Open AccessVGluT1‐ and GAD‐immunoreactive terminals in synaptic contact with PAG‐immunopositive neurons in principal sensory trigeminal nucleus of rat 3
Author(s) -
DONG Yulin,
ZHANG Fuxing,
PANG Youwang,
LI Jinlian
Publication year - 2007
Publication title -
acta pharmacologica sinica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.514
H-Index - 90
eISSN - 1745-7254
pISSN - 1671-4083
DOI - 10.1111/j.1745-7254.2007.00463.x
Subject(s) - neuroscience , nucleus , sensory system , biology
Aim: To trace the origin of abundant vesicular glutamate transporter 1‐like immunoreactive (VGluT1‐LI) axon terminals in the dorsal division of the principal sensory trigeminal nucleus (Vpd) and the relationships between VGluT1‐LI, as well as the glutamic acid decarboxylase (GAD)‐LI axon terminals, and phosphate‐activated glutaminase (PAG)‐LI thalamic projecting neurons in the Vpd. Methods: Following unilateral trigeminal rhizotomy, triple‐immunofluorescence histochemistry for VGluT1, GAD and PAG and the immunogold–silver method for VGluT1 or GAD, combined with the immunoperoxidase method for PAG were performed, respectively. Results : After unilateral trigeminal rhizotomy, the density of VGluT1‐like immunoreactivity (IR) in the Vpd on the lesion side was reduced compared to its contralateral counterpart. Under the confocal laser‐scanning microscope, the VGluT1‐LI or GAD‐LI axon terminals were observed to be in close apposition to the PAG‐LI thalamic projecting neuronal profiles, and further electron microscope immunocytochemistry confirmed that VGluT1‐ and GAD‐LI axon terminals made asymmetrical and symmetrical synapses upon the PAG‐LI neuronal structures. Conclusion : The present results suggest that the VGluT1 ‐LI axon terminals, which mainly arise from the primary afferents of the trigeminal ganglion, along with the PAG‐LI neuronal profiles, form the key synaptic connection involved in sensory signaling.