过度通气对在体大鼠脊髓背角WDR神经元兴奋性影响的实验研究

目的:考察过度通气对大鼠脊髓背角广动力范围(Wide dynamic range,WDR)神经元自发和疼痛诱发放电频率的影响。方法:将25只SD大鼠随机分为N(正常通气)和H(过度通气)两组。两组均在吸入麻醉下行椎板切除,记录与大鼠后足掌部皮肤感觉对应的脊髓背角WDR神经元放电频率百分比。N组正常通气120分钟,旨在排除手术创伤对WDR神经元的影响;H组实施过度通气60分钟后,恢复正常通气继续观察60分钟,目的为考察过度通气对该神经元电活动的影响。结果:(1)N组各采样点间WDR神经元自发和诱发放电频率百分比均无显著性差异。(2)H组过度通气后WDR神经元自发和疼痛诱发放电频率百分比较对照值显著降低,并随正常通气的恢复而恢复。(3)H组过度通气期间WDR神经元自发及诱发放电频率百分比均较N组相应时间点显著降低。结论:过度通气可使大鼠脊髓背角WDR神经元兴奋性降低。

THE EFFECTS OF HYPERVENTILATION ON THE EXCITABILITY OF RATS SPINAL CORD DORSAL HORN WDR NEURON IN VIVO

Objective: To observe the effects of hyperventilation on rat’s spinal cord dorsal horn WDR neurons excitability in vivo.Methods: 25 adult Sprague-Dawley rats were randomly divided into two groups,group N(normal ventilation,n = 10) and H(hyperventilation,n = l5).The rats of both groups were undergone vertebral arch resection under inhalational anesthesia.Single unit extra-cellular recordings of spontaneous and pitch induced activities were taken every ten minutes on spinal cord dorsal horn WDR neurons corresponding to hinder palm in each group.120 minutes normal ventilation was given in N group,which aimed at the exclusion of operation influence.60 minutes hyperventilation and 60 minutes normal ventilation were given in H group,to observe the effects of hyperventilation.Results:(1) No significant difference was found among each time point within N group;(2) In H group,the spike freque-ncy rate of both spontaneous and pitch induced activity of WDR neurons were decreased from about 20 minutes after the induction of hyperventilation;(3) In H group,the spike frequency rate of both spontaneo-us and pitch induced activity were significantly decreased during hyperventilation compared with that of N group.Con-clusion: Hyperventilation can inhibit the WDR neurons excitability in vivo.