【摘要】 研究了电刺激猫牙髓诱发束旁核(Pf)痛放电和尾核头部(Cd)对其抑制的若干特点。结果表明,Pf神经元痛放电为少数几次锋电位,潜伏期平均28.4ms(n=62),跟随频率多数在5CPS以下;Cd抑制48个Pf单位(77.4%)痛放电,这类Pf单位的痛放电潜伏期较长且跟频能力较差,抑制潜伏期约30～40ms,抑制持续期平均305ms,在Cd背侧浅层记录到牙髓最大诱发电位处能较深层更为有效地抑制Pf的痛放电;中缝背核(DRN)电蚀毁损不影响Cd的抑制作用;静注荷包牡丹碱不影响Cd的抑制作用,静注小剂量马钱子素则阻断Cd抑制作用。结果提示:Cd选择性地抑制Pf某一类神经元的伤害性发放,该抑制途径可能不经过中缝核系统,但可能与甘氨酸递质有关;cd背侧浅层刺激,可产生更强的镇痛作用。更多还原

【Abstract】 Certain characteristics of both the nociceptive discharges of parafascicular (Pf) neurons evoked by electrical stimulation of canine tooth pulp (TP) and the inhibitory effect of stimulation of the head of caudate nucleus(Cd) on these discharges were studied in cats. The results showed that TP-evoked Pf noxious discharge was a few spikes with a mean latency of 28.4ms (n=69) and most of Pf units could follow repetitive pulpal shocks less than 5 cps; forty eight (77.4%) Pf units studied were inhibited by conditioning Cd stimulation with a latency of inhibition of 30-40 ms and a duration of inhibition averaged 305 ms and these Pf units had both a longer response latency and a weaker frequency-following ability to TP shocks; the dorsal Cd, where the maximum field potentials evoked by TP could be recorded from,was more effective than the ventral Cd in inhibition of Pf units; Cd inhibitory effect was not affected by lesion of the dorsal raphe nucleus,or by administration of bicuculline, but could be blocked by brucine (0.1-0.2mg/kg,i.v.). These results suggest that Cd can selectively inhibit noxious discharge of certain type of neurons in Pf; the pathway of this inhibition is possibly not via the median raphe system but might involve glycine as a neurotransmitter; and the stimulation of the superficial dorsal part of Cd would produce stronger analgesia.更多还原