Zhang Y Z, Hannibal J, Zhao Q, Moller K, Danielsen N, Fahrenkrug J, Sundler F
Department of Physiology and Neuroscience, Lund University, Sweden.
Neuroscience. 1996 Oct;74(4):1099-110. doi: 10.1016/0306-4522(96)00168-6.
Pituitary adenylate cyclase activating peptide (PACAP) is expressed in a population of capsaicin-sensitive primary sensory neurons of small to medium size in the rat. In the present report we have examined the effect of sciatic nerve injury (unilateral transection) on PACAP expression (immunocytochemistry, radioimmunoassay, in situ hybridization and northern blot analysis) in dorsal root ganglia at the lumbar level and on immunoreactive PACAP in the spinal cord and in the sciatic nerve stump. For comparison, calcitonin gene-related peptide was examined. In dorsal root ganglia of the intact side immunoreactive PACAP and PACAP messenger RNA were localised to a population of nerve cell bodies of small to medium size. In dorsal root ganglia on the injured side, PACAP-immunoreactive nerve cell bodies were more numerous and PACAP messenger RNA was considerably more abundant as studied 14 days after sciatic nerve transection. By contrast, calcitonin gene-related peptide-containing nerve cell bodies were numerous and rich in calcitonin gene-related peptide messenger RNA in dorsal root ganglia on the intact side, while after transection both the number of immunoreactive nerve cell bodies and their content of messenger RNA were markedly reduced. There were indications of axotomy-induced expression of PACAP messenger RNA in larger neurons. In the dorsal horn of the spinal cord on the intact side PACAP and calcitonin gene-related peptide-immunoreactive fibres were densely accumulated in the superficial layers. On the transected side the densities of both PACAP and calcitonin gene-related peptide-immunoreactive nerve fibres were reduced in the medial part. The data obtained indicate a marked up-regulation of PACAP in sensory neurons following peripheral nerve injury. Since PACAP depresses a C-fibre evoked flexion reflex, this may have implications for sensory transmission. Further, in view of the known promoting effects of PACAP on neuronal survival and differentiation and non-neuronal cell growth as well as its proinflammatory effects a role of PACAP in the neuronal and periaxonal tissue restoration after injury is not inconceivable.
垂体腺苷酸环化酶激活肽（PACAP）在大鼠中小尺寸的辣椒素敏感初级感觉神经元群体中表达。在本报告中，我们研究了坐骨神经损伤（单侧横断）对腰段背根神经节中PACAP表达（免疫细胞化学、放射免疫测定、原位杂交和Northern印迹分析）以及脊髓和坐骨神经残端中免疫反应性PACAP的影响。为作比较，还检测了降钙素基因相关肽。在完整侧的背根神经节中，免疫反应性PACAP和PACAP信使核糖核酸定位于中小尺寸的神经细胞体群体。在损伤侧的背根神经节中，坐骨神经横断14天后研究发现，PACAP免疫反应性神经细胞体数量更多，PACAP信使核糖核酸含量也显著更高。相比之下，完整侧背根神经节中含降钙素基因相关肽的神经细胞体数量众多且降钙素基因相关肽信使核糖核酸丰富，而横断后免疫反应性神经细胞体数量及其信使核糖核酸含量均明显减少。有迹象表明轴突切断诱导较大神经元中PACAP信使核糖核酸表达。在完整侧脊髓背角，PACAP和降钙素基因相关肽免疫反应性纤维密集聚集在表层。在横断侧，内侧部分PACAP和降钙素基因相关肽免疫反应性神经纤维密度均降低。所获数据表明周围神经损伤后感觉神经元中PACAP显著上调。由于PACAP可抑制C纤维诱发屈肌反射，这可能对感觉传递有影响。此外，鉴于PACAP对神经元存活和分化以及非神经元细胞生长具有已知的促进作用及其促炎作用，PACAP在损伤后神经元和轴突周围组织修复中的作用并非不可想象。
