Figure 3.

Food deprivation identifies the minimal amount of DA required to sustain food consumption in DA−/− mice. Mice (n = 15) housed in groups of three were treated with 50 mg/kg l-DOPA, returned to their home cages, and food was added after 3, 6, or 9 hr of restriction. Water was available ad libitum during the food restriction studies. Amount of food and water consumed after 0 (A), 3 (B), 6 (C), or 9 (D) hr of food deprivation is shown. Black horizontal lines represent the time when food was present in the cage. (E) Total amount of food consumed when mice were food-deprived after l-DOPA treatment. (F) Water consumed by food-deprived DA−/− mice.