Quinine enhances the behavioral stimulant effect of cocaine in mice.

The Na(+)-dependent dopamine transporter (DAT) is primarily responsible for regulating free dopamine (DA) concentrations in the brain by participating in the majority of DA uptake; however, other DA transporters may also participate, especially if cocaine or other drugs of abuse compromise DAT. Recently, such cocaine-insensitive low-affinity mono- and poly-amine OCT transporters were described in astrocytes which use DA as a substrate. These transporters are from a different transporter family and while insensitive to cocaine, they are specifically blocked by quinine and some steroids.