Transient receptor potential melastatin 8 is required for nitroglycerin- and calcitonin gene-related peptide-induced migraine-like pain behaviors in mice.

ABSTRACT: Migraine is a complex neurovascular disorder that is one of the leading causes of disability and a reduced quality of life. Even with such a high societal impact, our understanding of the cellular and molecular mechanisms that contribute to migraine headaches is limited. To address this complex disorder, several groups have performed genome-wide association studies to elucidate migraine susceptibility genes, with many identifying transient receptor potential melastatin 8 (TRPM8), a cold-sensitive cation channel expressed in peripheral afferents innervating the trigeminovascular system, and the principal mediator of cold and cold pain associated with injury and disease. Interestingly, these migraine-associated single-nucleotide polymorphisms reside in noncoding regions of TRPM8, with those correlated with reduced migraine risk exhibiting lower TRPM8 expression and decreased cold sensitivity. Nonetheless, as a role for TRPM8 in migraine has yet to be defined, we sought to address this gap in our knowledge using mouse genetics and TRPM8 antagonism to determine whether TRPM8 channels or neurons are required for migraine-like pain (mechanical allodynia and facial grimace) in inducible migraine models. Our results show that both evoked and spontaneous pain behaviors are dependent on both TRPM8 channels and neurons, as well as required in both acute and chronic migraine models. Moreover, inhibition of TRPM8 channels prevented acute but not established chronic migraine-like pain. These results are consistent with its association with migraine in genetic analyses and establish that TRPM8 channels are a component of the underlying mechanisms of migraine.