γAminobutyrate B Receptors in Central Amygdaloid and Medial Amygdaloid Nuclei of Amygdala Modulate Aggression in Male Rats

Abstract

One neurochemical system most consistently linked with aggression is the GABAergic system. The aim of the present investigation was to examine the effect of injection of baclofen (GABA_B agonist) and CGP35348 (GABA_B antagonist) in the Central Amygdaloid (CA) and Medial Amygdaloid (MA) nuclei of the amygdala on offensive aggression behavior in the animal model. Sixty six adult male rats weighing 180-200g were used. Cannula was implanted into each ac and or am nuclei of amygdala using stereotaxic method. Each animal received 100 electrical shocks every session. After electrical shock, another rat was placed in the electroshock chamber and the animals were observed for various aggressive behaviors. Data were analyzed by Student’s T test and one way ANOVA and Tukey’s test as the post-hoc test. Significant level was considered to be p<0.05. It was shown that injection of baclofen into the am nucleus of amygdala led to a significant increase in offensive aggression behavior, whereas baclofen injection into the ac nucleus of amygdala led to a significant decrease in offensive aggression behavior. Injection of CGP35348 into the am nucleus of amygdala caused a significant decrease in aggressive behavior, but its injection into the ac nucleus of amygdala induced a significant increase in offensive aggression behavior. Results indicated that GABA_B receptors in the ac and am nuclei of amygdala are possibly involved in the modulation of offensive aggression behavior.