The effects of inhalational anesthetics and NO upon activities of spinal dorsal horn neuron

【背景】一氧化氮（NO）在多种组织器官中具有多种作用。NO与吸入麻醉剂的作用存在争议。我们将研究吸入麻醉剂和一氧化氮对脊髓背角神经元活动的影响。[方法]用氟烷麻醉雄性spague - dawley大鼠。气管切开后，给予机械通气。将导管插入静脉和动脉，通过抽吸使动物去脑，在L1和L2处横断脊髓，进行椎板切除术。动物被固定在一个立体框架上。术后用纯氧维持通气。记录细胞外单细胞动作电位，测量脉冲放电率。低阈值机械感受神经元、伤害感受器特异性神经元、宽动态范围神经元通过形态和距离脊髓背的深度来识别。研究对象分为四组：1。纯氧条件下，NO合成促进剂：l -精氨酸组2。在纯氧条件下，NO合成抑制剂：L-NAME给药组3。在1MAC氟烷（1.1%）下，NO合成促进剂：l -精氨酸给药4组。在1MAC氟烷（1.1%）下，NO合成抑制剂：L-NAME给药组。[结果]L- NAME对大鼠背角神经元的单单位活性无影响，L-精氨酸对大鼠背角神经元的单单位活性无影响。[结论]一氧化氮在吸入麻醉药的麻醉机制之间没有作用。

[background] Nitric oxide(NO) have a lot of actions in various tissues and organs. It is controversial about the action of NO with Inhalational anesthetics. We will investigate The effects of inhalational anesthetics and NO upon activities of spinal dorsal horn neuron.[method] Male Spargue-Dawley rats were anesthetized with halothane. Following tracheotomy, the animals were mechanically ventilated. Catheters were inserted into veins and arteries and the animal was decerebrated by aspiration and the spinal cord was transected at L1 and L2 and laminectomy was made. Animals were fixed on a stereotaxic frame. Following surgery, ventilation was maintained by pure oxygen. Extra-cellular single-cell action potentials were recorded and spike firing rate were measured. The low-threshold-mechanoreceptive neuron, nociceptor-specific neuron, wide-dynamic-range neuron was identified by the modality and by the depth from the cord dorsum. Four groups were studied : 1. Under pure oxygen, NO synthesis accelerator : L-arginine administrated group 2. Under pure oxygen, NO synthesis Inhibitor : L-NAME administrated group 3. Under 1MAC Halothane(1.1%), NO synthesis accelerator: L-arginine administrated group 4. Under 1MAC Halothane(1.1%), NO synthesis Inhibitor : L-NAME administrated group.[Results] L- NAME had no effect on the single-unit activity of dorsal horn neurons, and L-arginine had noeffects on the single-unit activity of dorsal horn neurons.[Conclusion] Our results suggest that NO had no action between the anesthetic mechanisms of Inhalational anesthetics.