ABSTRACT
Objective To observe the morphologic features of neurons labeled with green fluorescent protein (GFP) gene recombinant Sindibis virus in the deep part of lamina Ⅲ in the medullary dorsal horn (MDH) of the rat. Methods Neurons were infected and labeled with GFP gene recombinant Sindibis virus injected into lamina Ⅲ.Immunohistchemical staining showed the labeling results.The morphologic features of the GFP labeled neurons were revealed after reconstruction. Results A few GFP-labeled single neurons were found in the distal portions away from the virus injection site within the deep part of lamina Ⅲ of the MDH.According to the morphological features,especially their axons and axonal collaterals,GFP labeled neurons were classified into projection neurons and intrinsic neurons.The axons and their collaterals of the projection neurons entered to the superficial part of lamina Ⅲ,lamina Ⅱ and/or the medullary reticular formation.Most of the axons and their collaterals of the intrinsic neurons extended mainly within lamina Ⅲ.Conclusions According to the morphological features of axons and their axonal collaterals,GFP labeled neurons were classified into projection neurons and intrinsic neurons in the deep part of lamina Ⅲ of the MDH.GFP gene recombinant virus labeling technique is an effective method to investigate the morphological features of neurons.