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Campos-Ordoñez T, Buriticá J. Assessment of the inbred C57BL/6 and outbred CD1 mouse strains using a progressive ratio schedule during development. Physiol Behav 2024; 277:114485. [PMID: 38336087 DOI: 10.1016/j.physbeh.2024.114485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/26/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Inbred strains have a genetic similarity of at least 98.6% compared to their outbred counterparts. Several studies have shown that inbred C57BL/6 mice and outbred ICR (CD1) mice differ in locomotion, cognitive flexibility, and aggression. However, their performance in operant paradigms is not well understood. A progressive ratio (PR) schedule of reinforcement is a method of quantitative estimation of the incentive state of an animal for a reward by increasing response requirements for reinforcer delivery, which is relevant to assess the breakpoint (amount of response effort an animal is willing to invest for a single unit of reward). This study tested male and female C57BL/6 and CD1 mice with an open field to analyze locomotion. Then, we used conditioning chambers with a PR3 schedule for ten consecutive days (P30-P40). PR performance was measured with the breakpoint, and the mathematical principles of reinforcement (MPR) were used to estimate motivation, impulsivity, and motor skills to manipulate the operandum. We found that CD1 mice showed higher locomotor activity than C57BL/6 independently of sex. CD1 mice had a higher breakpoint. However, male CD1 mice gradually increased breakpoint until the last session. In the MPR model, CD1 mice showed decreased fixed paused parameter (impulsivity) than C57BL/6, independent of sex. Our data suggest that the higher breakpoint in CD1 strain may partially be related to impulsivity. Therefore, the MPR model can help identify factors that affect performances, such as motivation, impulsivity, and motor skills during a PR in adolescent CD1 and C57BL/6 mice. These findings are essential to characterize the differences in the behavioral performance between C57BL/6 and CD1 strains and their potential as animal models.
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Affiliation(s)
- Tania Campos-Ordoñez
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias. Universidad de Guadalajara, Jalisco 45200, México.
| | - Jonathan Buriticá
- Laboratorio de Cognición y Aprendizaje Comparado, Centro de Estudios e Investigaciones en Comportamiento, Universidad de Guadalajara, Jalisco 44130, México.
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2
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Alvarez-Sekely CS, Toscano-Zapien AL, Salles-Ize P, Zepeda-Ruiz WA, Lopez-Guzman MA, Velazquez-Martinez DN. Comparison of progressive hold and progressive response schedules of reinforcement. Behav Processes 2023; 205:104822. [PMID: 36669746 DOI: 10.1016/j.beproc.2023.104822] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
Progressive ratio (PR) schedules have been widely used to study motivation to work for a reinforcer. After a post-reinforcer pause, subjects engage in pressing a lever until a reinforcer is obtained. However, the discrete nature of lever presses allows alternative behaviors during inter-response time and has led to several behavioral explanations of pauses and work time. A progressive hold-down (PH) is incompatible with alternative responses and may allow a precise estimation of work time. Performance of rats trained in both PR and PH that received sucrose or intracranial self-stimulation (ICSS) as reinforcer were compared. We observed that rats mastered the PR and PH schedules. Post-reinforcer pauses (PSRP), work time and inter-reinforcer time increased as a function of the response or hold requirement. However, rats' performance suggested that the PH progression may be experienced by the rats as easier that the PR progression. Elimination of consummatory behavior with ICSS reduced post-reinforcer pause in accordance with predictions of explanatory models of fixed and variable schedules of reinforcement. In the case of PH performance, pauses showed little variation across intermediate requirements but increased rapidly on later requirements; since rats controlled their pause length and work time was close to the hold requirement, time allocation between PR and PH schedules diverged. Finally, the Mathematical Principles of Reinforcement model of Bradshaw and Killeen (Psychopharmacology 2012, 222: 549) rendered a good description of the performance in both PR and PH schedules.
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Affiliation(s)
- Celeste Sofia Alvarez-Sekely
- Departamento de Ciencias Cognitivas y del Comportamiento, Facultad de Psicología.Universidad Nacional Autonoma de Mexico, Mexico 04510, Mexico
| | - Ana Laura Toscano-Zapien
- Departamento de Ciencias Cognitivas y del Comportamiento, Facultad de Psicología.Universidad Nacional Autonoma de Mexico, Mexico 04510, Mexico
| | - Paloma Salles-Ize
- Departamento de Ciencias Cognitivas y del Comportamiento, Facultad de Psicología.Universidad Nacional Autonoma de Mexico, Mexico 04510, Mexico
| | - Wendy Andrea Zepeda-Ruiz
- Departamento de Ciencias Cognitivas y del Comportamiento, Facultad de Psicología.Universidad Nacional Autonoma de Mexico, Mexico 04510, Mexico
| | - Maria Almudena Lopez-Guzman
- Departamento de Ciencias Cognitivas y del Comportamiento, Facultad de Psicología.Universidad Nacional Autonoma de Mexico, Mexico 04510, Mexico
| | - David N Velazquez-Martinez
- Departamento de Ciencias Cognitivas y del Comportamiento, Facultad de Psicología.Universidad Nacional Autonoma de Mexico, Mexico 04510, Mexico.
