TY - JOUR
T1 - TRPM8 mRNA is expressed in a subset of cold-responsive trigeminal neurons from rat
AU - Nealen, Michele L.
AU - Gold, Michael S.
AU - Thut, Paul D.
AU - Caterina, Michael J.
PY - 2003/7/1
Y1 - 2003/7/1
N2 - Recent electrophysiological studies of cultured dorsal root and trigeminal ganglion neurons have suggested that multiple ionic mechanisms underlie the peripheral detection of cold temperatures. Several candidate "cold receptors," all of them ion channel proteins, have been implicated in this process. One of the most promising candidates is TRPM8, a nonselective cationic channel expressed in a subpopulation of sensory neurons that is activated both by decreases in temperature and the cooling compound menthol. However, evidence for the expression of TRPM8 in functionally defined cold-sensitive neurons has been lacking. Here, we combine fluorometric calcium imaging of cultured rat trigeminal neurons with single-cell RT-PCR to demonstrate that there are distinct subpopulations of cold responsive neurons and that TRPM8 likely contributes to cold transduction in one of them. TRPM8 is preferentially expressed within a subset of rapidly responsive, low-threshold (approximately 30°C), cold-sensitive neurons. A distinct class of slowly responsive cold-sensitive neurons that is activated at lower temperatures (approximately 20°C) generally lacks detectable TRPM8 mRNA. Together with previous findings, our data support the notion that cold responsive neurons are functionally heterogeneous.
AB - Recent electrophysiological studies of cultured dorsal root and trigeminal ganglion neurons have suggested that multiple ionic mechanisms underlie the peripheral detection of cold temperatures. Several candidate "cold receptors," all of them ion channel proteins, have been implicated in this process. One of the most promising candidates is TRPM8, a nonselective cationic channel expressed in a subpopulation of sensory neurons that is activated both by decreases in temperature and the cooling compound menthol. However, evidence for the expression of TRPM8 in functionally defined cold-sensitive neurons has been lacking. Here, we combine fluorometric calcium imaging of cultured rat trigeminal neurons with single-cell RT-PCR to demonstrate that there are distinct subpopulations of cold responsive neurons and that TRPM8 likely contributes to cold transduction in one of them. TRPM8 is preferentially expressed within a subset of rapidly responsive, low-threshold (approximately 30°C), cold-sensitive neurons. A distinct class of slowly responsive cold-sensitive neurons that is activated at lower temperatures (approximately 20°C) generally lacks detectable TRPM8 mRNA. Together with previous findings, our data support the notion that cold responsive neurons are functionally heterogeneous.
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U2 - 10.1152/jn.00843.2002
DO - 10.1152/jn.00843.2002
M3 - Article
C2 - 12634279
AN - SCOPUS:0037824388
SN - 0022-3077
VL - 90
SP - 515
EP - 520
JO - Journal of neurophysiology
JF - Journal of neurophysiology
IS - 1
ER -