RELATIONSHIP BETWEEN SOME MEASURES OF SYNAPTIC ULTRASTRUCTURE AS A FUNCTION OF DISTANCE FROM THE SOMA ON LAMPREY RETICULOSPINAL NEURONS
RELATIONSHIP BETWEEN SOME MEASURES OF SYNAPTIC ULTRASTRUCTURE AS A FUNCTION OF DISTANCE FROM THE SOMA ON LAMPREY RETICULOSPINAL NEURONS
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DOI：
10.1007/bf01206673
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发表时间：
1979-01-01
期刊：
影响因子：
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通讯作者：
QUINN, J
中科院分区：
文献类型：
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作者：
CHRISTENSEN, BN;QUINN, J
对细胞内注射辣根过氧化物酶标记的七鳃鳗(Petromyzon Marinus)网状脊髓神经元树突上的突触连接进行了研究。定义了突触连接的正常超微结构，并对每个连接进行了几项定量测量，以验证位于远端突触与位于近端树突位置的突触在超微结构上不同的假说。来自1个神经元的820个接触者和来自第二个神经元的279个接触者被量化，范围从体节20-340微米不等。绝大多数突触前终末含有透明的圆形小泡，并与突触后树突形成不对称的膜分化。一小部分人含有扁平或多形性的小泡，这些突触在距离胞体的距离上是均匀分布的。许多终末含有几个大的深色和透明的囊泡。对每个突触接触进行定量测量(4)。包括囊泡数量、分化膜长度、囊泡面积和终末面积。计算了与不同量化指标相关的比值(4)。来自突触连接的每个比率或测量被绘制为距离体体的距离的函数，以确定在任何距离处是否存在差异。突触连接一致相似，远端连接与近端树突连接无显著差异(P>；0.05)。如果远端突触确实补偿了它们的远程位置，它们会以其他方式做到这一点，可能是通过增加每个突触前轴突进行的突触接触的数量。
Synaptic junctions located on the dendrites of lamprey (Petromyzon marinus) reticulospinal neurons labeled with intracellularly-injected horseradish peroxidase were studied. The normal ultrastructure of the synaptic junctions was defined and several quantitative measures made from each junction to test the hypothesis that distally-located synapses are ultrastructurally different from those located at proximal dendritic sites. A total of 820 contacts from 1 neuron and 279 from a 2nd neuron ranging from 20-340 .mu.m from the soma were quantified. The vast majority of the presynaptic endings contained round, clear-cored vesicles and formed an asymmetrical membrane differentiation with the postsynaptic dendrite. A small fraction of the population contained flattened or pleomorphic vesicles and these synapses were equally distributed with respect to distance from the soma. Many of the terminals contained a few large dark- and clear-cored vesicles. Quantitative measures (4) of each synaptic contact were made. These included vesicle number, length of differentiated membrane, vesicle area and terminal area. Ratios (4) relating the different quantitative measures were also calculated. Each ratio or measurement from the synaptic junctions was plotted as a function of distance from the soma to determine if differences existed at any distance. Synaptic junctions were uniformly similar and distal junctions did not differ significantly (P > 0.05) from those at proximal dendritic sites. If distal synapses do compensate for their remote location they do this in some other way, possibly by increasing the number of synaptic contacts made by each presynaptic axon.