Binding of various antidepressants and other compounds to LeuT. (A). Affinity of desipramine, imipramine, fluoxetine and nortriptyline. Data are shown as mean ± SEM (vertical bars, N = 3). The IC50 values for inhibition [3H]leucine binding to LeuT were 80±5, 244±12, 858±64 and 75±14μM, respectively. (B). Mechanism of inhibition of [3H]leucine binding to LeuT by desipramine and nortriptyline. The plot shows that desipramine and nortriptyline are not competitive inhibitors of leucine binding to LeuT. A representative experiment is shown (N = 3).