Presynaptic Partners of Dorsal Raphe Serotonergic and GABAergic Neurons

Neuron (Impact Factor: 15.98). 08/2014; 83(3):645-662. DOI: 10.1016/j.neuron.2014.06.024
Source: PubMed

ABSTRACT The serotonin system powerfully modulates physiology and behavior in health and disease, yet the circuit mechanisms underlying serotonin neuron activity are poorly understood. The major source of forebrain serotonergic innervation is from the dorsal raphe nucleus (DR), which contains both serotonin and GABA neurons. Using viral tracing combined with electrophysiology, we found that GABA and serotonin neurons in the DR receive excitatory, inhibitory, and peptidergic inputs from the same specific brain regions. Embedded in this overall similarity are important differences. Serotonin neurons are more likely to receive synaptic inputs from anterior neocortex while GABA neurons receive disproportionally higher input from the central amygdala. Local input mapping revealed extensive serotonin-serotonin as well as GABA-serotonin connectivity with a distinct spatial organization. Covariance analysis suggests heterogeneity of both serotonin and GABA neurons with respect to the inputs they receive. These analyses provide a foundation for further functional dissection of the serotonin system.

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    • "Recent transsynaptic tracings reveal that DRN GABA neurons share a largely similar input pattern with 5-HT neurons (Dorocic et al. 2014; Weissbourd et al. 2014). However, neurons from the central amygdala and the bed nucleus of the stria terminalis preferentially innervate GABAergic neurons, suggesting that these brain areas exert a more powerful modulation of DRN functions through GABAergic interneurons (Weissbourd et al. 2014). A small fraction of DRN neurons (1000 in mice) in the rostral-dorsal part of the DRN expresses the dopamine markers tyrosine hydroxylase and dopamine transporter (DAT) (Flores et al. 2004). "
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    • "rong et al . , 1983 ) , dopaminergic ( Björklund and Dunnett , 2007 ) and serotonergic neurons ( Fu et al . , 2010 ; Russo and Nestler , 2013 ) , have been analyzed using traditional methods ; however , these studies were limited primarily to local areas . Recently , the projection , location and distribution of specific subtypes of interneurons ( Weissbourd et al . , 2014 ) and of serotonergic neurons ( Pollak Dorocic et al . , 2014 ) have been characterized in the mouse brain with manually sectioning and imaging ."
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    Frontiers in Neuroanatomy 05/2015; 9. DOI:10.3389/fnana.2015.00070 · 4.18 Impact Factor
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    • "d the same inputs , in largely the same proportions , with a few unique exceptions that include the motor cortices and subthalamic nucleus for the SNc and the lateral hypothalamus for the VTA . A similar approach has been used to examine the inputs to different groups of serotonergic neurons ( Ogawa et al . , 2014 ; Pollak Dorocic et al . , 2014 ; Weissbourd et al . , 2014 ) , as well as the dorsal striatum ( Wall et al . , 2013 ) and hippocampus ( Sun et al . , 2014 ) ."
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