中文摘要：

目的：研究鞘内注射牛肾上腺髓质22肽（bovine adrenal medulla 22,BAM22）对伤害性感受的影响。方法：以雄性SD大鼠为实验对象,通过甩尾反射实验揭示BAM22的药理特性;运用免疫组织化学方法检测在吗啡耐受大鼠中,鞘内注射BAM22对脊髓c-Fos蛋白表达的影响。结果：鞘内注射BAM22可剂量依赖性地延长伤害性热刺激引起的甩尾反射潜伏期,10 nmol BAM22可延长甩尾潜伏期达50%MPE,作用持续约1 h。在动物产生吗啡耐受后,鞘内注射10 nmol BAM22仍能明显抑制伤害性热刺激引起的脊髓背角各层c-Fos蛋白的表达。与对照组相比,其表达约减少70%。结论：本研究表明BAM22参与脊髓水平伤害性信息的调制;在吗啡耐受大鼠中,BAM22可通过感受神经元特异性受体调制疼痛过程。

英文摘要：

Objective： To investigate the effects of intrathecal （i. t. ） bovine adrenal medulla 22 （BAM22）, an opioid peptide, on nociception at the system and cellular levels. Methods： Tail-flick reflex （TEL） was used to characterize pharmacology of BAM22 in male Sprague-Dawley rats. Furthermore, the effects of BAM22 （ i. t. ） on noxious stimulus-evoked c-Fos-like immunoreactivity （FLI） was determined in morphine tolerant rats. Results： BAM22 （i. t. ） produced a dose-dependent increase in TFL. 10 nmol of the peptide increased TFL by approximately 50 % of MPE and the effects lasted approximately 1 h. In rats rendered tolerant to morphine, administration of BAM22 still significantly inhibited the ex- pression of heat-evoked FLI protein and the decrease occurred in each layer in laminae Ⅰ-Ⅵ by approximately 70 % compared with control. Conclusion： BAM22 modulated nociception in the spinal level. BAM22 significantly reduced noxious stimulus-evoked activation of the spinal dorsal horn neurons in morphine tolerant rats implied the involvement of sensory neuron-specific receptors in modulation of nociceptive processing.