Calcitonin gene-related peptide receptor expression in healthy and inflamed human pulp tissue J. Caviedes-Bucheli 1 , N. Arenas 2 , O. Guiza 2 , N. A. Moncada 2 , G. C. Moreno 1 , E. Diaz 1 & H. R. Munoz 1 1 Graduate Studies Department; and 2 Endodontic Department, School of Dentistry, Pontificia Universidad Javeriana, Bogota, Colombia Abstract Caviedes-Bucheli J, Arenas N, Guiza O, Moncada NA, Moreno GC, Diaz E, Munoz HR. Calcitonin gene-related peptide receptor expression in healthy and inflamed human pulp tissue. International Endodontic Journal, 38, 712–717, 2005. Aim To use radioreceptor analysis for comparing calcitonin gene-related peptide (CGRP) receptor expres- sion in human pulp tissue samples collected from teeth having a clinical diagnosis of acute irreversible pulpitis, healthy pulps and teeth with induced inflammation. Methodology Six pulp samples were obtained from teeth having a clinical diagnosis of acute irreversible pulpitis. Another eight pulp samples were obtained from healthy premolars where extraction was indicated for orthodontic purposes. In four of these premolars, inflammation was induced prior to pulp collection. All the samples were processed and labelled with 125 I-CGRP. Binding sites were identified by 125 I-CGRP and standard CGRP competition assays. Results CGRP receptor expression was found in all human pulp tissue samples. Most receptors were found in the group of pulps from teeth having a clinical diagnosis of acute irreversible pulpitis, followed by the group of pulps having induced inflammation. The least number of receptors was expressed in the group of healthy pulps. The Kruskal– Wallis and Mann–Whitney (post-hoc) tests showed statistically significant differences between the groups (P < 0.05). Conclusion CGRP receptor expression in human pulp tissue is significantly increased during inflammatory phenomena such as acute irreversible pulpitis. Keywords: calcitonin gene-related peptide receptor, human pulp, neurogenic inflammation, radioreceptor assay. Received 8 October 2004; accepted 16 May 2005 Introduction Dental pulp inflammation is a complex process invol- ving a great variety of nervous and vascular reactions, which are key components of the neurogenic phenom- enon that could lead to pulp necrosis (Kim 1990). Neuropeptides play an active role in homeostatic regulation under normal conditions and during neu- rogenic inflammation of the pulp, controlling its blood flow and regulating later stages of inflammation and repairing process (Olgart 1996). These neuropeptides include substance P, calcitonin gene-related peptide (CGRP), neurokinin A, vasoactive intestinal peptide and neuropeptide Y (Wakisaka 1990). CGRP is produced in the trigeminal cell bodies and is transported via axonal flow to the nerve terminals in the pulp, where it is co-stored with other sensory neuropeptides (Gazelius et al. 1987, Wakisaka & Akai 1989). These nerve terminals are mainly C-type fibres, which closely follow the pulp microcirculation. When stimulated, neuropeptides are released (Awawdeh et al. 2002). CGRP is a powerful vasodilator agent, which causes an increase in local blood flow and conse- quently, pulpal tissue pressure increases (Olgart et al. 1991). In addition to this effect, CGRP exerts stimula- tory effects on the growth of pulpal cells, such as fibroblasts and odontoblast-like cells (Trantor et al. Correspondence: Javier Caviedes-Bucheli, MSc, DDS, School of Dentistry, Pontificia Universidad Javeriana, Cra7 no. 40-62 Building 26, Bogota, Colombia (Tel.: +57 1 3208320, ext 2889; e-mail: javiercaviedes@cable.net.co). International Endodontic Journal, 38, 712–717, 2005 ª 2005 International Endodontic Journal 712