Neuronal Activity and Axonal Flow
It has been shown that several transport systems exist in the neuron and its processes. In the axon, material is transported at slow and fast rates, which differ by one or even two orders of magnitude. Material is transported in the dendrites at rates approximating axonal fast flow. A selective gate mechanism is postulated for both axonal and dendritic transport, as some organelles are observed either predominantely in the axons and rarely in the dendrites, or rarely in the axons and predominantely in the dendrites.
Substances important for the function of the neuron, e.g. synaptic proteins, neurotransmitters, and enzymes involved in their metabolism etc., are transported in the axons. It seems that the rate and intensity of axonal transport is related to the functional activity of the neurons.
A technique has been developed in our laboratories, combining the intracellular injection of radioactive substances, with electrophysiological recording followed by autoradiodraphy. Data for the intracellular transport of proteins, RNA, and choline derivatives as elucidated by this method are presented.
Key wordsAxonal transport dendritic transport orotic acid choline
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