Lewis and Fischer rats: a comparison of dopamine transporter and receptorslevels

Previous reports have shown that the inbred strains of rat, Lewis (LEW) and Fischer 344 (F344), differ in several behavioural and biochemical indices of mesolimbic dopamine (DA) function. Specifically, these two strains diffe r in their behavioural and neurochemical response to novel environments, an d acute amphetamine or cocaine challenge as well as in their susceptibility to addiction. To investigate if differences in DA D1-like, D2-like, D3 rec eptors and DA transporter could be correlated with these behavioural differ ences between strains, a comparative autoradiographic study of DA receptors and transporter within the striatal and accumbal regions was undertaken. W e observed strain and region specific differences in binding levels for DA D2-like and D3 receptors and for the DA transporter. Namely, DA transporter levels in the striatum, nucleus accumbens and olfactory tubercle of LEW ra ts were significantly lower than in F344 rats. DA D3 densities in the shell of the nucleus accumbens and olfactory tubercle of LEW rats were lower tha n the levels found in the F344 rats. Finally, LEW rats have a lower levels of D2-like receptors in the striatum and the core of the nucleus accumbens compared to F344 rats. These data suggest that differences in DA transporte r and DA receptors may in part contribute to differences in DA related beha viour seen between these two strains. (C) 1998 Elsevier Science B.V. All ri ghts reserved.