[(3)H]-F13640, a novel, selective and high-efficacy serotonin 5-HT(1A) receptor agonist radioligand.
F13640 is a selective and high-efficacy serotonin 5-HT(1A) receptor agonist that demonstrates outstanding analgesic potential in different animal models. Here, we use the radiolabelled compound to further characterise its binding properties at 5-HT(1A) receptors. F13640 was tritium-labelled to 47 and 64 Ci/mmol specific activity and used as radioligand at membrane preparations of CHO cells expressing human (h) 5-HT(1A) receptors. The K (d) of [(3)H]-F13640 was 1.8 nM at h5-HT(1A) receptors as determined from saturation binding experiments. In association time-course experiments, k (obs) of [(3)H]-F13640 was 0.06 min(-1). Dissociation experiments performed in the presence of unlabelled F13640 as competing ligand yielded a k (off) value of 0.05 min(-1), resulting in a calculated K (d) of 1.4 nM. In comparison, [(3)H]-8-OH-DPAT had a k (obs) of 0.50 min(-1), a k (off) of 0.25 min(-1) and a calculated K (d) of 0.37 nM. Surprisingly, [(3)H]-F13640 dissociation kinetics were distinctly slower in the presence of WAY-100635 and spiperone as competing ligands when compared with the agonist competitors, F13640 and (+)8-OH-DPAT. The competitive binding profile of [(3)H]-F13640 with eight chemically diverse 5-HT(1A) receptor agonists and antagonists correlated highly (r = 0.996) with that of [(3)H]-8-OH-DPAT. In conclusion, [(3)H]-F13640 is a potent agonist radioligand at 5-HT(1A) receptors and may be a useful tool in pharmacological studies at native and recombinant 5-HT(1A) receptors. In addition, [(3)H]-F13640 dissociates more slowly from h5-HT(1A) receptors than [(3)H]-8-OH-DPAT, a kinetic property that might be related to its powerful analgesic effects as observed in vivo.
Heusler
Peter
P
Department of Cellular and Molecular Biology, Centre de Recherche Pierre Fabre, Castres Cedex, France. peter.heusler@pierre-fabre.com
Palmier
Christiane
C
Tardif
Stéphanie
S
Bernois
Sophie
S
Colpaert
Francis C
FC
Cussac
Didier
D
D000818:Animals; D001667:Binding, Competitive; D016466:CHO Cells; D018929:Cell Culture Techniques; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D010880:Piperidines / Q000494:pharmacology*; D011485:Protein Binding; D011725:Pyridines / Q000494:pharmacology*; D011869:Radioligand Assay; D044282:Receptor, Serotonin, 5-HT1A / Q000096:biosynthesis / Q000378:metabolism*; D058825:Serotonin 5-HT1 Receptor Agonists / Q000494:pharmacology*; D014316:Tritium
D010880:Piperidines; D011725:Pyridines; D044282:Receptor, Serotonin, 5-HT1A; D058825:Serotonin 5-HT1 Receptor Agonists; D014316:Tritium; C473959:befiradol
Eur J Pharmacol. 1999 Feb 19;367(2-3):413-22
10079018
Nat Rev Drug Discov. 2006 Sep;5(9):730-9
16888652
J Pharm Pharmacol. 1988 Dec;40(12):888-91
2907586
Br J Pharmacol. 2000 Jul;130(6):1348-52
10903975
Neuropharmacology. 2002 Nov;43(6):945-58
12423664
J Neurochem. 1995 Nov;65(5):1909-16
7595473
Behav Brain Res. 1996;73(1-2):337-53
8788530
J Pharmacol Exp Ther. 1997 Oct;283(1):216-25
9336327
Fundam Clin Pharmacol. 2010 Jun;24(3):293-303
20015228
Biochem Pharmacol. 1993 Mar 9;45(5):1003-9
8461029
J Pharmacol Exp Ther. 2003 Nov;307(2):608-14
12970382
Eur J Pharmacol. 1995 Jan 16;288(2):173-86
7720779
Eur J Pharmacol. 1984 May 4;100(3-4):263-76
6203761
Neuroscience. 2004;124(4):901-11
15026130
Life Sci. 1997;60(9):653-65
9048968
Eur J Pharmacol. 1986 May 27;124(3):371-3
2942413
Proc Natl Acad Sci U S A. 1993 Sep 15;90(18):8547-51
8397408
Br J Pharmacol. 1990 Apr;99(4):803-9
1972896
Eur J Pharmacol. 1996 May 15;303(3):151-62
8813561
Trends Pharmacol Sci. 2007 Dec;28(12):615-20
18022255
Eur J Pharmacol. 1996 Apr 4;300(1-2):137-9
8741179
Naunyn Schmiedebergs Arch Pharmacol. 1998 Mar;357(3):205-17
9550290
J Biol Chem. 2002 May 3;277(18):15482-5
11854302
Br J Pharmacol. 1996 Nov;119(5):845-50
8922730
Neuropharmacology. 2003 Jun;44(7):873-81
12726819
Curr Top Med Chem. 2008;8(12):1024-34
18691130
J Pharmacol Exp Ther. 1986 Oct;239(1):136-43
2876092
Trends Pharmacol Sci. 2003 Dec;24(12):634-9
14654304
J Pharmacol Exp Ther. 2002 Jul;302(1):240-8
12065723
Nat Rev Drug Discov. 2004 Sep;3(9):801-8
15340390
Naunyn Schmiedebergs Arch Pharmacol. 1997 Nov;356(5):551-61
9402034
J Pharmacol Exp Ther. 1997 Mar;280(3):1241-9
9067310
Eur J Pharmacol. 1999 Dec 10;386(1):97-103
10611469
Br J Pharmacol. 2001 Jan;132(2):518-24
11159702
Brain Res. 1993 Jul 16;617(1):159-62
8374738
Curr Opin Investig Drugs. 2006 Jan;7(1):40-7
16425670
Nat Rev Drug Discov. 2002 Feb;1(2):103-10
12120091
Eur J Pharmacol. 1995 Jul 25;281(1):81-8
8566121
Neurochem Res. 2006 Sep;31(9):1135-40
16937076
Nature. 1983 Sep 8-14;305(5930):140-2
6225026
J Pharmacol Exp Ther. 2005 Mar;312(3):1034-42
15528450
Pharmacol Rev. 2002 Jun;54(2):323-74
12037145
J Med Chem. 1981 Aug;24(8):921-3
6460101