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Corticotropin‐releasing factor binding protein within the ventral tegmental area is expressed in a subset of dopaminergic neurons
Author(s) -
Wang HuiLing,
Morales Marisela
Publication year - 2008
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.21751
Subject(s) - ventral tegmental area , pars compacta , substantia nigra , biology , dopaminergic , dopamine , tyrosine hydroxylase , glutamate decarboxylase , medicine , population , in situ hybridization , endocrinology , gabaergic , neuroscience , messenger rna , genetics , biochemistry , inhibitory postsynaptic potential , enzyme , gene , environmental health
Corticotropin‐releasing factor (CRF) and related peptides play a role in mediating neuronal effects of stress. These peptides mediate stress responses by their interactions with the CRF receptors and the CRF‐binding protein (CRF‐BP). Because the CRF‐BP is implicated in neurotransmission within the ventral tegmental area (VTA), we investigated whether the CRF‐BP is expressed in VTA neurons. By in situ hybridization, we detected cellular expression of CRF‐BP mRNA in the VTA; no such expression was seen in neighboring substantia nigra pars compacta (SNC) or substantia nigra pars reticulata. By double in situ hybridization, we determined that VTA neurons with CRF‐BP mRNA coexpressed transcripts encoding either tyrosine hydroxylase [TH; a marker for dopamine (DA) neurons] or glutamic acid decarboxylase [GAD; synthesizing enzyme of γ‐aminobutyric acid (GABA)]. Neurons with CRF‐BP mRNA represented 25% of the total population of TH‐expressing neurons and 28% of the total population of GAD‐expressing neurons, indicating that discrete subpopulations of dopaminergic and GABAergic neurons are present in the VTA. Within the total population of neurons containing CRF‐BP mRNA, 70% coexpressed TH mRNA and only 27% coexpressed 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. We propose, based on the observation that the majority of VTA neurons expressing CRF‐BP mRNA are DAergic, that in the VTA interactions of CRF‐BP with CRF, or with CRF‐related peptides, are likely to be mediated predominantly by DAergic neurons. J. Comp. Neurol. 509:302–318, 2008. Published 2008 Wiley‐Liss, Inc.