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The nucleus accumbens 5-HTR₄-CART pathway ties anorexia to hyperactivity.
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PMID:  23233022     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In mental diseases, the brain does not systematically adjust motor activity to feeding. Probably, the most outlined example is the association between hyperactivity and anorexia in Anorexia nervosa. The neural underpinnings of this 'paradox', however, are poorly elucidated. Although anorexia and hyperactivity prevail over self-preservation, both symptoms rarely exist independently, suggesting commonalities in neural pathways, most likely in the reward system. We previously discovered an addictive molecular facet of anorexia, involving production, in the nucleus accumbens (NAc), of the same transcripts stimulated in response to cocaine and amphetamine (CART) upon stimulation of the 5-HT(4) receptors (5-HTR(4)) or MDMA (ecstasy). Here, we tested whether this pathway predisposes not only to anorexia but also to hyperactivity. Following food restriction, mice are expected to overeat. However, selecting hyperactive and addiction-related animal models, we observed that mice lacking 5-HTR(1B) self-imposed food restriction after deprivation and still displayed anorexia and hyperactivity after ecstasy. Decryption of the mechanisms showed a gain-of-function of 5-HTR(4) in the absence of 5-HTR(1B), associated with CART surplus in the NAc and not in other brain areas. NAc-5-HTR(4) overexpression upregulated NAc-CART, provoked anorexia and hyperactivity. NAc-5-HTR(4) knockdown or blockade reduced ecstasy-induced hyperactivity. Finally, NAc-CART knockdown suppressed hyperactivity upon stimulation of the NAc-5-HTR(4). Additionally, inactivating NAc-5-HTR(4) suppressed ecstasy's preference, strengthening the rewarding facet of anorexia. In conclusion, the NAc-5-HTR(4)/CART pathway establishes a 'tight-junction' between anorexia and hyperactivity, suggesting the existence of a primary functional unit susceptible to limit overeating associated with resting following homeostasis rules.
Authors:
A Jean; L Laurent; J Bockaert; Y Charnay; N Dusticier; A Nieoullon; M Barrot; R Neve; V Compan
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-12-11
Journal Detail:
Title:  Translational psychiatry     Volume:  2     ISSN:  2158-3188     ISO Abbreviation:  Transl Psychiatry     Publication Date:  2012  
Date Detail:
Created Date:  2012-12-12     Completed Date:  2013-05-17     Revised Date:  2013-07-11    
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Nlm Unique ID:  101562664     Medline TA:  Transl Psychiatry     Country:  United States    
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Languages:  eng     Pagination:  e203     Citation Subset:  IM    
Affiliation:
Institut de Génomique Fonctionnelle, Montpellier, France.
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MeSH Terms
Descriptor/Qualifier:
Amphetamine / pharmacology*
Animals
Anorexia / etiology*,  metabolism,  physiopathology
Cocaine / pharmacology*
Hyperkinesis / etiology*,  metabolism,  physiopathology
Male
Mice
Mice, Knockout
N-Methyl-3,4-methylenedioxyamphetamine / pharmacology
Nucleus Accumbens / drug effects,  metabolism*,  physiopathology
Piperidines / pharmacology
Propane / analogs & derivatives,  pharmacology
Real-Time Polymerase Chain Reaction
Receptors, Serotonin, 5-HT4 / drug effects,  metabolism*,  physiology
Serotonin 5-HT4 Receptor Antagonists / pharmacology
Chemical
Reg. No./Substance:
0/Piperidines; 0/RS 39604; 0/Serotonin 5-HT4 Receptor Antagonists; 158165-40-3/Receptors, Serotonin, 5-HT4; 300-62-9/Amphetamine; 42542-10-9/N-Methyl-3,4-methylenedioxyamphetamine; 50-36-2/Cocaine; 74-98-6/Propane
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Journal ID (nlm-ta): Transl Psychiatry
Journal ID (iso-abbrev): Transl Psychiatry
ISSN: 2158-3188
Publisher: Nature Publishing Group
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Copyright © 2012 Macmillan Publishers Limited
open-access:
Received Day: 17 Month: 08 Year: 2012
Revision Received Day: 06 Month: 10 Year: 2012
Accepted Day: 10 Month: 10 Year: 2012
Print publication date: Month: 12 Year: 2012
Electronic publication date: Day: 11 Month: 12 Year: 2012
pmc-release publication date: Day: 1 Month: 12 Year: 2012
Volume: 2 Issue: 12
First Page: e203 Last Page:
PubMed Id: 23233022
ID: 3565192
Publisher Item Identifier: tp2012131
DOI: 10.1038/tp.2012.131

The nucleus accumbens 5-HTR4-CART pathway ties anorexia to hyperactivity Alternate Title:Tight-junction between anorexia and hyperactivity
A Jean12349
L Laurent1239
J Bockaert123
Y Charnay5
N Dusticier6
A Nieoullon6
M Barrot7
R Neve8
V Compan1234*
1Institut de Génomique Fonctionnelle, Montpellier, France
2INSERM, U661, Montpellier, France
3Universités de Montpellier 1 and 2, UMR-5203, Montpellier, France
4Université de Nîmes, Nîmes, France
5Hôpitaux Universitaires de Genève, Division de Neuropsychiatrie, Chêne-Bourg, Switzerland
6Université d'Aix-Marseille, Marseille, France
7Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
8Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
*Neurobiology, Institut de Génomique Fonctionnelle, 141, rue de la Cardonille, Montpellier 34094, France. E-mail: Valerie.Compan@igf.cnrs.fr
9Authors equally contribute to this study.

