Synaptic amplifier of inflammatory pain in the spinal dorsal horn.
Inflammation and trauma lead to enhanced pain sensitivity (hyperalgesia), which is in part due to altered sensory processing in the spinal cord. The synaptic hypothesis of hyperalgesia, which postulates that hyperalgesia is induced by the activity-dependent long-term potentiation (LTP) in the spinal cord, has been challenged, because in previous studies of pain pathways, LTP was experimentally induced by nerve stimulation at high frequencies ( approximately 100 hertz). This does not, however, resemble the real low-frequency afferent barrage that occurs during inflammation. We identified a synaptic amplifier at the origin of an ascending pain pathway that is switched-on by low-level activity in nociceptive nerve fibers. This model integrates known signal transduction pathways of hyperalgesia without contradiction.
Ikeda
Hiroshi
H
Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria.
Stark
Johanna
J
Fischer
Harald
H
Wagner
Matthias
M
Drdla
Ruth
R
Jäger
Tino
T
Sandkühler
Jürgen
J
D000818:Animals; D002118:Calcium / Q000378:metabolism; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials; D006930:Hyperalgesia / Q000503:physiopathology*; D007249:Inflammation / Q000503:physiopathology*; D017774:Long-Term Potentiation; D036421:Nerve Fibers, Unmyelinated / Q000502:physiology*; D009473:Neuronal Plasticity; D009569:Nitric Oxide / Q000502:physiology; D010146:Pain / Q000503:physiopathology*; D018408:Patch-Clamp Techniques; D010487:Periaqueductal Gray / Q000502:physiology; D020671:Posterior Horn Cells / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013116:Spinal Cord / Q000503:physiopathology; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission
D009569:Nitric Oxide; D002118:Calcium