Dopamine has been implicated in circadian timing underlying the food entrainable oscillator (
Cortico‐basal ganglia‐thalamic (
- NSF-PAR ID:
- 10077842
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- European Journal of Neuroscience
- Volume:
- 48
- Issue:
- 8
- ISSN:
- 0953-816X
- Page Range / eLocation ID:
- p. 2857-2868
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract 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‐OE mice 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‐OE mice did not. Normalization of D2R by administration of doxycycline, a tetracycline analogue, rescuedFAA under 8‐hr restricted food. We next tested for circadian regulation ofFAA . When given ad libitum access to food, neither D2R‐OE nor 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‐OE mice but circadian timing behavior is not affected. We conclude that an increase in striatal D2R reducesFAA by modulating motivation and not by acting on a clock mechanism. -
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