Catalog Number Product Name Quantity $US/Euro Order 001-82 Bombesin Receptor Subtype-3 (BRS-3) (371-399) 100 µg 200         H-001-82 Bombesin Receptor Subtype-3 (BRS-3) (371-399) Antiserum 100 µl 450         B-001-82 Bombesin Receptor Subtype-3 (BRS-3) (371-399), Biotin labeled 20 µg 300         DBK-001-82 Bombesin Receptor Subtype-3 (BRS-3) (371-399) Dot Blot Kit kit 550         G-001-82 Bombesin Receptor Subtype-3 (BRS-3) (371-399) Purified IgG 200 µg 450         B-G-001-82 Bombesin Receptor Subtype-3 (BRS-3) (371-399) Purified IgG, Biotin labeled 100 µl 500         FG-G-001-82 Bombesin Receptor Subtype-3 (BRS-3) (371-399) Purified IgG, FAM labeled 100 µl 500         FRP-G-001-82 Bombesin Receptor Subtype-3 (BRS-3) (371-399) Purified IgG, R-PE labeled 100 µl 550

The distribution of the orphan bombesin receptor subtype-3 in the rat cns
Bombesin receptor subtype 3 (BRS-3) is an orphan G-protein coupled receptor that shares between 47 and 51% homology with other known bombesin receptors. The natural ligand for BRS-3 is currently unknown and little is known about the mechanisms regulating BRS-3 gene expression. Unlike other mammalian bombesin receptors that have been shown to be predominantly expressed in the CNS and gastrointestinal tract, expression of the BRS-3 receptor in the rat brain has previously not been observed.To gain further understanding of the biology of BRS-3, we have studied the distribution of BRS-3 mRNA and protein in the rat CNS. The mRNA expression pattern was studied using reverse transcription followed by quantitative polymerase chain reaction. Using immunohistological techniques, the distribution of BRS-3 protein in the rat brain was investigated using a rabbit affinity-purified polyclonal antiserum raised against an N-terminal peptide. The BRS-3 receptor was found to be widely expressed in the rat brain at both mRNA and protein levels. Particularly strong immunosignals were observed in the cerebral cortex, hippocampal formation, hypothalamus and thalamus. Other regions of the brain such as the basal ganglia, midbrain and reticular formation were also immunopositive for BRS-3.In conclusion, our neuroanatomical data provide evidence that BRS-3 is as widely expressed in the rat brain as other bombesin-like peptide receptors and suggest that this receptor may also have important roles in the CNS, mediating the functions of a so far unidentified ligand. 
Jennings CA, et al. Neuroscience. 2003;120(2):309-24.

Rational design of a peptide agonist that interacts selectively with the orphan receptor, bombesin receptor subtype 3
The orphan receptor, bombesin (Bn) receptor subtype 3 (BRS-3), shares high homology with bombesin receptors (neuromedin B receptor (NMB-R) and gastrin-releasing peptide receptor (GRP-R)). This receptor is widely distributed in the central nervous system and gastrointestinal tract; target disruption leads to obesity, diabetes, and hypertension, however, its role in physiological and pathological processes remain unknown due to lack of selective ligands or identification of its natural ligand. We have recently discovered (Mantey, S. A., Weber, H. C., Sainz, E., Akeson, M., Ryan, R. R. Pradhan, T. K., Searles, R. P., Spindel, E. R., Battey, J. F., Coy, D. H., and Jensen, R. T. (1997) J. Biol. Chem. 272, 26062-26071) that [d-Tyr(6),beta-Ala(11),Phe(13),Nle(14)]Bn-(6-14) has high affinity for BRS-3 and using this ligand showed BRS-3 has a unique pharmacology with high affinity for no known natural Bn peptides. However, use of this ligand is limited because it has high affinity for all known Bn receptors. In the present study we have attempted to identify BRS-3 selective ligands using a strategy of rational peptide design with the substitution of conformationally restricted amino acids into the prototype ligand [d-Tyr(6),beta-Ala(11),Phe(13),Nle(14)]Bn-(6-14) or its d-Phe(6) analogue. Each of the 22 peptides synthesized had binding affinities determined for hBRS-3, hGRPR, and hNMBR, and hBRS-3 selective ligands were tested for their ability to activate phospholipase C and increase inositol phosphates ([(3)H]inositol phosphate). Using this approach we have identified a number of BRS-3 selective ligands. These ligands functioned as receptor agonists and their binding affinities were reflected in their potencies for altering [(3)H]inositol phosphate. Two peptides with an (R)- or (S)-amino-3-phenylpropionic acid substitution for beta-Ala(11) in the prototype ligand had the highest selectivity for the hBRS-3 over the mammalian Bn receptors and did not interact with receptors for other gastrointestinal hormones/neurotransmitters. Molecular modeling demonstrated these two selective BRS-3 ligands had a unique conformation of the position 11 beta-amino acid. This selectivity was of sufficient magnitude that these should be useful in explaining the role of hBRS-3 activation in obesity, glucose homeostasis, hypertension, and other physiological or pathological processes.
Mantey SA,et al. J Biol Chem 2001 Mar 23;276(12):9219-29

