Changes in CGRP-immunoreactive nerve fibres during experimental tooth movement in rats

SUMMARY Immunohistochemical localization of calcitonin gene-related peptide (CGRP) was used to investigate changes in nerves expressing CGRP in periodontium and pulp during experimental mesial movement of the first maxillary molar in rats. The orthodontic appliance consisted of a coil spring connecting the first maxillary molar on one side to the central incisors. After 5 days with a continuous force of 30-50 g the animals were perfused after an overdose of anaesthetic. Serial sections from the experimental and control jaws were exposed to the avidin-biotin-peroxidase technique for demonstration of CGRP-immunoreactive (IR) nerve fibres. The induced tooth movement caused reproducible changes in the relative number of CGRP-IR nerves as well as morphological alterations within parts of the nerve supply of the experimental teeth and related tissue structures. The majority of the experimental teeth showed increased number of CGRP-IR nerves in the coronal pulp and periapical tissues. The results indicate that peptidergic nerve fibres immunoreactive for CGRP takes an active part in tissue responses in pulp and supporting tissues during experimental tooth movement