Research ReportNesfatin-1, a potent anorexic agent, decreases exploration and induces anxiety-like behavior in rats without altering learning or memory

- Chronic intraperitoneal injection of nesfatin-1 does not affect learning and memory.
- Chronic intraperitoneal injection of nesfatin-1 decreases exploration.
- Chronic intraperitoneal injection of nesfatin-1 induces anxiety-like behavior.
- The expression of BDNF and p-ERK1/2 was decreased in the hippocampus and prefrontal cortex of nesfatin-1-treated rats.

The anorectic neuropeptide nesfatin-1 has recently been characterized as a potential mood regulator, but the accurate effect of nesfatin-1 on anxiety and learning and memory behavior and the possible mechanisms remains unknown. In the present study, to test the hypothesis that nesfatin-1 might affect the anxiety-like and learning and memory behaviors in rats via ERK/CREB/BDNF pathway, nesfatin-1 was administered intraperitoneally to rats with the doses (10, 20, 40 μg/kg), and the behavioral performance was tested using the open field task, the Morris water maze (MWM), and the Y maze. Moreover, the protein expression of brain-derived neurotrophic factor (BDNF), total and phosphorylated-ERK in the hippocampus and the prefrontal cortex (PFC) were evaluated. The results showed that chronic administration of nesfatin-1 could decrease the moving distance, the duration in the center, and the frequencies of rearing and grooming in the open field task, decrease the moving distance, frequency, and the preference index of new arm in the Y maze, although there was no significant difference of the performance in the MWM task among groups. Furthermore, 3 weeks' consecutive administration of nesfatin-1 resulted in the decrease of protein expression of BDNF and phosphorylated-ERK in the hippocampus and the PFC. These results provided evidence that exogenous nesfatin-1 could decrease exploration and induce anxiety-like behavior in rats, the mechanism of which might be related to the reduced protein expression of BDNF and phosphorylated-ERK in the hippocampus and the PFC.