Jurna Ilmar, Spohrer Birgit, Bock Rudolf
Institut für Pharmakologie und Toxikologie, Universität des Saarlandes, D-6650 Homburg/SaarGermany Institut für Anatomie, Universität des Saarlandes, D-6650 Homburg/SaarGermany.
Pain. 1992 May;49(2):249-256. doi: 10.1016/0304-3959(92)90149-6.
It was aimed to assess if intrathecal (i.t.) injections of acetylsalicylic acid and salicylic acid depress C fibre-evoked activity in the sensory part of the nociceptive system. In rats under urethane anaesthesia, activity was elicited in single neurones in the dorsomedial part of the ventral nucleus (VDM) of the thalamus and in ascending axons of the spinal cord by supramaximal electrical stimulation of the sural nerve. Acetylsalicylic acid and salicylic acid injected i.t. significantly reduced the activity evoked in thalamic neurones. The maximum depression amounted to about 50% of the activity evoked in the controls and was produced by acetylsalicylic acid at a dose of 50 micrograms (0.28 mumol)/rat and by salicylic acid at a dose of 37.5 micrograms (0.27 mumol)/rat. Indomethacin injected i.t. also reduced C fibre-evoked activity in the thalamus in a dose-dependent fashion, 100 micrograms producing a 50% depression. Salicylic acid (37.5 micrograms/rat, i.e.) depressed C fibre-evoked activity in ascending axons but had no effect on A beta fibre-evoked activity. It is concluded that i.t. injection of acetylsalicylic acid selectively inhibits nociceptive impulse transmission in the spinal cord by an action of the salicylic acid moiety. It is possible that prostaglandins are involved in the central action of salicylic acid.
本研究旨在评估鞘内注射乙酰水杨酸和水杨酸是否会抑制伤害性感受系统感觉部分中C纤维诱发的活动。在氨基甲酸乙酯麻醉的大鼠中，通过对腓肠神经进行超强电刺激，在丘脑腹侧核背内侧部分（VDM）的单个神经元以及脊髓的上行轴突中诱发活动。鞘内注射乙酰水杨酸和水杨酸可显著降低丘脑神经元诱发的活动。最大抑制程度约为对照组诱发活动的50%，乙酰水杨酸以50微克（0.28微摩尔）/大鼠的剂量、水杨酸以37.5微克（0.27微摩尔）/大鼠的剂量可产生此效果。鞘内注射吲哚美辛也以剂量依赖的方式降低丘脑中C纤维诱发的活动，100微克可产生50%的抑制。水杨酸（即37.5微克/大鼠）可抑制上行轴突中C纤维诱发的活动，但对Aβ纤维诱发的活动无影响。结论是，鞘内注射乙酰水杨酸通过水杨酸部分的作用选择性地抑制脊髓中的伤害性冲动传递。前列腺素可能参与了水杨酸的中枢作用。