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3
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Binge eating behavior and incentive motivation with a cafeteria diet. Behav Processes 2021; 190:104447. [PMID: 34174369 DOI: 10.1016/j.beproc.2021.104447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/21/2021] [Accepted: 06/19/2021] [Indexed: 11/21/2022]
Abstract
Binge-like eating behavior (BLE) has been characterized as an eating disorder in which subjects have an enhanced intake of food, mainly fats. However, intake of fats and carbohydrates may have differential effects on motivation. Previously it was shown that BLE produces an increase in operant responding for vegetable shortening, but others were unable to replicate the finding using sucrose as the reinforcer. Our aim was to determine if BLE behavior induced with a cafeteria-like diet (CaLD) with several options with fat content would produce an increment in performance. Male Wistar rats were trained under an exponential progressive ratio schedule of sucrose reinforcement; thereafter, the limited access model was used to induce BLE using CaLD options. Finally, subjects were tested for increments in break points (BPs) in the progressive ratio schedule. Rats with intermittent access to CaLD options showed a clear BLE with an escalation in their intake; however they showed compensatory decrements of chow intake that rendered a similar body weight gain to a continuous access group. Although we were unable to observe an increase in BPs after BLE we were able to observe a protection against the decrements of BP previously observed with sugar. Different mechanisms for processing high fat and high carbohydrate reinforcers are variables worth exploring to gain a better understanding of BLE behavior in rodent models.
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Althobaiti YS, Almutairi FM, Alshehri FS, Altowairqi E, Marghalani AM, Alghorabi AA, Alsanie WF, Gaber A, Alsaab HO, Almalki AH, Hakami AY, Alkhalifa T, Almalki AD, Hardy AMG, Shah ZA. Involvement of the dopaminergic system in the reward-related behavior of pregabalin. Sci Rep 2021; 11:10577. [PMID: 34011976 PMCID: PMC8134490 DOI: 10.1038/s41598-021-88429-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 04/08/2021] [Indexed: 01/23/2023] Open
Abstract
There has been an increase in cases of drug addiction and prescription drug abuse worldwide. Recently, pregabalin abuse has been a focus for many healthcare agencies, as highlighted by epidemiological studies. We previously evaluated the possibility of pregabalin abuse using the conditioned place preference (CPP) paradigm. We observed that a 60 mg/kg dose could induce CPP in mice and that pregabalin-rewarding properties were mediated through glutamate neurotransmission. Notably, the dopaminergic reward circuitry is also known to play a crucial role in medication-seeking behavior. Therefore, this study aimed to explore the possible involvement of dopaminergic receptor-1 in pregabalin-induced CPP. Mice were randomly allocated to receive saline or the dopamine-1 receptor antagonist SKF-83566 (0.03 mg/kg, intraperitoneal). After 30 min, the mice received either saline or pregabalin (60 mg/kg) during the conditioning phase. Among the control groups that received saline or SKF-83566, the time spent in the two conditioning chambers was not significantly altered. However, among the pregabalin-treated group, there was a marked increase in the time spent in the drug-paired chamber compared to the time spent in the vehicle-paired chamber. Notably, blocking dopamine-1 receptors with SKF-83566 completely prevented pregabalin-induced place preference, thus demonstrating the engagement of the dopaminergic system in pregabalin-induced reward-related behavior.
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Affiliation(s)
- Yusuf S Althobaiti
- Department of Pharmacology and Toxicology, College of Pharmacy, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia.
- Addiction and Neuroscience Research Unit, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia.
- General Administration for Precursors and Laboratories, General Directorate of Narcotics Control, Ministry of Interior, Riyadh, Saudi Arabia.
