Table 2.

Summary of receptor binding studies in Helixbrain^a

Peptide2-b	IC50(μm)2-c
FMRFa	0.53
FLRFa	1.3
PFLRFa	0.86
DPFLRFa	3.4
NDPFLRFa	9
SDPFLRFa	15
pQDPFLRFa	10
pQYPFLRFa	0.22
daYPFLRFa	0.20

^F2-aThis table is composed from data in Table 2 of Payza et al. (1989).

^F2-bAbbreviations include “a” = NH₂, “pQ” = pyroglutamic acid, “da” = des-amino, “nL” = norleucine.

^F2-cConcentration needed to displace 50%¹²⁵I-da YFnLRFa from a Helix brain membrane preparation.