text: (-)-Isoprenaline and a nonconventional << beta(3)-adrenoceptor >> agonist, (+/-)-[4-[3-[(1,1-dimethylethyl)amino]-2-hydroxypropoxy]-1,3-dihydro-2H-benzimida zol-2-one] hydrochloride ([[ (+/-)-CGP12177A ]]), induced concentration-dependent relaxation of (-)-phenylephrine (0.3 microM) preconstricted spiral preparations.