Table 2

Agonist potencies to stimulate [cAMP]i by the recombinant human 5-HT7(a) receptor isoform stably expressed in murine fibroblasts

Intrinsic ActivityDrugKi (nM)EC50(nM)Emax2-aEC50/Ki
Agonists5-CT0.49.7  ± 2.699  ± 124
5-HT2.678  ± 8100 30
5-MeOT2.2129  ± 2197  ± 159
DP-5-CT8.6626  ± 15290  ± 473
5-MeO-DMT313042  ± 114486  ± 698
Tryptamine5713342  ± 271399  ± 3234
8-OH-DPAT6662870  ± 795099  ± 2952
α-Me-5-HT26597500  ± 1775094  ± 8367
Partial agonists1-NP768222  ± 189631  ± 6108
Incomplete characterization2-b Sumatriptan951>100000<40
2-Me-5-HT4604>100000<35
  • 2-a Maximal stimulation of basal cAMP relative to 5-HT (intrinsic activity = 1.0).

  • 2-b Complete CRCs were not generated since the highest concentration of compound tested was 1 mM. Values represent maximal stimulation at 1 mM. Response parameters represent mean ± S.E. of 5 to 10 determinations.