Aim To study the role of acetylcholine(ACh) and cholinergic receptor in the nociceptive modulation in hippocampal CA1 area of normal rats.Methods The trains of electric impulses applied to sciatic nerve were set as noxious stimulation.The discharges of pain-related neuron in the CA1 area were recorded extracellularly by glass microelectrode.Results The intracerebroventricular(icv) micro-injection of ACh caused the decrease in the pain-evoked discharge frequency and the prolongation of latency of pain-excita...