大鼠丘脑中央下核及其邻近结构神经元对皮肤伤害性刺激的反应

RESPONSES OF NEURONS IN THALAMIC NUCLEUS SUBMEDIUS AND ITS ADJACENT STRUCTURES TO CUTANEOUS NOXIOUS STIMULATION IN THE RAT

利用细胞外记录技术，在麻醉大鼠丘脑中央下核（Ｓｉｎ）及其邻近结构内，共记录到１９２个神经元。７８％的神经元对皮肤伤害性刺激发生反应。其中，大多数（１１８）被兴奋，２８个被抑制，４个对某些部位的刺激兴奋，而对另一些部位的刺激抑制。发现某些神经元有很长的后发放效应，另一些则在兴奋之后跟随着较长的抑制期，少数的反应仅在刺激给与和撤除的瞬间发生。感受野大且呈双侧分部。８０％对机械刺激反应的神经元也对伤害性热刺激发生相同的反应。没有发现对非伤害性刺激反应的神经元。神经元的反应特性在Ｓｍ及其邻近结构之间没有任何差异。结果提示，Ｓｉｎ及其邻近结构可能参与机体的伤害性感受并与痛觉的情绪激动成分有关。

A total of 192 neurons in the thalamic nucleus submedius(Sin)and its adjacent structures were recorded extracellularly in the anesthetized rats.Seventy eight percent of the recorded neurons responded to cutaneous noxious stimulation, among them 118 neurons were excited,28 were inhibited, and a few neurons (4)were excited by stimulation of some sites of the body,but inhibited by stimulation of other sites.The recephve fields were very large and bilateral.In some cases the neuronal responses had very long after-discharges, but for other neurons, the excitatory responses were followed by long inhibitory periods.A few neurons were excited only phasically at the onset and offset of stimulation. About 80% of the neurons responsive to mechanical noxious stimulation responded also to thermal noxious stimulation.No neurons were found to be responsive to innocuous stimulation.No marked differences in the response characteristics were found between neurons in the Sm and those in its adjacent structures. The results show that Sm and its adjacent structures may be involved in nociception and related more closely to the affective-motivational aspect of pain.