Their Offspring. PLoS One 2015; 10:e0131107. [PMID: 26134991 PMCID: PMC4489893 DOI: 10.1371/journal.pone.0131107] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 05/28/2015] [Indexed: 01/18/2023] Open
Abstract
The aims of this study were, first, to examine the metabolic consequences for female rats of having unrestricted access to 10% sucrose solution and, second, to test for effects of this dietary intervention on their offspring. In Stage 1 females were mated following a 4-week period in which one group was given the sucrose in addition to their normal chow and a control group was given chow and water only. Sucrose was removed at parturition and the pups monitored until weaning. Despite the development of glucose intolerance in sucrose-fed mothers, no effects were detected on litter size or pup weights. In Stage 2 voluntary activity of offspring was assessed over postnatal days (PND) 51-60 and their glucose tolerance measured at PND89-94. Again no effect of maternal diet was detected. Only male offspring were used in Stage 3, which began when they were 13 weeks old. Four groups were given 10% sucrose solution for 48 days in a 2 x 2 design, in which one factor was maternal diet and the other was whether they were given 2-h access to an activity wheel on alternate days. Higher fasting glucose levels were found in offspring of sugar-fed mothers. Exercise increased insulin sensitivity in these rats but not in offspring of control mothers. Behavioural measures of memory in Stage 3 did not reveal any effects of maternal diet or exercise. Overall, this study suggested that, while providing 10% sucrose solution ad-libitum was sufficient to impair maternal metabolism, the impact of this dietary manipulation on offspring may be revealed only when the offspring's diet is similarly manipulated.
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Affiliation(s)
- Michael D. Kendig
- School of Psychology (A18), University of Sydney, Sydney, New South Wales 2006, Australia
| | - Winda Ekayanti
- Human Nutrition Unit, School of Molecular Bioscience, Building G08, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Hayden Stewart
- Human Nutrition Unit, School of Molecular Bioscience, Building G08, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Robert A. Boakes
- School of Psychology (A18), University of Sydney, Sydney, New South Wales 2006, Australia
- * E-mail:
| | - Kieron Rooney
- Exercise, Health and Performance, Faculty of Health Sciences (C42), Cumberland Campus, University of Sydney, Lidcombe, New South Wales 2142, Australia
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales 2006, Australia
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Boakes RA, Patterson AE, Kendig MD, Harris JA. Temporal distributions of schedule-induced licks, magazine entries, and lever presses on fixed- and variable-time schedules. J Exp Psychol Anim Learn Cogn 2015; 41:52-68. [PMID: 25706546 DOI: 10.1037/xan0000046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this article, schedule-induced drinking (SID) refers to increased drinking by hungry rats exposed to intermittent delivery of food pellets. Two major accounts of SID differ in their explanation of why such drinking tends be concentrated soon after pellet delivery. Temporal discrimination theories propose that drinking is a form of displacement activity that occurs when a pellet is least likely. Adventitious reinforcement theories propose that drinking is displaced to early in an interpellet interval (IPI) by magazine-directed behavior that occurs toward the end of an IPI. The main aim of this study was to examine the latter response-competition account by recording distributions of both licking and magazine entries as SID developed when pellets were delivered to different groups either on a fixed-time (FT 30 s) or on a variable-time schedule (VT 30 s), as in Experiment 1. Although VT 30-s schedules produced essentially flat distributions of magazine entries, licking still tended to be concentrated early in an IPI. Furthermore, there was no indication (Experiments 1 and 2) that magazine entry distributions developed ahead of licking distributions. Experiment 3 examined distributions of lever presses instead of licks: Initially high rates of lever pressing declined both with response-independent schedules (FT and VT) and when a minimal response-dependency was introduced (recycling conjunctive schedule), yet this response also tended to be most frequent soon after pellet delivery. Overall, the data were generally consistent with temporal conditioning theories.
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Boakes RA, Rooney KB, Kendig MD, Martire SI. Access to glucose-sweetened yoghurt or solution produces enlarged fat pads in the rat. Obes Res Clin Pract 2014. [DOI: 10.1016/j.orcp.2014.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Kendig MD, Ekayanti W, Stewart H, Boakes RA, Rooney KB. Metabolic effects of access to 10% sucrose solution in female rats and transmission of some effects to their offspring. Obes Res Clin Pract 2014. [DOI: 10.1016/j.orcp.2014.10.098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kendig MD, Lin CS, Beilharz JE, Rooney KB, Boakes RA. Maltodextrin can produce similar metabolic and cognitive effects to those of sucrose in the rat☆. Appetite 2014; 77:1-12. [DOI: 10.1016/j.appet.2014.02.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 02/17/2014] [Accepted: 02/19/2014] [Indexed: 01/18/2023]
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Kendig MD. Cognitive and behavioural effects of sugar consumption in rodents. A review. Appetite 2014; 80:41-54. [PMID: 24816323 DOI: 10.1016/j.appet.2014.04.028] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 04/13/2014] [Accepted: 04/30/2014] [Indexed: 12/01/2022]
Abstract
The pronounced global rise in sugar consumption in recent years has been driven largely by increased consumption of sugar-sweetened beverages. Although high sugar intakes are recognised to increase the risk of obesity and related metabolic disturbances, less is known about how sugar might also impair cognition and learned behaviour. This review considers the effects of sugar in rodents on measures of learning and memory, reward processing, anxiety and mood. The parallels between sugar consumption and addictive behaviours are also discussed. The available evidence clearly indicates that sugar consumption can induce cognitive dysfunction. Deficits have been found most consistently on tasks measuring spatial learning and memory. Younger animals appear to be particularly sensitive to the effects of sugar on reward processing, yet results vary according to what reward-related behaviour is assessed. Sugar does not appear to produce long-term effects on anxiety or mood. Importantly, cognitive impairments have been found when intake approximates levels of sugar consumption in people and without changes to weight gain. There remain several caveats when extrapolating from animal models to putative effects of sugar on cognitive function in people. These issues are discussed in conjunction with potential underlying neural mechanisms and directions for future research.
