RT Journal Article
SR Electronic
T1 nNOS-expressing neurons in the ventral tegmental area and substantia nigra pars compacta
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 251843
DO 10.1101/251843
A1 Eleanor J Paul
A1 Eliza Kalk
A1 Kyoko Tossell
A1 Elaine E. Irvine
A1 Dominic J. Withers
A1 James Leiper
A1 Mark A Ungless
YR 2018
UL http://biorxiv.org/content/early/2018/01/22/251843.abstract
AB GABA neurons in the ventral tegmental area (VTA) and substantia nigra pars compact (SNc) play key roles in reward and aversion through their local inhibitory control of dopamine neuron activity and through long-range projections to several target regions including the nucleus accumbens. It is not clear if some of these GABA neurons are dedicated local interneurons or if they all collateralize and send projections externally as well as making local synaptic connections. Testing between these possibilities has been challenging in the absence of interneuron-specific molecular markers. We hypothesised that one potential candidate might be neuronal nitric oxide synthase (nNOS), a common interneuronal marker in other brain regions. To test this, we used a combination of immunolabelling (including antibodies for nNOS that we validated in tissue from nNOS-deficient mice) and cell-type-specific virus-based anterograde tracing in mice. We show that nNOS-expressing neurons in the parabrachial pigmented (PBP) part of the VTA and the SNc are GABAergic local interneurons, whereas nNOS-expressing neurons in the Rostral Linear Nucleus (RLi) are mostly glutamatergic and project to a number of regions, including the lateral hypothalamus, the ventral pallidum, and the median raphe nucleus. Taken together, these findings indicate that nNOS is expressed by neurochemically- and anatomically-distinct neuronal sub-groups in a sub-region-specific manner in the VTA and SNc.