Introduction

In mental diseases (for example, depression, anxiety, eating disorders), the brain does not systematically adjust energy expenditures to intakes, as highlighted by the ‘paradoxical' association between restrictive diet and motor hyperactivity in Anorexia nervosa.1, 2, 3 Here, we set out to study potential neural underpinnings of this apparent homeostatic failure. We reasoned that if at least one single molecular pathway triggers both anorexia and motor hyperactivity, its abnormal activation could prevail over homeostasis rules. In this situation, interpreting motor hyperactivity as an ‘intention' of patients with anorexia could be challenged because their motor hyperactivity would be anorexia-dependent. In contrast, if two parallel and different pathways trigger anorexia on one hand, and motor hyperactivity on the other hand, a complex coincidence of two parallel impairments in both the feeding and motor neural networks could be in cause.

Among the cumulative neural events related to anorexia, as in most eating disorders, altered 5-HT volume transmission4 is at the forefront of investigations.5 With exceptions, regardless stimulation of 5-HT1A and 5-HT2B receptors (5-HTR1A, 5-HTR2B) in the hypothalamus,6 increased activity of 5-HT transmission in brain following treatments classically reduces feeding and body weight.7 For instance, the 3,4-N-methylenedioxymethamphetamine (MDMA, ecstasy) diminishes feeding in rodents and humans, and enhances motor hyperactivity.8, 9, 10, 11

The hypothalamus appears central in regulating feeding behavior,12 but motivation disorders related to self-imposed food restriction despite energy demand (anorexia) may involve disturbances in the nucleus accumbens (NAc),7, 13, 14 a brain structure involved in reward and feeding.15, 16, 17, 18 Considering the ability of 5-HT4 receptors (5-HTR4) knockout (KO) mice to better resist stress-induced anorexia, we detected a first example of an addictive molecular facet of anorexia.14, 19 Indeed, stimulating NAc-5-HTR4, as MDMA, provokes anorexia only if production of the same transcripts stimulated in response to cocaine and amphetamine (CART) is increased in the NAc.14

We investigated, here, whether the NAc-5-HTR4/CART molecular pathway triggers not only anorexia but also motor hyperactivity. To address this possibility, we used (i) an addiction- and hyperactive-related animal model: the 5-HTR1B KO (KO1B) mice, (ii) the ability of MDMA to mimic both anorexia and hyperactivity and (iii) siRNA- and viral-mediated knockdown and surplus strategies combined to molecular and behavioral techniques.


Methods
Animals

Male KO1B, KO4 and control mice (WT1B, WT4) from heterozygous breeding (129/SvTer)19, 20 were housed with food and water available ad libitum.14 Male WT 129/SvPas mice were used when KO mice were not required. All experiments were performed on mice aged of 4–6 months, except a set, aged of 2 months (Figures 1a and b), following the Guide for Care and Use of Laboratory Animals (authorization n° 21CAE011) (see Supplementary Information).

Surgery

As described in detail,14 a sterile 26-gauge stainless steel guide was unilaterally implanted in the left shell NAc for infusing 1 μl of each compound in freely moving mice (1 μl/min). The localization of the injection site was assessed in each mouse (see Supplementary Information).

Pharmacological and nucleic acid treatments in freely moving mice

As established,11, 14, 21 MDMA (10 mg kg−1, Sigma, L'Isle d'Abeau Chesnes, Saint-Quentin-Fallavier, France) and selective dose of 5-HTR4 antagonist, RS39604 (0.5 mg kg−1, Tocris, Ellisville, USA) were dissolved in NaCl (9%) before acute intraperitoneal (i.p.) administration. The 5-HTR4 agonist BIMU8 (Tocris, Ellisville, USA) and RS39604 was injected in the NAc at selective dose (4 × 10−4 μg μl−1). Acute injection in the NAc of (i) double-stranded siRNA-5-HTR4 (si5-HTR4), siCART provoked 5-HTR4 and CART downregulation compared with siRNA controls (siCt: 0.05 μg μl−1), respectively; and of (ii) viral vector of mHtr4 gene (HSV-5-HTR4; 107 infectious units per ml, 1 μl min−1), an overexpression of 5-HTR4 compared with HSV-LacZ construct (see Supplementary Information).

Biochemical analyses

As described,22 the levels of 5-HT and 5-HIAA were evaluated in brain tissue samples containing the NAc (+1.6 mm), striatum (+1.0 mm), dorsal hippocampus (−2.2 mm) and amygdala (−3.2 mm from the bregma)23 of WT4 and KO4 mice sacrificed 5 min after the end of the open-field session. As reported in detail,14, 19 receptor autoradiography was performed using (125I)SB207710 and (3H)GR113808, two specific 5-HTR4 antagonists (see Supplementary Information).

