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Alternating Access to a Highly Palatable Diet Alters Amphetamine Sensitivity and Self‐Administration
Author(s) -
Moore Catherine F,
Sabino Valentina,
Cottone Pietro
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1185.2
Subject(s) - amphetamine , nucleus accumbens , overeating , dopamine , medicine , endocrinology , hypophagia , dopaminergic , psychology , food intake , dextroamphetamine , obesity
Eating disorders and certain forms of obesity are associated with mesolimbic dopaminergic reward dysfunction. Overeating of diets rich in sugar and fat alter dopamine neurotransmission in the nucleus accumbens, likely contributing to the persistence of excessive intake. Amphetamine‐like drugs, which act in the mesolimbic pathway to enhance the release of dopamine, also confer long‐lasting neuroadaptations. However, it is not yet known if a history of disordered eating can alter sensitivity to these drugs. In this study, we investigated the effects of palatable food diet alternation on sensitivity to amphetamine (AMPH) and AMPH self‐administration. Ad libitum diet alternation occurred for 5 weeks prior to any testing. One group was provided a chow diet 7 days a week ( ‘Chow/Chow’ ), and a second group was provided chow 5 days a week followed by 2 days of access to a highly palatable, chocolate flavored, high‐sucrose diet ( ‘Chow/Palatable’ ). While continuing diet alternation, we measured locomotor activity following an AMPH challenge (0, 0.1, 0.5, 1.0 mg/kg) to test sensitivity during the 2 days of access to the palatable diet as well as when animals were withdrawn from palatable food. Following this within‐subject AMPH challenge schedule, animals were allowed to self‐administer AMPH in water (0.05 mg/ml) in the home cage. ‘Chow/Palatable’ rats exhibited excessive food intake when fed the palatable diet, and pronounced hypophagia when fed the chow diet. ‘Chow/Palatable’ rats also dramatically escalated the intake of the palatable diet during the first hour of renewed access, and during withdrawal, showed compulsive‐like eating as assessed in the light/dark conflict test. During access to palatable food, ‘Chow/Palatable’ rats showed decreased locomotor sensitivity to AMPH at the highest dose, but showed no differences from ‘Chow/Chow’ rats during palatable food withdrawal. When allowed to orally self‐administer AMPH in the home cage, ‘ Chow/Palatable’ rats showed an increase in intake during palatable food access, with no differences from ‘Chow/Chow’ rats during withdrawal. These results show that palatable food diet alternation affects AMPH sensitivity and self‐administration, specifically during access to palatable food. Support or Funding Information Research was supported by grant numbers DA030425, MH091945, and MH093650 from NIH and NIMH, by the Peter Paul Career Development Professorship (PC), the McManus Charitable Trust (VS), and Boston University's Undergraduate Research Opportunities Program (UROP). CM is supported by the Burroughs Wellcome Fund through the Transformative Training Program in Addiction Sciences and the NIH/NIGMS Training in Biomolecular Pharmacology (GM008541‐17).