Motor and neurochemical correlates of aggressive behavior in male mice

Abstract

We tested aggressive behavior in male albino mice by placing two individuals in one cage. Three successive tests with one-day-long intervals were performed; pairs were formed in a randomized order. Three animal groups, I-III, were classified according to the test results. These were absolute dominants, an intermediate group (animals were sometimes winners in conflicts, sometimes were defeated, or demonstrated no aggressive behavior), and submissive individuals (defeated in all cases). One day before testing and 1 h after each test, the intensity of motor activity (duration and velocity of running in a "locomotion wheel") was measured in all animals. Three days after testing, we measured the levels of noradrenaline (NA) and serotonin (ST) in the hypothalamus and those of NA and adrenaline (A) in the blood. Mice of groups I and II demonstrated high background indices of locomotor activity, while in group III these indices were comparatively low. In the course of testing, these indices in group I were in general preserved, while in groups II and III they dropped significantly. In mice of group I, the highest levels of NA in the hypothalamus and blood, high NA/ST ratio in the hypothalamus, and high NA/A ratio in the blood were observed. Animals of group II were characterized by intermediate levels of NA and ST in the hypothalamus together with rather high concentrations of A and the lowest NA/A ratio in the blood. In mice of group III, the highest level of ST and the lowest NA/ST ratio in the hypothalamus, as well as an intermediate NA/A ratio in the blood, were observed. We conclude that, generally, the response of an animal to emotional stress related to an antagonistic conflict can be classified into three types. These are an NA-ergic type in dominants, an intermediate A-ergic type, and an ST-ergic (vagotonic) type in submissive individuals. These types correlate with the three ethological models of behavior, "struggle," "escape," and catatonia.

Correlation between level of aggressiveness of personality and characteristics of EEG frequency components

“…The level of activity of the ST-ergic system is in reverse dependence on the domination behavior [6]. Clinical symptoms of exhaustion of the ST-ergic transmission in humans are frequently accompanied by mental disorders manifested in aggression, suicidal attempts, and increased anxiety [4].…”

“…A few researchers suppose that these properties are mostly inborn. The formation of aggressiveness and manifestations of aggressive behavior are based on numerous biological processes determined by the structure of the genome, influences of sex hormones, specificities of the CNS (first of all, by peculiarities of functioning of cerebral neurochemical systems), and specificity of functioning of the neuroendocrine axes (in particular, of the hypothalamo-sympathoadrenal axis) [1][2][3][4][5][6]. There are proofs that aggressive behavior correlates with a few specific manifestations of the unitary and field electrical activity at all cerebral levels (in the brainstem, limbic system, and cortex) [7].…”

On the Potential Role of the Neural Crest Cells in Integrating Pigmentation Into Behavioral and Physiological Syndromes

“…Epinephrine and nor-epinephrine levels are also related with behavioral traits such as aggressiveness, boldness, and social dominance (Koolhaas et al, 1999(Koolhaas et al, , 2010Chichinadze, 2004;Vaz-Serrano et al, 2011), which are often associated with MbC (Ducrest et al, 2008;Santos et al, 2011;San-Jose and Roulin, 2018). Dopamine plays also an important role in regulating aggressive behaviors (Pavlov et al, 2012).…”