Accumbal dopamine and serotonin in anticipation of the next aggressive episode in rats

Abstract

Autonomic and limbic neural activities are linked to aggressive behavior, and it is hypothesized that activities in the cardiovascular and monoaminergic systems play a role in preparing for an aggressive challenge. The objective was to learn about the emergence of monoamine activity in nucleus accumbens before an aggressive confrontation that was omitted at the regular time of occurrence, dissociating the motoric from the aminergic activity. Dopamine, serotonin, heart rate and behavioral activity were monitored before, during and after a single 10-min confrontation in resident male Long-Evans rats fitted with a microdialysis probe in the n. accumbens and with a telemetry sender (experiment 1). DA, but not 5-HT efflux, was confirmed to increase in n. accumbens during and after a single aggressive episode. In aggressive males that confronted an opponent daily for 10 days (experiment 2) heart rate rose 1 h before the regularly scheduled encounter relative to control rats, as measured on day 11 in the absence of any aggression. Concurrently, DA levels increased by 60-70% over baseline levels and 5-HT levels decreased by 30-35% compared to baseline levels. These changes were sustained over 1 h, and contrasted with no significant changes in DA, 5-HT, heart rate or behavioral activity in control rats. The rise in mesolimbic DA appears to be significant in anticipating the physiological and behavioral demands of an aggressive episode, and the fall in 5-HT in its termination, dissociated from the actual execution of the behavior.

Neural and Behavioral Correlates of Alcohol-Induced Aggression Under Provocation

“…This inter-individual provocation-specific effect on neural correlates of alcohol-induced aggression strengthens the idea that the amygdala and ventral striatum are especially involved in alcohol-heightened aggression in stressful and threatening situations, such as being provoked (cf., Heinz et al, 2011). Increased ventral striatum reactivity in individuals with high levels of alcohol-induced reactive aggression suggests an involvement of dopamine, which has been discussed to facilitate aggression by increasing arousal and stress (Miczek et al, 2002;Ferrari et al, 2003;Nelson and Trainor, 2007). However, the interplay between neurotransmitters such as serotonin, dopamine, and GABA in alcoholinduced human aggression is not well understood (Miczek et al, 2002;Seo et al, 2008;Heinz et al, 2011).…”

“…Moreover, alcohol might exert its effects on aggression by increasing dopamine levels in the ventral striatum (Dichiara and Imperato, 1986;Boileau et al, 2003;Heinz et al, 2011), a potential neural mechanism underlying experimentally induced aggression in animals (Miczek et al, 2002;Ferrari et al, 2003;Nelson and Trainor, 2007) and humans (Krämer et al, 2011;Beyer et al, 2014). Using fMRI, alcohol-induced increased dopamine levels might be reflected by increased activation of the ventral striatum in humans (cf, Gilman et al, 2008).…”

Fos responses of dopamine neurons to sociosexual stimuli in male zebra finches

“…In mammals, the A10 neurons in particular are known to influence agonistic behavior. Mesolimbic dopamine release in male rats increases substantially in relation to aggression and in anticipation of an aggressive interaction (Ferrari et al, 2003). In mice, TH mRNA and dopamine transporter mRNA both increase significantly within the VTA of males who repeatedly win aggressive encounters (Filipenko et al, 2001), and septal DA, which arises primarily in the VTA (Lindvall, 1975), influences aggression in rats (Clarke and File, 1982).…”

Escalated Aggression after Alcohol Drinking in Male Mice: Dorsal Raphé and Prefrontal Cortex Serotonin and 5-HT1B Receptors

“…In vivo microdialysis has been used as a more sensitive tool to temporally assess this relationship. In rats, extracellular levels of 5-HT in the nucleus accumbens decrease in anticipation of an aggressive encounter while cortical 5-HT levels decrease during and after an aggressive confrontation (van Erp and Miczek, 2000;Ferrari et al, 2003). These studies reveal that 5-HT levels in specific brain regions serve to regulate distinct phases of aggressive behavior and perhaps the prefrontal cortex may be most involved in the execution of and recovery from an aggressive encounter (van Erp and Miczek, 2000;Halász et al, 2006;Miczek and Fish, 2006).…”