In these terms, it appears logical to examine the biological activity of ureidoacids, which have a clear structural similarity to both GABA and pyracetam. It is necessary to bear in mind, in this connection, that since ureidoacids are fairly strong organic acids they, like GABA, are ionized in neutral media. The subjects chosen for study were the ureidoacids (Ia-e) and carbamoylproline (II) [5-7], obtained by reacting the appropriate aminoacids with sodium cyanate as ...