Comparison of Displacemental Potencies of Terazosin Enantiomers for α₁-Adrenoceptor Subtypes

抄録

The present study was designed to assess displacemental potencies of terazosin and its isomers for α_1High and α_1Low adrenoceptor subtypes in rat brain, heart, bovine prostate and canine aorta using a radioligand binding assay method. Although no significant difference in pK_i values of each terazosin isomer for α_1High in canine aorta and rat brain were observed, the displacemental potency of (S-) terazosin for those in rat heart and bovine prostate was stronger than that of (R+) isomer (p<0.01). On the other hand, only in α_1Low subtypes of bovine prostate was stronger displacemental potency of (S-) terazosin than (R+) isomer (p<0.05) observed. Thus, these results imply that there is a different affinity between (S-) terazosin and (R+) isomer on the α_1High in bovine prostate and rat heart and α_1Low in bovine prostate.