Background:

M40 is a potent, non-selective galanin receptor antagonist.

M40 (1 μM) displaces [mono[125IJodo-Tyr26]galanin from binding sites in the hippocampus, hypothalamus, and spinal cord. M40 has a lower affinity than galanin for all membranes. The IC50 values are 6 nM in the hippocampus, 15 nM in the hypothalamus, 12 nM in the spinal cord, and 3 nM in the insulinoma cells. M40 (1 μM) completely blocks 125I-labeled galanin-binding sites[1].

参考文献:
[1]. Bartfai T, et al. Galanin-receptor ligand M40 peptide distinguishes between putative galanin-receptor subtypes. Proc Natl Acad Sci U S A. 1993 Dec 1;90(23):11287-91.