8-OH-DPAT in the median raphe, dorsal periaqueductal gray and corticomedial amygdala nucleus decreases, but in the medial septal area it can increase maternal aggressive behavior in rats

Abstract

 The purpose of the present study was to analyze the role of somatodendritic autoreceptors and postsynaptic 5-HT_1A receptors in the modulation of maternal aggressive behavior. The 5-HT_1A receptor agonist 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin) was microinjected (0.2, 0.5 and 2.0 μg/0.2 μl) in different brain areas of female Wistar rats: median raphe nucleus (MnR); medial septal area (MS); anterior corticomedial amygdaloid nucleus (ACoM); and dorsal periaqueductal gray (DPAG). The behaviors of lactating female rats with pups against a conspecific male intruder were recorded on day 7 post-partum. Results showed that in the median raphe nuclei, in the dorsal periaqueductal gray and in the corticomedial amygdaloid nucleus 8-OH-DPAT decreased maternal aggression; while in the medial septum, the intermediate dose (0.5 μg/0.2 μl) of the 5-HT_1A receptor agonist increased the aggressive behavior of the lactating female rat. It is concluded that the main role of the 5-HT_1A somatodendritic autoreceptors and the postsynaptic receptors of the brain areas studied is to decrease maternal aggression, however, at a specific dosage, 8-OH-DPAT acting on postsynaptic receptors of the medial septal area can increase aggressiveness.