title: Glutamate control of pulpal blood flow in the incisor dental pulp of the rat.
abstract: Glutamate is present in primary sensory afferents innervating the dental pulp and is known to exert vasoactive effects. The aims of this study were (i) to assess pulpal blood flow (PBF) after glutamate infusion in the dental pulp and (ii) to observe the distribution of glutamatergic nerve fibers expressing the vesicular transporters of glutamate (VGluT). The PBF was monitored with laser Doppler flowmetry before and after glutamate (0.5 M) infusion in the dental pulp vs. saline infusion. Immunochemistry for VGluT1, 2, and 3 was performed in addition to immunochemistry for the vascular and neuronal markers smooth-muscle actin (SMA), isolectin B4 (IB4), and calcitonin gene-related peptide (CGRP). Glutamate infusion resulted in a PBF increase that lasted for 60 s. Positive immunolabeling was observed for the three glutamate transporters, but was more pronounced for VGluT3. Moreover, VGluT3 immunoreactivity was observed within nerve fibers entering the dental pulp and terminating at the periphery and at the vicinity of odontoblasts. Also, VGluT3 was colocalized with the vascular marker SMA, and in some nerve fibers with IB4, but not with CGRP. This study provides support for a control of dental pulp microcirculation by neurons expressing VGluT3.
authors.affiliation: UFR de Biologie, Université Diderot, Paris, France.
authors.forename: Fouzia
authors.initials: F
authors.lastname: Zerari-Mailly
authors.forename: Adeline
authors.initials: A
authors.lastname: Braud
authors.forename: Nicolas
authors.initials: N
authors.lastname: Davido
authors.forename: Babacar
authors.initials: B
authors.lastname: Touré
authors.forename: Jean
authors.initials: J
authors.lastname: Azérad
authors.forename: Yves
authors.initials: Y
authors.lastname: Boucher
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D003782:Dental Pulp / Q000098:blood supply* / Q000294:innervation / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism; D007180:Incisor / Q000378:metabolism*; D037102:Lectins / Q000378:metabolism; D008297:Male; D008833:Microcirculation / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009804:Odontoblasts / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride; D053675:Versicans; D050496:Vesicular Glutamate Transport Proteins / Q000378:metabolism*
chemical_list: D000199:Actins; D015740:Calcitonin Gene-Related Peptide; D018698:Glutamic Acid; D006023:Glycoproteins; D037102:Lectins; D012965:Sodium Chloride; D053675:Versicans; D050496:Vesicular Glutamate Transport Proteins; C508324:Vcan protein, rat; C498862:Acta2 protein, rat