Ultrastructural organization of receptor cell axons in frog olfactory nerve.
Ultrastructural organization of receptor cell axons in frog olfactory nerve.
复制标题
青蛙嗅神经受体细胞轴突的超微结构组织。
DOI：
10.1016/0006-8993(90)90340-h
复制
发表时间：
1990
期刊：
影响因子：
2.9
通讯作者：
Gesteland,RC
中科院分区：
文献类型：
--
作者：
Daston,MM;Adamek,GD;Gesteland,RC
重复的气味或电刺激的青蛙嗅觉神经导致持久的减少受体神经元的兴奋性。在海龟的嗅神经电刺激引起细胞外钾浓度的增加，由于钾从活跃的轴突流出。钾离子浓度升高会使轴突膜去极化并使其失活。如果轴突在神经中彼此平行移动很长一段距离，由于一个轴突的活动而导致的离子浓度变化将降低其相邻轴突的兴奋性。这种现象可能具有类似于Limulus中首次描述的邻居之间的侧抑制的效应，并且可能充当神经信息的具有长时间常数的过滤器。两栖动物嗅神经由密集的、小直径的、无髓纤维组成。在这项研究中，我们已经研究了超微结构的青蛙（蛙）嗅神经的纵向和横截面，以确定轴突是否遵循曲折的过程和改变邻居经常沿着的长度嗅神经，或者他们是否遵循平行的轨迹，从而倾向于保持接近相同的邻居。我们发现，轴突在神经内有一条非常直的路线，而且轴突往往在长距离内与同一个轴突保持相邻。我们认为嗅神经的解剖学基底有利于强烈的抑制性轴突-轴突相互作用。
Repeated odorant or electrical stimulation of the frog olfactory nerve leads to long-lasting reduction of excitability of the receptor neurons. In the turtle olfactory nerve electrical stimulation causes an increase in extracellular potassium concentration due to the efflux of potassium from active axons. Elevated potassium concentration depolarizes an axon membrane and inactivates it. If axons travel parallel to each other in the nerve for extended distances, changes in ionic concentration due to activity in one axon will reduce excitability of its neighbors. This phenomenon may have effects like those of lateral inhibition among neighbors first described inLimulusand may act as a filter with a long time constant, for the nervous message. The amphibian olfactory nerve consists of densely packed, small-diameter, unmyelinated fibers. In this study we have examined the ultrastructure of the frog (Rana pipiens) olfactory nerve in longitudinal and cross-sections to determine whether axons follow a sinuous course and change neighbors often along the length of the olfactory nerve, or whether they follow parallel trajectories and thus tend to stay close to the same neighbors. We have found that axons have a very straight course within the nerve and that axons tend to remain adjacent to the same individual axons over long distances. We think that the anatomical substrate of the olfactory nerve favors strong inhibitory axon-axon interaction.