Dopamine (DA) neurons in the midbrain ventral tegmental area (VTA) provide a critical modulation of limbic striatal and cortical targets that facilitates appropriate motor control, approach behaviors, motivation and cognition. Deficits in these forebrain dopamine systems are associated with mental health disorders such as schizophrenia, depression, attention deficit hyperactivity disorder and substance abuse. Hence, it is important to gain a clear understanding of how DA neuron activity is itself regulated. DA neurons fire tonically via pacemaker potentials, but important signals regarding future expectancy are generated by bursts and pauses in the activity pattern that are mediated by afferent drive. In our prior research, we examined excitatory afferents to VTA DA neurons from the prefrontal cortex. We discovered a surprising degree of specificity in these connections, in that prefrontal cortical afferents synapsed only onto DA neurons projecting back to the prefrontal cortex and not onto the more numerous DA cell population projecting to the nucleus accumbens. In the present proposal, we wish to address the likelihood of additional specificity in other synaptic inputs to these same DA neuron populations in the VTA that correlate with their activity levels and functions. This goal will be accomplished through the following five specific aims. We will examine both mesoprefrontal and mesoaccumbens DA neurons specifically for (1) their general excitatory and inhibitory drive as identified by glutamate and GABA in synaptic inputs, (2) specific excitatory afferents from the brainstem laterodorsal and pedunculopontine tegmentum, (3) extrinsically derived inhibitory afferents from the nucleus accumbens, (4) intrinsically derived inhibitory synapses from GABA neurons within the VTA, and (5) mixed/modulatory afferents from the lateral hypothalamus. Evidence consistent with selective afferent drive to different populations of DA neurons will provide valuable insight into the function of each cell group and the contributions they make to normal and abnormal behaviors. Evidence for selectivity in these afferents also has important implications for the development of specific pharmacological treatments for mental health disorders that involve these populations.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
5R01MH067937-02
Application #
6830235
Study Section
Special Emphasis Panel (ZRG1-IFCN-4 (05))
Program Officer
Vicentic, Aleksandra
Project Start
2003-12-01
Project End
2008-11-30
Budget Start
2004-12-01
Budget End
2005-11-30
Support Year
2
Fiscal Year
2005
Total Cost
$267,786
Indirect Cost
Name
University of Pittsburgh
Department
Neurosciences
Type
Schools of Arts and Sciences
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Bourdy, Romain; Sánchez-Catalán, María-José; Kaufling, Jennifer et al. (2014) Control of the nigrostriatal dopamine neuron activity and motor function by the tail of the ventral tegmental area. Neuropsychopharmacology 39:2788-98
Barrot, Michel; Sesack, Susan R; Georges, François et al. (2012) Braking dopamine systems: a new GABA master structure for mesolimbic and nigrostriatal functions. J Neurosci 32:14094-101
Holmstrand, Ericka C; Sesack, Susan R (2011) Projections from the rat pedunculopontine and laterodorsal tegmental nuclei to the anterior thalamus and ventral tegmental area arise from largely separate populations of neurons. Brain Struct Funct 216:331-45
Balcita-Pedicino, Judith Joyce; Omelchenko, Natalia; Bell, Roland et al. (2011) The inhibitory influence of the lateral habenula on midbrain dopamine cells: ultrastructural evidence for indirect mediation via the rostromedial mesopontine tegmental nucleus. J Comp Neurol 519:1143-64
Omelchenko, Natalia; Sesack, Susan R (2010) Periaqueductal gray afferents synapse onto dopamine and GABA neurons in the rat ventral tegmental area. J Neurosci Res 88:981-91
Holmstrand, Ericka C; Asafu-Adjei, Josephine; Sampson, Allan R et al. (2010) Ultrastructural localization of high-affinity choline transporter in the rat anteroventral thalamus and ventral tegmental area: differences in axon morphology and transporter distribution. J Comp Neurol 518:1908-24
Omelchenko, Natalia; Sesack, Susan R (2009) Ultrastructural analysis of local collaterals of rat ventral tegmental area neurons: GABA phenotype and synapses onto dopamine and GABA cells. Synapse 63:895-906
Omelchenko, Natalia; Bell, Roland; Sesack, Susan R (2009) Lateral habenula projections to dopamine and GABA neurons in the rat ventral tegmental area. Eur J Neurosci 30:1239-50
Hikosaka, Okihide; Sesack, Susan R; Lecourtier, Lucas et al. (2008) Habenula: crossroad between the basal ganglia and the limbic system. J Neurosci 28:11825-9
Omelchenko, N; Sesack, S R (2007) Glutamate synaptic inputs to ventral tegmental area neurons in the rat derive primarily from subcortical sources. Neuroscience 146:1259-74

Showing the most recent 10 out of 13 publications