RT Journal Article
SR Electronic
T1 Ventral Tegmental Area Glutamate Neurons: Electrophysiological Properties and Projections
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 15076
OP 15085
DO 10.1523/JNEUROSCI.3128-12.2012
VO 32
IS 43
A1 Thomas S. Hnasko
A1 Gregory O. Hjelmstad
A1 Howard L. Fields
A1 Robert H. Edwards
YR 2012
UL http://www.jneurosci.org/content/32/43/15076.abstract
AB The ventral tegmental area (VTA) has a central role in the neural processes that underlie motivation and behavioral reinforcement. Although thought to contain only dopamine and GABA neurons, the VTA also includes a recently discovered population of glutamate neurons identified through the expression of the vesicular glutamate transporter VGLUT2. A subset of VGLUT2+ VTA neurons corelease dopamine with glutamate at terminals in the NAc, but others do not express dopaminergic markers and remain poorly characterized. Using transgenic mice that express fluorescent proteins in distinct cell populations, we now find that both dopamine and glutamate neurons in the medial VTA exhibit a smaller hyperpolarization-activated current (Ih) than more lateral dopamine neurons and less consistent inhibition by dopamine D2 receptor agonists. In addition, VGLUT2+ VTA neurons project to the nucleus accumbens (NAc), lateral habenula, ventral pallidum (VP), and amygdala. Optical stimulation of VGLUT2+ projections expressing channelrhodopsin-2 further reveals functional excitatory synapses in the VP as well as the NAc. Thus, glutamate neurons form a physiologically and anatomically distinct subpopulation of VTA projection neurons.