Results It was found that a subpopulation of dorsal raphe nucleus ( DRN) neurons the intensely labeled with CTB. These CTB-labeled neurons were densely distributed in the dorsomedian part of the DRN with some in a surrounding area outside the DRN. 结果大部分DRN神经元有CTB的强阳性标记,且集中分布在DRN的背中线部分,部分分布在DRN外侧的周边区域。