Hao J X, Shi T J, Xu I S, Kaupilla T, Xu X J, Hökfelt T, Bartfai T, Wiesenfeld-Hallin Z
Department of Medical Laboratory Sciences and Technology, Karolinska Institute, Huddinge University Hospital, Sweden.
Eur J Neurosci. 1999 Feb;11(2):427-32. doi: 10.1046/j.1460-9568.1999.00447.x.
We have previously suggested that the neuropeptides galanin and galanin message-associated peptide (GMAP) may have an inhibitory role in spinal nociception. The present study examined the effects of intrathecal (i.t.) administration of these two peptides on allodynia-like behaviours in response to mechanical and cold stimulation in rats after photochemically induced ischaemic peripheral nerve injury. I.t. galanin significantly alleviated the mechanical- and cold-allodynia-like behaviours in nerve injured rats, and was not associated with motor impairment or sedation. I.t. GMAP relieved mechanical allodynia much less than galanin. I.t. M-35, a high-affinity galanin receptor antagonist, did not significantly alter the response of the rats to mechanical or cold stimulation. At 1 or 2 weeks postinjury, around 15% of dorsal root ganglion (DRG) neuron profiles showed galanin-like immunoreactivity. These profiles were mostly small sized. Although the number of galanin positive cells was thus increased in the DRG in the present model, the increase was substantially less than after complete sciatic nerve section, as previously shown. The present results showed that spinal administration of galanin inhibited some abnormal pain-like behaviours in rats after partial peripheral nerve injury. These results further support an inhibitory function for galanin in nociception. However, endogenous galanin may not play a significant role in suppressing nociceptive input after partial ischaemic peripheral nerve injury, as the upregulation of galanin is moderate.
我们之前曾提出，神经肽甘丙肽和甘丙肽信息相关肽（GMAP）可能在脊髓伤害感受中发挥抑制作用。本研究检测了鞘内注射这两种肽对光化学诱导的缺血性周围神经损伤后大鼠机械性和冷刺激诱发的痛觉过敏样行为的影响。鞘内注射甘丙肽显著减轻了神经损伤大鼠的机械性和冷痛觉过敏样行为，且与运动功能障碍或镇静无关。鞘内注射GMAP对机械性痛觉过敏的缓解作用远不及甘丙肽。鞘内注射高亲和力甘丙肽受体拮抗剂M-35并未显著改变大鼠对机械性或冷刺激的反应。在损伤后1或2周，约15%的背根神经节（DRG）神经元显示甘丙肽样免疫反应性。这些神经元大多体积较小。尽管在本模型中DRG中甘丙肽阳性细胞数量因此增加，但如先前所示，其增加幅度远小于坐骨神经完全切断后。本研究结果表明，鞘内注射甘丙肽可抑制部分周围神经损伤后大鼠的一些异常疼痛样行为。这些结果进一步支持了甘丙肽在伤害感受中的抑制功能。然而，内源性甘丙肽在部分缺血性周围神经损伤后对伤害性传入的抑制作用可能并不显著，因为甘丙肽的上调程度适中。
