Saland L C, Perrone-Bizzozero N I, Sower A, Samora A, Ramirez D, Apodaca A
Department of Anatomy, University of New Mexico School of Medicine, Albuquerque 87131-5221, USA.
Neurosci Lett. 1996 Apr 19;208(2):138-42. doi: 10.1016/0304-3940(96)12551-9.
The levels and distribution of the growth-associated protein, GAP-43, were examined in the pituitary glands of young and aging Sprague-Dawley rats, using immunohistochemical techniques on tissue sections and Western blot analyses. GAP-43-immunoreactive innervation was observed in sections in the intermediate and neural lobes of animals aged 8-15 months, while in the oldest rats studied (17 months), stained fibers were observed mainly in the neural, but not the intermediate lobe. Western blots revealed reduced levels of GAP-43 in samples from 15 month old animals, as compared to 12 month old rats, in the neurointermediate lobes. There was no immunoreactivity for GAP-43 in the anterior lobes in the tissue sections or in the blots in any of the glands examined. A diminished level of GAP-43 in pituitary innervation in aged animals suggests a reduced ability for nerve terminals to undergo 'plastic' changes in their relationship to target endocrine cells. Since GAP-43 has also been suggested to modulate neurotransmitter release, a reduction in the protein in aging nerve terminals may diminish availability of transmitters at presynaptic sites.
采用组织切片免疫组化技术和蛋白质印迹分析，检测了幼年和老年斯普拉格-道利大鼠垂体中生长相关蛋白GAP - 43的水平和分布。在8 - 15月龄动物的垂体中间叶和神经叶切片中观察到GAP - 43免疫反应性神经支配，而在研究的最老的大鼠（17月龄）中，染色纤维主要在神经叶中观察到，而中间叶未观察到。蛋白质印迹显示，与12月龄大鼠相比，15月龄动物神经中间叶样本中GAP - 43水平降低。在所检查的任何腺体的组织切片前叶或印迹中，均未检测到GAP - 43的免疫反应性。老年动物垂体神经支配中GAP - 43水平降低，提示神经末梢与靶内分泌细胞关系发生“可塑性”变化的能力下降。由于GAP - 43也被认为可调节神经递质释放，老年神经末梢中该蛋白的减少可能会降低突触前部位神经递质的可用性。
