Thermal inhibition of nociceptor-driven spinal cord neurones in the cat: a possible neuronal basis for thermal analgesia.
Extracellular and intracellular recordings were made from within the dorsal horn of 10 anaesthetised and gallamine triethiodide-paralysed cats. Inhibition of background and residual noxious-evoked discharge by cooling and warming was demonstrated in 7 out of 33 nociceptor-driven dorsal horn neurones. Five units were inhibited by warming of the noxious mechanical excitatory receptive field. Four units were inhibited by 100%. One unit was inhibited by 42%. Cold stimulation inhibited two units. The background and residual noxious evoked discharge was inhibited by 100%. Cooling (32-20 degrees C) excited two units; warming (32-43 degrees C) also excited two units. Heating above 43 degrees C excited 8 units; cold below 20 degrees C excited 3 units. The units inhibited by thermal stimulation may provide some neuronal basis for thermal analgesia.
D000698:Analgesia / Q000379:methods*; D000818:Animals; D002415:Cats; D017679:Cryotherapy; D005260:Female; D006358:Hot Temperature / Q000627:therapeutic use*; D008297:Male; D009433:Neural Inhibition; D009619:Nociceptors / Q000502:physiology; D010146:Pain / Q000503:physiopathology*; D012867:Skin / Q000294:innervation; D012881:Skin Temperature; D013116:Spinal Cord / Q000503:physiopathology*