A progressive and cumulative suppression of the activity of spinal neurones in the nonspinal rat.
Electrical stimulation of the skin of the hindpaw of the rat, at frequencies ranging from 2 to 0.2 s-1, halted the tonic or evoked activity of spinal neurones. The duration of this effect increased with each successive stimulus until it outlasted the interstimulus interval. Tonic activity did not return immediately following termination of the stimulation, and activity was often depressed for periods of up to 5 min. Neurones displaying this behaviour were found in laminae 1 and 4--7 of the cord. Some neurones failed to demonstrate this behaviour following the administration of strychnine. This phenomenon provides a possible substrate for habituation of the flexor reflex that occurs with repetitive and noxious stimulation of the skin.
D000200:Action Potentials; D000818:Animals; D004558:Electric Stimulation; D007395:Interneurons / Q000502:physiology; D009433:Neural Inhibition; D051381:Rats; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*