[125I]BE 2254, a new high affinity radioligand for α1-adrenoceptors

[125I]BE 2254 (IBE 2254), a new iodinated radioligand of high specific radioactivity (2175 Ci/mmol) was developed and used to characterize α1-adrenoceptors in rat cerebral cortex membranes. IBE 2254 possessed a high affinity, Ksub(D) 78+-14 pM with a Bsub(max) of 210+-26 fmol/mg and 90% specific binding at Ksub(D) value. α1-Adrenergic antagonists competed for IBE 2254 binding in the following order: prazosin >= WB 4101 > phentolamine > corynanthine > yohimbine > rauwolscine, a strong indication that IBE 2254 binds to α1-adrenoceptors. IBE 2254 appears to be a very useful tool for studying α1-adrenoceptors. (Auth.)