Serotonin metabolism and serotonergic receptors in Norway rats selected for low aggressiveness to man

Expression of Serotonin Transporter Gene and Startle Response in Rats with Genetically Determined Fear-Induced Aggression

“…Very little is known about the involvement of 5-HTT in the regulation of fear-induced aggression, but we previously showed that the level of 5-HT, sensitivity and density of 5-HT 1A receptors, and expression of the corresponding genes are significantly decreased in the brain of rats selected for high aggression towards humans [14,15].…”

“…As 5-HTT gene is expressed only in the midbrain (which is confirmed by reduction of its level in the structures distant from the midbrain), presumably, rat selection for fear-induced aggression leads to changes in the genetic system, reducing the 5-HTT mRNA life span. The detected reduction of 5-HTT gene expression is in good agreement with the data on reduced level of 5-HT, desensitization and reduced density of 5-HT 1A receptors, and expression of their gene in the brain of highly aggressive rats [14,15], but does not agree with the data obtained on mice with 5-HTT genetic knockout [6]. However, different changes in 5-HTT status in rats and mice eventuated in similar consequences.…”

Effects of d,l-fenfluramine on aggressive and impulsive responding in adult males with a history of conduct disorder

“…Studies have documented that diminished CSF 5-HT levels are related to: suicides and violent suicide attempts (Asberg et al 1987;Coccaro et al 1989Coccaro et al , 1990; Modai et al 1989); a history of criminal violence (Brown et al 1979;Linnoila 1983;Virkkunen et al 1989); alcohol dependence and corresponding violent behavior (Virkkunen et al 1994a;FilsAime et al 1996;Hibbeln et al 1998); and diagnosed psychopathologies highlighted by impulse control problems (Brown and Goodwin 1984;Virkkunen et al 1987;Cocarro et al 1990Cocarro et al , 1995Stein et al 1993). These findings are bolstered by studies linking reduced 5-HT levels to aggressive and impulsive behavior in non-human populations (Raleigh et al 1984;McGuire and Raleigh 1987;Higley et al 1996;Popova et al 1991;Mehlman et al 1994). Importantly, the above data are corroborated by studies focused on manipulation of the 5-HT system.…”

CSF 5-HIAA and aggression in female macaque monkeys: species and interindividual differences

“…Comparative studies indicate that the correlation between severe aggression and low CNS serotonin, whether naturally occurring or pharmacologically induced, may represent a generalized trend across species. For example, when Popova and colleagues (Popova et al 1991a) selectively bred wild rats over 24-27 generations for "domestication", they found a parallel increase in both tameness and midbrain and hypothalamic 5-HIAA across generations, with the mean level in the midbrain and the cortices higher in the "domesticated" rats than in the aggressive rats. Similarly, silver foxes selected for over 30 years for domestication have higher serotonin concentrations in the midbrain and hypothalamus, and higher 5-HIAA concentrations in the midbrain, hypothalamus and hippocampus when they are compared to nonselected wild silver foxes bred in captivity over the same time span (Popova et al 1991b).…”