Rod cells dissociated from mature salamander retina: ultrastructure and uptake of horseradish peroxidase.
Rod cells dissociated from mature salamander retina: ultrastructure and uptake of horseradish peroxidase.
复制标题
从成熟蝾螈视网膜分离的杆状细胞：辣根过氧化物酶的超微结构和摄取。
DOI：
10.1083/jcb.100.1.175
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Raviola,E
中科院分区：
文献类型：
--
作者：
Townes-Anderson,E;MacLeish,PR;Raviola,E
To test the effects of isolation on adult neurons, we investigated the fine structure and synaptic activity of rod cells dissociated from the mature salamander retina and maintained in vitro. First, freshly isolated rod cells appeared remarkably similar to their counterparts in the intact retina: the outer segment retained its stack of membranous disks and the inner segment contained its normal complements of organelles. Some reorganization of the cell surface, however, was observed:(a) radial fins, present at the level of the cell body, were lost; and (b) the apical and distal surfaces of the inner and outer segments, respectively became broadly fused. Second, the synaptic endings or pedicles retained their presynaptic active zones: reconstruction of serially sectioned pedicles by using three-dimensional computer graphics revealed that 73% of the synaptic ribbons remained attached to the plasmalemma either at the cell surface or along its invaginations. Finally, tracer experiments that used horseradish peroxidase demonstrated that dissociated rod cells recycled synaptic vesicle membrane in the dark and thus probably released transmitter by exocytosis. Under optimal conditions, a maximum of 40% of the synaptic vesicles within the pedicle were labeled. As in the intact retina, uptake of horseradish peroxidase was suppressed by light. Thus, freshly dissociated receptor neurons retained many of their adult morphological and physiological characteristics. In long-term culture, the photoreceptors tended to round up; however, active zones were present even 2 wk after removal of the postsynaptic processes.Rod cells from the tiger salamander are ideally suited for the study of the cell biology of isolated adult neurons: they survive intact after dissociation (1); they can be maintained in culture for long periods of time (2); and they give normal hyperpolarizing responses to light (1). Although the electrical responses of these cells have been studied in some detail (3-5), a number of crucial properties are still unknown; it seems especially important to establish whether solitary rod cells, maintained in vitro, preserve their morphologically differentiated state and whether their synaptic endings retain functional active zones capable of releasing transmitter by exocytosis in the dark.
