Distinct distributions of two bombesin receptor subtypes in the rat central nervous system

Brain Res. 1992 Oct 16;593(2):168-78. doi: 10.1016/0006-8993(92)91305-x.


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.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Autoradiography / methods
  • Binding Sites
  • Bombesin / analogs & derivatives*
  • Bombesin / metabolism*
  • Brain / metabolism*
  • Gastrin-Releasing Peptide
  • Iodine Radioisotopes
  • Male
  • Molecular Sequence Data
  • Neurokinin B / analogs & derivatives
  • Neurokinin B / metabolism
  • Organ Specificity
  • Peptides / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Bombesin
  • Receptors, Neurotransmitter / classification
  • Receptors, Neurotransmitter / metabolism*
  • Structure-Activity Relationship


  • Iodine Radioisotopes
  • Peptides
  • Receptors, Bombesin
  • Receptors, Neurotransmitter
  • Gastrin-Releasing Peptide
  • Neurokinin B
  • neuromedin B
  • Bombesin