Quantitative Real-Time PCR

Mice were sacrificed 3-h after the different treatments and NAc (2 × 1.2 mm3) and hypothalamus (3.9 mm3) were micro-dissected from 1 mm-thick sections to treat total mRNA and treat complementary DNA in reactions containing CART or 5-HTR4 primers, as described in detail.14, 24

Activity

Naive or feeding-tested mice were tested in the open-field19 after i.p. administration of NaCl or MDMA combined with (i) i.p. administration of RS39604 in KO1B, KO4, WT1B and WT4 mice and intra-accumbal infusion of (ii) si5-HTR4, RS39604, siCt (or NaCl) as controls in WT 129 Sv/Pas mice and (iii) HSV-5-HTR4, BIMU8 combined or not with siCART, compared with controls (NaCl, HSV-LacZ, siCt) in WT 129 Sv/Pas mice. Ten min after RS39604 injection, 3 h after injection of the siRNAs or BIMU8, or 1 day after viral infection, the traveled path length was monitored.19

Feeding tests

Classic feeding paradigms11, 19 were used in fed mice or, following (i) 100% food deprivation for 24 h or (ii) 20% food-restriction for 3 consecutive days. Four days before the experiments, mice were isolated in metabolic cages for baseline period with ad libitum access to food (pellet form, 16.5% crude proteins, 3.6% crude fat, 4.6% crude fibers, 5.2% ash). Food-deprived WT1B and KO1B mice were treated with i.p. administration of NaCl or RS39604 combined or not with MDMA. WT129Sv/Pas mice received acute infusion of HSV-5-HTR4 or HSV-LacZ in the NAc and were 20% food-deprived for 3 days. The amount of food consumed (not include the spillage) was measured with 1 mg precision.

Place conditioning paradigm

An unbiased place conditioning protocol was adapted.25 Mice received i.p. administration of NaCl, MDMA combined or not with RS39604, or injection in the NAc of NaCl or RS39604, 30 min before being confined to a single conditioning zone on alternate conditioning days. A preference score is the difference between times spent by each mouse in the MDMA-, NaCl-, RS39604-, or MDMA plus RS39604-paired zone during the preconditioning and testing phases (see Supplementary Information).

Statistical analysis

Data obtained in multiple sessions over time (food intake, locomotion) were analyzed using repeated measures analysis of variance (STATVIEW 5 software, SAS Institute Inc., San Francisco, CA, USA). When effects of independent variables (treatment, genotype, time), or interactions were significant, one-way analysis of variance (treatment, time or genotype) analyses were performed. For multiple comparisons, the Scheffé F-test was used. Differences with P<0.05 were considered significant.


Results
KO1B self-imposed food restriction following restriction and displayed hyperactivity: Anorexia-like symptoms still observed after MDMA

Considering the influence of 5-HT in the potential rewarding facet of anorexia,14 we tested whether an animal model predisposes to abuse of cocaine, and to be hyperactive persists to self-restrict following food restriction. Young KO1B and WT1B mice (2 months) were then selected26, 27 and deprived of 20% of their normal food rations for 3 days in their home cages (means±s.e.m. of normal food ration for 24 h expressed in g. in WT1B: 4.80±0.09 vs KO1B: 4.82±0.16). When food was reintroduced and available ad libitum after the diet period, WT1B mice were eating more than their normal meal size (Figure 1a). This rebound in food intake was reduced in KO1B mice that even ate less than their predeprivation food ration after 3 days ad libitum (Figure 1a). Moreover, KO1B mice did display increased locomotion compared with saline-injected WT1B mice (Figures 1d and f), as reported.26, 28

Following MDMA in KO1B mice, anorexia (Figure 1c), and hyperactivity although reduced (Figures 1e and f), are still observed, consistently with a previous study using a 5-HTR1B antagonist (GR127935).11

The absence of 5-HTR1B then predisposes to anorexia-like symptoms in challenge situations. We next tested whether this predisposition requires 5-HTR4.

Inactivating 5-HTR4 in KO1B mice suppressed their anorexia and hyperactivity

Selective inactivation of 5-HTR414 in food-restricted KO1B mice restores adaptive feeding and motor responses because the mutant did not self-restrict (Figure 1b) and were not hyperactive anymore (Figures 1d and f). Inactivating 5-HTR4 suppressed anorexia (Figure 1c) and hyperactivity (Figures 1e and f) induced by MDMA in KO1B compared with NaCl-treated KO1B mice. Identical dose of antagonist only reduced both effects in WT1B mice (Figures 1c–f), suggesting a gain-of-function of 5-HTR4 owing the absence of 5-HTR1B. To ensure this issue, we first assessed whether the gene defective-mutation of 5-HTR4 reduce hyperactivity induced by novelty and MDMA. This is the observed effect (Supplementary Figure S1). We then evaluated the density of 5-HTR4 sites and mRNA in the brain of KO1B mice.

Only the NAc of KO1B mice over-expressed both 5-HTR4 and CART whereas its hypothalamus over-expressed 5-HTR4 but down-expressed CART

Among brain areas examined (Supplementary Table S1), 5-HTR4 density (Figure 2a) and mRNA content (Figure 2b) were higher in the NAc and hypothalamus of KO1B compared with WT1B mice. The levels of CART mRNA were higher in the NAc and weaker in the hypothalamus of KO1B compared with WT1B mice (Figures 2c and d). Because CART in both the NAc and hypothalamus decreases feeding,14, 29 its opposite changes could underlie the adequate feeding behavior of KO1B mice in baseline conditions.11, 30 Accordingly, the ability of KO1B mice to self-restrict of food might depend on excessive NAc-5-HTR4. We next focused on the NAc because additionally, marked increases in 5-HT metabolism were not detected in the NAc of KO4 mice following the open-field session (Supplementary Table S2). To avoid bias of adaptive changes in KO mice and determine whether a 5-HTR4 surplus within the NAc triggers both anorexia and hyperactivity, mHtr4 gene (HSV-5-HTR4) was transferred in the NAc of WT mice.

