Localization and translation of mRNA in dendrites and axons

The neurons of the brain extend axons and dendrites many hundreds of micrometres away from the cell body. The first electron microscope studies of these processes revealed that many of the structures that are found in the cell body are also present in dendrites. For example, particles resembling ribosomes and membrane structures like those of the endoplasmic reticulum (two structures that are important for protein synthesis) were seen in distal regions of dendrites, near synapses. Subsequent studies focused on identifying messenger RNAs in dendrites and providing evidence of dendritic protein synthesis. Transfection technologies have now been used to analyse translation within dendrites in response to pharmacological stimuli. These studies provide us with clues to the physiological role of the dendrite not just as a signal transducer, but also as a modulator of long-term synaptic efficacy.