Ultrastructural characterization of the synapses of the crossed temporodentate pathway in rats.
Ultrastructural characterization of the synapses of the crossed temporodentate pathway in rats.
复制标题
大鼠交叉颞齿状通路突触的超微结构特征。
DOI：
10.1002/cne.902670204
复制
发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Steward,O
中科院分区：
文献类型：
--
作者：
Davis,L;Vinsant,SL;Steward,O
本研究对内嗅皮层至对侧齿状回的交叉颞齿状回通路的突触超微结构进行了观察，并对稀疏交叉通路与大量同侧颞齿状回通路的突触进行了比较。用电镜变性和电镜放射自显影技术鉴定交叉通路的突触。对于变性研究，在单侧内嗅皮质损伤后1、2或4天处死成年雄性Sprague道利大鼠，并制备用于电子显微镜检查。为了通过放射自显影技术鉴定突触，将3 H-脯氨酸注射到4只动物的内嗅皮质中，使其存活3天，并准备进行EM放射自显影。在病变对侧的齿状回分子层中发现的交叉通路的退化突触在棘上形成了不对称的突触，并且具有与同侧颞齿通路的突触难以区分的突触前细胞器。在所有存活时间段，变性突触的数量都很低（损伤后1天为14.80个/10，000 μ m2，损伤后2天为1.95个/10，000 μ m2），损伤后4天未发现变性突触。损伤后1天发现的退化突触中，98%表现出电子透明变性。在2天postlesion 83%的退化的突触在背侧叶片和18%的腹侧叶片表现出透亮变性，其余的电子致密。EM放射自显影证实了标记的终末类型的变性研究，并表明交叉通路的密度高于变性结果。我们的结论是，交叉颞齿通路的突触有一个类似的超微结构的同侧颞齿通路的突触，但表现出快速的退化形式，使他们很快消失后的病变。
The present, study was undertaken to define the ultrastructure of synapses of the crossed temporodentate pathway from the entorhinal cortex to the contralateral dentate gyrus and to compare the synapses of the sparse crossed pathway with those of the massive ipsilateral temporodentate pathway. The synapses of the crossed pathway were identified by using EM degeneration and EM autoradiographic techniques. For the degeneration studies, adult male Sprague‐Dawley rats were killed 1, 2, or 4 days following a unilateral entorhinal cortex lesion and prepared for electron microscopy. To identify the synapses by using autoradiographic techniques, four animals received injections of3H‐proline into the entorhinal cortex, were allowed to survive for 3 days, and were prepared for EM autoradiography. Degenerating synapses of the crossed pathway that were found in the molecular layer of the dentate gyrus contralateral to a lesion formed asymmetric synapses on spines and possessed presynaptic organelles indistinguishable from synapses of the ipsilateral temporodentate pathway. The number of degenerating synapses was very low at all survival intervals (14.80 degenerating synapses/10,000μm2at 1 day postlesion and 1.95 degenerating synapses/10,000μm2at 2 days postlesion); no degenerating synapses were found at 4 days postlesion. Ninety‐eight percent of the degenerating synapses found at 1 day postlesion exhibited electron‐lucent degeneration. At 2 days postlesion 83% of the degenerating synapses in the dorsal blade and 18% of those in the ventral blade showed lucent degeneration; the remainder were electron dense. EM autoradiography confirmed the degeneration studies in terms of the type of terminals that were labeled and suggested that the density of the crossed pathway was higher than the degeneration results implied. We conclude that synapses of the crossed temporodentate pathway have a similar ultrastructure to synapses of the ipsilateral temporodentate pathway but exhibit a rapid form of degeneration such that they disappear very rapidly following the lesion.
DOI：
10.1016/s0021-9258(19)70391-3
发表时间：
1980-11
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Loretta M. HallcherS;W. Sherman
通讯作者：
Loretta M. HallcherS;W. Sherman