TY - JOUR
T1 - Effects of selective spinal nerve ligation on acetic acid-induced nociceptive responses and ASIC3 immunoreactivity in the rat dorsal root ganglion
AU - Omori, Megumi
AU - Yokoyama, Masataka
AU - Matsuoka, Yoshikazu
AU - Kobayashi, Hiroyuki
AU - Mizobuchi, Satoshi
AU - Itano, Yoshitaro
AU - Morita, Kiyoshi
AU - Ichikawa, Hiroyuki
PY - 2008/7/11
Y1 - 2008/7/11
N2 - We investigated changes in pain behavior after injection of acetic acid in the hindpaws of rats with L5 spinal nerve ligation (SNL)-induced neuropathy. We also examined immunoreactivity for acid-sensing ion channel 3 (ASIC3) in the dorsal root ganglion (DRG) of rats with L5 SNL. Two weeks after SNL, the withdrawal threshold to a mechanical stimulus was significantly lower in the SNL group than in the sham-operated group (n = 9 per group, P < 0.01). After acetic acid injection, spontaneous pain responses in the SNL group were significantly increased compared to those in the sham-operated group (n = 5, P < 0.05). L5 SNL significantly increased the proportion of total ASIC3-immunoreactive (ir) neurons in the ipsilateral L4 DRG compared to that in sham-operated rats (n = 4, P < 0.01). Analysis of cell size showed that the proportion of large (> 1200 mm2) ASIC3-ir neurons in the ipsilateral L4 DRG significantly increased after L5 SNL (P < 0.05). In the ipsilateral L5 DRG, the proportion of ASIC3-ir neurons was not significantly affected by treatment. However, L5 SNL significantly increased (P < 0.01) the proportion of small (< 1200 mm2) ASIC3-ir neurons and significantly decreased (P < 0.01) the proportion of large ASIC3-ir neurons compared to proportions in sham-operated animals. These findings suggest that ASIC3 is associated with hyperalgesia in response to a chemical stimulus in the L5 SNL rat model.
AB - We investigated changes in pain behavior after injection of acetic acid in the hindpaws of rats with L5 spinal nerve ligation (SNL)-induced neuropathy. We also examined immunoreactivity for acid-sensing ion channel 3 (ASIC3) in the dorsal root ganglion (DRG) of rats with L5 SNL. Two weeks after SNL, the withdrawal threshold to a mechanical stimulus was significantly lower in the SNL group than in the sham-operated group (n = 9 per group, P < 0.01). After acetic acid injection, spontaneous pain responses in the SNL group were significantly increased compared to those in the sham-operated group (n = 5, P < 0.05). L5 SNL significantly increased the proportion of total ASIC3-immunoreactive (ir) neurons in the ipsilateral L4 DRG compared to that in sham-operated rats (n = 4, P < 0.01). Analysis of cell size showed that the proportion of large (> 1200 mm2) ASIC3-ir neurons in the ipsilateral L4 DRG significantly increased after L5 SNL (P < 0.05). In the ipsilateral L5 DRG, the proportion of ASIC3-ir neurons was not significantly affected by treatment. However, L5 SNL significantly increased (P < 0.01) the proportion of small (< 1200 mm2) ASIC3-ir neurons and significantly decreased (P < 0.01) the proportion of large ASIC3-ir neurons compared to proportions in sham-operated animals. These findings suggest that ASIC3 is associated with hyperalgesia in response to a chemical stimulus in the L5 SNL rat model.
KW - Acetic acid
KW - Acid-sensing ion channel 3 (ASIC3)
KW - Dorsal root ganglion (DRG)
KW - Pain behavior
KW - Spinal nerve ligation (SNL)
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U2 - 10.1016/j.brainres.2008.03.040
DO - 10.1016/j.brainres.2008.03.040
M3 - Article
C2 - 18534561
AN - SCOPUS:45849146514
VL - 1219
SP - 26
EP - 31
JO - Molecular Brain Research
JF - Molecular Brain Research
SN - 0006-8993
ER -