Pregabalin exhibits robust activity in preclinical assays indicative of potential antiepileptic, anxiolytic, and antihyperalgesic clinical efficacy. It binds with high affinity to the alpha(2)-delta subunit of voltage-gated calcium channels and is a substrate of the system L neutral amino acid transporter. A series of pregabalin analogues were prepared and evaluated for their alpha(2)-delta binding affinity as demonstrated by their ability to inhibit binding of [(3)H]gabapentin to pig brain membranes and for their potency to inhibit the uptake of [(3)H]leucine into CHO cells, a measure of their ability to compete with the endogenous substrate at the system L transporter. Compounds were also assessed in vivo for their ability to promote anxiolytic, analgesic, and anticonvulsant actions. These studies suggest that distinct structure activity relationships exist for alpha(2)-delta binding and system L transport inhibition. However, both interactions appear to play an important role in the in vivo profile of these compounds.