Differential antinociceptive effects of spinal opioids on foot withdrawal responses evoked by C fibre or A delta nociceptor activation
Differential antinociceptive effects of spinal opioids on foot withdrawal responses evoked by C fibre or A delta nociceptor activation
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DOI：
10.1038/sj.bjp.0701239
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发表时间：
1997-07-01
影响因子：
7.3
通讯作者：
Yeomans, DC
中科院分区：
文献类型：
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作者：
Lu, Y;Pirec, V;Yeomans, DC
1鞘内应用μ、δ和κ阿片类药物减弱了动物伤害感受的几项试验的反应。然而，这些阿片类药物的效力取决于使用的测试。造成这些差异的一个因素是，不同类型的伤害性刺激激活不同类型的伤害感受器，这可能对阿片抑制的敏感性不同。我们使用了最近开发的行为测试，该测试允许对由有髓鞘（A δ）和无髓鞘C热感受器的激活引起的伤害性感受进行差异评估。选择性激动剂对两种类型的反应均无效。δ（1）药物对C纤维介导的反应的效力略高于A δ介导的反应。3鞘内注射μ和δ（2）药物对A δ和C伤害感受器介导的反应都具有抗伤害感受性。然而.与δ（1）效应不同，μ和δ（2）药物的剂量-反应曲线对于A δ比对于C纤维介导的反应明显更陡，潜在地表明药物作用于这2种反应类型的机制的差异。
1 Intrathecal application of mu, delta, and kappa opioids attenuate responses on several tests of animal nociception. However, the potency of these opioids differ depending on which tests were used. One factor contributing to these discrepancies is that different types of noxious stimuli activate different sets of nociceptor types, which may be differentially sensitive to opiate inhibition To examine this hypothesis, we used a recently developed behavioural test which allows for differential assessment of nociception evoked by the activation of myelinated (A delta) and unmyelinated C thermonociceptors.2 Administration of a kappa-selective agonist was ineffective on either type of response. delta(1) drugs were slightly more potent on C fibre-mediated responses than on A delta-mediated responses.3 Intrathecal mu and delta(2) drugs were antinociceptive on both A delta and C nociceptor-mediated responses. However. unlike the delta(1) effects, the dose-response curves for mu and delta(2) drugs were significantly more steep for A delta than for C fibre-mediated responses, potentially indicating differences in the mechanisms by which the drugs act on these 2 response types.