BACKGROUND: Studies have shown that agmatine can reduce inhibition of neuronal regeneration by in-creasing cyclic adenosine monophosphate and brain-derived neurotrophic factor (BDNF) in the hippocampusof morphine-dependent rats. The hypothesis that agmatine exerts similar effects on facial nerve injury de-serves further analysis. OBJECTIVE: To study the effects of peritoneal agmatine injection on BDNF levels in the rat brainstem af-ter facial nerve injury. DESIGN, TIME AND SETTING: A controlled animal experiment was performed at the Department ofOtolaryngology-Head and Neck Surgery at the Second Affiliated Hospital, Chongqing University of MedicalSciences (Chongqing, China), between October and December in 2007. MATERIALS: Twenty-four male Sprague-Dawley rats were randomly divided into a control, a lesion, andan agmatine treatment group, with eight rats in each group. Bilateral facial nerve anastomosis was induced inthe lesion and agmatine treatment groups, while the control group remained untreated. A rat BDNF En-zyme-linked immunosorbent assay kit was used to measure BDNF levels in the brainstem facial nucleus. METHODS: Starting on the day of lesion, the agmatine group received a peritoneal injection of 100 mg/kgagmatine, once per day, for a week, whereas rats in the lesion group received saline injections. MAIN OUTCOME MEASURES: BDNF levels in the brainstem containing facial nucleus were measuredby ELISA. RESULTS: Twenty-four rats were included in the final analysis without any loss. Two weeks after lesion,BDNF levels were significantly higher in the lesion group than in the control group (P < 0.01). A significantincrease was noted in the agmatine group compared to the lesion group (P < 0.01). CONCLUSION: Agmatine can substantially increase BDNF levels in the rat brainstem after facial nerveinjury. BACKGROUND: Studies have shown that agmatine can reduce inhibition of neuronal regeneration by in-creasing cyclic adenosine monophosphate and brain-derived neurotrophic factor (BDNF) in the hippocampus of morphine-dependent rats. The hypothesis that agmatine exerts similar effects on facial nerve injury de- serves further analysis. OBJECTIVE: To study the effects of peritoneal agmatine injection on BDNF levels in the rat brainstem af-ter facial nerve injury. DESIGN, TIME AND SETTING: A controlled animal experiment was performed at the Department of Otolaryngology-Head and Neck Surgery at the Second Affiliated Hospital, Chongqing University of Medical Sciences (Chongqing, China), between October and December in 2007. MATERIALS: Twenty-four male Sprague-Dawley rats were differentiated into a control, a lesion, andan agmatine treatment group, with eight rats in each group. Bilateral facial nerve anastomosis was induced inthe lesion and agmatine treatment groups, while the control group rema METHODS: Starting on the day of lesion, the agmatine group received a peritoneal injection of 100 mg / kg agmatine, once per day, for a week, for a week, for a week, for a week, for rats in the lesion group received saline injections. MAIN OUTCOME MEASURES: BDNF levels in the brainstem containing facial nucleus were measuredby ELISA. RESULTS: Twenty-four rats were included in the final analysis without any loss. After lesion, BDNF levels were significantly higher in the lesion group than in the control group (P <0.01). A significantincrease was noted in the agmatine group compared to the lesion group (P <0.01). CONCLUSION: Agmatine can substantially increase BDNF levels in the rat brainstem after facial nerveinjury.