Sullivan A F, Dashwood M R, Dickenson A H
Eur J Pharmacol. 1987 Jun 19;138(2):169-77. doi: 10.1016/0014-2999(87)90430-4.
The effects of intrathecal clonidine alone and prior to intrathecal morphine were studied on electrically evoked A beta and C fibre activity in the dorsal horn of the halothane-anaesthetised rat. Clonidine reduced C fibre-evoked activity in a dose-dependent manner, to a maximum 52% inhibition which was reversed by rauwolscine and yohimbine but not naloxone. High doses of clonidine also produced small inhibitions of A fibre-evoked activity. Clonidine potentiated the inhibitory action of intrathecal morphine on electrically evoked C fibre activity but not A fibre activity. In addition, the location of alpha 2-adrenoceptor and opiate binding sites in consecutive sections of rat lumbar cord was investigated using in vitro autoradiography with selective ligands, and it was demonstrated that both opiate and alpha 2-receptor types are present within the same superficial layers of the dorsal horn of the same animal. The results indicate that alpha 2-adrenoceptors and opiate receptors can interact in the modulation of nociceptive transmission in rat spinal cord.
研究了鞘内注射可乐定单独使用以及在鞘内注射吗啡之前使用时，对氟烷麻醉大鼠背角电诱发的 Aβ 和 C 纤维活动的影响。可乐定以剂量依赖方式降低 C 纤维诱发的活动，最大抑制率为 52%，利血平与育亨宾可逆转此抑制作用，但纳洛酮不能。高剂量可乐定也对 A 纤维诱发的活动产生轻微抑制。可乐定增强了鞘内吗啡对电诱发 C 纤维活动的抑制作用，但对 A 纤维活动无此作用。此外，使用选择性配体的体外放射自显影技术研究了大鼠腰段脊髓连续切片中 α2 -肾上腺素能受体和阿片类结合位点的定位，结果表明在同一动物背角的相同浅层中同时存在阿片类和 α2 -受体类型。结果表明，α2 -肾上腺素能受体和阿片受体在大鼠脊髓伤害性信息传递的调制中可相互作用。
