The cellular architecture of the ventral tegmental area (VTA), the main hub of the brain reward system, remains only partially characterized. To extend the characterization to inhibitory neurons, we have identified three distinct subtypes of somatostatin (Sst)-expressing neurons in the mouse VTA. These neurons differ in their electrophysiological and morphological properties, anatomical localization, as well as mRNA expression profiles. Importantly, similar to cortical Sst-containing interneurons, most VTA Sst neurons express GABAergic inhibitory markers, but some of them also express glutamatergic excitatory markers and a subpopulation even express dopaminergic markers. Furthermore, only some of the proposed marker genes for cortical Sst neurons were expressed in the VTA Sst neurons. Physiologically, one of the VTA Sst neuron subtypes locally inhibited neighboring dopamine neurons. Overall, our results demonstrate the remarkable complexity and heterogeneity of VTA Sst neurons and suggest that these cells are multifunctional players in the midbrain reward circuitry.

中文翻译：

---

小鼠腹侧被盖区表达生长抑素的异质神经元群体

腹侧被盖区（VTA）的细胞结构是大脑奖励系统的主要枢纽，仅部分表征。为了将特征扩展到抑制性神经元，我们在小鼠VTA中鉴定了生长抑素（Sst）表达神经元的三个不同亚型。这些神经元的电生理学和形态学特性，解剖学定位以及mRNA表达谱均不同。重要的是，类似于含有皮质Sst的中间神经元，大多数VTA Sst神经元表达GABA能抑制标记，但其中一些还表达谷氨酸能兴奋性标记，并且亚群甚至表达多巴胺能标记。此外，在VTA Sst神经元中仅表达了一些建议的皮质Sst神经元标记基因。在生理上 VTA Sst神经元亚型之一局部抑制邻近的多巴胺神经元。总的来说，我们的结果证明了VTA Sst神经元的显着复杂性和异质性，并表明这些细胞是中脑奖赏回路中的多功能参与者。