Effects and mechanisms of exogenous nesfatin-1 injection in the central nucleus of the amygdale on exploratory behavior in rats

Abstract

Objective To explore the effects and mechanisms of nesfatin-1 injection in the central nucleus of the amygdale(CeA) on exploratory behavior in rats. Methods Fifty rats were divided into 5 groups randomly: nesfatin-1 low dose group, nesfatin-1 high dose group, SHU9119 group, SHU9119+ nesfatin-1 low dose group and control group.Drugs were administrated via CeA to examine behavioral changes of rats by elevated plus maze model test and nesfatin-1 mRNA expression in CeA of anxiety rats (10 rats). Results Compared with the control group, anxiety behaviors of rats in nesfatin-1 low dose group and nesfatin-1 high dose group were improved remarkably, showing that the open arm entries were significantly reduced (OE, t=4.16-12.87, P<0.01), open arm entry proportion was decreased remarkably (OE%, t=2.39-4.39, P<0.01-0.05), and time proportion in open arm was decreased significantly (OT%, t=5.43-20.55, P<0.01), which presented dose dependent.Compared with the control group, anxiety degree of rats in nesfatin-1 low dose group and nesfatin-1 high dose group significantly enhanced, showing that the rats head dipping reduced obviously (HD, t=6.97-16.73, P<0.01), while rearing was increased significantly (RE, t=6.60-13.25, P<0.01), which was presented dose dependent. Melanocortin receptor antagonist SHU9119 can partly eliminate nesfatin-1 induce-anxiety(t=2.11-3.08, P<0.01-0.05). Real-time PCR results showed that nesfatin-1 mRNA expression of anxiety model rats was significantly increased (t=3.40-5.58, P<0.05). Conclusion Amygdala nesfatin-1 can increase anxiety and fear of rats, which may be associated with melanocortin systems. Key words: Nesfatin-1; Anxiety; Fear; Elevated plus maze; Amygdale