Polyribosomes Associated with Dendritic Spines in the Denervated Dentate Gyrus: Evidence for Local Regulation of Protein Synthesis During Reinnervation

Publisher Summary

Evidence has been steadily accumulating in recent years that neurons of the mature mammalian central nervous system can dramatically remodel their synaptic connections either in response to denervating lesions or in response to patterns of activity. Many of these observations of neuronal “plasticity” have involved the dendritic spine, where neurons of the mammalian brain, particularly cortical neurons, receive the majority of their excitatory synaptic inputs. Numerous studies have demonstrated alterations in spine size or number in response to denervation and reinnervation, and in response to alterations in afferent activity. The malleability of spines is somewhat difficult to reconcile with classical notions of neuronal cell biology. A major tenet of cellular neurobiology is that the major synthetic activity of the neuron occurs in the cell body. Accordingly, the construction and maintenance of the detailed morphological specializations of the neuron (including the spine and associated postsynaptic membrane specialization) are thought to depend on the specific transport of already synthesized material from the cell body. This chapter summarizes the observations on the changes in the incidence of polyribosomes associated with dendritic spines during post-lesion reinnervation of the dentate granule cells.