Increased Asics Expression via the Camkii-CREB Pathway in a Novel Mouse Model of Trigeminal Pain.

BACKGROUND/AIMS: Migraine is a disabling condition that severely impacts socioeconomic function and quality of life. The focus of this study was to develop a mouse model of trigeminal pain that mimics migraine. METHODS: After undergoing dural cannulation surgery, mice were treated with repeated dural doses of an acidic solution to induce trigeminal pain. RESULTS: The method elicited intermittent, head-directed wiping and scratching as well as the expression of both the c-FOS gene in the spinal trigeminal nucleus caudalis and calcitonin gene related peptide (CGRP) in the periaqueductal grey matter. Interestingly, the acid-induced trigeminal pain behaviour was inhibited by amiloride, an antagonist of acid-sensing ion channels (ASICs), but not by AMG-9810, an inhibitor of transient receptor potential cation channel V1(TRPV1). In addition, the relative mRNA and protein expression levels of ASIC1a and ASIC3 were increased in the acid-induced trigeminal nociceptive pathways. Furthermore, blocking CaMKII with KN-93 significantly reduced the acid-induced trigeminal pain behaviour and c-FOS gene expression. CONCLUSION: The data suggested that chronic intermittent administration of an acidic solution to mice resulted in trigeminal hypersensitivity and that dural acid-induced trigeminal pain behaviour in mice may mechanistically mimic migraine. The observations here identify an entirely novel treatment strategy for migraine.