Nociceptive cortical responses during capsaicin-induced tactile allodynia in mice with spinal dorsal column lesioning.
We investigated nociceptive cortical responses using transcranial flavoprotein fluorescence imaging in anesthetized mice with capsaicin-induced allodynia. Tactile stimuli applied to the hindpaw produced fluorescence increases in the contralateral somatosensory cortex of naïve mice. Lesioning of the ipsilateral dorsal column in the spinal cord abolished most of the cortical responses. However, the responses to the same tactile stimuli appeared again after capsaicin was injected into the hindpaw. The capsaicin treatment reduced the thresholds of the hindpaw withdrawal responses. These findings strongly suggest that the responses to tactile stimuli in the lesioned mice after capsaicin injection represented nociceptive cortical responses.
Department of Neurophysiology, Brain Research Institute, Niigata University, 1-757 Asahi-machi, Chuo-ku, Niigata 951-8585, Japan.
Seiji
S
Komagata
Keisuke
K
Tamaki
Ryuichi
R
Hishida
Nobuaki
N
Takeshita
Katsuei
K
Shibuki
D000818:Animals; D002211:Capsaicin / Q000633:toxicity; D007839:Functional Laterality / Q000502:physiology; D006930:Hyperalgesia / Q000139:chemically induced / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009437:Neuralgia / Q000503:physiopathology*; D018689:Sensory System Agents / Q000633:toxicity; D013003:Somatosensory Cortex / Q000503:physiopathology*; D013116:Spinal Cord / Q000502:physiology
D018689:Sensory System Agents; D002211:Capsaicin