RT Journal Article
SR Electronic
T1 Reward without Dopamine
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 10827
OP 10831
DO 10.1523/JNEUROSCI.23-34-10827.2003
VO 23
IS 34
A1 Claire Matson Cannon
A1 Richard D. Palmiter
YR 2003
UL http://www.jneurosci.org/content/23/34/10827.abstract
AB Dopamine (DA) is believed to play a fundamental role in reward processes. Virtually all drugs of abuse activate dopaminergic systems, as do “natural” rewards such as sexual interaction and food. Sweet-tasting solutions, for example, are a well characterized natural reward. In the present experiments, we used mice that cannot make DA (DD mice) to test the hypothesis that DA is necessary for reward. Sucrose preference, assessed with a computerized “lickometer,” was used to determine whether DD mice respond preferentially for rewarding stimuli. DD mice preferentially chose sucrose over water, and also preferred the noncaloric sweetener saccharin. Furthermore, the rate of licking, bout size, and length were greater in DD mice drinking sweets than in controls. These data refute the necessity of DA for the reward processes manifested by sucrose preference. However, DD mice initiated licking less frequently than control mice and had fewer total licks. We suggest that DD mice have a deficit of goal-directed behavior that is not specific to reward processes. Lastly, juvenile DD mice demonstrate robust sucrose preference before experience with food in the presence of DA. Thus, DA is not required for mice to learn to consume sweet solutions preferentially. We conclude that DA is not required to find the sweet tastes of sucrose or saccharin rewarding.