Hu Edward H, Bloomfield Stewart A
Department of Ophthalmology, New York University School of Medicine, New York, New York 1001, USA.
J Neurosci. 2003 Jul 30;23(17):6768-77. doi: 10.1523/JNEUROSCI.23-17-06768.2003.
We examined whether coupling between neighboringalpha-type ganglion cells (alpha-GCs) in the rabbit retina underlies their synchronous spike activity. Simultaneous recordings were made from arrays of alpha-GCs to determine the synchrony of both spontaneous and light-evoked spike activity. One cell within each array was then injected with the biotinylated tracer Neurobiotin to determine which of the cells were coupled via gap junctions. Cross-correlation analyses indicated that neighboring off-center alpha-GCs maintain short-latency (approximately 2.5 msec) synchronous spiking, whereas the spontaneous spike activities of on-centeralpha-GC neighbors are not correlated. Without exception, those off-centeralpha-GCs showing synchronous spiking were found to be tracer coupled to both amacrine cells and neighboring off-centeralpha-GCs. In contrast, on-center alpha-GCs were never tracer coupled. Furthermore, whereas spikes initiated in an off-center alpha-GC with extrinsic current injection resulted in short-latency synchronized spiking in neighboring off-center alpha-GCs, this was never seen between on-center alpha-GCs. These results indicate that electrical coupling via gap junctions underlies the short-latency concerted spike activity of neighboring alpha-GCs.
我们研究了兔视网膜中相邻α型神经节细胞（α-GCs）之间的耦合是否是其同步放电活动的基础。从α-GCs阵列进行同步记录，以确定自发和光诱发放电活动的同步性。然后向每个阵列中的一个细胞注射生物素化示踪剂神经生物素，以确定哪些细胞通过缝隙连接耦合。互相关分析表明，相邻的离中心α-GCs保持短潜伏期（约2.5毫秒）的同步放电，而中心onα-GC邻居的自发放电活动则不相关。无一例外，那些显示同步放电的离中心α-GCs被发现与无长突细胞和相邻的离中心α-GCs都有示踪剂耦合。相比之下，中心onα-GCs从未有示踪剂耦合。此外，虽然在外源电流注入下，离中心α-GC引发的放电会导致相邻离中心α-GCs出现短潜伏期的同步放电，但在中心onα-GCs之间从未观察到这种情况。这些结果表明，通过缝隙连接进行的电耦合是相邻α-GCs短潜伏期协同放电活动的基础。
