cohol rats were genetically engineere test the hypothesis that NPY deficient genotype NPY or to produce an excess of NPY NPY EX In separate experiments the twe ps were offered solutions of increasing alcohol concentration The quantity of each solution consumed per day ps were compared to normal rats in terms of their alcohol preference possessing the genotype NPY The ured Figure 1 Consumption g kg day 15 12 0 0 NPY NPY 5 10 15 20 25 Concentration of alcohol solution Consumption g kg day 15 12 6 0 Figure 2 y the relationship between NPY levels and alcohol NPY EX NPY B 25 5 10 15 20 Concentration of alcohol solution Source adapted from Thiele et al Nature 1998 396 pages 366 369 e the difference in consumption of the 6 alcohol solution between the and NPY rats figure 1 EX and NPY rats figure 2 the alcohol consumption of the NPY rats with the NPY EX rats