7a—d and 8a—d which represent conformationally restricted analogues of GABA. Whereas the new spirocyclic amino acid esters 7a—d and 8a—d showed no activity at GABA receptors they proved to be active as GABAuptakeinhibitors. An examination of the relationship between structure and GABAuptake inhibition revealed a strong dependence of activity upon the length of the alkyl chain in N‐arylalkyl substituents