As for the cocaine studies discussed in the previous section, studies of the effects of other psychostimulants in VMAT2 KO and other gene KO mouse strains have supported, to some extent, the evidence from candidate gene studies in that manipulations of these genes do affect responses to drugs of abuse. However, as in the previous case, most of these effects required homozygous deletion, not something that is observed in humans. On the other hand, in the case of VMAT2 +/− and DAT +/− KO mice, which would potentially model the range of variation in these genes that is actually observed in humans, effects upon a number of the behavioral responses to amphetamine-like drugs were observed.
