Kramer A P, Stent G S
J Neurosci. 1985 Mar;5(3):768-75. doi: 10.1523/JNEUROSCI.05-03-00768.1985.
The sharp, nonoverlapping boundaries of the major and minor receptive fields of the mechanosensory neuron Pv of the leech, as well as the mutual exclusion during embryonic development of growing axon branches belonging to the same Pv cell, have suggested that peripheral axon arborization of these neurons is constrained by a process of neuronal self-avoidance. To provide a direct experimental test of this proposal, the development of the major and minor receptive fields of the Pv neuron was studied in embryos of the leech, Haementeria ghilianii, after surgically preventing or delaying the outgrowth of the axon branches which establish only a minor or only the major field of that neuron. As predicted by the proposal of self-avoidance, interference with the outgrowth of a minor field axon branch resulted in the spread of the major field axon branch into what is normally minor field territory. Conversely, similar interference with the establishment of the major field resulted in the spread of the minor field axon branches into what is normally major field territory. The findings presented here indicate that neuronal self-avoidance does play a significant role in the development of mechanosensory receptive field structure but suggest also that the detailed pattern of arborization of the sensory axons is guided by prespecified pathways of only ephemeral availability or recognizability.
水蛭机械感觉神经元Pv的主要和次要感受野具有清晰、不重叠的边界，并且在胚胎发育期间，属于同一Pv细胞的生长轴突分支相互排斥，这表明这些神经元的外周轴突分支形成受到神经元自我回避过程的限制。为了对这一观点进行直接的实验验证，在外科手术阻止或延迟仅形成该神经元次要或主要感受野的轴突分支生长后，研究了水蛭Haementeria ghilianii胚胎中Pv神经元主要和次要感受野的发育情况。正如自我回避观点所预测的，干扰次要感受野轴突分支的生长会导致主要感受野轴突分支扩展到通常属于次要感受野的区域。相反，对主要感受野形成的类似干扰会导致次要感受野轴突分支扩展到通常属于主要感受野的区域。此处呈现的研究结果表明，神经元自我回避在机械感觉感受野结构的发育中确实发挥了重要作用，但也表明感觉轴突分支形成的详细模式是由仅具有短暂可用性或可识别性的预先确定的通路引导的。
