TABLE 4

Pharmacological profile of ligands with agonist/partial agonist efficacy on hMT1, hMT2 and native melatonin receptors

pKi, pEC50, and pIC50 values were obtained as detailed in footnotes.

2-[125I]IMLT Binding (COS-7 Cells)aCHO CellsInhibition [3H]Dopamine Release in Rabbit Retinad (pIC50)
Stimulation GTPγS BindingbInhibition-Forskolin Stimulated cAMP Accumulationc
hMT1 (pKi)hMT2(pKi)Ki Ratio (MT1/MT2)hMT1 (pEC50)hMT2 (pEC50)pEC50 Ratio (MT1/MT2)hMT1 (pEC50)hMT2 (pEC50)pEC50 Ratio (MT1/MT2)
2-Iodomelatonin10.29.70.39.79.81.11110.10.111.2
S 200989.110.2148.810169.410.37.912
Melatonin9.19.84.98.69.84.59.59.71.610.7
GR1964298.6e9.3e4.7e89.012.610.5
6-Chloromelatonin7.99.7578.39.39.68.19.85010.4
6-Hydroxymelatonin9.48.37.37.27.40.68.7
5-Methoxyluzindole7.59.6130N.D.N.D.1.3
8M-PDOT7.28.520N.D.N.D.9.3
N-Acetylserotonin6.76.71.25.76.67.97.3
5-MCA-NAT5.66.610N.D.N.D.N.D.
IIK78.4f10.3f908.7f10.3f44N.D.
  • IMLT, iodomelatonin; N.D., not determined.

  • a Dubocovich et al. (1997); COS-7 cells transiently transfected.

  • b Audinot et al. (2003).

  • c Browning et al., (2000); CHO cells stably transfected.

  • d Dubocovich (1985, 1995); inhibition of calcium dependent release of dopamine elicited by electrical stimulation.

  • e M. L. Dubocovich, unpublished observations; CHO cells stably transfected.

  • f Faust et al. (2000); NIH 3T3 cells stably transfected.