Stereoselectivity of 8-OH-DPAT Enantiomers at Cloned Human 5-HT1D Receptor Sites

The cAMP responses of (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and its enantiomers were measured at cloned human 5-HT1D alpha and 5-HT1D beta receptors in transfected C6-glial cells. R(+)-8-OH-DPAT demonstrated potent intrinsic activity (EC50 value: 30 nM) at 5-HT1D alpha receptor sites, its maximal effect being comparable to that of sumatriptan. Racemic 8-OH-DPAT and S(-)-8-OH-DPAT showed similar agonist efficacy but were respectively 2 and 75 times less potent than R(+)-8-)OH-DPAT. This differs from the lack of stereoselectivity of the 8-OH-DPAT enantiomers for 5-HT1A receptors.