[The effects of prolonged selection for behavior on the stress response and Activity of the reproductive system of male Brown rats (Rattus norvegicus)].

Two Norway rat (Rattus norvegicus) populations contrasting in behavior have been raised at the Institute of Cytology and Genetics, Novosibirsk, Russia with long-term selection for the absence or enhancement of an aggressive response towards humans. They are designated as tame and aggressive, respectively. In this work we investigated the effects of the selection on behavior, stress responsiveness, and fertility in males of the 78th generation.

[Aggression and acoustic startle response in adult and infant rats with genetically defined aggression towards man and its absence].

The aim of the current study was to investigate the association between expression of acoustic startle response and fear-induced aggression. The intensity of aggressive response towards man and acoustic startle response in adult and 15-day old Norway rats selectively bred for 70 generation for high level or the lack of fear-induced aggression was studied. Adult rats of aggressive strain demonstrated high aggression and increased amplitude of acoustic startle response compared to rats selectively bred for the lack of fear-induced aggression.

[Functional correlates of the brain 5-HT2A and 5-HT2C serotonin receptors and expression of 5-HT2A AND 5-HT2C genes in aggressive and nonaggressive Norway rats].

Functional activity of the brain 5-HT2A and 5-HT2C serotonin receptors and expression of 5-HT2A and 5-HT2C genes in Norway rats selectively bred for 60 generations for high level and for a lack of fear-induced aggression towards humans were studied. There were no essential differences between aggressive and tame rats in 5-HT2A receptor mRNA level in the midbrain, hippocampus and frontal cortex as well as in the intensity of head-twitch induced by selective 5-HT2A agonist DOI. At the same time, administration of 5-HT2C receptor selective agonist MK-212 reduced the amplitude of acoustic startle response in tame but not in aggressive animals.