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XB-ART-45301
Mech Dev July 1, 2012; 129 (5-8): 125-35.

Neural activity and branching of embryonic retinal ganglion cell dendrites.

Hocking JC , Pollock NS , Johnston J , Wilson RJ , Shankar A , McFarlane S .


Abstract
The shape of a neuron''s dendritic arbor is critical for its function as it determines the number of inputs the neuron can receive and how those inputs are processed. During development, a neuron initiates primary dendrites that branch to form a simple arbor. Subsequently, growth occurs by a process that combines the extension and retraction of existing dendrites, and the addition of new branches. The loss and addition of the fine terminal branches of retinal ganglion cells (RGCs) is dependent on afferent inputs from its synaptic partners, the amacrine and bipolar cells. It is unknown, however, whether neural activity regulates the initiation of primary dendrites and their initial branching. To investigate this, Xenopus laevis RGCs developing in vivo were made to express either a delayed rectifier type voltage-gated potassium (KV) channel, Xenopus Kv1.1, or a human inward rectifying channel, Kir2.1, shown previously to modulate the electrical activity of Xenopus spinal cord neurons. Misexpression of either potassium channel increased the number of branch points and the total length of all the branches. As a result, the total dendritic arbor was bigger than for control green fluorescent protein-expressing RGCs and those ectopically expressing a highly related mutant non-functional Kv1.1 channel. Our data indicate that membrane excitability regulates the earliest differentiation of RGC dendritic arbors.

PubMed ID: 22587886
Article link: Mech Dev
Grant support: [+]
Genes referenced: bmp2 clstn2 fos kcna1 kcnj2 myc myh3


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