A New Method for Studying Licking Behavior Determinants in Rodents: Application to Diet-Induced Obese Mice

OBJECTIVE An original device for exploring taste-guided reward behavior in rodents using a newly designed computer-controlled liquid delivery system equipped with "lickometers" is described. METHODS This octagonal shaped "gustometer" is composed of eight shutters that give random access during a few seconds to eight bottles delivering different liquid stimuli. This original design, which forces the animal to move for access to the drinking source, allows a simultaneous analysis of the licking behavior and motivation to drink. Determination of the sucrose licking behavior in diet-induced obese mice was used to validate this method because nutritional obesity disturbs the sweet taste perception in rodents. RESULTS A rise in sucrose response threshold and a decrease in the motivation to drink sweet solutions were found in mice fed the obesogenic diet. These data were highly reproducible among independent studies and corroborated the existence of functional links between diet-induced obesity and gustation in rodents. CONCLUSIONS The FRM-8 gustometer appears to be especially suitable for exploring determinants of behavioral outputs in response to oro-sensory stimuli in the mouse. It also provides substantial information on the taste-reward relationship, useful for better understanding the origin of gustatory efficiency or, conversely, dysfunction, as reported in nutritional obesity.