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-O ₄ ^– 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-O ₄ ^– 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.