NEUROBIOLOGIC STUDIES OF NEURONS AND GLIA IN CELL CULTURE

神经肌肉接头形成于组织培养隔室系统中， 两个不同的胆碱能神经元群支配一个共同的 肌肉细胞群。受刺激和未受刺激的传入神经 单方面刺激的制剂同样失去连接， 双边刺激的准备失去更多的连接比 单方面的刺激。这些影响与赫布模型相矛盾， 活动依赖性突触加强和消除。损失 优先影响距离神经元最远的神经元的连接 在空间上与受神经支配的肌肉分开。我们假设空间 邻近效应可能参与许多发育性突触 重塑现象钙增加的动力学、适应和 已经在受刺激的感觉神经元中确定了恢复。只有 初始积累动力学随慢性活化而改变。一些 立即早期基因（IEGs）的特征在于， 它们的单细胞分布和对去极化刺激的反应。一 对特定电活动模式的高度选择性 已经得到了证实。爆发比稳定更有效 刺激，但c-fos响应1/min，而不是1/2分钟的爆发 (same动作电位总数），而努尔77的反应相同 无论是哪种模式。北方印迹分析未能显示 GAP-43在感觉（DRG）神经元中的转录， 在突触靶点存在或不存在的情况下， DRG细胞。这表明磷酸化或其他后- 转录变化可能涉及该蛋白在以下方面的任何作用： 神经系统的可塑性

Neuromuscular junctions form in a tissue culture compartmental system in which two separate populations of cholinergic neurons innervate a common population of muscle cells. Stimulated and unstimulated afferents in unilaterally stimulated preparations lose connections equally, and bilaterally stimulated preparations lose more connections than do unilaterally stimulated ones. These effects contradict the Hebb model of activity-dependent synapse strengthening and elimination. Loss preferentially affects connections that are from neurons furthest away spatially from the innervated muscle. We postulate that spatial contiguity effects may be involved in many developmental synaptic remodeling phenomena. The kinetics of calcium increase, adaptation and recovery have been determined in stimulated sensory neurons. Only the initial accumulation kinetics change with chronic activation. A number of immediate early genes (IEGs) have been characterized with regard to their single cell distribution and responses to depolarizing stimuli. A high degree of selectivity for specific patterns of electrical activity has been demonstrated. Bursts are more effective than steady stimulation, but c-fos responds to 1/min but not 1/2 mins to bursts (same total number of action potentials) while Nur 77 responds equally well to either pattern. Northern blot analysis fails to show a change in GAP-43 transcription in sensory (DRG) neurons with electrical stimulation in either the absence or presence of synaptic targets for the DRG cells. This suggests phosphorylation or other post- transcriptional changes may be involved in any role this protein has in plasticity in the nervous system.