Figure 4.

D2 modulation has a greater effect in GT NVHL rats (n=7). (a, left) NVHL rats showed similar levels of magazine entries as sham controls (n=7). Center: both doses of eticlopride (10 ng/kg and 20 ng/kg) decreased responding in NVHL rats, but only higher doses of eticlopride decreased the response in sham animals. Right: lever press response did not show any variation. (b) Sham (n=7) and NVHL (n=6) ST rats showed a different response pattern: while sham rats increased lever pressing across sessions, NVHL rats did not (left). Center: quinpirole administration decreased the response in both groups. Right: magazine response was similar in both groups. Data show mean of lever press and magazine entries response. *p<0.05.