Abstract
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.
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Project supported in part by grants from the National Natural Science Foundation of China (No 30470907).
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Dong, Yl., Zhang, Fx., Pang, Yw. et al. VGluT1- and GAD-immunoreactive terminals in synaptic contact with PAG-immunopositive neurons in principal sensory trigeminal nucleus of rat. Acta Pharmacol Sin 28, 180–184 (2007). https://doi.org/10.1111/j.1745-7254.2007.00463.x
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DOI: https://doi.org/10.1111/j.1745-7254.2007.00463.x
