CRF neurons projecting to the VTA are found in the limbic forebrain and the paraventricular nucleus of the hypothalamus (Rodaros et al., 2007). About one quarter of VTA DA neurons, mostly located in the parabrachial pigmented (PBP) region of the VTA express both CRF-R2 and the CRF binding protein (CRF-BP). These are both required for a slowly developing, transient potentiation of NMDAR-mediated synaptic transmission elicited by application of CRF (Ungless et al., 2003). Whether, like oxA/hcrt-1, CRF is important for drug-evoked synaptic plasticity in VTA DA neurons has not been investigated. Furthermore, genetically modified mice have not been used thus far to study the role of these peptide systems in drug-evoked synaptic plasticity.
