Ghrelin is a 28-amino acid peptide hormone synthesized predominatly in stomach and hypothalamus.Recent evidence showed that Ghrelin/GHSR1a signaling has important roles in divergent neuronal functions,including learning and memory.Here, we investigated the effect of ghrelin on amygdala-dependent condition taste aversion (CTA) memory processes.Ghrelin (10 μM, 0.75 μL/side) or vehicle (0.9% saline) was locally infused into basolateral amygdala (BLA) 20 min before conditioning.Surprisingly, we found that local administration ofghrelin into BLA significantly inhibited CTA memory formation as test 24 h after conditioning.The inhibitory effect of ghrelin can be completely reversed by antibody against GHSR1 a receptor (5 ng) and phosphoinositide 3-Kinase inhibitor LY294002 (1 μM).Ghrelin had no effect on CTA memory retrieval when delivered shortly before testing.Importantly, no difference was seen on total liquid consuming among the groups.We further confirmed our behavioral findings with qRT-PCR to quantify the mRNA expression of c-fos and zif268 in BLA shortly after memory retrieval.All together, our data indicated that ghrelin/GHSRla signaling inhibits CTA memory acquisition and Pl3-kinase was involved in its effect.