Chromosomal mapping of the psychomotor stimulant effects of cocaine in BXD recombinant inbred mice.

To elucidate genes associated with cocaine's locomotor stimulant effects, we used recombinant inbred-quantitative trait loci (RI-QTL) analyses to identify chromosomal loci associated with locomotor activity before (baseline) and after cocaine treatment. RI-QTL analyses seek to identify associations between a quantitative measure of a phenotype and one or more previously mapped marker loci across a panel of RI strains. In the present study, 11 BXD RI strains were used to identify several putative QTLs for each phenotype. Both baseline locomotor activity and cocaine's locomotor stimulant effects are polygenic, with both unique and overlapping genetic influences. The largest associations for baseline activity were observed on chromosomes 5 and 9 and the largest associations for cocaine's psychomotor stimulant effects on chromosomes 3 and 17.