Fig 7. Structure activity relationships for various drug classes against Hs.5HT7R and Sm.5HTR.

Comparison of IC₅₀s for compounds inhibiting cAMP generation via Hs.5HT7R (abscissa) or Sm.5HTR (ordinate). Compounds with no preferential selectivity for either receptor, showing similar IC₅₀s, would cluster along the solid line. Hits in the lower right quadrant (red square) show sub-μM potency at Sm.5HTR but supra-μM potency at Hs.5HT7R. Four compounds meet this criterion (bromocriptine = ‘39’, rotundine = ‘37’, tetrandrine = ‘31’ and tetrabenazine = ‘32’). Compound classes are indicated as follows: ergot alkaloids (green), isoquinolines (blue), tricyclic and tetracyclic antidepressants (magenta), sulfonyl compounds (orange), miscellaneous structures (open). Individual compounds are: 1, SB269970; 2, amisulpride; 3, SB742457; 4, olanzapine; 5, mianserin; 6, quetiapine; 7, clozapine; 8, cyproheptadine; 9, ketotifen; 10, loratadine; 11, maprotiline; 12, clomipramine; 13, desloratadine; 14, rupatadine; 15, vortioxetine; 16, amitriptyline; 17, risperidone; 18, domperidone; 19, chlorprothixene; 20, clemastine; 21, aripiprazole; 22, ketanserin; 23, ifenprodil; 24, tripelennamine; 25, fluoxetine; 26, atomoxetine; 27, orphenadrine; 28, lisuride; 29, benztropine; 30, cyclizine; 31, tetrandrine; 32, tetrabenazine; 33, berberine; 34, 6, 7-diethoxy-1, 2, 3, 4-tetrahydroisoquinoline; 35, corynoline; 36, alfuzosin; 37, rotundine; 38, fanchinoline; 39, bromocriptine; 40, metergoline; 41, LY215840; 42, nicergoline; 43, mesulergine; 44, dihydroergocristine.