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Affiliation(s)
- Michael D Kendig
- School of Psychology (A18), University of Sydney, Sydney, NSW 2006, Australia.
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Kendig MD, Rooney KB, Corbit LH, Boakes RA. Persisting adiposity following chronic consumption of 10% sucrose solution: Strain differences and behavioural effects. Physiol Behav 2014; 130:54-65. [DOI: 10.1016/j.physbeh.2014.03.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 02/24/2014] [Accepted: 03/13/2014] [Indexed: 11/24/2022]
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Kendig MD, Rooney KB, Corbit LH, Boakes RA. Comparison of the behavioral and metabolic effects of chronic 10% sucrose drink consumption in Albino and Hooded Wistar rats. Obes Res Clin Pract 2013. [DOI: 10.1016/j.orcp.2013.12.698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Motbey CP, Karanges E, Li KM, Wilkinson S, Winstock AR, Ramsay J, Hicks C, Kendig MD, Wyatt N, Callaghan PD, McGregor IS. Mephedrone in adolescent rats: residual memory impairment and acute but not lasting 5-HT depletion. PLoS One 2012; 7:e45473. [PMID: 23029034 PMCID: PMC3445542 DOI: 10.1371/journal.pone.0045473] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 08/17/2012] [Indexed: 11/19/2022] Open
Abstract
Mephedrone (4-methylmethcathinone, MMC) is a popular recreational drug, yet its potential harms are yet to be fully established. The current study examined the impact of single or repeated MMC exposure on various neurochemical and behavioral measures in rats. In Experiment 1 male adolescent Wistar rats received single or repeated (once a day for 10 days) injections of MMC (30 mg/kg) or the comparator drug methamphetamine (METH, 2.5 mg/kg). Both MMC and METH caused robust hyperactivity in the 1 h following injection although this effect did not tend to sensitize with repeated treatment. Striatal dopamine (DA) levels were increased 1 h following either METH or MMC while striatal and hippocampal serotonin (5-HT) levels were decreased 1 h following MMC but not METH. MMC caused greater increases in 5-HT metabolism and greater reductions in DA metabolism in rats that had been previously exposed to MMC. Autoradiographic analysis showed no signs of neuroinflammation ([(125)I]CLINDE ligand used as a marker for translocator protein (TSPO) expression) with repeated exposure to either MMC or METH. In Experiment 2, rats received repeated MMC (7.5, 15 or 30 mg/kg once a day for 10 days) and were examined for residual behavioral effects following treatment. Repeated high (30 mg/kg) dose MMC produced impaired novel object recognition 5 weeks after drug treatment. However, no residual changes in 5-HT or DA tissue levels were observed at 7 weeks post-treatment. Overall these results show that MMC causes acute but not lasting changes in DA and 5-HT tissue concentrations. MMC can also cause long-term memory impairment. Future studies of cognitive function in MMC users are clearly warranted.
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Affiliation(s)
- Craig P. Motbey
- School of Psychology, University of Sydney, New South Wales, Australia
| | - Emily Karanges
- School of Psychology, University of Sydney, New South Wales, Australia
| | - Kong M. Li
- Department of Pharmacology, University of Sydney, New South Wales, Australia
| | - Shane Wilkinson
- School of Chemistry, University of Sydney, New South Wales, Australia
| | - Adam R. Winstock
- Institute of Psychiatry, Kings College, University of London, United Kingdom
| | - John Ramsay
- TICTAC Communications Ltd., St George’s College, University of London, United Kingdom
| | - Callum Hicks
- School of Psychology, University of Sydney, New South Wales, Australia
| | - Michael D. Kendig
- School of Psychology, University of Sydney, New South Wales, Australia
| | - Naomi Wyatt
- Life Sciences Division, Australian Nuclear Science and Technology Organisation, Sydney, New South Wales, Australia
| | - Paul D. Callaghan
- Life Sciences Division, Australian Nuclear Science and Technology Organisation, Sydney, New South Wales, Australia
| | - Iain S. McGregor
- School of Psychology, University of Sydney, New South Wales, Australia
- * E-mail:
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