| | - Farooq M Almutairi
- Addiction and Neuroscience Research Unit, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
- Deanship of Scientific Research, Taif University, Taif, 21944, Saudi Arabia
- Department of Clinical Laboratories Sciences, University of Hafar Al-Batin, College of Clinical Laboratories Sciences, Hafar Al-Batin, 39923, Saudi Arabia
| | - Fahad S Alshehri
- Department of Pharmacology and Toxicology, College of Pharmacy, Umm Al-Qura University, Makkah, 21955, Saudi Arabia
| | - Ebtehal Altowairqi
- Department of Pharmacology and Toxicology, College of Pharmacy, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
| | - Aliyah M Marghalani
- Addiction and Neuroscience Research Unit, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
| | - Amal A Alghorabi
- Addiction and Neuroscience Research Unit, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
| | - Walaa F Alsanie
- Addiction and Neuroscience Research Unit, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, Taif, 21944, Saudi Arabia
| | - Ahmed Gaber
- Addiction and Neuroscience Research Unit, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
- Department of Biology, Faculty of Science, Taif University, Taif, 21944, Saudi Arabia
| | - Hashem O Alsaab
- Addiction and Neuroscience Research Unit, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
- Department of Pharmaceutics and Pharmaceutical Technology, Taif University, Taif, 21944, Saudi Arabia
| | - Atiah H Almalki
- Addiction and Neuroscience Research Unit, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
- Department of Pharmaceutical Chemistry, College of Pharmacy, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
| | - Alqassem Y Hakami
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
- King Abdullah International Medical Research Center, Jeddah, Saudi Arabia
| | - Turki Alkhalifa
- General Administration for Precursors and Laboratories, General Directorate of Narcotics Control, Ministry of Interior, Riyadh, Saudi Arabia
| | - Ahmad D Almalki
- General Administration for Precursors and Laboratories, General Directorate of Narcotics Control, Ministry of Interior, Riyadh, Saudi Arabia
| | - Ana M G Hardy
- Department of Physiology and Pharmacology, College of Medicine and Life Sciences, University of Toledo, Toledo, OH, USA
| | - Zahoor A Shah
- Department of Medicinal and Biological Chemistry, College of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH, USA
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Zepeda-Ruiz WA, Vazquez-Herrera NV, Velazquez-Martinez DN. Dissociation between binge eating behavior and incentive motivation. Behav Processes 2020; 181:104273. [PMID: 33068639 DOI: 10.1016/j.beproc.2020.104273] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 10/05/2020] [Accepted: 10/05/2020] [Indexed: 12/28/2022]
Abstract
Binge-like eating behavior (BLE) has been characterized as an eating disorder in which subjects have an enhanced intake of food, mainly fats. However, intake of fats and carbohydrates may have differential effects on motivation. Previously it was shown that BLE produces an increase in operant responding for vegetable shortening. Our aim was to determine if BLE behavior induced with a sucrose solution would produce an increment in performance for sucrose reinforcers. Male Wistar rats were trained under an exponential progressive ratio schedule of sucrose reinforcement; thereafter, the limited access model was used to induce BLE. Finally, subjects were tested for increments in break points (BPs) in the progressive ratio schedule. We were unable to observe an increase in BPs after BLE. No increments in BPs were observed when a distinctive flavor (vanilla-flavored sucrose) was correlated with BLE induction and reinforcement, or when different types of ratio progression in the operant schedules were employed. However, rats adjusted their BPs according to reinforcer concentration after BLE induction, demonstrating that valuation (cost/benefit decision) of reinforcers was intact. Extent of training, alterations of reward processing after extended exposure to sucrose, and different mechanisms for processing high fat and high carbohydrate reinforcers are variables worth exploring to gain a better understanding of BLE behavior in rodent models.
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Affiliation(s)
- Wendy Andrea Zepeda-Ruiz
- Departamento de Psicofisiolgía, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, 04369 Mexico
| | - Nayeli Valeria Vazquez-Herrera
- Departamento de Psicofisiolgía, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, 04369 Mexico
| | - David N Velazquez-Martinez
- Departamento de Psicofisiolgía, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, 04369 Mexico.
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6
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Activation of the mGlu 1 metabotropic glutamate receptor has antipsychotic-like effects and is required for efficacy of M 4 muscarinic receptor allosteric modulators. Mol Psychiatry 2020; 25:2786-2799. [PMID: 30116027 PMCID: PMC6588501 DOI: 10.1038/s41380-018-0206-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 06/01/2018] [Accepted: 06/28/2018] [Indexed: 12/25/2022]
Abstract
Recent clinical and preclinical studies suggest that selective activators of the M4 muscarinic acetylcholine receptor have potential as a novel treatment for schizophrenia. M4 activation inhibits striatal dopamine release by mobilizing endocannabinoids, providing a mechanism for local effects on dopamine signaling in the striatum but not in extrastriatal areas. G protein-coupled receptors (GPCRs) typically induce endocannabinoid release through activation of Gαq/11-type G proteins whereas M4 transduction occurs through Gαi/o-type G proteins. We now report that the ability of M4 to inhibit dopamine release and induce antipsychotic-like effects in animal models is dependent on co-activation of the Gαq/11-coupled mGlu1 subtype of metabotropic glutamate (mGlu) receptor. This is especially interesting in light of recent findings that multiple loss of function single nucleotide polymorphisms (SNPs) in the human gene encoding mGlu1 (GRM1) are associated with schizophrenia, and points to GRM1/mGlu1 as a gene within the "druggable genome" that could be targeted for the treatment of schizophrenia. Herein, we report that potentiation of mGlu1 signaling following thalamo-striatal stimulation is sufficient to inhibit striatal dopamine release, and that a novel mGlu1 positive allosteric modulator (PAM) exerts robust antipsychotic-like effects through an endocannabinoid-dependent mechanism. However, unlike M4, mGlu1 does not directly inhibit dopamine D1 receptor signaling and does not reduce motivational responding. Taken together, these findings highlight a novel mechanism of cross talk between mGlu1 and M4 and demonstrate that highly selective mGlu1 PAMs may provide a novel strategy for the treatment of positive symptoms associated with schizophrenia.
