Effects of Mild Early Life Stress on Abnormal Emotion-related Behaviors in 5-HTT Knockout Mice
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A low-expressing polymorphic variant of the serotonin transporter (5-HTT) gene has been associated with emotional disorders in humans and non-human primates following exposure to early life trauma. 5-HTT gene knockout (KO) mice exhibit increased anxiety- and depression-related behaviors, and provide a model to study interactions between 5-HTT gene variation and early life stress. The present study assessed the effects of postnatal footshock stress on the development of emotion-related behaviors in 5-HTT KO mice. Results showed that 5-HTT KO mice displayed a profile of suppressed exploratory behavior and increased anxiety-like behavior in the light/dark, elevated plus-maze and open field tests, as well as increased depression-related behavior in the forced swim test following repeated exposure to the test. Postnatal exposure to footshock stress did not affect emotion-related behaviors in non-mutant C57BL/6J mice or modify phenotypic abnormalities in 5-HTT KO. Data provide further evidence of emotional abnormalities following genetic disruption of the 5-HTT.
Keywords5-HT Serotonin transporter Anxiety Depression Gene Mouse
We are grateful to Dr. Lyn C. Daws for mouse genotyping and for critical comments. Research supported by the National Institute on Alcohol Abuse and Alcoholism and National Institute of Mental Health Intramural Research Programs.
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