title: Distinct distributions of two bombesin receptor subtypes in the rat central nervous system.
abstract: We have previously demonstrated the presence of two distinct bombesin receptor subtypes in the rat CNS and distinguished them as bombesin/gastrin-releasing peptide (BBS/GRP) and neuromedin B (NMB)-preferring binding sites. In the present study, we conducted a complete evaluation of the distribution of these binding sites throughout the rat brain using in vitro receptor autoradiography. The BBS/GRP-preferring binding sites were characterized as those that bound 125I-(Tyr4)BBS but not 125I-(D-Tyr0)NMB. At these sites 125I-(Tyr4)BBS binding was inhibited in the presence of 100 nM BBS but not by the same concentration of NMB. In contrast, NMB-preferring sites bound both radioligands and binding at these sites was inhibited in the presence of 100 nM NMB. Our results indicate that the distributions of BBS/GRP and NMB-preferring binding sites are widespread and distinct at all levels of the rat brain suggesting these peptides mediate separate functions in the rat central nervous system.
authors.affiliation: Johns Hopkins University School of Medicine, Department of Psychiatry and Behavioral Sciences, Baltimore, MD 21205.
authors.forename: E E
authors.initials: EE
authors.lastname: Ladenheim
authors.forename: R T
authors.initials: RT
authors.lastname: Jensen
authors.forename: S A
authors.initials: SA
authors.lastname: Mantey
authors.forename: T H
authors.initials: TH
authors.lastname: Moran
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001345:Autoradiography / Q000379:methods; D001665:Binding Sites; D001839:Bombesin / Q000031:analogs & derivatives* / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D019886:Gastrin-Releasing Peptide; D007457:Iodine Radioisotopes; D008297:Male; D008969:Molecular Sequence Data; D015287:Neurokinin B / Q000031:analogs & derivatives / Q000378:metabolism; D009928:Organ Specificity; D010455:Peptides / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018004:Receptors, Bombesin; D017981:Receptors, Neurotransmitter / Q000145:classification / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D007457:Iodine Radioisotopes; D010455:Peptides; D018004:Receptors, Bombesin; D017981:Receptors, Neurotransmitter; D019886:Gastrin-Releasing Peptide; D015287:Neurokinin B; C038393:neuromedin B; D001839:Bombesin