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Title: Overexpression of striatal D2 receptors reduces motivation thereby decreasing food anticipatory activity
Abstract

Dopamine has been implicated in circadian timing underlying the food entrainable oscillator (FEO) circuitry and overexpression of the dopamine D2 receptor (D2R) in the striatum has been reported to reduce motivation to obtain food rewards in operant tasks. In the present study, we explored both of these mechanisms by examining food anticipatory activity (FAA) in dopamine D2 receptor‐overexpressing (D2R‐OE) mice under various durations of food availability. First, we noted that at baseline, there were no differences between D2R‐OEmice and their littermates in activity level, food intake, and body weight or in circadian activity. Under conditions of very restricted food availability (4 or 6 hr), both genotypes displayedFAA. In contrast, under 8‐hr food availability, control mice showedFAA, but D2R‐OEmice did not. Normalization of D2R by administration of doxycycline, a tetracycline analogue, rescuedFAAunder 8‐hr restricted food. We next tested for circadian regulation ofFAA. When given ad libitum access to food, neither D2R‐OEnor controls were active during the daytime. However, after an interval of food restriction, all mice showed elevated locomotor activity at the time of previous food availability in the day, indicating circadian timing of anticipatory activity. In summary, motivation is reduced in D2R‐OEmice but circadian timing behavior is not affected. We conclude that an increase in striatal D2R reducesFAAby modulating motivation and not by acting on a clock mechanism.

 
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Award ID(s):
1749500
NSF-PAR ID:
10080227
Author(s) / Creator(s):
 ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
European Journal of Neuroscience
Volume:
51
Issue:
1
ISSN:
0953-816X
Page Range / eLocation ID:
p. 71-81
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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