WIDE DYNAMIC-RANGE BUT NOT NOCICEPTIVE-SPECIFIC NEURONS ENCODE MULTIDIMENSIONAL FEATURES OF PROLONGED REPETITIVE HEAT PAIN
WIDE DYNAMIC-RANGE BUT NOT NOCICEPTIVE-SPECIFIC NEURONS ENCODE MULTIDIMENSIONAL FEATURES OF PROLONGED REPETITIVE HEAT PAIN
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DOI：
10.1152/jn.1993.69.3.703
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发表时间：
1993-03-01
影响因子：
2.5
通讯作者：
PRICE, DD
中科院分区：
文献类型：
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作者：
COGHILL, RC;MAYER, DJ;PRICE, DD
1.为了更好地表征脊髓中长时间伤害性刺激的编码所涉及的时间和空间机制，在未麻醉的脊髓横断大鼠中检查背角宽动态范围（WDR）和伤害性特异性（NS）神经元对长时间重复伤害性热刺激（45-49 ℃）的反应。为了将这些神经元的反应与疼痛的意识维度联系起来，人类受试者被提供了相同类型的长时间重复刺激，因此疼痛强度和疼痛不愉快的心理物理评级可以与NS和WDR神经元的反应的幅度和时间特征进行比较。WDR神经元表现出高速率的脉冲放电在整个45分钟的重复伤害性刺激，只有部分减少（31%的峰值率下降）发生后2分钟的刺激。与此形成鲜明对比的是，在相同条件下刺激的NS神经元在刺激开始后2分钟内出现短暂的初始活动期后，放电显著减少（从峰值速率减少73%）。疼痛强度和疼痛不愉快的心理物理评级，像WDR神经元的反应，并没有从初始水平大幅下降，在7分钟的疼痛刺激。此外，在NS神经元的脉冲频率仅为最大值的27%的时间段内，这些评级仍保持在较高水平.分级伤害性刺激的特点的能力，WDR神经元编码伤害性强度在长时间的重复刺激，并进一步描绘WDR和心理物理反应之间的关系。WDR放电频率和疼痛强度和不愉快的心理物理评级都以单调的方式增加刺激温度的分级增加。这些结果表明，在长时间的重复伤害性刺激过程中，疼痛并没有明显减轻。NS神经元的反应显着下降，而WDR和心理物理反应不，这一事实表明，WDR神经元单独足以引起感觉强度和情感反应，以延长疼痛。此外，由于受试者可以在NS神经元反应最小时定位和定性描述疼痛，因此WDR神经元单独可以编码疼痛的一些空间和定性方面。
1. To better characterize temporal and spatial mechanisms involved in the coding of prolonged nociceptive stimuli in the spinal cord, the responses of dorsal horn wide dynamic range (WDR) and nociceptive-specific (NS) neurons to prolonged, repetitive noxious heat stimuli (45-49-degrees-C) were examined in unanesthetized, spinal cord transected rats. To relate these neuronal responses to conscious dimensions of pain, human subjects were presented with identical types of prolonged, repetitive stimuli, so that psychophysical ratings of pain intensity and pain unpleasantness could be compared with the magnitudes and temporal features of the responses of NS and WDR neurons.2. WDR neurons exhibited high rates of impulse discharge throughout 45 min of repetitive nociceptive stimulation, with only partial reduction (31% decrease from peak rates) occurring after 2 min of stimulation. In sharp contrast, NS neurons stimulated under the same conditions displayed substantial reduction of firing (73% decrease from peak rates) after a brief, initial period of activity that occurred within 2 min after onset of stimulation. Psychophysical ratings of pain intensity and pain unpleasantness, like the responses of WDR neurons, did not decrease substantially from initial levels during 7 min of painful stimulation. Furthermore, these ratings remained at high levels during time periods where the impulse frequencies of NS neurons were only at 27% of maximal levels.3. Graded nociceptive stimuli were employed to characterize the ability of WDR neurons to encode nociceptive intensity over long durations of repetitive stimulation and to delineate further the relationship between WDR and psychophysical responses. Both WDR discharge frequencies and psychophysical ratings of pain intensity and unpleasantness increased in a monotonic manner to graded increases in stimulus temperatures.4. These results indicate that pain does not decrease substantially during the course of prolonged, repetitive nociceptive stimulation. The fact that the responses of NS neurons decline significantly, whereas both WDR and psychophysical responses do not, suggests that WDR neurons alone are sufficient to evoke both sensory intensity and affective responses to prolonged pain. Furthermore, because subjects could localize and qualitatively describe pain at times when responses of NS neurons were minimal, WDR neurons alone can encode some spatial and qualitative aspects of pain.