Neuromedin B (NMB) and GRP are two members of the mammalian bombesin family of peptides. These two peptides activate structurally similar but pharmacologically distinct G-protein-coupled receptors. NMB is expressed in a subset of sensory neurons that co-label with calcitonin gene-related peptide and TRPV1, suggestive of a role for NMB in nociception. NMB-SAP removes neurons expressing the NMB receptor. In the periphery NMB and GRP have a wide variety of actions including smooth muscle contraction and exocrine and endocrine functions. In the CNS these peptides regulate food intake and body temperature, as well as stress behavioral responses. Additionally, immunolocalization studies showed that NMB protein is present in the dorsal horn of the spinal cord and expression was also seen in sensory neurons.
NMB-SAP is a chemical conjugate of Neuromedin B (10 AA) and the ribosome-inactivating protein, saporin. It eliminates Neuromedin B receptor expressing cells.