Abstract
In this study we examined the genetic contribution of the D4R in food and cocaine self-administration using D4R mice. Mice were examined for operant responding to food pellets or intravenous cocaine. Compared to wild-type mice (D4R(+/+)), both heterozygous (D4R(+/-)) and knockout (D4R(-/-)) mice showed no difference in responding for food or cocaine. Our findings suggest that the D4R is not directly involved in mediating operant response behaviors for food or cocaine.