title: The glutamatergic component of the mesocortical pathway emanating from different subregions of the ventral midbrain.
abstract: The mesocortical pathway projecting from the ventral tegmental area (VTA) to the prefrontal cortex (PFC) plays a critical role in a number of cognitive and emotional processes. While this pathway has been traditionally viewed as dopaminergic, recent data indicate that a considerable proportion of rostromedial VTA neurons possess markers for glutamate transmission. However, the relative density of the glutamatergic projection to the PFC from these rostromedial regions is unknown. In the present study, anterograde tracer injections into 4 ventral midbrain subregions were coupled with immunohistochemical analysis of labeled axons in PFC for markers of dopamine (DA; tyrosine hydroxylase [TH]) and glutamate (vesicular glutamate transporter 2; VGLUT2). We found that while tracer injections into the interfascicular nucleus produced labeled fibers in the PFC that were mainly TH positive, tracer injections into the rostral linear nucleus, rostral VTA, and parabrachial pigmented nucleus produced labeled fibers in PFC that contained mainly VGLUT2-positive rather than TH-positive varicosities. When viewed in the light of the previously documented strong γ-aminobutyric acidergic component, it would seem that the rostromedial mesocortical projection is actually an amino acid pathway that in addition has a DA component.
authors.affiliation: Department of Psychiatry and Brain Research Centre, University of British Columbia, Vancouver, BC V6T 2B5, Canada.
authors.forename: Natalia
authors.initials: N
authors.lastname: Gorelova
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Mulholland
authors.forename: L Judson
authors.initials: LJ
authors.lastname: Chandler
authors.forename: Jeremy K
authors.initials: JK
authors.lastname: Seamans
mesh_terms: D018663:Adrenergic Agents / Q000009:adverse effects; D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives / Q000378:metabolism; D003911:Dextrans / Q000378:metabolism; D018690:Excitatory Amino Acid Agonists / Q000009:adverse effects; D005968:Glutamate Decarboxylase / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism*; D007051:Ibotenic Acid / Q000009:adverse effects; D008297:Male; D009412:Nerve Fibers / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D016627:Oxidopamine / Q000009:adverse effects; D010835:Phytohemagglutinins / Q000378:metabolism; D017397:Prefrontal Cortex / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D017557:Ventral Tegmental Area / Q000166:cytology* / Q000293:injuries / Q000502:physiology*; D050599:Vesicular Glutamate Transport Protein 2 / Q000378:metabolism
chemical_list: D018663:Adrenergic Agents; D003911:Dextrans; D018690:Excitatory Amino Acid Agonists; D010835:Phytohemagglutinins; D050599:Vesicular Glutamate Transport Protein 2; C076397:biotinylated dextran amine; C100156:leukoagglutinins, plants; D007051:Ibotenic Acid; D018698:Glutamic Acid; D001710:Biotin; D016627:Oxidopamine; D014446:Tyrosine 3-Monooxygenase; D005968:Glutamate Decarboxylase