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Quantitative Analysis of Mouse Dural Afferent Neurons Expressing TRPM 8, VGLUT 3, and NF 200
Author(s) -
Ren Lynn,
Chang Michelle Jaehee,
Zhang Zhiyu,
Dhaka Ajay,
Guo Zhaohua,
Cao YuQing
Publication year - 2018
Publication title -
headache: the journal of head and face pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.14
H-Index - 119
eISSN - 1526-4610
pISSN - 0017-8748
DOI - 10.1111/head.13188
Subject(s) - trpm8 , trigeminal ganglion , calcitonin gene related peptide , transient receptor potential channel , trpv1 , neuroscience , afferent , neuropeptide , chemistry , receptor , endocrinology , medicine , microbiology and biotechnology , sensory system , biology
Objective To quantify the abundance of dural afferent neurons expressing transient receptor potential channel melastatin 8 (TRPM8), vesicular glutamate transporter 3 (VGLUT3), and neurofilament 200 (NF200) in adult mice. Background With the increasing use of mice as a model system to study headache mechanisms, it is important to understand the composition of dural afferent neurons in mice. In a previous study, we have measured the abundance of mouse dural afferent neurons that express neuropeptide calcitonin gene‐related peptide as well as two TRP channels TRPV1 and TRPA1, respectively. Here, we conducted quantitative analysis of three other dural afferent subpopulations in adult mice. Methods We used the fluorescent tracer Fluoro‐Gold to retrogradely label dural afferent neurons in adult mice expressing enhanced green fluorescent protein in discrete subpopulations of trigeminal ganglion (TG) neurons. Mechanoreceptors with myelinated fibers were identified by NF200 immunoreactivity. We also conducted Ca 2+ ‐imaging experiments to test the overlap between TRPM8 and VGLUT3 expression in mouse primary afferent neurons (PANs). Results The abundance of TRPM8‐expressing neurons in dural afferent neurons was significantly lower than that in total TG neurons. The percentages of dural afferent neurons expressing VGLUT3 and NF200 were comparable to those of total TG neurons, respectively. TRPM8 agonist menthol evoked Ca 2+ influx in less than 7% VGLUT3‐expressing PANs in adult mice. Conclusions TG neurons expressing TRPM8, VGLUT3, and NF200 all innervate adult mouse dura. TRPM8 and VGLUT3 are expressed in distinct subpopulations of PANs in adult mice. These results provide an anatomical basis to investigate headache mechanisms in mouse models.