Overexpression of 5-HTR4 in the NAc ties anorexia to hyperactivity

Injecting HSV-5-HTR4 in the NAc of WT mice increased the density of NAc-5-HTR4 at 54-h postinjection (Figure 3a). The NAc-5-HTR4 mRNA content was still higher at 72 h than in control mice (HSV-LacZ), with the highest level observed at 30-h postinjection (Figure 3b). Consistently, CART mRNA content at 72-h postinjection was increased in the NAc (Figure 3c) and unchanged in the hypothalamus (Figure 3c) following injection of HSV-5-HTR4 in the NAc, compared with controls. Stimulating NAc-5-HTR4 also increases CART mRNA content in the NAc but not in the hypothalamus.14

The feeding and motor behaviors were then analyzed. At 24-h postinjection, overexpressing NAc-5-HTR4 decreased feeding (35%, Figure 3d) and enhanced motor activity (148%, Figure 3e). HSV-5-HTR4 mice did further self-restrict after restriction compared with controls (Figure 3f), mimicking feeding responses of KO1B mice, following 20% of their normal food rations for 3 days.

Subsequently, NAc-5-HTR4 surplus increased CART, decreased feeding and increased motor activity. To circumvent the ectopic expression after viral vector injection, potential conclusion was ensured using pharmacological and RNA interference approaches, as we established.14

In the NAc, stimulation of 5-HTR4 increases motor activity, and their blockade reduces hyperactivity

The distance covered in the open-field is enhanced following stimulation of NAc-5-HTR4 with a specific dose of BIMU8, an agonist (198%), and unchanged following their specific blockade with antagonist or RNA interference (si5-HTR4) infused in the NAc (Figures 4a and b). In contrast, antagonism or knockdown of NAc-5-HTR4 reduced hyperactivity induced by i.p. administration of MDMA (Figure 4a).

CART knockdown in the NAc inhibits stimulating NAc-5-HTR4-induced motor hyperactivity

We next examined whether CART in the NAc mediates the motor effects of BIMU8, a 5-HTR4 agonist. Blocking CART with RNA interference (siCART) in the NAc suppressed the motor hyperactivity induced by stimulation of 5-HTR4 (Figure 4b).

We finally tested whether MDMA's preference requires 5-HTR4 because a rewarding effect could prevail over self-preservation.

Inactivating 5-HTR4 suppressed MDMA's preference in WT and reduced it in KO1B mice

Using the conditioned place preference test, we found that The KO1B mice displayed a higher preference for MDMA than WT1B mice (Figure 5a), which is reduced after i.p. administration of a 5-HTR4 antagonist (Figure 5a). An absence of preference for MDMA is further shown when 5-HTR4 is locally inactivated in the NAc of adult WT4 mice (Figure 5b).


Discussion

Over the last ten decades, parallel neural systems have been described to control feeding and motor behaviors. Here, we found a first example of a molecular signal foul-up between motor hyperactivity and anorexia, providing a common pathway of control. This would lead us to reconsider the belief that patients with anorexia nervosa intend to accelerate their weight loss with over-exercise3, 31, 32, 33 because hyperactivity could be more inevitable than deliberate.

These findings strengthen the addictive facet of restrictive diet, now also observed in mice, dispossessed of 5-HTR1B and/or endowed of a NAc-5-HTR4 surplus because they self-restrict despite an upstream ‘starter' period of restrictive diet, believed to trigger ‘spiral' restrictions in humans.34

Animal models of anorexia-like symptoms predisposition, identified herein, mimic the activity-based anorexia rat model,35 and are to the best of our knowledge, unique. It is noteworthy to observe that KO1B mice persist to self-restrict their intake of food. Excluding adaptive mechanisms, KO1B mice would be expected to consume a higher amount of food because stimulating 5-HTR1B decreases feeding.11, 36 This phenotype is apparently not related to the reduced activity of 5-HTR2C in KO1B mice37 because stimulating 5-HTR2C decreases feeding.38 In contrast, present results showed a gain-of-function of 5-HTR4, consistent with the inhibitory influence of 5-HTR4 on feeding.14, 19 Also, inactivating 5-HTR4 suppressed motor hyperactivity in KO1B mice, consistently with the weaker efficacy of MDMA to enhance locomotion in KO4 and 5-HTR4 antagonist-treated WT mice.

The surplus of 5-HTR4 in KO1B mice further suggests a negative 5-HTR1B control of 5-HTR4 accordant with series of results; (i) The decreased levels of NAc-5-HT in KO1B mice39 because lesion of 5-HT neurons, though in rats, upregulates 5-HTR4 in brain areas including the NAc;40 (ii) The 5-HTR1B and 5-HTR4 location does not overlap (for example. in the striatum,40, 41 on 5-HT neurons24, 42, 43) likely related to their common binding to p11;44, 45 (iii) KO1B mice are hyperactive and less ‘anxious'46 while KO4 mice are hypoactive and more ‘anxious' under stress.19, 47

Molecular events for driving self-restriction and motor hyperactivity are detected in the NAc. The NAc-5-HTR4 surplus induced sustained anorexia and motor hyperactivity, mimicking the molecular and behavioral phenotypes of KO1B mice (NAc-5-HTR4/CART surplus, anorexia, hyperactivity). Similarly, stimulation of NAc-5-HTR4 decreases feeding14 and increases locomotion.

