Researchers at Case Western University in Cleveland and at Baylor University in Houston have found that knocking out a serotonin gene (Pet-1) in mice impairs their development of brain serotonin neurons and results in adults with highly aggressive and anxious behaviors. Previous research suggests that defects in the central serotonin system plays a significant role in the development of aggression, impulsivity, anxiety, depression, suicide, and obsessive-compulsive disorder. Human and mouse serotonin systems share many features, and a gene very similar to Pet-1 is present in humans.

Principal investigator Evan Deneris, Ph.D., says these findings suggest that a Pet-1-dependent process influences adult behaviors through its control of serotonin neuron development. He regards the knockout mice as a new model for investigating how flaws in the embryonic development of serotonin neurons affects serotonin-modulated behaviors in adults. Deneris plans further mice studies to examine how the Pet-1 gene affects other behaviors regulated by serotonin — such as sleep-wake patterns, learning and memory, and breathing.