Disease relevance of Neuromedin B

• Particularly relevant is the BB3 expression in lung carcinoids and other neuroendocrine lung tumors, whereas gastrointestinal carcinoids preferably express NMB receptors [1].
• Cultures of HBE cells from four of the five subjects with severe obstructive lung disease gave a positive response to GRP and NMB in proliferation assays, compared to five of fifteen without severe obstructive lung disease, but this difference was not significant (p = 0.13) [2].
• Intracerebroventricular injections of BN, GRP and NMB produced hypothermia in a dose-dependent manner [3].

High impact information on Neuromedin B

• Earlier studies have shown that GRP and NMB are expressed in different regions of both the CNS and peripheral organs [4].
• This analysis suggests that the bombesin-like peptides should be reclassified into the GRP subfamily, the NMB subfamily, and the skin peptide subfamily [5].
• The cDNA of the human neuromedin B gene (NMB) mapped to 15q11-qter recognizes an XbaI RFLP [6].
• Using clones stably transfected with the NMB receptor however, we found that NMB stimulated the incorporation of [3H]thymidine 2.5- to 8-fold over basal levels [7].
• 6. Although bath application of GRP or NMB had little or no effect on the resting membrane properties of CA1 pyramidal cells per se, these neuropeptides produced a dramatic increase in the number and amplitude of miniature inhibitory postsynaptic currents in these cells in a TTX-sensitive manner [8].

Chemical compound and disease context of Neuromedin B

• Bombesin (BN) and structurally related peptides, gastrin-releasing peptide (GRP) and neuromedin B (NMB), injected into the lateral ventricle produce multiple effects such as hypothermia, anorexia and hormone release [3].

Biological context of Neuromedin B

• GRP increased incorporation of [3H]thymidine and [3H]choline in explants, whereas NMB induced cell proliferation and Leu8-phyllolitorin yielded variable results [9].
• Some nuclei have a high affinity for NMB, similar to cortical BBS binding sites, other regions have a low affinity similar to pancreatic BBS binding sites [10].
• Our results showed that devazepide completely blocked the suppression of gastric emptying produced by BN, GRP18-27 and NMB but had no effect on BN-induced suppression of food intake [11].
• We examined the actions of porcine GRP and NMB on ion transport in the porcine proximal jejunum in vitro and compared their activities to those of their respective C-terminal amphibian homologs BB and ranatensin (RT) [12].
• Neuromedin B (NMB) did not show any effect on food intake [13].

Anatomical context of Neuromedin B

• We studied the effects of the bombesin analogues, gastrin releasing peptide (GRP) and neuromedin B (NMB), on guinea pig tracheal epithelial cell (GPTEC) migration [14].
• These data demonstrate that GRP and NMB elicit migration of airway epithelial cells but may not play a significant role in the early repair of the airway epithelium in culture [14].
• Isolated muscle strips from the cat fundus and duodenum showed a higher sensitivity to GRP-10 than to NMB [15].
• The 27-amino acid peptide gastrin-releasing peptide (GRP) and the decapeptide neuromedin B (NMB) are structurally related to bombesin (BB) and exist within the mammalian small intestine [12].
• 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 [16].

Associations of Neuromedin B with other chemical compounds

• 2. The inward current elicited by NMB or GRP was unaffected by K+ channel blockade with external Ba2+ or by replacement of potassium gluconate in the electrode solution with caesium acetate [8].
• BN, [Tyr4]-BN, NMB and litorin, were 10-20 times more potent than GRP and NMC [17].
• Neither GRP-R KO nor WT mice suppressed glucose intake following NMB administration [18].
• Balb/c 3T3 cells rarely generated outward currents in response to Bn, GRP, and NmB but did not respond to both AVP and Bk with outward current flows [19].

Gene context of Neuromedin B

• The affinities of various agonists for binding to the huGRP-R were Bn (Ki = 1.4 +/- 0.2 nM) = 4 x GRP = 300 x NMB [20].
• Specific [125I] BW1023U90 binding was inhibited with high affinity by GRP as well as bombesin (BB) but not neuromedin B (NMB) [21].
• Finally, in GH3 cells, high levels of NMB mRNA and GRP-R mRNA were found, while GRP mRNA and NMB-R mRNA remained undetectable even in high amounts (200 micrograms) of total RNA [22].
• To determine whether the inhibition of gastric emptying by BN-like peptides is mediated by a CCK-dependent mechanism, we examined the ability of the CCK-A receptor antagonist, devazepide, to block the inhibition of saline gastric emptying produced by BN, GRP18-27 and NMB [11].
• In binding studies the affinity of the mGRP-r in Sf9 cells for the agonists bombesin (Bn), GRP, and neuromedin B (NMB) varied differently with infection time: with Bn the affinity decreased 3-fold with longer infection times, with GRP it remained unchanged, and with NMB it decreased 10-fold [23].

Analytical, diagnostic and therapeutic context of Neuromedin B

• In total RNA from the reaggregate cell cultures we detected high levels of NMB mRNA as well as a strong signal for GRP-R mRNA [22].

References