As difference in feeding responses to activation of 5-HTR subtypes, stimulation of 5-HTR1B, 5-HTR2C, 5-HTR1-7 and 5-HTR6 in the NAc did not change locomotion in basal conditions, however, in rats (Supplementary Figure S2).48, 49, 50 Likewise, blocking or silencing NAc-5-HTR4 did not change locomotion but suppressed hyperactivity induced by MDMA, in tune with the effect of the whole blockade of 5-HTR1B, 5-HTR2B and 5-HTR2C.28, 51, 52, 53, 54 In rats, inactivating NAc-5-HTR4 did not however, alter hyperactivity after MDMA,50 suggesting differences between doses and species.55, 11

To the end, stimulating NAc-5-HTR4 in mice not only triggers anorexia but also hyperactivity, consistent with opposite changes in feeding and locomotion detected only in KO4 mice, compared with other 5-HTR KO mice (Supplementary Figure S2).

The present study extends observations at a molecular level. Ectopic (viral mHtr4 gene) or ‘physiological' surplus of NAc-5-HTR4 in KO1B mice upregulates NAc-CART, as observed following stimulation of NAc-5-HTR4.14 A final experiment in our series bore out our hypothesis because NAc-CART knockdown suppressed not only anorexia14 but also motor hyperactivity induced by NAc-5-HTR4 stimulation. In addition, locomotion is unchanged following CART peptide56 or siCART injection in the NAc. Identifying the cellular origin of this action would require long investigations. Nonetheless, NAc-neurons containing GABA projecting to the lateral hypothalamus express CART14, 57, 58, 59 and might also express 5-HTR4 (Supplementary Figure S2).24, 40, 43, 58 Injecting si5-HTR4 in the NAc decreased the density of 5-HTR4 not only in the NAc but also in the lateral hypothalamus (−14%, not illustrated). The 5-HTR4 located on these neurons may influence feeding and locomotion (Supplementary Figure S2) because the lateral hypothalamus, in relation to the NAc, controls feeding and its stimulation enhances locomotion in the activity-based rat model for anorexia nervosa.15, 60, 61, 62, 63 Colocalization of 5-HTR4/CART is more conceivable than in two different neuronal populations, considering the 5-HTR4 control of CART within the NAc via a cAMP/PKA signaling pathway.14 Interestingly, it appears that 5-HT receptors expressed in the different subnuclei of the hypothalamus (arcuate nucleus: 5-HTR1B, 5-HTR2C) may provoke an anorexia associated or not with different changes in locomotion, as induced by fenfluramine64, 65 that increase,51 decrease66, 67 or does not modify locomotion68 while, 5-HTR4 likely located on the afferent neurons of the NAc to the lateral hypothalamus may provoke an anorexia associated with motor hyperactivity.

Finally, the present study suggests that activation of the NAc-5-HTR4 promotes a rewarding effect because (i) mice with NAc-5-HTR4 surplus limit their food intake despite energy requirements; (ii) inactivating NAc-5-HTR4 can reduce and even suppress the preference for MDMA, as also observed in 5-HTR2B KO mice.69 Chronic stimulation may desensitize 5-HTR470 and has been excluded from our subtasks. Nonetheless, increased cAMP production in the NAc71 upon stimulation of the 5-HTR4 in freely moving mice14 could trigger addiction.

In conclusion, motor hyperactivity is anorexia-dependent upon activation of the NAc-5-HTR4/CART pathway. Probably, a rewarding effect associated with energy expenditure (anorexia/hyperactivity) may facilitate to limit excessive intakes (overeating/resting). Present and previous findings6, 14, 64, 72 bring out at least two modes of action of 5-HT to regulate feeding. In baseline conditions, feeding may be regulated via the hypothalamic 5-HTR2C/CART pathway but, when motivation comes into play, the NAc-5-HTR4/5-HTR1B/CART pathway might prevail over the autonomic nervous control of feeding because NAc-5-HTR4/CART surplus makes the brain ‘silent' to energy loss. Finally, it is conceivable that an anorectic-rewarding pathway of the NAc predisposes animals to a possible dependence on restrictive diet and hyperactivity, two hallmarks of anorexia nervosa.


Notes

Supplementary Information accompanies the paper on the Translational Psychiatry website (http://www.nature.com/tp)

We greatly appreciate the help of E. Nestler, and the advices of R. Hen. We thank C. Dantec for the open-field data, L. Forichon and F. Arnal for mouse breeding and, M. Valbrun for her help in editing the text. Part of this study has been financially supported by ANR (Agence National de la Recherche: ANR-MNP 2009, SERFEED).


Notes

Authors declare no conflict of interest.


