International Union for Circumpolar Health Ministry of Public Health and Social Development of RF Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Medical Sciences Siberian Branch of Russian Academy of Sciences Medical Polar Fund “Science” The Northern Forum

Abstracts

Alcohol, smoking, and drug abuse

Obsessive-compulsive disorder (OCD) is a debilitating psychiatric condition that is characterized by intrusive and persistent thoughts (obsessions) and repetitive behaviors (compulsions). The neural mechanisms that control OCD are poorly understood; however selective serotonin reuptake inhibitors represent some of the most effective treatments of OCD symptoms, leading to the premise that the serotonin system in the brain plays an important role in OCD. The small number of animal models available that reveal consistent and spontaneous (non-drug-induced or non-behaviorally-induced) differences in compulsive-like behaviors contributes to this lack of knowledge. Rodent nest-building behavior is an adaptation to cold ambient temperatures, i.e., to the arctic, and therefore understanding the neural pathways regulating this behavior will allow insights into how adaptations to extreme environments can change neurophysiology. House mice bidirectionally selected for high (BIG mice) and low (SMALL mice) levels of repetitive nest-building behavior nesting behavior reveal a 40-fold difference in the amount of cotton collected in the cage. Nest-building behavior in mice is highly repetitive and in big nest-builders can be characterized as compulsive-like. Fluoxetine, an effective drug for reduction of OCD symptoms, was administered orally and dose-dependently reduced repetitive nesting behavior in male BIG mice with the 100 mg/kg dose showing the largest decrease in nesting behavior (< 40% of pre-drug levels). Smaller decreases were revealed in animals exposed to 50 mg/kg and 30 mg/kg, respectively. The largest effects of fluoxetine were not apparent until the end of the treatment period, which is similar to the delayed full response in humans. Wheel-running activity, measured as the number of wheel revolutions per day, was not different among drug and control groups. In addition, male BIG and SMALL mice differed in marble burying behavior, an established model of compulsive-like behavior in mice. In a four week study, BIG male mice buried significantly more marbles than SMALL mice. These results strengthen our assertion that BIG mice represent a compulsive-like phenotype compared to SMALL mice.

Note. Abstracts are published in author's edition

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