Non-associative learning and anxiety in rats treated with a single systemic administration of the gastrin-releasing peptide receptor antagonist RC-3095

The gastrin-releasing peptide receptor (GRPR) has been implicated in the modulation of emotionally-motivated memory. In the present study, we investigated the role of the GRPR on non-emotional, non-associative memory, and anxiety. Adult male Wistar rats were given a systemic injection of the GRPR antagonist [D-Tpi6, Leu13 psi(CH2NH)-Leu14] bombesin (6-14) (RC-3095) (0.2, 1.0 or 5.0 mg/kg) 30 min before exposure to an open field or an elevated plus maze. Habituation to the open field was tested in a retention trial carried out 24 h after the first exposure to the open field. Rats given RC-3095 at the doses of 1.0 or 5.0 mg/kg showed impaired habituation. Animals treated with 5.0 mg/kg of RC-3095 spent significantly more time in the closed arms of the elevated plus maze. No effects of RC-3095 on locomotion or exploratory behavior were observed. The results implicate the GRPR in the regulation of non-emotional, non-associative memory as well as in anxiety.