“…Lewis rats have a higher intake of and preference for drugs including cocaine, morphine, ethanol, and nicotine (Horan, Smith, Gardner, Lepore, & Ashby, 1997; Kosten & Ambrosio, 2002; Suzuki, George, & Meisch, 1988; Suzuki, Otani, Koike, & Misawa, 1988). They also demonstrate the differences from Fischer rats in stress measures (including corticosterone levels), drug responsiveness (including amphetamine-induced locomotion) and brain function (including ventral striatal differences), and these differences have been linked to specific genetic locations between the different strains (Potenza et al, 2004; Potenza et al, 2008). Lewis and Fischer rats differ with respect to dopamine (DA) neurotransmission, with Lewis rats having higher levels of DA release in response to stimulants (Camp, Browman, & Robinson, 1994; Strecker, Eberle, & Ashby, 1995), as well as lower levels of DA receptors and DA transporters (Flores, Wood, Barbeau, Quirion, & Srivastava, 1998) than Fischer rats.…”