Neuromedin B (NMB) is a member of Bombesin (BN)-like peptide family in mammals.
Potency to stimulate contraction of rat uterine smooth muscle, that is used as bioassay for isolation of Neuromedin B (NMB), is compared with Bombesin (BN). The relative potency, calculated on molar basis by taking BN as 100, is 48% for GRP and 4.9% for NMB. NMB also has contractile activity on rat stomach strip, but the potency (ratio of peptide concentration required to elicit 50% maximum response; EC50) is only 5% of BN (EC50 of BN/EC50 of NMB) and about 10% of GRP (EC50 of GRP/ EC50 of NMB)[1].
Potencies of NMB and GRP for smooth muscle contraction of fundus in wild-type and NMB-R-deficient mice with ED50 of 14.4±2.3 (n=8) and 10.9±2.3 (n=8) in wild-type mice and NMB-R-deficient mice, respectively[1].
References:
[1]. Ohki-Hamazaki H. Neuromedin B. Prog Neurobiol. 2000 Oct;62(3):297-312.