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7
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Bruce JAM, Jackson SMK, Bizo LA, McEwan JAS, Foster TM. Reinforcer quality matters: A test of the Mathematical Principles of Reinforcement with domestic hens (Gallus gallus domesticus). J Exp Anal Behav 2019; 112:88-96. [PMID: 31250443 DOI: 10.1002/jeab.538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 06/17/2019] [Indexed: 11/09/2022]
Abstract
This study evaluated the ability of Killeen's (1994) Mathematical Principles of Reinforcement to account for the effects of changes in reinforcer quality on hens' rates of responding on fixed-ratio schedules. Hens were trained to peck a key on a fixed-ratio schedule of reinforcement and then experienced an ascending series of ratio values in two separate conditions. In different conditions, the food reinforcer was either wheat or puffed wheat. Response rates initially increased with increases in ratio requirement before eventually decreasing at larger ratios. Quantitative fits of the model accounted for the data well. The fits revealed that different foods were systematically associated with changes in the specific activation parameter, a, and these were consistent with previous reports of preference for those food items.
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Affiliation(s)
| | | | - Lewis A Bizo
- The University of Waikato.,University of New England
| | | | - T Mary Foster
- The University of Waikato.,University of New England
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8
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Hailwood JM, Heath CJ, Phillips BU, Robbins TW, Saksida LM, Bussey TJ. Blockade of muscarinic acetylcholine receptors facilitates motivated behaviour and rescues a model of antipsychotic-induced amotivation. Neuropsychopharmacology 2019; 44:1068-1075. [PMID: 30478410 PMCID: PMC6397643 DOI: 10.1038/s41386-018-0281-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/02/2018] [Accepted: 11/17/2018] [Indexed: 02/07/2023]
Abstract
Disruptions to motivated behaviour are a highly prevalent and severe symptom in a number of neuropsychiatric and neurodegenerative disorders. Current treatment options for these disorders have little or no effect upon motivational impairments. We assessed the contribution of muscarinic acetylcholine receptors to motivated behaviour in mice, as a novel pharmacological target for motivational impairments. Touchscreen progressive ratio (PR) performance was facilitated by the nonselective muscarinic receptor antagonist scopolamine as well as the more subtype-selective antagonists biperiden (M1) and tropicamide (M4). However, scopolamine and tropicamide also produced increases in non-specific activity levels, whereas biperiden did not. A series of control tests suggests the effects of the mAChR antagonists were sensitive to changes in reward value and not driven by changes in satiety, motor fatigue, appetite or perseveration. Subsequently, a sub-effective dose of biperiden was able to facilitate the effects of amphetamine upon PR performance, suggesting an ability to enhance dopaminergic function. Both biperiden and scopolamine were also able to reverse a haloperidol-induced deficit in PR performance, however only biperiden was able to rescue the deficit in effort-related choice (ERC) performance. Taken together, these data suggest that the M1 mAChR may be a novel target for the pharmacological enhancement of effort exertion and consequent rescue of motivational impairments. Conversely, M4 receptors may inadvertently modulate effort exertion through regulation of general locomotor activity levels.
