[Autoradiographic studies on the distribution of 14C-piracetam in rat and dog]

Autoradiographic and scintillation counting techniques were used to show that after p.o. and i.v. application of radioactivity labelled piracetam (2-oxo-pyrrolidine-1-acetamide-2-14C) the distribution patterns of this compound are similar in dog and rat. Whereas the level of the drug reaches its maximum in many organs between 30 and 120 min the uptake of piracetam-14C in the brain is somewhat retarded. On the other hand the substance seems to be present much longer in the central nervous system than in most of the other organs. As shown by autoradiographic analysis of brain slices of the dog piracetam-14C is preferably concentrated in the grey matter of the cerebrum and cerebellum, caudate nucleus, hippocampus, lateral geniculate body and chorioide plexus. On the other hand the content in the white matter is low. The heuristic conclusions of this characteristic pattern of distribution of piracetam-14C in the central nervous system are discussed.