Uptake of SPECT radiopharmaceuticals in neocortical brain cultures

The uptake, retention and uptake antagonism of 201Tl-DDC, 201Tl-Cl, 123I-IMP, 99mTc-HMPAO and 99mTc-O4- were compared in rat neocortex cultures. 201Tl-DDC and 123I-IMP revealed the highest uptake of radioactivity in the cultures. 99mTc-HMPAO and 123I-IMP showed the highest retention of radioactivity within the tissue in washout experiments. Blocking of bioelectric activity by tetrodotoxin did not significantly affect the uptake of the radiopharmaceuticals (RPHA). Inhibition of Na-K-ATPase by ouabain inhibited the uptake of 201Tl-Cl (77%) and 201Tl-DDC (27%). Imipramine showed a significantly stronger inhibitory effect on 123I-IMP uptake in comparison with the effect on other RPHA. 99mTc-O4- was not concentrated within the cultured tissue. Under the in vitro conditions used in this study, the various RPHA were characterised by distinct differences in their interaction with cortical brain tissue.