References
Beumont PJ,Arthur B,Russell JD,Touyz SW. Excessive physical activity in dieting disorder patients: proposals for a supervised exercise programInt J Eat DisordYear: 19941521368124324
Davis C. Eating disorders and hyperactivity: a psychobiological perspectiveCan J PsychiatryYear: 1997421681759067066
Casper RC. The 'drive for activity' and "restlessness" in anorexia nervosa: potential pathwaysJ Affect DisordYear: 2006929910716448703
Descarries L,Beaudet A,Watkins KC. Serotonin nerve terminals in adult rat neocortexBrain ResYear: 19751005635881192194
Kumar KK,Tung S,Iqbal J. Bone loss in anorexia nervosa: leptin, serotonin, and the sympathetic nervous systemAnn N Y Acad SciYear: 20101211516521062295
Yadav VK,Oury F,Suda N,Liu ZW,Gao XB,Confavreux C,et al. A serotonin-dependent mechanism explains the leptin regulation of bone mass, appetite, and energy expenditureCellYear: 200913897698919737523
Compan V,Laurent L,Jean A,Macary C,Bockaert J,Dumuis A. Serotonin signaling in eating disordersWIREs Membrane Transport and Signaling (invited by G. Knudsen)Year: 20121715719
Rochester JA,Kirchner JT. Ecstasy (3,4-methylenedioxymethamphetamine): history, neurochemistry, and toxicologyJ Am Board Fam PractYear: 19991213714210220237
Geyer MAC,C.W. Behavioral pharmacology of ring-substituted amphetamine analogs. Amphetamine and its AnalogsIn: Cho AR, Segal OS (eds).Academic Press: New YorkYear: 1994177201
Frith CH,Chang LW,Lattin DL,Walls RC,Hamm J,Doblin R. Toxicity of methylenedioxymethamphetamine (MDMA) in the dog and the ratFundam Appl ToxicolYear: 198791101192887476
Conductier G,Crosson C,Hen R,Bockaert J,Compan V. 3,4-N-methlenedioxymethamphetamine-induced hypophagia is maintained in 5-HT1B receptor knockout mice, but suppressed by the 5-HT2C receptor antagonist RS102221NeuropsychopharmacologyYear: 2005301056106315668722
Schwartz MW,Woods SC,Porte D,Seeley RJ,Baskin DG. Central nervous system control of food intakeNatureYear: 200040466167110766253
Compan V. Serotonin receptors in neurobiology. do limits of neuronal plasticity represent an opportunity for mental diseases, such as addiction to food and illegal drugs? use and utilities of serotonin receptor knock-out miceCRC press, New frontiers in Neurosciences: Boca Raton, FloridaYear: 2007157180
Jean A,Conductier G,Manrique C,Bouras C,Berta P,Hen R,et al. Anorexia induced by activation of serotonin 5-HT4 receptors is mediated by increases in CART in the nucleus accumbensProc Natl Acad Sci U S AYear: 2007104163351634017913892
Stratford TR,Kelley AE. GABA in the nucleus accumbens shell participates in the central regulation of feeding behaviorJ NeurosciYear: 199717443444409151760
Bassareo V,Di Chiara G. Modulation of feeding-induced activation of mesolimbic dopamine transmission by appetitive stimuli and its relation to motivational stateEur J NeurosciYear: 1999114389439710594666
Reynolds SM,Berridge KC. Fear and feeding in the nucleus accumbens shell: rostrocaudal segregation of GABA-elicited defensive behavior versus eating behaviorJ NeurosciYear: 2001213261327011312311
Hoebel BG. Brain neurotransmitters in food and drug rewardAm J Clin NutrYear: 198542(5 Suppl113311502865893
Compan V,Zhou M,Grailhe R,Gazzara RA,Martin R,Gingrich J,et al. Attenuated response to stress and novelty and hypersensitivity to seizures in 5-HT4 receptor knock-out miceJ NeurosciYear: 20042441241914724239
Saudou F,Amara DA,Dierich A,LeMeur M,Ramboz S,Segu L,et al. Enhanced aggressive behavior in mice lacking 5-HT1B receptorScienceYear: 1994265187518788091214
Lucas G,Compan V,Charnay Y,Neve RL,Nestler EJ,Bockaert J,et al. Frontocortical 5-HT4 receptors exert positive feedback on serotonergic activity: viral transfections, subacute and chronic treatments with 5-HT4 agonistsBiol PsychiatryYear: 20055791892515820713
Dusticier N,Nieoullon A. Comparative analysis of the effects of in vivo electrical stimulation of the frontal cortex and g-butyrolactone administration on dopamine and dihydroxyphenylacetic acid (DOPAC) striatal contents in the ratNeurochem IntYear: 19871027528020501096
Franklin KBJ,Paxinos G. The mouse brain in stereotaxic coodinatesAcademic press: San DiegoYear: 1997
Conductier G,Dusticier N,Lucas G,Cote F,Debonnel G,Daszuta A,et al. Adaptive changes in serotonin neurons of the raphe nuclei in 5-HT(4) receptor knock-out mouseEur J NeurosciYear: 2006241053106216930432
Robledo P,Balerio G,Berrendero F,Maldonado R. Study of the behavioural responses related to the potential addictive properties of MDMA in miceNaunyn Schmiedebergs Arch PharmacolYear: 200436933834914758467
Brunner D,Buhot MC,Hen R,Hofer M. Anxiety, motor activation, and maternal-infant interactions in 5HT1B knockout miceBehav NeurosciYear: 199911358760110443785
