大鼠下丘脑-缰核系统对中缝大核痛反应神经元放电的影响

在大鼠尾部给以伤害性刺激后,外侧缰核和中缝大核的单位按其反应型式可分为四种类型,即痛兴奋单位、广动力型单位、痛抑制单位和无反应单位。电刺激下丘脑外侧区对外侧缰核中各种单位的自发放电主要产生抑制作用,对其中痛兴奋单位和痛抑制单位的自发放电尤为明显。刺激下丘脑外侧区对中缝大核中痛兴奋单位的自发放电有明显兴奋作用,刺激外侧缰核则有抑制作用,损毁外侧缰核后,下丘脑外侧区的兴奋作用消失。分别刺激下丘脑外侧区和外侧缰核对中缝大核中痛抑制单位的自发放电都有明显的抑制作用;损毁外侧缰核后下丘脑外侧区的抑制作用仍存在。以上结果提示,下丘脑外侧区影响中缝大核活动的途径有二。其一可能是通过去除外侧缰核对中缝大核中痛兴奋单位的紧张性抑制作用;另外还可能通过外侧缰核以外的途径抑制中缝大核中痛抑制单位的活动。

INFLUENCE OF HYPOTHALAMUS-HABENULAR NUCLEUS SYSTEM ON SPONTANEOUS DISCHARGES OF PAIN SENSITVE NEURONS OF NUCLEUS RAPHE MAGNUS OF RATS

Discharges of neurons in lateral habenular nucleus(LHb)and nucleus raphemagnus(NRM)were recorded.The recorded units were divided into four types:pain-excitative,pain-inhibitive,wide-dynamic and pain-nonsensitive neurons.Spontaneous discharge frequencies of all the four types of neurons in LHb,especially those of pain-excitative and pain-inhibitive neurons,were decreased byelectrical stimulation of the area hypothalamus lateralis(AHL).Spontaneous discharge frequencies of pain-excitative neurons in NRM wereincreased by AHL stimulation but decreased by LHb stimulation.After a lesionwas made to LHb the effect of stimulation of AHL on the neurons in NRM disap-peared.Spontaneous discharge frequencies of pain-inhibitive neurons of NRM weredecreased by stimulation either of AHL or of LHb.After a lesion was made toLHb the effect of AHL on neurons in NRM still persisted.The experimental results suggested that AHL may activate NRM neurons byreleasing the inhibition of NRM from LHb and inhibit the pain-inhibitive neuronsin NRM through pathway besides LHb.