Oxytocin receptors are expressed on dopamine and glutamate neurons in the mouse ventral tegmental area that project to nucleus accumbens and other mesolimbic targets.
The mesolimbic dopamine (DA) circuitry determines which behaviors are positively reinforcing and therefore should be encoded in the memory to become a part of the behavioral repertoire. Natural reinforcers, like food and sex, activate this pathway, thereby increasing the likelihood of further consummatory, social, and sexual behaviors. Oxytocin (OT) has been implicated in mediating natural reward and OT-synthesizing neurons project to the ventral tegmental area (VTA) and nucleus accumbens (NAc); however, direct neuroanatomical evidence of OT regulation of DA neurons within the VTA is sparse. To phenotype OT-receptor (OTR) expressing neurons originating within the VTA, we delivered Cre-inducible adeno-associated virus that drives the expression of fluorescent marker into the VTA of male mice that had Cre-recombinase driven by OTR gene expression. OTR-expressing VTA neurons project to NAc, prefrontal cortex, the extended amygdala, and other forebrain regions but less than 10% of these OTR-expressing neurons were identified as DA neurons (defined by tyrosine hydroxylase colocalization). Instead, almost 50% of OTR-expressing cells in the VTA were glutamate (GLU) neurons, as indicated by expression of mRNA for the vesicular GLU transporter (vGluT). About one-third of OTR-expressing VTA neurons did not colocalize with either DA or GLU phenotypic markers. Thus, OTR expression by VTA neurons implicates that OT regulation of reward circuitry is more complex than a direct action on DA neurotransmission. J. Comp. Neurol. 525:1094-1108, 2017. © 2016 Wiley Periodicals, Inc.
Department of Pharmacodynamics, University of Florida, Gainesville, Florida, USA.
Joanna
http://orcid.org/0000-0002-3070-8072
J
Peris
Department of Pharmacodynamics, University of Florida, Gainesville, Florida, USA.
Kaley
K
MacFadyen
Department of Pharmacodynamics, University of Florida, Gainesville, Florida, USA.
Justin A
JA
Smith
Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA.
Annette D
AD
de Kloet
Department of Pharmacodynamics, University of Florida, Gainesville, Florida, USA.
Lei
L
Wang
Department of Pharmacodynamics, University of Florida, Gainesville, Florida, USA.
Eric G
EG
Krause
D000818:Animals; D004298:Dopamine / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009434:Neural Pathways / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D009714:Nucleus Accumbens / Q000378:metabolism*; D018045:Receptors, Oxytocin / Q000096:biosynthesis*; D017557:Ventral Tegmental Area / Q000378:metabolism*
D018045:Receptors, Oxytocin; D018698:Glutamic Acid; D004298:Dopamine
RRID: AB_11180326; RRID: AB_11180858; RRID:AB_1524535; dopamine; glutamate; nucleus accumbens; oxytocin receptors; ventral tegmental area