Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610-0244, USA.
Exp Brain Res. 2013 Jul;228(3):305-12. doi: 10.1007/s00221-013-3563-8. Epub 2013 May 17.
Operant escape from nociceptive thermal stimulation of 13 Long-Evans rats was compared before and after lateral spinal hemisection, to determine whether this lesion configuration provides an appropriate preclinical model of the hyperalgesia that can be associated with human spinal cord injury. Escape from 44 °C and from 47 °C stimulation was not affected following sham spinal surgery but was significantly reduced over 20 weeks of postoperative testing following lateral spinal hemisection. This result is opposite to previous reports of enhanced reflex withdrawal in response to thermal stimulation of rats following lateral spinal hemisection. In addition, the latency of reflexive lick/guard responses to 44 °C was increased and the duration of lick/guard responding was decreased in the present study (hyporeflexia). Thus, previous assessments of simple withdrawal reflexes have described a hyperreflexia following lateral spinal hemisection that was not replicated by lick/guard testing, and postoperative escape responding revealed hypoalgesia rather than the increased pain sensitivity expected in a model of chronic pain.
13 只长耳大仓鼠的伤害性热刺激操作性逃避反应在脊髓侧半横切术前后进行了比较,以确定这种损伤构型是否提供了与人脊髓损伤相关的痛觉过敏的合适临床前模型。假手术前后,44°C 和 47°C 刺激的逃避反应不受影响,但在脊髓侧半横切术后 20 周的术后测试中,逃避反应明显减少。这一结果与之前关于大鼠脊髓侧半横切术后热刺激引起的反射性退缩增强的报告相反。此外,在本研究中,对 44°C 的反射性舔/护反应潜伏期延长,舔/护反应持续时间缩短(低反射性)。因此,之前对简单退缩反射的评估描述了脊髓侧半横切术后的反射亢进,而舔/护测试并未复制这一现象,术后逃避反应显示痛觉过敏而不是预期的慢性疼痛模型中增加的疼痛敏感性。