Coexpression of VGLUT1 and VGLUT2 in trigeminothalamic projection neurons in the principal sensory trigeminal nucleus of the rat.
VGLUT1 and VGLUT2 have been reported to show complementary distributions in most brain regions and have been assumed to define distinct functional elements. In the present study, we first investigated the expression of VGLUT1 and VGLUT2 in the trigeminal sensory nuclear complex of the rat by dual-fluorescence in situ hybridization. Although VGLUT1 and/or VGLUT2 mRNA signals were detected in all the nuclei, colocalization was found only in the principal sensory trigeminal nucleus (Vp). About 64% of glutamatergic Vp neurons coexpressed VGLUT1 and VGLUT2, and the others expressed either VGLUT1 or VGLUT2, indicating that Vp neurons might be divided into three groups. We then injected retrograde tracer into the thalamic regions, including the posteromedial ventral nucleus (VPM) and posterior nuclei (Po), and observed that the majority of both VGLUT1- and VGLUT2-expressing Vp neurons were retrogradely labeled with the tracer. We further performed anterograde labeling of Vp neurons and observed immunoreactivies for anterograde tracer, VGLUT1, and VGLUT2 in the VPM and Po. Most anterogradely labeled axon terminals showed immunoreactivities for both VGLUT1 and VGLUT2 in the VPM and made asymmetric synapses with dendritic profiles of VPM neurons. On the other hand, in the Po, only a few axon terminals were labeled with anterograde tracer, and they were positive only for VGLUT2. The results indicated that Vp neurons expressing VGLUT1 and VGLUT2 project to the VPM, but not to the Po, although the functional differences of three distinct populations of Vp neurons, VGLUT1-, VGLUT2-, and VGLUT1/VGLUT2-expressing ones, remain unsettled.
Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an 710032, People's Republic of China.
Shun-Nan
SN
Ge
Yun-Fei
YF
Ma
Hiroyuki
H
Hioki
Yan-Yan
YY
Wei
Takeshi
T
Kaneko
Noboru
N
Mizuno
Guo-Dong
GD
Gao
Jin-Lian
JL
Li
D000818:Animals; D002452:Cell Count; D002772:Cholera Toxin / Q000378:metabolism; D005434:Flow Cytometry; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D009415:Nerve Net / Q000737:chemistry / Q000378:metabolism*; D020656:Posterior Thalamic Nuclei / Q000166:cytology / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism; D015347:RNA Probes; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013266:Stilbamidines; D013788:Thalamus / Q000166:cytology / Q000378:metabolism*; D014276:Trigeminal Nerve / Q000166:cytology / Q000378:metabolism*; D020651:Ventral Thalamic Nuclei / Q000737:chemistry / Q000378:metabolism; D050598:Vesicular Glutamate Transport Protein 1 / Q000096:biosynthesis*; D050599:Vesicular Glutamate Transport Protein 2 / Q000096:biosynthesis*
C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D015347:RNA Probes; D012333:RNA, Messenger; C493475:Slc17a6 protein, rat; C493466:Slc17a7 protein, rat; D013266:Stilbamidines; D050598:Vesicular Glutamate Transport Protein 1; D050599:Vesicular Glutamate Transport Protein 2; D002772:Cholera Toxin