Details

Autor(en) / Beteiligte

• LeSauter, Joseph
• Balsam, Peter D.
• Simpson, Eleanor H.
• Silver, Rae

Titel

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

Ist Teil von

• The European journal of neuroscience, 2020-01, Vol.51 (1), p.71-81

Ort / Verlag

France: Wiley Subscription Services, Inc

Erscheinungsjahr

2020

Quelle

Psychology & Behavioral Sciences Collection

Beschreibungen/Notizen

• 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‐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 displayed FAA. In contrast, under 8‐hr food availability, control mice showed FAA, but D2R‐OE mice did not. Normalization of D2R by administration of doxycycline, a tetracycline analogue, rescued FAA under 8‐hr restricted food. We next tested for circadian regulation of FAA. 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 reduces FAA by modulating motivation and not by acting on a clock mechanism. When food availability is restricted to 8 hr during the mouse's inactive phase, control mice show food anticipatory activity (FAA) by running in their wheel prior to the appearance of the meal. In contrast, mice with overexpression of the dopamine D2 receptor (D2R‐OE) do not show FAA in these conditions. Treating the D2R‐OE mice with doxycycline to switch off overexpression of the transgenic D2Rs results in rescue of FAA.