Serotonin receptor: A rheostat in brain for emotion that may be linked to ...( PITTSBURGH Oct. 1 Although drugs tha...),Health

PITTSBURGH, Oct. 1 Although drugs that target the brain's serotonin system are widely used to treat depression, the basic biological mechanism by which they help to alleviate symptoms is poorly understood. Now, new University of Pittsburgh research suggests these drugs work by acting on a specific serotonin receptor called the 5-HT1A autoreceptor, which the study's investigators found plays a key role in regulating the response of the amygdala.

The findings, published in the journal Nature Neuroscience, also provide a model of how specific changes in 5-HT1A autoreceptors and associated amygdala reactivity may impact a person's risk for developing depression. Much like a rheostat, these serotonin receptors regulate the brain's emotional responses and may contribute to one's vulnerability for depression and other psychiatric disorders.

The amygdala is a critical component of brain circuitry that processes clues from the environment about potential threats and generates appropriate behavioral and physiological responses such as the "fight or flight" response to these challenges. Research has indicated that depression and other mood disorders, such as anxiety, are associated with emotional brain circuitry problems involving the amygdala.

The 5-HT1A autoreceptor is located on the surface of serotonin neurons, which are responsible for producing the serotonin neurotransmitter and delivering it to several areas of the brain, including the amygdala. The effect serotonin release has is varied and complex, due to the number of different serotonin receptors found in these brain regions. In contrast, the 5-HT1A autoreceptor on serotonin neurons in the brain stem is rather uniform: it reduces the neuron's activity and its subsequent release of serotonin to downstream targets, a process called negative feedback inhibition. As more serotonin is released and becomes available in the brain, the neurotransmitter also acts on these 5-HT1A autorecept
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Contact: Lisa Rossi
RossiL@upmc.edu
412-647-3555
University of Pittsburgh Medical Center
1-Oct-2006