CENTRAL DELAY OF THE LASER-ACTIVATED RAT TAIL-FLICK REFLEX
CENTRAL DELAY OF THE LASER-ACTIVATED RAT TAIL-FLICK REFLEX
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DOI：
10.1016/0304-3959(94)90183-x
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发表时间：
1994-07-01
期刊：
影响因子：
7.4
通讯作者：
CASEY, KL
中科院分区：
文献类型：
--
作者：
DANNEMAN, PJ;KIRITSYROY, JA;CASEY, KL
热激活的大鼠甩尾（TF）反射的潜伏期取决于4个变量，其中没有一个先前被确定：皮肤伤害感受器（T-N）的激活;到背角（T-A）的传入传导;中枢神经系统（CNS）内的传导（中枢延迟）;以及从腹角（VH）到尾肌（T-E）的传导和尾肌的激活。用CO_2红外激光（10 W，45 msec）同步激活大鼠尾部皮肤伤害性感受器，测定10只清醒大鼠TF潜伏期（EMG反应）。基于来自尾尖和尾根附近刺激点的反应潜伏期的变化，反射传入肢中的传导速度估计为0.76 +/- 0.11 m/sec。这表明这种反应是由C纤维介导的。然后用戊巴比妥麻醉大鼠，在激光或高强度电（10 mA，1 msec）刺激尾部期间，记录脊髓节段S-3-Co-1的浅层背角的多单位活动和诱发电位（EP）。两种刺激引起的单位活动和EP由两种不同的成分组成，对应于A和C纤维的激活。激光和电诱发活动之间的潜伏期差异表明，激光激活伤害感受器需要60.00 +/- 7.33毫秒。在3只大鼠的S-3-Co-1处电刺激VH产生4毫秒的TF（EMG）反应。中枢延迟（计算为总TF时间减去（T-N + T-A + T-E））为82.3 ± 13.08毫秒。这代表了内在的、疼痛激活的、脊髓上系统对反射的调制可能发生的时间范围。
The latency of the heat-activated rat tail-flick (TF) reflex is dependent upon 4 variables, none of which has previously been determined: activation of cutaneous nociceptors (T-N); afferent conduction to the dorsal horn (T-A); conduction within the central nervous system (CNS) (central delay); and conduction from the ventral horn (VH) to, and activation of, tail muscles (T-E). Using a CO2 infrared laser (10 W, 45 msec) to produce synchronous activation of tail-skin nociceptors, TF latency (EMG response) was measured in 10 awake rats. Based on shifts in response latency from points of stimulation near the tip and base of the tail, conduction velocity in the afferent limb of the reflex was estimated to be 0.76 +/- 0.11 m/sec. This indicates that the response is mediated by C fibers. The rats were then anesthetized with pentobarbital and multiple-unit activity and evoked potentials (EPs) were recorded from the superficial dorsal horn at spinal segments S-3-Co-1 during laser or high-intensity electrical(10 mA, 1 msec) stimulation of the tail. Unit activity and EPs elicited by both stimuli consisted of two distinct components, corresponding to activation of A and C fibers. The difference in latency between laser and electrical evoked activity indicated that 60.00 +/- 7.33 msec was required for activation of nociceptors by the laser. Electrical stimulation of the VH at S-3-Co-1 in 3 rats produced a TF (EMG) response in 4 msec, Central delay, calculated as total TF time minus (T-N + T-A + T-E), was 82.3 +/- 13.08 msec. This represents the time frame during which modulation of the reflex by an intrinsic, pain-activated, supraspinal system could occur.