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Affiliation(s)
- Jonathan M. Hailwood
- 0000000121885934grid.5335.0Department of Psychology and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB UK
| | - Christopher J. Heath
- 0000000096069301grid.10837.3dSchool of Life, Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA UK
| | - Benjamin U. Phillips
- 0000000121885934grid.5335.0Department of Psychology and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB UK
| | - Trevor W. Robbins
- 0000000121885934grid.5335.0Department of Psychology and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB UK
| | - Lisa M. Saksida
- 0000 0004 1936 8884grid.39381.30Molecular Medicine Research Group, Robarts Research Institute & Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, ON Canada ,0000 0004 1936 8884grid.39381.30The Brain and Mind Institute, Western University, London, ON Canada
| | - Timothy J. Bussey
- 0000000121885934grid.5335.0Department of Psychology and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Downing Street, Cambridge, CB2 3EB UK ,0000 0004 1936 8884grid.39381.30Molecular Medicine Research Group, Robarts Research Institute & Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, ON Canada ,0000 0004 1936 8884grid.39381.30The Brain and Mind Institute, Western University, London, ON Canada
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9
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Valencia-Torres L, Olarte-Sánchez CM, Lyons DJ, Georgescu T, Greenwald-Yarnell M, Myers MG, Bradshaw CM, Heisler LK. Activation of Ventral Tegmental Area 5-HT 2C Receptors Reduces Incentive Motivation. Neuropsychopharmacology 2017; 42:1511-1521. [PMID: 27882999 PMCID: PMC5362069 DOI: 10.1038/npp.2016.264] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/01/2016] [Accepted: 11/16/2016] [Indexed: 11/20/2022]
Abstract
Obesity is primarily due to food intake in excess of the body's energetic requirements, intake that is not only associated with hunger but also the incentive value of food. The 5-hydroxytryptamine 2C receptor (5-HT2CR) is a target for the treatment of human obesity. Mechanistically, 5-HT2CRs are positioned to influence both homeostatic feeding circuits within the hypothalamus and reward circuits within the ventral tegmental area (VTA). Here we investigated the role of 5-HT2CRs in incentive motivation using a mathematical model of progressive ratio (PR) responding in mice. We found that the 5-HT2CR agonist lorcaserin significantly reduced both ad libitum chow intake and PR responding for chocolate pellets and increased c-fos expression in VTA 5-HT2CR expressing γ-aminobutyric acid (GABA) neurons, but not 5-HT2CR expressing dopamine (DA) neurons. We next adopted a chemogenetic approach using a 5-HT2CRCRE line to clarify the function of subset of 5-HT2C receptor expressing VTA neurons in the modulation of appetite and food-motivated behavior. Activation of VTA 5-HT2C receptor expressing neurons significantly reduced ad libitum chow intake, operant responding for chocolate pellets, and the incentive value of food. In contrast, chemogenetic inhibition of VTA 5-HT2C receptor expressing neurons had no effect on the feeding behavior. These results indicate that activation of the subpopulation of 5-HT2CR neurons within the VTA is sufficient to significantly reduce homeostatic feeding and effort-based intake of palatable food, and that this subset has an inhibitory role in motivational processes. These findings are relevant to the treatment of obesity.
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Affiliation(s)
- Lourdes Valencia-Torres
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK,Rowett Institute of Nutrition and Health, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK, Tel/Fax: +44 (0) 1224 438750, E-mail: or
| | | | - David J Lyons
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK
| | - Teodora Georgescu
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK
| | - Megan Greenwald-Yarnell
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Martin G Myers
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Christopher M Bradshaw
- Division of Psychiatry, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Lora K Heisler
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK,Rowett Institute of Nutrition and Health, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK, Tel/Fax: +44 (0) 1224 438750, E-mail: or
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10
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Bailey MR, Simpson EH, Balsam PD. Neural substrates underlying effort, time, and risk-based decision making in motivated behavior. Neurobiol Learn Mem 2016; 133:233-256. [PMID: 27427327 PMCID: PMC5007005 DOI: 10.1016/j.nlm.2016.07.015] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 07/11/2016] [Accepted: 07/12/2016] [Indexed: 11/16/2022]
Abstract
All mobile organisms rely on adaptive motivated behavior to overcome the challenges of living in an environment in which essential resources may be limited. A variety of influences ranging from an organism's environment, experiential history, and physiological state all influence a cost-benefit analysis which allows motivation to energize behavior and direct it toward specific goals. Here we review the substantial amount of research aimed at discovering the interconnected neural circuits which allow organisms to carry-out the cost-benefit computations which allow them to behave in adaptive ways. We specifically focus on how the brain deals with different types of costs, including effort requirements, delays to reward and payoff riskiness. An examination of this broad literature highlights the importance of the extended neural circuits which enable organisms to make decisions about these different types of costs. This involves Cortical Structures, including the Anterior Cingulate Cortex (ACC), the Orbital Frontal Cortex (OFC), the Infralimbic Cortex (IL), and prelimbic Cortex (PL), as well as the Baso-Lateral Amygdala (BLA), the Nucleus Accumbens (NAcc), the Ventral Pallidal (VP), the Sub Thalamic Nucleus (STN) among others. Some regions are involved in multiple aspects of cost-benefit computations while the involvement of other regions is restricted to information relating to specific types of costs.
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Affiliation(s)
- Matthew R Bailey
- Department of Psychology, Columbia University, New York, NY, USA.