Mice lacking bombesin receptor subtype-3 develop metabolic defects and obesity
Mammalian bombesin-like peptides are widely distributed in the central nervous system as well as in the gastrointestinal tract, where they modulate smooth-muscle contraction, exocrine and endocrine processes, metabolism and behaviour. They bind to G-protein-coupled receptors on the cell surface to elicit their effects. Bombesin-like peptide receptors cloned so far include, gastrin-releasing peptide receptor (GRP-R), neuromedin B receptor (NMB-R), and bombesin receptor subtype-3 (BRS-3). However, despite the molecular characterization of BRS-3, determination of its function has been difficult as a result of its low affinity for bombesin and its lack of an identified natural ligand. We have generated BRS-3-deficient mice in an attempt to determine the in vivo function of the receptor. Mice lacking functional BRS-3 developed a mild obesity, associated with hypertension and impairment of glucose metabolism. They also exhibited reduced metabolic rate, increased feeding efficiency and subsequent hyperphagia. Our data suggest that BRS-3 is required for the regulation of endocrine processes and metabolism responsible for energy balance and adiposity. BRS-3-deficient mice provide a useful new model for the investigation of human obesity and associated diseases.
Ohki-Hamazaki H, et al. Nature 1997 Nov 13;390(6656):165-9

Mantey SA, et al. J Pharmacol Exp Ther. 2004 Apr 21 [Epub ahead of print]

BALB 3T3 cells stably transfected with hBRS-3, hGRP-R or hNMB-R were incubated with [3H]inositol and total [3H]IP determined as described in Methods. For each peptide a dose-response curve was performed with concentrations from 0.01 nM to 1 µM (Fig. 5). Results were expressed as the concentration causing one-half the maximal increase, EC50, seen with 1 µM peptide calculated from the dose-response curves in Fig. 5 using the curve-fitting program, KaleidaGraph. Each value is a mean ± SEM from at least three experiments. For hBRS-3/BALB 3T3 cells, the control and 1 µM [D-Tyr6,ß-Ala11,Phe13,Nle14]Bn(6-14) values were 10624 ± 571 dpm and 37660 ± 4106 dpm, respectively. For hGRP-R/BALB 3T3 cells, the control and 1 µM [D-Tyr6, ß-Ala11, Phe13, Nle14] Bn(6-14) values were 9231 ± 2260 dpm and 43060 ± 9137 dpm, respectively. With hNMB-R/BALB 3T3 cells the control and 1 µM [D-Tyr6,ß-Ala11,Phe13,Nle14]Bn(6-14) values were 2020 ± 166 dpm and 40667 ± 2371 dpm, respectively.
Mantey SA, et al. J Pharmacol Exp Ther. 2004 Apr 21 [Epub ahead of print]

Fig. 1. Structures of various conformationally restricted amino acids used. Mantey SA, et al. J Pharmacol Exp Ther. 2004 Apr 21 [Epub ahead of print]

