Quartu Marina, Serra Maria Pina, Mascia Francesca, Boi Marianna, Lai Maria Letizia, Spano Alessia, Del Fiacco Marina
Department of Cytomorphology, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy.
Brain Res Bull. 2006 Apr 28;69(4):393-403. doi: 10.1016/j.brainresbull.2006.02.003. Epub 2006 Mar 2.
The occurrence of Ret and GFRalpha-1 receptors is shown by immunohistochemistry in the human trigeminal sensory system at pre-, postnatal and adult age. Receptor-labeled neurons occur in both trigeminal ganglion and mesencephalic nucleus. In adult trigeminal ganglion, about 75% of Ret- and 65% of GFRalpha-1-labeled neurons are small- and medium-sized. The proportion of Ret+ and GFRalpha-1+ trigeminal ganglion neurons in the adult is about 25 and 60%, respectively. The majority of Ret+ are double labeled for GFRalpha-1 and glial cell line-derived neurotrophic factor (GDNF). Most of the GFRalpha-1+ cells contain GDNF and about 50% of them contain Ret. Triple labeling shows many Ret+/GDNF+/GFRalpha-1+ neurons, but also a number of Ret-/GDNF+/GFRalpha-1+ and Ret+/GDNF-/GFRalpha-1+ cells. Both Ret+ and GFRalpha-1+ neuronal subpopulations overlap with that containing calcitonin gene-related peptide. Ret+ pericellular basket-like nerve fibers occur in the adult trigeminal ganglion. Centrally, immunoreactivity is restricted to the spinal nucleus pars caudalis and pars interpolaris and to the mesencephalic nucleus. In adult specimens, Ret+ nerve fibers and puncta gather in the inner substantia gelatinosa. Ret+ neurons occur in the spinal nucleus and are more frequent in newborn than in adult subjects. Central GFRalpha-1+-labeled neurons and punctate elements are sparse. These findings support the involvement of GDNF and possibly other cognate ligands in the trophism of human trigeminal primary sensory neurons from prenatal life to adulthood, indicating a selective commitment to cells devoted to protopathic and proprioceptive sensory transmission. They also support the possibility that receptor molecules other than Ret could be active in transducing the ligand signal.
通过免疫组织化学方法显示，在人类三叉神经感觉系统的产前、产后及成年期均存在Ret和GFRalpha - 1受体。受体标记的神经元出现在三叉神经节和中脑核中。在成年三叉神经节中，约75%的Ret标记神经元和65%的GFRalpha - 1标记神经元为中小型。成年三叉神经节中Ret +和GFRalpha - 1 +神经元的比例分别约为25%和60%。大多数Ret +神经元同时标记有GFRalpha - 1和胶质细胞源性神经营养因子（GDNF）。大多数GFRalpha - 1 +细胞含有GDNF，其中约50%含有Ret。三重标记显示许多Ret + /GDNF + /GFRalpha - 1 +神经元，但也有一些Ret - /GDNF + /GFRalpha - 1 +和Ret + /GDNF - /GFRalpha - 1 +细胞。Ret +和GFRalpha - 1 +神经元亚群均与含有降钙素基因相关肽的亚群重叠。成年三叉神经节中出现Ret +细胞周围篮状神经纤维。在中枢，免疫反应性局限于脊髓尾侧核、极间核和中脑核。在成年标本中，Ret +神经纤维和点状结构聚集在内侧胶状质中。Ret +神经元出现在脊髓核中，在新生儿中比在成人中更常见。中枢GFRalpha - 1 +标记的神经元和点状结构稀疏。这些发现支持GDNF以及可能其他相关配体参与人类三叉神经初级感觉神经元从产前到成年期的营养作用，表明对专门负责浅感觉和本体感觉传递的细胞有选择性作用。它们还支持除Ret之外的受体分子可能在转导配体信号中起作用的可能性。
