Primary afferent depolarization evoked by a painful stimulus.
Pulses of intense radiant heat applied to the plantar pad of unanesthetized spinal cats produced negative dorsal root potentials, increased excitability of cutaneous A fibers, and marked activation of ipsilateral flexor motoneurons. The same effects were obtained during cold block of A fiber conduction in the appropriate peripheral nerve. We conclude that adequate noxious activation of cutaneous C fibers depolarizes cutaneous A fibers.
D000818:Animals; D002415:Cats; D003080:Cold Temperature; D005071:Evoked Potentials; D006358:Hot Temperature; D009046:Motor Neurons; D010146:Pain; D012867:Skin