Rocha BA,Fumagalli F,Gainetdinov RR,Jones SR,Ator R,Giros B,et al. Cocaine self-administration in dopamine-transporter knockout miceNat NeurosciYear: 1998113213710195128
Scearce-Levie K,Viswanathan SS,Hen R. Locomotor response to MDMA is attenuated in knockout mice lacking the 5-HT1B receptorPsychopharmacology (Berl)Year: 19991411541619952039
Kristensen P,Judge ME,Thim L,Ribel U,Christjansen KN,Wulff BS,et al. Hypothalamic CART is a new anorectic peptide regulated by leptinNatureYear: 199839372769590691
Lucas JJ,Yamamoto A,Scearce-Levie K,Saudou F,Hen R. Absence of fenfluramine-induced anorexia and reduced c-Fos induction in the hypothalamus and central amygdaloid complex of serotonin 1B receptor knock-out miceJ NeurosciYear: 199818553755449651234
Holtkamp K,Hebebrand J,Herpertz-Dahlmann B. The contribution of anxiety and food restriction on physical activity levels in acute anorexia nervosaInt J Eat DisordYear: 20043616317115282686
Konttinen H,Silventoinen K,Sarlio-Lahteenkorva S,Mannisto S,Haukkala A. Emotional eating and physical activity self-efficacy as pathways in the association between depressive symptoms and adiposity indicatorsAm J Clin NutrYear: 2010921031103920861176
Steanovv TS,Vekova AM,Kurktschiev DP,Temelkova-Kurktschiev TS. Relationship of physical activity and eating behaviour with obesity and type 2 diabetes mellitus: Sofia Lifestyle (SLS) studyFolia Med (Plovdiv)Year: 201153111821644400
Dignon A,Beardsmore A,Spain S,Kuan A. 'Why I won't eat': patient testimony from 15 anorexics concerning the causes of their disorderJ Health PsycholYear: 20061194295617035265
van Kuyck K,Casteels C,Vermaelen P,Bormans G,Nuttin B,Van Laere K. Motor- and food-related metabolic cerebral changes in the activity-based rat model for anorexia nervosa: a voxel-based microPET studyNeuroimageYear: 20073521422117239617
Vickers SP,Dourish CT,Kennett GA. Evidence that hypophagia induced by d-fenfluramine and d-norfenfluramine in the rat is mediated by 5-HT2C receptorsNeuropharmacologyYear: 20014120020911489456
Clifton PG,Lee MD,Somerville EM,Kennett GA,Dourish CT. 5-HT1B receptor knockout mice show a compensatory reduction in 5-HT2C receptor functionEur J NeurosciYear: 20031718519012534984
Kennett GA,Curzon G. Evidence that hypophagia induced by mCPP and TFMPP requires 5-HT1C and 5-HT1B receptors; hypophagia induced by RU 24969 only requires 5-HT1B receptorsPsychopharmacology (Berl)Year: 198896931002906446
Ase AR,Reader TA,Hen R,Riad M,Descarries L.. Altered serotonin and dopamine metabolism in the CNS of serotonin 5-HT(1A) or 5-HT(1B) receptor knockout miceJ NeurochemYear: 2000752415242611080193
Compan V,Daszuta A,Salin P,Sebben M,Bockaert J,Dumuis A. Lesion study of the distribution of serotonin 5-HT4 receptors in rat basal ganglia and hippocampusEur J NeurosciYear: 19968259125988996808
Compan V,Segu L,Buhot MC,Daszuta A. Selective increases in serotonin 5-HT1B/1D and 5-HT2A/2C binding sites in adult rat basal ganglia following lesions of serotonergic neuronsBrain ResYear: 19987931031119630549
Doucet E,Pohl M,Fattaccini CM,Adrien J,Mestikawy SE,Hamon M. In situ hybridization evidence for the synthesis of 5-HT1B receptor in serotoninergic neurons of anterior raphe nuclei in the rat brainSynapseYear: 19951918287709340
Vilaro MT,Cortes R,Mengod G. Serotonin 5-HT4 receptors and their mRNAs in rat and guinea pig brain: distribution and effects of neurotoxic lesionsJ Comp NeurolYear: 200548441843915770652
Svenningsson P,Chergui K,Rachleff I,Flajolet M,Zhang X,El Yacoubi M,et al. Alterations in 5-HT1B receptor function by p11 in depression-like statesScienceYear: 2006311778016400147
Warner-Schmidt JL,Flajolet M,Maller A,Chen EY,Qi H,Svenningsson P,et al. Role of p11 in cellular and behavioral effects of 5-HT4 receptor stimulationJ NeurosciYear: 2009291937194619211900
Malleret G,Hen R,Guillou JL,Segu L,Buhot MC. 5-HT1B receptor knock-out mice exhibit increased exploratory activity and enhanced spatial memory performance in the Morris water mazeJ NeurosciYear: 1999196157616810407051
Segu L,Lecomte MJ,Wolff M,Santamaria J,Hen R,Dumuis A,et al. Hyperfunction of muscarinic receptor maintains long-term memory in 5-HT4 receptor knock-out micePLoS ONEYear: 20105e952920209108
Francis HM,Kraushaar NJ,Hunt LR,Cornish JL. Serotonin 5-HT4 receptors in the nucleus accumbens are specifically involved in the appetite suppressant and not locomotor stimulant effects of MDMA ('ecstasy')Psychopharmacology (Berl)Year: 20112133556320740276
Pratt WE,Blackstone K,Connolly ME,Skelly MJ. Selective serotonin receptor stimulation of the medial nucleus accumbens causes differential effects on food intake and locomotionBehav NeurosciYear: 20091231046105719824770
Francis HM,Kraushaar NJ,Hunt LR,Cornish JL. Serotonin 5-HT4 receptors in the nucleus accumbens are specifically involved in the appetite suppressant and not locomotor stimulant effects of MDMA ('ecstasy')Psychopharmacology (Berl)Year: 201021335536320740276
