鞘内注射哌唑嗪对氯胺酮抗伤害作用的影响

目的　探讨脊髓α1 受体和氯胺酮(Ket, 37. 5mg·kg-1,ip)抗伤害作用的关系。方法　用热水甩尾法观察大鼠鞘内预先注射α1 受体拮抗剂哌唑嗪(Pra, 10, 30μg)对Ket抗伤害作用的影响。并用c fos基因免疫组织化学技术,观察Ket对痛刺激诱发的大鼠脊髓c- fos表达的调节作用及鞘内预先注射Pra(30μg)对Ket调节作用的影响。结果　鞘内单独注射各剂量Pra对动物痛阈均无明显影响(P>0 .05), 鞘内预注Pra(10μg)对Ket抗伤害作用无明显影响(P>0 .05)。而鞘内预注Pra(30μg)则可明显减弱Ket抗伤害作用(P<0 .05)。痛刺激前给予Ket明显减少背角各层Fos免疫阳性神经元的数量(P<0 .05),Ket对痛刺激诱发的脊髓ⅠⅣ层c fos表达的抑制作用可被鞘内预注Pra所减弱(P<0 .05)。结论　脊髓α1 受体参与Ket抗伤害作用。

Effect of pretreatment with intrathecal prazosin on the antinociception of ketamine in rats

Aim To investigate whether spinal cord α_1-adrenoceptors are involved in the antinociceptive effect of systemic ketamine (37.5 mg ·kg~(-1),ip) in rats.Methods Antinociceptive tests were investigated with warm water tail-flick test. The effect of pretreatment with intrathecal α_1-adrenoceptor antagonist prazosin (10,30 μg) on the antinociception of ketamine was observed. In a separate study, the influence of ketamine on the Fos expression of neurons in the spinal cord in rats receiving noxious thermal stimulation was investigated. And the effect of pretreatment with intrathecal prazosin (30 μg) on suppression of ip ketamine on Fos expression of neurons in the spinal was studied. Results Intrathecal prazosin alone did not affect basal TFL (P>0.05). Pretreatment with intrathecal prazosin (30 μg) significantly reduced the antinociception of ketamine 10 min after injection but not 10μg (P<0.05). Pretreatment with ketamines howed suppression of Fos activity which was partly reversed by pretreatment with intrathecal prazosin (P<0.05). Conclusion The spinal cord α_1-adrenoceptors are involved in the antinociception of ketamine.