title: [A dopaminergic projection from the dorsal raphe nucleus to the inner ear].
abstract: OBJECTIVE
  To investigate the efferent pathway from the dorsal raphe nucleus to the inner ear.
  
  
  METHODS
  Eleven adult cats weighing 2.0 - 3.0 kg were used. The animals had no middle-ear disease and their auricle reflex was sensitive to sound. They were divided into experimental group (8 cats) and control group (3 cases). The fluorescent tracer cholera toxin subunit-B (CTB) was injected into cat cochlea and the CTB-labelled neurons of dorsal raphe nucleus (DRN) were identified using an immunofluorescence technique after a survival period of 7 days. For studying other fluorescence labelling, the sections containing CTB-labelled neurons were divided into four groups and incubated in antisera directed against tyrosine hydroxylase (TH), serotonin (5-HT), gamma-aminobutyric acid (GABA) and dopamine B-hydroxylase (DBH), respectively. Single-and double-labelled neurons were identified from the DRN.
  
  
  RESULTS
  (1) A subpopulation of dorsal raphe nucleus (DRN) neurons were intensely labelled with CTB and these CTB-labelled neurons were densely distributed in a dorsomedial part of the DRN; (2) Four immunolabelling, TH, 5-HT, GABA and DBH were presented throughout the DRN. Of the total population of CTB-labelled neurons, 100% were TH-labelled neurons (double labelling) and no double-stained neuron with 5-HT, GABA and DBH was observed in the DRN.
  
  
  CONCLUSIONS
  There was a projection from DRN to the inner ear and this pathway might be a dopaminergic projection.
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, Xiangya Second Hospital, Central South University, Changsha 410011, China. x16y2003@yahoo.com.cn
authors.forename: Xin-Ming
authors.initials: XM
authors.lastname: Yang
authors.forename: Shu-Hui
authors.initials: SH
authors.lastname: Wang
authors.forename: Yi-Da
authors.initials: YD
authors.lastname: Yang
authors.forename: Qing-Lai
authors.initials: QL
authors.lastname: Tang
authors.forename: Ting
authors.initials: T
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Tan
authors.forename: Ke-Ying
authors.initials: KY
authors.lastname: Song
authors.forename: Qiang-He
authors.initials: QH
authors.lastname: Liu
mesh_terms: D000818:Animals; D002415:Cats; D007758:Ear, Inner / Q000294:innervation* / Q000378:metabolism; D004525:Efferent Pathways; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D011903:Raphe Nuclei / Q000378:metabolism / Q000502:physiology*