von Bernhardi R
Biocenter, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
J Exp Biol. 1998 Apr;201(Pt 7):1035-41.
Neurites of individual leech neurones in culture retract in response to electrical stimulation or K+ depolarisation. The aim of these experiments was to assess whether retraction of neurites is prevented by the establishment of cell-cell contacts. Retzius and anterior pagoda (AP) cells were isolated from leech ganglia and plated either as single cells or in pairs. A profusion of well-developed neurites was observed after 5-9 days in culture on laminin-rich leech extracellular matrix extract. Brief trains of action potentials in single cells caused neurites to retract reversibly by approximately 26% of their average length, confirming and extending and earlier results. In contrast, retraction after stimulation was significantly decreased in cultures of paired cells that had formed synapses or contacts between their processes. Even free neurites that had not made contact failed to retract; many neurites continued to elongate during and after electrical stimulation. These results indicate that the retraction of neurites induced by electrical stimulation is prevented by the establishment of intercellular contacts. By stabilising the neurites of neurones contacting potential target cells, the search for additional targets and the strengthening of connections that are being made can continue in the presence of electrical activity.
培养中的单个水蛭神经元的神经突会因电刺激或钾离子去极化而回缩。这些实验的目的是评估神经突的回缩是否会因细胞间接触的建立而受到抑制。从水蛭神经节中分离出Retzius细胞和前宝塔（AP）细胞，将它们以单细胞或成对的形式接种。在富含层粘连蛋白的水蛭细胞外基质提取物上培养5-9天后，观察到大量发育良好的神经突。单细胞中的短暂动作电位序列会导致神经突可逆地回缩，回缩幅度约为其平均长度的26%，这证实并扩展了早期的结果。相比之下，在已形成突触或其突起之间有接触的成对细胞培养物中，刺激后的回缩明显减少。即使是尚未接触的游离神经突也不会回缩；许多神经突在电刺激期间和之后继续伸长。这些结果表明，电刺激诱导的神经突回缩会因细胞间接触的建立而受到抑制。通过稳定与潜在靶细胞接触的神经元的神经突，在存在电活动的情况下，可以继续寻找其他靶标并加强正在形成的连接。
