Vesicular glutamate transporters in axons that innervate the human dental Pulp

Introduction: Vesicular glutamate transporters (VGLUTs) are involved in the transport of transmitter glutamate into synaptic vesicles and are used as markers for glutamatergic neurons. Methods: To assess which types of VGLUTs are involved in the glutamate signaling in pulpal axons and to investigate their distribution, we performed light microscopic immunohistochemistry by using antibodies against VGLUT1, VGLUT2, calcitonin gene-related peptide, and Western blot analysis in human dental pulp. Results: VGLUT1 was expressed in a large number of pulpal axons, especially in the peripheral pulp where the axons branch extensively. The VGLUT1 immunopositive axons showed bead-like appearance, and the majority of these also expressed calcitonin gene-related peptide. VGLUT2 was expressed in few axons throughout the pulp. Conclusions: Our findings suggest that VGLUT1 is involved mainly in the glutamate-mediated signaling of pain, primarily at the level of the peripheral pulp.