AUTORADIOGRAPHIC STUDIES ON DISTRIBUTION OF PSYCHOACTIVE DRUGS IN RAT BRAIN .3. C-14-PSILOCIN

The distribution of14C psilocin was studied in 74 regions of the rat brain, using autoradiograms of sagittal serial sections 1, 30 and 60 min, 2, 4, 8 and 24 hours after intravenous injection. The absolute contents of psilocin in the various brain structures was determined by photometry and was found to range from 15.5 to 1.78 μg/g brain weight after one minute and from 0.57 to 0.06 μg/g brain weight after 24 hours. After the longer periods of time the highest values of psilocin were found in the neocortex, the hippocampus, and the thalamus, whilst the values were low in the hypothalamus, the nuclei of the so-called extra-pyramidal motor system and in the reticular formation. The distribution pattern of14C-psilocin was compared with the numerical nerve and glial cell density, the volume cell density, the capillary density, the contents of oxidative enzymes, the uptake of labelled amino acids, the lipid contents, and other patterns known through chemical or histochemical studies, but no meaningful correlation emerged. A very similar distribution pattern was found, however, in studies of neuroleptic and antidepressive drugs. © 1969 Springer-Verlag.