Serotoninergic depletion generates aggressive behaviour in male Sprague Dawley rats.

M. MULLE BERNEDO; ASTORGA V.; GARCIA S.; CABRERA R.

Paris

Congreso; The International Society for Neurochemistry and the European Society for Neurochemistry; 2017

The International Society for Neurochemistry and the European Society for Neurochemistry

The serotoninergic system modulates appetitive, motivational and aggressive behavior. The 5-HT synthesis reduction by drug increase aggressive behavior in species and strains prone to it.In this study, we attempted 1- to generate aggressive behavior with para-chlorophenylalanine (pCPA) by inhibiting tryptophan hydroxylase, and 2- to examine dose/day response related to 5-HT depletion.Male Sprague-Dawley 60 days old rats were used. A resident/ intruder paradigm was applied. Animals were divided into 5 groups: Naïve, pCPA treated rats (300 mg/kg, i.p) evaluated on the 3rd and 6th day after the administration and the respective saline control.Offensive behavior (OB) was measured as attempted mounts, lateral threats, and footsteps. Persecution latency time (PLT) was examined as a different parameter of OB. Bites, clinch and clinch attacks were considered as aggressive behavior (AB). We also measured non-social interaction (freezing, lying, sitting and grooming), social interaction (sniffing and heterogrooming) and locomotor activity. The test was recorded and the videos were analyzed with Kinovea 0.8.15 software. 5-HT levels were measured in plasma, olfactory bulb and raphe nucleus with HPLC fluorescence. All data were analyzed by ANOVA I and Tukey post hoc test.We observed a significant decrease in PLT (p≤ 0.001) and a significant increase (p≤ 0.001) in OB between the treated, control and naïve groups. There was a significant increase (p≤ 0.05) of AB between the treated group tested on the 3rd and 6thday. There were no significant differences in social interaction, non-social interaction and locomotor activity. The treated groups showed a significant decrease of 5-HT levels in plasma, olfactory bulb and raphe nucleus versus control and naïve groups depending on the day of evaluation. On the 3rd day, the difference was p≤0.01 and on the 6th-day p≤ 0.05. The depletion of 5-HT affects OB, PLT, and AB. This is related to dose/day response, suggesting that a certain 5-HT level is necessary to generate aggressive behavior.