Receptor autoradiography as mean to explore the possible functional relevance of neuropeptides: focus on new agonists and antagonists to study natriuretic peptides, neuropeptide Y and calcitonin gene-related peptides

Evidence for the Existence of an Additional Class of Neuropeptide Y Receptor Sites in Rat Brain

“…Previous studies have clearly demonstrated that 125 (Dumont et al, 2000c(Dumont et al, , 2004a recognized a heterogeneous population of receptor binding sites in the mammalian brains. All three radioligands bind to the Y 5 receptor subtype, although with different affinities (Michel et al, 1998;Dumont et al, 2004a (Cabrele et al, 2001); and nonpeptide Y 5 antagonists, such as CGP71683A (Criscione et al, 1998), JCF109 (Feletou et al, 1999), CP732925 (Elliott et al, 2003), and CP760542 and CP781214 (Yannielli et al, 2004).…”

“…All three radioligands bind to the Y 5 receptor subtype, although with different affinities (Michel et al, 1998;Dumont et al, 2004a (Cabrele et al, 2001); and nonpeptide Y 5 antagonists, such as CGP71683A (Criscione et al, 1998), JCF109 (Feletou et al, 1999), CP732925 (Elliott et al, 2003), and CP760542 and CP781214 (Yannielli et al, 2004). As shown in Fig.…”

“…The various effects of this peptide family are mediated by the activation of at least five receptor subtypes designated as Y 1 , Y 2 , Y 4 , Y 5 , and y 6 (Michel et al, 1998). They have all been cloned and belong to the seven transmembrane G protein-coupled receptor type 1 superfamily (Michel et al, 1998;Dumont et al, 2004a). They are expressed as functional receptors in various rat and human tissues, except for the y 6 subtype, which is restricted to mouse and rabbit (Michel et al, 1998).…”

“…Furthermore, quantitative receptor autoradiography has demonstrated that labeling seen with 125 I-rPP (a Y 4 ligand with low affinity for the Y 5 receptor) was not identical to that of specific 125 I-hPP. In some rat brain nuclei such as the interpeduncular nuclei, nucleus tractus solitarius, and area postrema, higher levels of specific 125 I-hPP binding sites were detected compared with specific 125 I-rPP binding (Trinh et al, 1996) (Gehlert et al, 1997) and 125 I-GR231118 (Dumont and Quirion, 2000;Schober et al, 2000) binding sites even if these two radioligands are known to possess high affinities for the Y 4 receptor subtype (Dumont et al, 2004a). These results could be taken as evidence for the existence of yet another class of sites preferentially recognized by PPrelated molecules.…”

Modulation by Brain Natriuretic Peptide of GABA Receptors on Rat Retinal ON-Type Bipolar Cells

“…NPs and NPRs are widely distributed in the CNS (DiCicco-Bloom et al, 2004;Dumont et al, 2004), suggesting possible involvement of NPs in neuromodulation in CNS. Localization of NPs in the retina also has been reported in several species (Stone and Glembotski, 1986;Shyjan et al, 1992;Palm et al, 1994;Wolfensberger et al, 1994;Fernandez-Durango et al, 1995;Moriwaki et al, 1998;Haverkamp et al, 1999;Spreca et al, 1999;Blute et al, 2000;Cao et al, 2004;Rollin et al, 2004).…”