XXXX signaling modulates spine density and morphology independent of dendrite structure in cultured neonatal Purkinje cells.

@entity2252 @entity12715
Neurotrophins cooperate with neural activity to modulate CNS neuronal survival and dendritic differentiation. In a previous study, we demonstrated that a critical balance of @entity2252 and neural activity is required for Purkinje cell survival in cocultures of purified granule and Purkinje cells (Morrison and Mason, 1998). Here we investigate whether @entity12715 signaling regulates dendrite and spine development of Purkinje cells. @entity2252 treatment of purified Purkinje cells cultured alone did not elicit formation of mature dendrites or spines. In cocultures of granule and Purkinje cells, however, continuous treatment with @entity2252 over a 2 week postnatal culture period increased the density of Purkinje cell dendritic spines relative to controls without causing a shift in the proportions of headed and filopodia-like spines. The increase in spine number was blocked by adding @entity12715 -IgG to the medium together with @entity2252 . Although @entity2252 alone did not consistently modify the morphology of dendritic spines, treatment with @entity12715 -IgG alone yielded spines with longer necks than those in control cultures. None of these treatments altered Purkinje cell dendritic complexity. These analyses reveal a role for @entity12715 signaling in modulating spine development, consistent with recently reported effects of neurotrophins on synaptic function. Moreover, spine development can be uncoupled from dendrite outgrowth in this reductionist system of purified presynaptic and postsynaptic neurons.
