Characterization of two novel tritiated radioligands for labelling Neuropeptide FF (NPFF1and NPFF2) receptors

Franck Talmont, Laura Piedra Garcia, Honoré Mazarguil, Jean-Marie Zajac, Catherine Mollereau, Franck Talmont, Laura Piedra Garcia, Honoré Mazarguil, Jean-Marie Zajac, Catherine Mollereau

Index: Neurochem. Int. 55(8) , 815-9, (2009)

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Abstract

The binding characteristics of [ 3H]-NPVF and [ 3H]-EYF, the two first tritiated probes for the respective labelling of NPFF 1 and NPFF 2 receptors, are presented. In membranes from CHO cells transfected with the human NPFF 1 receptor, [ 3H]-NPVF labelled one class of binding sites with a high affinity (Bmax = 4 pmol/mg protein, Kd = 2.65 nM). In membranes from CHO cells transfected with the human NPFF 2 receptor, [ 3H]-EYF labelled one class of binding sites with a high affinity (Bmax = 16 pmol/mg protein, Kd = 0.54 nM). Both radioligands exhibited time-dependent binding, low (10–20%) non-specific binding and poor cross-reactivity towards the related receptor subtype. The potency of different NPFF ligands to displace [ 3H]-NPVF and [ 3H]-EYF binding profiles was in good agreement with the profile previously measured by using 125I-probes (NPFF 1 receptor: NPVF ≥ 1DMe = SPA-NPFF > NPFF = SQA-NPFF = QFW-NPSF > NPSF > RF9; NPFF 2 receptor: SPA-NPFF > > SQA-NPFF = QFW-NPSF = 1DMe = NPFF ≫ NPSF = NPVF > RF9). Therefore, [ 3H]-NPVF and [ 3H]-EYF are new valuable tools for performing binding on NPFF receptors.