Abstract
[(125)I]Iodo-ASEM, a new radioligand with high affinity and selectivity for α7-nAChRs (K(i) = 0.5 nM; α7/α4β2 = 3414), has been synthesized in radiochemical yield of 33 ± 6% from the corresponding di-butyltriazene derivative and at high specific radioactivity (1600Ci/mmol; 59.2 MBq/μmol). [(125)I]Iodo-ASEM readily entered the brains of normal CD-1 mice and specifically and selectively labeled cerebral α7-nAChRs. [(125)I]iodo-ASEM is a new useful tool for studying α7-nAChR.