研究指出

丘脑腹后外侧核(VPL)可接受躯体伤害性传入信息

在VPL中可记录到对伤害性刺激出现放电增加和放电减少的痛反应神经元。表明VPL某些神经元对伤害性刺激的反应与丘脑非特异投射系统核团中痛反应神经元的活动相似The somatic and visceral noxious stimuli could simultaneously induce the increase of discharges of pain-excitation neutons (PEN) and the decrease of discharges of pain-inhibition neurons (PIN) in the Nucleus Ventralis posterolalis(VPL) of thalamus in the rat

and the electric activities of the two kinds of neurons cooperated each other. By the injection of morphine (5mg/kg) and the electroacupuncture of "Zusanli"

the discharges of PEN were reduced and the discharges of PIN were enhanced. The results suggested that VPL of thalamus in the rat be ifivolved in the modulating action on pain sensation and the analgesic effects of morphine and electroacupuncture by the simultaneous electric activities of PEN and PIN in VPL.