Leptin receptor expression in the basolateral nucleus of amygdala of conditioned taste aversion rats.

Abstract

To determine whether serum leptin level and the leptin receptor (OB-R) expression in the basolateral amygdala (BLA) change following conditioned taste aversion (CTA) formation. The serum leptin concentration was measured by rat leptin RIA kit, long and short forms of leptin receptor (OB-Rb and OB-Ra) mRNA in the brain sections were examined by in situ hybridization (ISH) and the expression of OB-R was assessed by immunohistochemistry ABC method with a highly specific goat anti-OB-R antibody. The level of serum leptin didn't show significant difference between CTA and control group. Comparing with the control group, the CTA group had an increase on count of OB-R immunohistochemistry positive-stained cells in the BLA (127+/-12 vs 48+/-9 per 1 mm(2)). The OB-Rb mRNA expression level enhanced by 11.9 % in the BLA, while OB-Ra mRNA level increased by 7.4 % on the choroid plexus in CTA group. So BLA was supposed to be a region where interactions between gustatory and vagal signals take place. BLA is one of the sites, which are responsible for CTA formation in the brain. Leptin and OB-R maybe involved in neuronal communication for CTA. So leptin and its receptors probably take part in CTA and integration of autonomic and extroceptive information.