| | - Eleanor H Simpson
- Department of Psychiatry, Columbia University, New York, NY, USA; New York State Psychiatric Institute, New York, NY, USA
| | - Peter D Balsam
- Department of Psychiatry, Columbia University, New York, NY, USA; New York State Psychiatric Institute, New York, NY, USA; Barnard College, Columbia University, New York, NY, USA
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Pezze MA, Marshall HJ, Cassaday HJ. The dopamine D1 receptor agonist SKF81297 has dose-related effects on locomotor activity but is without effect in a CER trace conditioning procedure conducted with two versus four trials. LEARNING AND MOTIVATION 2016; 55:53-64. [PMID: 27524835 PMCID: PMC4974238 DOI: 10.1016/j.lmot.2016.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In an appetitively motivated procedure, we have previously reported that systemic treatment with the dopamine (DA) D1 receptor agonist SKF81297 (0.4 and 0.8 mg/kg) depressed acquisition at a 2 s inter-stimulus-interval (ISI), suitable to detect trace conditioning impairment. However since DA is involved in reinforcement processes, the generality of effects across appetitively- and aversively-motivated trace conditioning procedures cannot be assumed. The present study tested the effects of SKF81297 (0.4 and 0.8 mg/kg) in an established conditioned emotional response (CER) procedure. Trace-dependent conditioning was clearly shown in two experiments: while conditioning was relatively strong at a 3-s ISI, it was attenuated at a 30-s ISI. This was shown after two (Experiment 1) or four (Experiment 2) conditioning trials conducted in – as far as possible – the same CER procedure. Contrary to prediction, in neither experiment was there any indication that trace conditioning was attenuated by treatment with 0.4 or 0.8 mg/kg SKF81297. In the same rats, locomotor activity was significantly enhanced at the 0.8 mg/kg dose of SKF81297. These results suggest that procedural details of the trace conditioning variant in use are an important determinant of the profile of dopaminergic modulation.
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Affiliation(s)
- M A Pezze
- School of Psychology, University of Nottingham, United Kingdom
| | - H J Marshall
- School of Psychology, University of Nottingham, United Kingdom
| | - H J Cassaday
- School of Psychology, University of Nottingham, United Kingdom
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Salamone JD, Correa M, Yohn S, Lopez Cruz L, San Miguel N, Alatorre L. The pharmacology of effort-related choice behavior: Dopamine, depression, and individual differences. Behav Processes 2016; 127:3-17. [PMID: 26899746 DOI: 10.1016/j.beproc.2016.02.008] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/08/2016] [Accepted: 02/12/2016] [Indexed: 12/22/2022]
Abstract
This review paper is focused upon the involvement of mesolimbic dopamine (DA) and related brain systems in effort-based processes. Interference with DA transmission affects instrumental behavior in a manner that interacts with the response requirements of the task, such that rats with impaired DA transmission show a heightened sensitivity to ratio requirements. Impaired DA transmission also affects effort-related choice behavior, which is assessed by tasks that offer a choice between a preferred reinforcer that has a high work requirement vs. less preferred reinforcer that can be obtained with minimal effort. Rats and mice with impaired DA transmission reallocate instrumental behavior away from food-reinforced tasks with high response costs, and show increased selection of low reinforcement/low cost options. Tests of effort-related choice have been developed into models of pathological symptoms of motivation that are seen in disorders such as depression and schizophrenia. These models are being employed to explore the effects of conditions associated with various psychopathologies, and to assess drugs for their potential utility as treatments for effort-related symptoms. Studies of the pharmacology of effort-based choice may contribute to the development of treatments for symptoms such as psychomotor slowing, fatigue or anergia, which are seen in depression and other disorders.
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Affiliation(s)
- John D Salamone
- Dept. of Psychology Sciences, University of Connecticut, Storrs, CT 06269-1020, USA.
| | - Merce Correa
- Dept. of Psychology Sciences, University of Connecticut, Storrs, CT 06269-1020, USA; Area de Psicobiol., Dept. Psic., Universitat de Jaume I, Castelló 12071, Spain
| | - Samantha Yohn
- Dept. of Psychology Sciences, University of Connecticut, Storrs, CT 06269-1020, USA
| | - Laura Lopez Cruz
- Dept. of Psychology Sciences, University of Connecticut, Storrs, CT 06269-1020, USA; Area de Psicobiol., Dept. Psic., Universitat de Jaume I, Castelló 12071, Spain
| | - Noemi San Miguel
- Dept. of Psychology Sciences, University of Connecticut, Storrs, CT 06269-1020, USA; Area de Psicobiol., Dept. Psic., Universitat de Jaume I, Castelló 12071, Spain
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Mathes CM, Bohnenkamp RA, Blonde GD, Letourneau C, Corteville C, Bueter M, Lutz TA, le Roux CW, Spector AC. Gastric bypass in rats does not decrease appetitive behavior towards sweet or fatty fluids despite blunting preferential intake of sugar and fat. Physiol Behav 2015; 142:179-88. [PMID: 25660341 PMCID: PMC4358755 DOI: 10.1016/j.physbeh.2015.02.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/14/2015] [Accepted: 02/02/2015] [Indexed: 01/14/2023]
Abstract
After Roux-en-Y gastric bypass surgery (RYGB), patients report consuming fewer fatty and dessert-like foods, and rats display blunted sugar and fat preferences. Here we used a progressive ratio task (PR) in our rat model to explicitly test whether RYGB decreases the willingness of rats to work for very small amounts of preferred sugar- and/or fat-containing fluids. In each of two studies, two groups of rats - one maintained on a high-fat diet (HFD) and standard chow (CHOW) and one given CHOW alone - were trained while water-deprived to work for water or either Ensure or 1.0 M sucrose on increasingly difficult operant schedules. When tested before surgery while nondeprived, HFD rats had lower PR breakpoints (number of operant responses in the last reinforced ratio) for sucrose, but not for Ensure, than CHOW rats. After surgery, at no time did rats given RYGB show lower breakpoints than SHAM rats for Ensure, sucrose, or when 5% Intralipid served postoperatively as the reinforcer. Nevertheless, RYGB rats showed blunted preferences for these caloric fluids versus water in 2-bottle preference tests. Importantly, although the Intralipid and sucrose preferences of RYGB rats decreased further over time, subsequent breakpoints for them were not significantly impacted. Collectively, these data suggest that the observed lower preferences for normally palatable fluids after RYGB in rats may reflect a learned adjustment to altered postingestive feedback rather than a dampening of the reinforcing taste characteristics of such stimuli as measured by the PR task in which postingestive stimulation is negligible.
