胞内记录猫体感皮层内脏伤害性感受神经元的电生理特性

INTRACELLULAR ELECTROPHYSIOLOGICAL CHARACTERISTICS OF VISCERAL NOCICEPTIVE NEURONS IN CORTEX SⅠ AREA OF CATS 

为了从细胞水平探讨皮层内脏伤害感受的特性及机制，本文应用细胞内电位记录技术，观察了猫体感皮层内脏大神经皮层代表区的８５１个神经元对电刺激内脏大神经的诱发反应及电生理特性。其中４１２个单位为内脏伤害性感受神经元，其自发放电有多种形式，根据诱发反应现象分为特异性和非特异性伤害感受神经元，内脏伤害性诱发反应分为兴奋性反应（５１７％）、抑制性反应（３１３１％）及混合性反应（１７％）三类。在形式上具有潜伏期长、反应形式复杂等特点。实验发现８５个神经元为内脏及肋间神经的会聚反应细胞。部分神经元用神经生物素进行细胞内电泳标记以显示功能细胞所在层次及形态。结果说明皮层体感神经元具有内脏伤害性感受的作用，并从细胞及突触后电反应特点上探讨了内脏痛的感受机制。

In the present work we investigated electrophysiological properties of visceral nociceptive neurons in the primary somatosensory cortex (SⅠ). Intracellular recordings of 851 neurons in the representing area of greater splanchnic nerve (GSN) in SⅠ area were made in 22 cats. The neurons showed a variaty of modes in sponteneous discharges, which could be classified into visceral nociceptive neurons (VNNs) and non visceral nociceptive neurons (NVNNs). VNNs (412) could be further divided into specific and non specific subtypes, with three distinct response modes: excitatory, inhibitory, and mixed response. These responses were characterized by longer latency and complex responsive fashion. In addition, 85 single convergence neurons induced by input from GSN and intercostal nerve were observed. Neurobiotin was injected into some of the cells by electrophoresis to identify the depth and morphology following recordings. The results indicated that VNNs were located in the SⅠ area.