Departments of Anatomy and Biochemistry, The University of New Mexico School of Medicine, Albuquerque, New Mexico 87131-5211.
Mol Cell Neurosci. 1993 Dec;4(6):576-82. doi: 10.1006/mcne.1993.1071.
This study demonstrates the presence of the growth-associated protein, GAP-43, in nerve fibers innervating the adult rat neurointermediate pituitary. Previous studies demonstrated that innervation to the proopiomelanocortin cells of the intermediate pituitary could undergo degeneration after chemical denervation with 6-hydroxydopamine (6-OHDA), followed by recovery/regeneration of terminals 3 to 4 weeks after drug treatment. Here, we investigated the modulation of GAP-43 levels following chemical denervation of the pituitary. For these studies, pituitary tissue sections were stained with antibody to GAP-43 and analyzed by light and electron microscopic techniques. Using these methods for immunolocalization of GAP-43, staining was observed only in nerve fibers of the intermediate and neural lobes. Additional groups of animals were studied for GAP-43 protein content in the pituitary. One week after 6-OHDA injections to adult male rats, reduced amounts of GAP-43 were observed by Western blot analysis, compared to control tissue, and sections showed little or no immunostaining in the intermediate lobe after exposure to the drug. Three weeks after drug treatment, the levels of GAP-43 were closer to controls by Western blot analysis, in agreement with the reinnervation of the pituitary as seen in immunostained sections. The loss of GAP-43 immunostaining from denervated tissue, followed by its recovery during reinnervation, supports the hypothesis that nerve fibers innervating this adult neuroendecrine area are capable of undergoing synaptic plasticity.
本研究证明了生长相关蛋白 GAP-43 存在于支配成年大鼠神经垂体中间部的神经纤维中。先前的研究表明，用 6-羟多巴胺（6-OHDA）化学去神经支配后，中间部的 proopiomelanocortin 细胞的支配神经可以发生退化，然后在药物治疗后 3 到 4 周恢复/再生末端。在这里，我们研究了化学去神经支配垂体后 GAP-43 水平的调节。对于这些研究，使用针对 GAP-43 的抗体对垂体组织切片进行染色，并通过光镜和电子显微镜技术进行分析。使用这些方法进行 GAP-43 的免疫定位，观察到染色仅存在于中间和神经叶的神经纤维中。对另一组动物进行了垂体中 GAP-43 蛋白含量的研究。在成年雄性大鼠给予 6-OHDA 注射后 1 周，与对照组织相比，Western blot 分析显示 GAP-43 含量减少，并且在暴露于药物后中间叶的切片显示出很少或没有免疫染色。在药物治疗 3 周后，Western blot 分析显示 GAP-43 水平更接近对照，这与免疫染色切片中观察到的垂体再支配一致。失神经支配组织中 GAP-43 免疫染色的丢失，随后在再支配过程中的恢复，支持了支配这个成年神经内分泌区的神经纤维能够发生突触可塑性的假说。
