Xu I S, Luo L, Ji R R, Hökfelt T, Xu X J, Wiesenfeld-Hallin Z
Department of Medical Laboratory Sciences and Technology, Karolinska Institute, Huddinge University Hospital, Sweden.
Neuropeptides. 1998 Oct;32(5):447-52. doi: 10.1016/s0143-4179(98)90070-1.
We examined the effects of intrathecal (i.t.) administration of neuropeptide Y (NPY) on the excitability of the flexor reflex in normal rats and 24 h after inflammation induced by subcutaneous carrageenan. In normal rats, i.t. NPY at low doses (10 and 100 ng) caused a brief facilitation of the flexor reflex with no subsequent depression. At higher doses (1 and 10 microg), the effect of NPY was mainly inhibitory, causing substantial and usually prolonged depression of the flexor reflex. At 24 h after the injection of carrageenan, when inflammation was at its peak, the magnitude of the reflex was increased and discharge duration became prolonged. I.t. NPY produced similar pattern of dose-dependent facilitatory and depressive effects on the flexor reflex. The facilitatory effect of i.t. NPY, particularly for the higher doses, was significantly enhanced in inflamed rats compared to normals. In contrast, the depressive effect of high doses of i.t. NPY was unchanged. These data suggest that the changes in levels of NPY and NPY receptors in the spinal cord known to occur after inflammation, are associated with an increased excitatory effect of this peptide.
我们研究了鞘内注射神经肽Y（NPY）对正常大鼠以及皮下注射角叉菜胶诱导炎症24小时后的大鼠屈肌反射兴奋性的影响。在正常大鼠中，低剂量（10和100纳克）的鞘内NPY引起屈肌反射短暂易化，随后无抑制作用。在较高剂量（1和10微克）时，NPY的作用主要是抑制性的，导致屈肌反射明显且通常是持续性的抑制。在注射角叉菜胶24小时后，炎症达到高峰时，反射幅度增加且放电持续时间延长。鞘内NPY对屈肌反射产生了类似的剂量依赖性易化和抑制作用模式。与正常大鼠相比，鞘内NPY的易化作用，尤其是较高剂量时，在炎症大鼠中显著增强。相反，高剂量鞘内NPY的抑制作用没有变化。这些数据表明，已知炎症后脊髓中NPY和NPY受体水平的变化与该肽兴奋性作用的增强有关。