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Affiliation(s)
- Clare M Mathes
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL, USA
| | - Ryan A Bohnenkamp
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL, USA
| | - Ginger D Blonde
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL, USA
| | - Chanel Letourneau
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL, USA
| | - Caroline Corteville
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich, Switzerland
| | - Marco Bueter
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich, Switzerland; Zurich Center for Integrative Human Physiology, University of Zurich, Switzerland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich, Switzerland; Zurich Center for Integrative Human Physiology, University of Zurich, Switzerland; Institute of Laboratory Animal Science, Vetsuisse Faculty University of Zurich, Switzerland
| | - Carel W le Roux
- Diabetes Complications Research Centre, School of Medicine and Medical Science, University College Dublin, Ireland; Investigative Medicine, Imperial College London, UK; Gastrosurgical Laboratory, University of Gothenburg, Sweden
| | - Alan C Spector
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL, USA.
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Bezzina G, Body S, Cheung THC, Hampson CL, Bradshaw CM, Glennon JC, Szabadi E. Evidence for a role of 5-HT2C receptors in the motor aspects of performance, but not the efficacy of food reinforcers, in a progressive ratio schedule. Psychopharmacology (Berl) 2015; 232:699-711. [PMID: 25134499 DOI: 10.1007/s00213-014-3700-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 07/28/2014] [Indexed: 12/25/2022]
Abstract
RATIONALE 5-Hydroxytryptamine2C (5-HT2C) receptor agonists reduce the breakpoint in progressive ratio schedules of reinforcement, an effect that has been attributed to a decrease of the efficacy of positive reinforcers. However, a reduction of the breakpoint may also reflect motor impairment. Mathematical models can help to differentiate between these processes. OBJECTIVE The effects of the 5-HT2C receptor agonist Ro-600175 ((αS)-6-chloro-5-fluoro-α-methyl-1H-indole-1-ethanamine) and the non-selective 5-HT receptor agonist 1-(m-chlorophenyl)piperazine (mCPP) on rats' performance on a progressive ratio schedule maintained by food pellet reinforcers were assessed using a model derived from Killeen's Behav Brain Sci 17:105-172, 1994 general theory of schedule-controlled behaviour, 'mathematical principles of reinforcement'. METHOD Rats were trained under the progressive ratio schedule, and running and overall response rates in successive ratios were analysed using the model. The effects of the agonists on estimates of the model's parameters, and the sensitivity of these effects to selective antagonists, were examined. RESULTS Ro-600175 and mCPP reduced the breakpoint. Neither agonist significantly affected a (the parameter expressing incentive value), but both agonists increased δ (the parameter expressing minimum response time). The effects of both agonists could be attenuated by the selective 5-HT2C receptor antagonist SB-242084 (6-chloro-5-methyl-N-{6-[(2-methylpyridin-3-yl)oxy]pyridin-3-yl}indoline-1-carboxamide). The effect of mCPP was not altered by isamoltane, a selective 5-HT1B receptor antagonist, or MDL-100907 ((±)2,3-dimethoxyphenyl-1-(2-(4-piperidine)methanol)), a selective 5-HT2A receptor antagonist. CONCLUSIONS The results are consistent with the hypothesis that the effect of the 5-HT2C receptor agonists on progressive ratio schedule performance is mediated by an impairment of motor capacity rather than by a reduction of the incentive value of the food reinforcer.
