To characterize the alpha(1)-adrenoceptor subtypes, we developed a flow cytometry method using the fluorescent ligand BODIPY-FL prazosin and the anti-peptide antibody against the alpha(1b)-adrenoceptor amino terminus (designated 1B-N1-C) as probes, Three alpha(1)-adrenoceptors (alpha(1a), alpha(1b) and alpha(1d)) expressed in CHO cells were detected by BODIPY-FL prazosin; however, only alpha(1b)-adrenoceptor subtype was detected by the anti-peptide antibody 1B-N1-C, Furthermore, the flow cytometry analysis with 1B-N1-C specifically identified alpha(1b)-adrenoceptor in native cells of hamster DDT1-MF2 cells, rat hepatocytes and1 cardiomyocytes.