The ability of [D-Tyr6,ß-Ala11,Phe13,Nle14]Bn(6-14) and various analogues of DTyr6, Apa11,Phe13,Nle14]Bn(6-14) with position 11 chloro-substitutions to inhibit binding at the hBRS-3 (top), hGRP-R (middle) or hNMB-R (bottom). BALB 3T3 cells stably transfected with hBRS-3 (0.5 x 106 cells/ml), hGRP-R (0.3 x 106 cell/ml) or hNMB-R (0.03 x 106 cells/ml) were incubated for 60 min at 22oC with 50 pM I125-[D-Tyr6,ß- Ala11,Phe13,Nle14]Bn(6-14), 125I-[Tyr4]Bn or 125I-[D-Tyr0]NMB, respectively, with or without the indicated concentrations of the various peptides added. Results are expressed as the percentage of saturable binding without unlabeled peptide added (percent control). Results are the mean ± SEM from at least three experiments, and in each experiment the data points were determined in duplicate. Numbers refer to the peptide number in Table 1. Abbreviations: See Table 1 legend.
Mantey SA, et al. J Pharmacol Exp Ther. 2004 Apr 21 [Epub ahead of print]

Ability of Bn, NMB and analogues of [D-Tyr6,ß-Ala11,Phe13,Nle14]Bn(6-14) with various position 11 or 14 conformationally restrictive substitutions to inhibit binding at hBRS-3 (top), hGRP-R (middle) or hNMB-R (bottom). The experimental conditions were similar to those outlined in the Fig. 2 legend. The results are expressed as the percentage of saturable binding without unlabeled peptide added (percent control) and are means ± SEM from at least three experiments with each data point determined in duplicate. Numbers refer to peptide numbers in Fig. 1 and legend of Table 1. Abbreviations: see Fig. 1 and legend of Table 1.
Mantey SA, et al. J Pharmacol Exp Ther. 2004 Apr 21 [Epub ahead of print]

4. Comparison of the ability of [D-Tyr6,ß-Ala11,Phe13,Nle14]Bn(6-14) and various hBRS-3 selective ligands to inhibit binding to hBRS-3 (top), hGRP-R (middle) or hNMB-R (bottom). The experimental conditions are same as outlined in the Fig. 2 legend. The results are expressed as the percentage of saturable binding without unlabeled peptide added (percent control). Results are the means ± SEM of at least three experiments and in each experiment the data points were determined in duplicate. Numbers refer to peptide numbers in Table 1. Abbreviations: see legend of Table 1 and Fig. 1. Peptide 2 (Table 1) and peptide 3 (Table 1) were reported to be hBRS-3 selective ligands in ref. (Mantey et al., 2001).
Mantey SA, et al. J Pharmacol Exp Ther. 2004 Apr 21 [Epub ahead of print]

Ability of NMB, Bn, and various analogues of [D-Tyr6,b- Ala11,Phe13,Nle14]Bn-(6–14) altered in positions 6 or 13 to inhibit binding to hBRS-3- (top), hGRP-R- (middle), or hNMB-R- (bottom) transfected BALB 3T3 cells. BALB 3T3 cells stably transfected with hBRS-3 (0.5 3 106 cells/ml), hGRP-R (0.2 3 106 cells/ml), and hNMB-R (0.1 3 106 cells/ml) were incubated for 60 min at 22 °C with 50 pM 125I-[D-Tyr6,b-Ala11,Phe13,Nle14]Bn-(6–14), 125I-[Tyr4]Bn, or 125I-[DTyr0] NMB, respectively, with or without the indicated concentration of the various peptides added. Results are expressed as the percentage of saturable binding without unlabeled peptide added (percent control). Results are the mean 6 S.E. from at least three experiments, and in each experiment the data points were determined in duplicate. Numbers refer to the peptide number in Table I.

Comparison of the ability of [D-Tyr6, b-Ala11, Phe13,Nle14]Bn-(6–14) and various analogues with changes due to amino acid deletion, addition, or substitution at positions 6, 7, 9, and 11 to inhibit binding to the hBRS-3- (top), the hGRP-R- (middle), and the hNMB-R- (bottom) transfected BALB 3T3 cells. The experimental conditions were same as outlined in the legend to Fig. 2. The results are expressed as the percentage of saturable binding without unlabeled peptide added (percent control). Results are the mean 6 S.E. of at least three experiments and in each experiment the data points were determined in duplicate. Numbers refer to the peptide number in Table I.