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Affiliation(s)
- G Bezzina
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, Medical School, Nottingham, NG7 2UH, UK
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Olarte-Sánchez CM, Valencia-Torres L, Cassaday HJ, Bradshaw CM, Szabadi E. Quantitative analysis of performance on a progressive-ratio schedule: effects of reinforcer type, food deprivation and acute treatment with Δ⁹-tetrahydrocannabinol (THC). Behav Processes 2015; 113:122-31. [PMID: 25637881 PMCID: PMC4534516 DOI: 10.1016/j.beproc.2015.01.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 01/26/2015] [Accepted: 01/26/2015] [Indexed: 12/27/2022]
Abstract
Rats' performance on a progressive-ratio schedule maintained by sucrose (0.6M, 50 μl) and corn oil (100%, 25 μl) reinforcers was assessed using a model derived from Killeen's (1994) theory of schedule-controlled behaviour, 'Mathematical Principles of Reinforcement'. When the rats were maintained at 80% of their free-feeding body weights, the parameter expressing incentive value, a, was greater for the corn oil than for the sucrose reinforcer; the response-time parameter, δ, did not differ between the reinforcer types, but a parameter derived from the linear waiting principle (T0), indicated that the minimum post-reinforcement pause was longer for corn oil than for sucrose. When the rats were maintained under free-feeding conditions, a was reduced, indicating a reduction of incentive value, but δ was unaltered. Under the food-deprived condition, the CB1 cannabinoid receptor agonist Δ(9)-tetrahydrocannabinol (THC: 0.3, 1 and 3 mg kg(-1)) increased the value of a for sucrose but not for corn oil, suggesting a selective enhancement of the incentive value of sucrose; none of the other parameters was affected by THC. The results provide new information about the sensitivity of the model's parameters to deprivation and reinforcer quality, and suggest that THC selectively enhances the incentive value of sucrose.
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Affiliation(s)
- C M Olarte-Sánchez
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, UK.
| | - L Valencia-Torres
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, UK.
| | - H J Cassaday
- School of Psychology, University of Nottingham, UK.
| | - C M Bradshaw
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, UK.
| | - E Szabadi
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, UK.
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What's Special about the Ethical Challenges of Studying Disorders with Altered Brain Activity? Curr Top Behav Neurosci 2014; 19:137-57. [PMID: 25205325 DOI: 10.1007/7854_2014_333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Where there is no viable alternative, studies of neuronal activity are conducted on animals. The use of animals, particularly for invasive studies of the brain, raises a number of ethical issues. Practical or normative ethics are enforced by legislation, in relation to the dominant welfare guidelines developed in the United Kingdom and elsewhere. Guidelines have typically been devised to cover all areas of biomedical research using animals in general, and thus lack any specific focus on neuroscience studies at the level of the ethics, although details of the specific welfare recommendations are different for invasive studies of the brain. Ethically, there is no necessary distinction between neuroscience and other biomedical research in that the brain is a final common path for suffering, irrespective of whether this involves any direct experience of pain. One exception arises in the case of in vitro studies, which are normally considered as an acceptable replacement for in vivo studies. However, to the extent sentience is possible, maintaining central nervous system tissue outside the body naturally raises ethical questions. Perhaps the most intractable challenge to the ethical use of animals in order to model neuronal disorder is presented by the logical impasse in the argument that the animal is similar enough to justify the validity of the experimental model, but sufficiently different in sentience and capacity for suffering, for the necessary experimental procedures to be permissible.
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Valencia-Torres L, Bradshaw CM, Bouzas A, Hong E, Orduña V. Effect of streptozotocin-induced diabetes on performance on a progressive ratio schedule. Psychopharmacology (Berl) 2014; 231:2375-84. [PMID: 24402135 DOI: 10.1007/s00213-013-3401-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 12/02/2013] [Indexed: 12/29/2022]
Abstract
RATIONALE It has been suggested that streptozotocin (STZ)-induced diabetes causes a motivational deficit in rodents. However, some of the evidence adduced in support of this suggestion may be interpreted in terms of a motor impairment rather than a motivational deficit. OBJECTIVE This experiment examined the effect of STZ-induced diabetes on performance on a progressive ratio schedule. The data were analysed using a new model derived from Killeen's (Behav Brain Sci 17:105-172, 1994) Mathematical Principles of Reinforcement model which enables the effects of interventions on motivation or incentive value to be separated from effects on motor function. METHOD Animals were trained under a progressive ratio schedule using food-pellet reinforcement. Then they received a single intraperitoneal injection of 50 mg/kg of STZ or the vehicle. Training continued for 30 sessions after treatment. Running and overall response rates in successive ratios were analysed using the new model, and estimates of the model's parameters were compared between groups. RESULTS The parameter expressing incentive value was reduced in the group treated with STZ, whereas the parameters expressing motor capacity and post-reinforcement pausing were not affected by the treatment. Blood glucose concentration was significantly elevated in the STZ-treated group compared to the vehicle-treated group. CONCLUSIONS The results are consistent with the suggestion that STZ-induced diabetes is associated with a reduction of the incentive value of food.
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