Abstract|Pain 1| Volume 357, SUPPLEMENT 1, e92, October 15, 2015

Unexpected meningeal reaction to pain in trigeminal region: association with calcitonin gene related polipeptide

      Background: Recently we observed that two different types of pain: infraorbital nerve constriction injury (IONC) and facial formalin injection in rats (Filipović et al. Plos One 2012) are accompanied by dural neurogenic inflammation (DNI) characterized by extravasation of plasma proteins and inflammatory cells. This previously unknown phenomenon is specific only for trigeminal region, since peripheral types of pain like partial transection of the sciatic nerve (ScNT) and sciatic nerve constriction injury (SCI) are avoid of extravasation of lumbar or cranial dura (Filipović et al., J Neural Transmission 2004).
      Objective: To investigate possible association of pain induced DNI with calcitonin gene-related peptide (CGRP).
      Material and methods: We investigated third type of pain in trigeminal region: Freund adjuvant induced inflammation and pain in temporomandibular joint (TMJ) of rat. DNI was investigated by Evans blue-plasma protein extravasation, and cell histology. CGRP was investigated by immunohistochemistry and radioimmunoassay. Effect of several analgesics drugs (aspirin, morphine, sumatriptan) was tested as well
      Results: TMJ induced pain was accompanied by dural plasma proteins and inflammatory cells and increase in CGRP level in dura.
      Conclusion: In addition to IONC and facial formalin injection, TMJ induced pain is accompanied by neurogenic dural extravasation, as well. Pain induced DNI is associated with CGRP expression in meninges.