ABSTRACT
Objective To study the effect of intracerebroventricular(icv) injectionon acetylcholine(ACh) on the elecric activities of pain-related neurons in the hippocampal CA1 area of rat.Methods Trains of the electric impulses applied to the right sciatic nerve were used as noxious stimuli.The discharges of neurons were led out by extracellular recording method with glass microelectrodes.Results Icv injection of ACh(20?g/10?l) caused an decrease of the evoked discharge frequency of pain-excited neurons(PEN) and a prolongation latency as well as an increase of the evoked discharge of pain-inhibited neurons(PIN) and a shortening of inhibitory duration.Conclusion The response of pain-related neurons in hippocampal CA1 area to the noxious stimulation is weakened by icv injection of ACh,exhibiting analgesic effect.