Bankson MG,Cunningham KA. 3,4-Methylenedioxymethamphetamine (MDMA) as a unique model of serotonin receptor function and serotonin-dopamine interactionsJ Pharmacol Exp TherYear: 200129784685211356903
Geyer MA. Serotonergic functions in arousal and motor activityBehav Brain ResYear: 19967331358788473
Baumann MH,Clark RD,Rothman RB. Locomotor stimulation produced by 3,4-methylenedioxymethamphetamine (MDMA) is correlated with dialysate levels of serotonin and dopamine in rat brainPharmacol Biochem BehavYear: 20089020821718403002
Doly S,Valjent E,Setola V,Callebert J,Herve D,Launay JM,et al. Serotonin 5-HT2B receptors are required for 3,4-methylenedioxymethamphetamine-induced hyperlocomotion and 5-HT release in vivo and in vitroJ NeurosciYear: 2008282933294018337424
Colado MI,O'Shea E,Green AR. Acute and long-term effects of MDMA on cerebral dopamine biochemistry and functionPsychopharmacology (Berl)Year: 200417324926315083264
Jaworski JN,Kozel MA,Philpot KB,Kuhar MJ. Intra-accumbal injection of CART (cocaine-amphetamine regulated transcript) peptide reduces cocaine-induced locomotor activityJ Pharmacol Exp TherYear: 20033071038104414551286
Yang SC,Shieh KR,Li HY. Cocaine- and amphetamine-regulated transcript in the nucleus accumbens participates in the regulation of feeding behavior in ratsNeuroscienceYear: 200513384185115908130
Hubert GW,Kuhar MJ. Colocalization of CART with substance P but not enkephalin in the rat nucleus accumbensBrain ResYear: 2005105081415978559
Hubert GW,Manvich DF,Kuhar MJ. Cocaine and amphetamine-regulated transcript-containing neurons in the nucleus accumbens project to the ventral pallidum in the rat and may inhibit cocaine-induced locomotionNeuroscienceYear: 200916517918719825396
Maldonado-Irizarry CS,Swanson CJ,Kelley AE. Glutamate receptors in the nucleus accumbens shell control feeding behavior via the lateral hypothalamusJ NeurosciYear: 199515677967887472436
Stratford TR,Kelley AE. Evidence of a functional relationship between the nucleus accumbens shell and lateral hypothalamus subserving the control of feeding behaviorJ NeurosciYear: 199919110401104810594084
Stratford TR,Swanson CJ,Kelley A. Specific changes in food intake elicited by blockade or activation of glutamate receptors in the nucleus accumbens shellBehav Brain ResYear: 19989343509659985
Verhagen LA,Luijendijk MC,de Groot JW,van Dommelen LP,Klimstra AG,Adan RA,et al. Anticipation of meals during restricted feeding increases activity in the hypothalamus in ratsEur J NeurosciYear: 2011341485149122034979
Heisler LK,Cowley MA,Tecott LH,Fan W,Low MJ,Smart JL,et al. Activation of central melanocortin pathways by fenfluramineScienceYear: 200229760961112142539
Heisler LK,Jobst EE,Sutton GM,Zhou L,Borok E,Thornton-Jones Z,et al. Serotonin reciprocally regulates melanocortin neurons to modulate food intakeNeuronYear: 20065123924916846858
Aulakh CS,Hill JL,Wozniak KM,Murphy DL. Fenfluramine-induced suppression of food intake and locomotor activity is differentially altered by the selective type A monoamine oxidase inhibitor clorgylinePsychopharmacology (Berl)Year: 1988953133173137616
Heffner TG,Seiden LS. Possible involvement of serotonergic neurons in the reduction of locomotor hyperactivity caused by amphetamine in neonatal rats depleted of brain dopamineBrain ResYear: 198224481906288184
Vickers SP,Benwell KR,Porter RH,Bickerdike MJ,Kennett GA,Dourish CT. Comparative effects of continuous infusion of mCPP, Ro 60-0175 and d-fenfluramine on food intake, water intake, body weight and locomotor activity in ratsBr J PharmacolYear: 20001301305131410903970
Doly S,Bertran-Gonzalez J,Callebert J,Bruneau A,Banas SM,Belmer A,et al. Role of serotonin via 5-HT2B receptors in the reinforcing effects of MDMA in micePLoS ONEYear: 20094e795219956756
Dumuis A,Bouhelal R,Sebben M,Cory R,Bockaert J. A nonclassical 5-hydroxytryptamine receptor positively coupled with adenylate cyclase in the central nervous systemMol PharmacolYear: 1988348808872849052
Self DW,Genova LM,Hope BT,Barnhart WJ,Spencer JJ,Nestler EJ. Involvement of cAMP-dependent protein kinase in the nucleus accumbens in cocaine self-administration and relapse of cocaine-seeking behaviorJ NeurosciYear: 199818184818599465009
Rogge G,Jones D,Hubert GW,Lin Y,Kuhar MJ. CART peptides: regulators of body weight, reward and other functionsNat Rev NeurosciYear: 2008974775818802445
Supplementary Material Supplementary Information Click here for additional data file (tp2012131x1.pdf)


Article Categories:
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Keywords: feeding, 5-HT1B, 5-HT4, knockout, locomotion, reward.

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