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Distinct Circuits Underlie the Effects of 5-HT1B Receptors on Aggression and Impulsivity
Nautiyal KM, Tanaka KF, Barr MM, Tritschler L, Le Dantec Y, David DJ, Gardier AM, Blanco C, Hen R and Ahmari SE
Neuron, 86:813-826, 2015

New research has found that activity levels at receptors for the neurotransmitter serotonin affect aggression and impulsivity in different ways at different times in the lifespan. These findings may help inform treatment for a range of psychiatric disorders involving high aggression, impulsivity, or both, such as drug and alcohol addiction, pathological gambling, and attention-deficit hyperactivity disorder. 

Published recently in the journal Neuron, the research was led by Susanne E. Ahmari, MD, PhD.  Dr. Ahmari and her team examined changes in aggression and impulsivity resulting from manipulations of one of several receptors for serotonin in the mouse brain, called the serotonin 1B receptor (5-HT1BR). Activation of this receptor can limit the release of serotonin and other neurotransmitters. Mice bred to have a lack of 5-HT1BR serotonin receptors throughout the brain showed increased aggressive as well as impulsive behavior, but Dr. Ahmari and her colleagues found that the effects of the receptor on the two behaviors differed.  Restoring normal levels of the serotonin receptor only reduced aggression when it was done early in a mouse?s life. These findings suggest that some serotonin receptors affect aggression only during a critical period early in development. In contrast, restoring the 5-HT1BR receptor in adulthood reduced impulsivity in the mice, suggesting that impulsive behavior is affected by these receptors across the lifespan rather than during an initial critical period. 

The results of this project suggest that although aggression and impulsivity both can occur in conditions like addiction, they may require distinct pharmacological treatments, and that those treatments may also need to be administered at different times. Dr. Ahmari stated, "These findings are exciting because they suggest that impulsivity, a key element of psychiatric disorders ranging from bipolar disorder to addiction, may be amenable to targeted pharmacologic treatment in adults."

Contributors:
Susanne E. Ahmari, MD, PhD (Department of Psychiatry, University of Pittsburgh School of Medicine)

Katherine M. Nautiyal, PhD, Mary M. Barr, Carlos Blanco, MD and René Hen, PhD (Department of Psychiatry, Columbia University)

Kenji F. Tanaka, MD, PhD (Department of Neuropsychiatry, School of Medicine, Keio University, Japan)

Laurent Tritschler, PhD, Yannick Le Dantec, PhD, Denis J. David PhD, and Alain M. Gardier, PharmD, PhD (Université Paris-Sud, INSERM UMR-S 1178, Université Paris-Saclay, France)

This paper appears in the journal Neuron.  Click here to view the abstract.