A dense cluster of D<sub>1sub>+ cells in the mouse nucleus accumbens
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- 作者：Sarah Petryszyn ; Maria Gabriela Sá ; nchez ; Dave Gagnon ; Jean-Martin Beaulieu ; André ; Parent and Martin Parent
- 刊名：Synapse
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：71
- 期：1
- 页码：51-54
- 全文大小：590K
- ISSN：1098-2396
文摘
The striatum is known to be largely composed of intermingled medium-sized projection neurons expressing either the D<sub>1sub> or the D<sub>2sub> dopamine receptors. In the present study, we took advantage of the double BAC Drd1a-TdTomato/Drd2-GFP (D<sub>1sub>/D<sub>2sub>) transgenic mice to reveal the presence of a peculiar cluster of densely-packed D<sub>1sub>+ cells located in the shell compartment of the nucleus accumbens. This spherical cluster has a diameter of 110 µm and is exclusively composed by D<sub>1sub>+ cells, which are all immunoreactive for the neuronal nuclear marker (NeuN). However, in contrast to other D<sub>1sub>+ or D<sub>2sub>+ striatal cells, those that form the accumbens cluster are devoid of calbindin (CB) and DARPP-32, two faithful markers for striatal projection neurons. Using GAD-GFP transgenic mice, we confirm the GABAergic nature of the D<sub>1sub>+ clustered neurons. Intracellular injections from fixed brain slices indicate that these neurons are endowed with distinctive morphological features, including a small (5–6 µm), round cell body giving rise to a single primary dendrite that branches into two secondary processes. Single-neuronal injections combined to electron microscopy reveal the existence of GAP junctions linking these D<sub>1sub>+ cells. Based on their location, morphological characteristics and neurochemical phenotype, we conclude that the D<sub>1sub>+ accumbens cluster form a highly compact group of small neurons distinct from the larger and more diffusely distributed D<sub>1sub>+ or D<sub>2sub>+ striatal projection neurons that surround it. This remarkable nucleus might play a crucial role in the limbic function of the murine striatum.