Organ culture of the trigeminal ganglion induces enhanced expression of calcitonin gene-related peptide via activation of extracellular signal-regulated protein kinase 1/2

János Tajti, Anikó Kuris, László Vécsei, Cang Bao Xu, Lars Edvinsson

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Background and objective: Clinical and experimental studies have revealed a central role of calcitonin gene-related peptide (CGRP) in primary headaches. The role of extracellular signal-regulated kinase 1 and 2 (ERK1/2) in neuronal and glial cell expression of CGRP-immunoreactivity (-ir) in rat trigeminal ganglia was studied with an organ culture method. Experimental procedures: Sections of adult rat trigeminal ganglia were cultured for up to 48 hours, examined with immunohistochemistry and quantitative real-time polymerase chain reaction (PCR) assay. Specific antibodies against CGRP, phosphorylated ERK1/2 (pERK1/2), total ERK1/2 (tERK1/2), phosphorylated p38 (pp38), phosphorylated C-Jun-N-terminal protein kinase (pJNK), pro-calcitonin (pro-CT), CGRP receptor activity modifying protein 1 (RAMP1), glutamine synthetase (GS) and pro-CT were used. To explore molecular mechanisms involved in the organ culture-induced CGRP-ir in neurons and glial cells, the effects of the MEK/ERK1/2 inhibitor U0126, its inactive analogue U0124, the p38 inhibitor SB203580 and the JNK inhibitor SP600125 were studied. Results: In fresh ganglia, small-and medium-sized neurons were CGRP-ir while some larger neurons displayed RAMP1-ir. Glial cells were negative to both. After organ culture, neurons showed enhanced CGRP-and RAMP1-ir. In addition, some glial cells were RAMP1-and CGRP-ir. Isolated glial cells and neurons were found to contain CGRP mRNA, and showed pro-CT-ir, suggestive of local formation of CGRP. Neurons and glial cells showed enhanced pERK1/2-ir already after two hours of organ culture and this remained elevated for 48 hours. There was transient pJNK-ir in neurons at two hours, while pp38-ir was not altered. U0126 reduced the enhanced pERK1/2-ir, while U0124 had no such effect; the CGRP-ir in neurons and glial cells was reduced at 48 hours and in parallel the CGRP mRNA expression was lower at 24 hours. Conclusion: We suggest that in conditions of elevated CGRP expression, inhibition of ERK1/2 might be an option for novel treatment.

Original languageEnglish
Pages (from-to)95-105
Number of pages11
JournalCephalalgia
Volume31
Issue number1
DOIs
Publication statusPublished - Jan 2011

Keywords

  • CGRP
  • ERK1/2
  • neurons
  • satellite glial cells
  • trigeminal ganglion

ASJC Scopus subject areas

  • Clinical Neurology

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