ABSTRACT
BACKGROUND: The endocannabinoid system plays a key role in the control of many emotional-correlated reactions such as stress, depressed mood, and anxiety. Moreover, citicoline has neuroprotective properties and indicates beneficial effects in the treatment of depressive problems. Acute restraint stress (ARS) is an experimental model used for the induction of rodent models of depression. OBJECTIVE: This research was designed to assess the effects of intracerebroventricular (i.c.v.) injection of cannabinoid CB1 receptor agents on citicoline-induced response to depression-like behaviors in the non-acute restraint stress (NARS) and ARS mice. METHODS: For i.c.v. microinjection, a guide cannula was implanted in the left lateral ventricle of male mice. The ARS model was carried out by movement restraint for 4 h. Depression-related behaviors were assessed by forced swimming test (FST), tail suspension test (TST), and splash test. RESULTS: The results exhibited that the ARS mice showed depressive-like responses. I.c.v. infusion of ACPA (1 µg/mouse) induced an antidepressant-like effect in the NARS and ARS mice by reduction of immobility time in the FST and TST as well as enhancement of grooming activity time in the splash test. On the other hand, i.c.v. microinjection of AM251 dose-dependently (0.5 and 1 µg/mouse) induced a depressant-like effect in the NARS mice. I.p. injection of citicoline (80 mg/kg) induced an antidepressant-like response in the NARS and ARS mice. Furthermore, ACPA (0.25 µg/mouse, i.c.v.) potentiated the antidepressant-like response induced by citicoline (20 mg/kg, i.p.) in the NARS and ARS mice. However, AM251 (0.25 µg/mouse, i.c.v.) reversed the antidepressant-like effect produced by the citicoline (80 mg/kg, i.p.) in the NARS and ARS mice. Interestingly, our results indicated a synergistic effect between citicoline and ACPA based on the induction of an antidepressant-like effect in the NARS and ARS mice. CONCLUSIONS: These results suggested an interaction between citicoline and cannabinoid CB1 receptors on the modulation of depression-like behaviors in the NARS and ARS mice.
