NOCICEPTIVE RESPONSES IN THE NEOSTRIATUM AND GLOBUS-PALLIDUS OF THE ANESTHETIZED RAT
NOCICEPTIVE RESPONSES IN THE NEOSTRIATUM AND GLOBUS-PALLIDUS OF THE ANESTHETIZED RAT
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DOI：
10.1152/jn.1993.69.6.1890
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发表时间：
1993-06-01
影响因子：
2.5
通讯作者：
DONG, WK
中科院分区：
文献类型：
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作者：
CHUDLER, EH;SUGIYAMA, K;DONG, WK
1.细胞外记录麻醉大鼠新纹状体(尾状核-壳核，CPU)和苍白球(GP)神经元。少数细胞(3%)为低阈值机械感受性(LTM)神经元。大多数(97%)的躯体感觉CPU和GP神经元对皮肤的伤害性机械刺激有不同的或唯一的反应。根据伤害性机械刺激的反应特性，伤害性神经元可分为三类：宽动态范围(WDR)神经元(21%)、伤害性特异性(NS)神经元(67%)和抑制性(INH)神经元(13%)。2.与GP相比，CPU内WDR、NS和INH神经元的反应性质和比例均无明显差异。伤害性神经元多位于CPU-GP交界处。此外，类似功能分类的神经元通常沿着单个微电极轨道彼此聚集在200-400微米范围内。3.伤害性感受性神经元的感受野较大，多为双侧，部分感受区遍及全身。三叉神经区，特别是口周区，比身体其他部位更多地出现在伤害性神经元的感受野中(63个细胞中有62个)。然而，在感受野中没有观察到偏爱三叉神经的任何特定部分。一些神经元的感受野是不连续的。伤害性挤压皮肤使WDR和NS神经元的自发放电分别增加482%和221%。WDR神经元和NS神经元的放电适应率无明显差异。在WDR和NS神经元中观察到后放电活动。在伤害性挤压后，INH神经元的静息活动水平平均下降了43%。WDR神经元的von Frey刺激阈值(11.0g/mm2)明显低于NS神经元(33.6g/mm2)和INH神经元(32.6g/mm2)。用校准钳测定WDR、NS和INH神经元的平均刺激阈值分别为1.6、4.8和2.2g/mm2。伤害性神经元的个体刺激-反应函数符合负加速(对数)曲线。然而，WDR神经元的斜率明显大于NS神经元。结果表明，新纹状体和苍白球内的大部分体感神经元(特别是沿CPU-GP交界处)接受伤害性信息。这些数据与投射到CPU和GP的几个假定的传入伤害性感受通路有关。由于一些WDR神经元具有编码刺激强度的能力，因此这些细胞可能在对伤害性刺激的运动反应分级中发挥作用。NS和INH神经元不能编码刺激的大小，以及CPU和GP中大多数伤害性神经元的大感受场，表明这些神经元参与了伤害性刺激的发生和协调对伤害性事件(例如，撤退、定向和避免痛苦刺激)的大运动反应。
1. Extracellular recordings were made from neurons in the neostriatum (caudate nucleus-putamen, CPu) and globus pallidus (GP) of anesthetized rats. Few cells (3%) were classified as low-threshold-mechanoreceptive ( LTM) neurons. The majority (97%) of somatosensory CPu and GP neurons responded differentially or exclusively to noxious mechanical stimulation of the skin. Nociceptive neurons were classified into the following three groups on the basis of their response properties to noxious mechanical stimulation: wide-dynamic-range (WDR) neurons (21%); nociceptive-specific (NS) neurons (67%); and inhibited (INH) neurons (13%). 2. No differences in the response properties or in the proportions of WDR, NS, and INH neurons were found in the CPu compared with the GP. Nociceptive neurons were located most often along the CPu-GP border. Additionally, neurons of similar functional classification were often clustered within 200-400 mum of each other along a single microelectrode track. 3. The receptive fields of nociceptive CPu and GP neurons were often large and bilateral; some receptive fields encompassed the entire body. The trigeminal region, especially the perioral area, was included in the receptive fields of nociceptive neurons more often (62 of 63 cells) than any other part of the body. However, no preference for any particular division of the trigeminal nerve was observed in the receptive fields. Some neurons had receptive fields that were discontinuous.4. Noxious pinching of the skin significantly increased the spontaneous neuronal discharge of WDR and NS neurons by an average of 482 and 221%, respectively. There were no significant differences between the discharge adaptation rates of WDR and NS neurons. Afterdischarge activity was observed in some WDR and NS neurons. INH neurons decreased their resting activity levels by an average of 43% after a noxious pinch.5. The von Frey stimulus threshold of WDR neurons (11.0 g/mm2) was significantly lower than that of NS neurons (33.6 g/mm2) and INH neurons (32.6 g/mm2). Mean stimulus thresholds of WDR, NS, and INH neurons determined by using calibrated forceps were 1.6, 4.8, and 2.2 g/mm2, respectively.6. Individual stimulus-response functions of nociceptive neurons were best fit by a negatively accelerating (logarithmic) curves. However, WDR neurons had significantly steeper slopes than NS neurons.7. The results demonstrate that a large proportion of somatosensory neurons within the neostriatum and globus pallidus (especially along the CPu-GP border) receive nociceptive information. These data are discussed in relation to several putative afferent nociceptive pathways projecting to the CPu and GP. Because some WDR neurons have the ability to encode stimulus intensity, it is possible that these cells may play a role in grading motor responses to noxious stimulation. The inability of NS and INH neurons to encode stimulus magnitude and the large receptive fields of most nociceptive neurons in the CPu and GP suggest that these neurons are involved with signaling the occurrence of noxious stimuli and coordinating gross motor responses to noxious events (e.g., withdrawal, orientation, and avoidance of painful stimuli).