THE EFFECT OF VASOACTIVE DRUGS UPON THE SPINAL PAIN MODULATION

本研究的目的是探讨血管活性药物对猫腰髓背角的宽动态范围（WDR）神经元的影响。方法：在一氧化二氮-氧-异氟醚麻醉下，猫的性别，准备与中脑丘去脑和腰椎椎板切除术。在T12-L1处横断脊髓。WDR细胞，主要对有害的外周刺激作出反应，用微电极在离脊髓背1500-2000微米的深度处取样。用D10 mg组和D20 mg组分别于脊髓背侧表面滴注钙通道阻滞剂地尔硫卓10 mg /ml和20 mg/ml，观察大鼠脊髓背侧痛阈的变化。然后每隔5分钟观察一次WDR时细胞自发放电和诱发放电的变化。用α 2-肾上腺素能激动剂可乐定5 μ g/ml（C5 μ g组）或50 μ g /ml（C50 μ g组）进行地尔硫实验。地尔硫卓呈剂量依赖性抑制作用。结论：钙通道阻滞剂和α2肾上腺素能受体激动剂对WDR神经元的单位放电有抑制作用。结论：钙通道和α2肾上腺素能受体与疼痛有关。

The purpose of this study is to investigate the effects of vasoactive drugs on the wide dynamic range (WDR) neuron of the dorsal horn of the feline lumber spinal cord.Methods : Under nitrous oxide-oxygen-isoflurane anesthesia, cats of both sex were prepared with midcollicular decerebration and lumber laminectomy. The spinal cord win transected at T12-L1. WDR cells, responding primarily to noxious peripheral stimuli, were sampled with a microelectrode at the depth of 1500-2000 micrometer from the cord dorsum. Spontaneous activity and noxiously evoked activity by pinching the receptive field on the hind paw were measured.Diltiazem, as calcium channel blocker, 10 mg /ml (D 10 mg Group) or 20 mg/ml (D 20 mg Group) was administered on the surface of the cord dorsum by the drip method. Then, changes of the cell's firings of spontaneous and evoked activities in WDR were investigated every five minutes. Recoveries of firings were followed until the firings recovered by the control level.Clonidine, as α 2-adrenergic agonist, 5 micro g/ml (C 5 micro g Group) or 50 micro g /ml (C 50 micro g Group) was administered as some manner of diltiazem experiment.Results : All groups showed the suppressive effect. Diltiazem showed the suppressive effect on dose dependent manner. However, clonidine did not show the dose dependent manner.Discussion : Our results suggested that calcium channel blocker and α2 adrenergic agonist have suppressive effects on single-unit activities of WDR neuron. Therefore, both drugs are considered to be applied on the clinical use for the chronic intractable pain patients.Conclusion : Calcium channel and α2-adrenergic receptor are related with pain.