Corticotropin releasing factor (CRF) and CRF-related peptides mediate stress responses, in part, by their interactions with the CRF-binding protein (CRF-BP). The CRF-BP plays a role in dopamine (DA) and glutamate neurotransmission within the ventral tegmental area (VTA). Here we investigated whether specific local neurons could be a source of CRF-BP in the VTA. By in situ hybridization we detected cellular expression of CRF-BP mRNA in the VTA, but not in neighboring substantia nigra compacta (SNC) or substantia nigra reticulata. The selective expression of CRF-BP mRNA proved to be useful in demarcating boundaries between the SNC and the VTA. By double in situ hybridization we determined that VTA neurons with CRF-BP mRNA co-expressed transcripts encoding either tyrosine hydroxylase (TH, a maker for DAergic neurons) or glutamic acid decarboxylase (GAD, synthesizing enzyme of ?-amino butyric acid, GABA). We found that 25% of the total population of TH expressing neurons contained CRF-BP mRNA, providing support to the notion that discrete subpopulations of dopamine neurons are present in the VTA. We determined that within the total population of neurons expressing CRF-BP mRNA 70% co-expressed CRF-BP mRNA TH mRNA, and only 25% co-expressed GAD mRNA. ? As far as we are aware, we provide the first anatomical evidence that a molecule, CRF-BP, is encoded by DAergic neurons of the VTA, but not by those of the SNC. Based on the observation that the majority of VTA neurons expressing CRF-BP mRNA are DAergic, we propose that in the VTA interactions of CRF-BP with CRF, or with CRF-related peptides, are likely to be predominately mediated by DAergic neurons.
| Yamaguchi, Tsuyoshi; Qi, Jia; Wang, Hui-Ling et al. (2015) Glutamatergic and dopaminergic neurons in the mouse ventral tegmental area. Eur J Neurosci 41:760-72 |
| Root, David H; Mejias-Aponte, Carlos A; Zhang, Shiliang et al. (2014) Single rodent mesohabenular axons release glutamate and GABA. Nat Neurosci 17:1543-51 |
| Wang, Hui-Ling; Morales, Marisela (2008) Corticotropin-releasing factor binding protein within the ventral tegmental area is expressed in a subset of dopaminergic neurons. J Comp Neurol 509:302-18 |
