Ren K, Ruda M A, Jacobowitz D M
Neurobiology and Anesthesiology Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, MD 20892.
Brain Res Bull. 1993;31(1-2):13-22. doi: 10.1016/0361-9230(93)90004-u.
Calretinin (CR), a recently identified calcium-binding protein, is present in nervous tissue, including sensory pathways, where it may play an important role in regulation of cellular activity. Using immunocytochemistry, we examined the cellular localization of CR in dorsal root ganglia (DRG) and spinal cord of normal rats and after multiple unilateral dorsal root ganglionectomies. In DRG, CR-immunoreactive cell bodies and axons were a small subpopulation (10%) of medium- to large-sized neurons. In the spinal cord, CR-like immunoreactivity (LI) in neurons and fibers was found in all laminae except motoneurons. Dense fiber networks were also found in Clarke's column. The densest staining of both cell bodies and fibers was in the superficial laminae, especially lamina II, and in the lateral spinal and lateral cervical nuclei. CR-immunoreactive fibers were also observed in the fasciculi cuneatus and gracilis. Fasciculus gracilis exhibited the greatest number of labeled axons at the lumbosacral levels, but few labeled axons were found at the rostral thoracic and cervical levels. In contrast, the corticospinal tract at the base of the dorsal column was devoid of CR-immunoreactive fibers. Unilateral multiple lumbar ganglionectomies resulted in a loss of CR-LI in the dorsal columns ipsilateral to the surgery. In the spinal gray matter ipsilateral to the ganglionectomies, CR-LI was reduced in Clarke's column and slightly enhanced in the medial third of lamina II. Our observations demonstrate a unique distribution pattern of CR-LI compared to other calcium-binding proteins in the spinal cord, and suggest a role for CR in nociceptive and proprioceptive pathways.
钙视网膜蛋白（CR）是一种最近发现的钙结合蛋白，存在于神经组织中，包括感觉通路，在其中它可能在细胞活动调节中发挥重要作用。我们采用免疫细胞化学方法，研究了正常大鼠以及多次单侧背根神经节切除术后，CR在背根神经节（DRG）和脊髓中的细胞定位。在DRG中，CR免疫反应性细胞体和轴突是中大型神经元中的一个小亚群（10%）。在脊髓中，除运动神经元外，所有板层均发现神经元和纤维中有CR样免疫反应性（LI）。在克拉克柱中也发现了密集的纤维网络。细胞体和纤维的染色最密集的区域是浅表板层，尤其是板层II，以及脊髓外侧核和外侧颈核。在楔束和薄束中也观察到了CR免疫反应性纤维。薄束在腰骶水平显示出最多的标记轴突，但在胸段上部和颈段水平发现的标记轴突很少。相比之下，背柱基部的皮质脊髓束没有CR免疫反应性纤维。单侧多次腰神经节切除术导致手术同侧背柱中CR-LI丧失。在神经节切除术同侧的脊髓灰质中，克拉克柱中的CR-LI减少，板层II内侧三分之一处略有增强。我们的观察结果表明，与脊髓中其他钙结合蛋白相比，CR-LI具有独特的分布模式，并提示CR在伤害性感受和本体感受通路中发挥作用。
