Aim: 

In neurons, an active system of protein synthesis is present not only in the cell body but also in dendritic, axonal and presynaptic compartments. The activity of protein synthesis in nerve endings can be studied using synaptosomal brain fractions. We have recently demonstrated that brain plastic events are accompanied by modification of protein synthesis patterns in synaptosomes. Notably, rats trained with two-way active avoidance task displayed enhanced local expression of at least two synaptic proteins.

Methods: 

To survey for other genes that may undergo transcriptional modulation, we used RT-PCR methods to determine the content of discrete synaptosomal mRNAs in rats subjected to the same training protocol.

Results: 

To date, correlative analyses between behavioral responses and synaptosomal mRNA content showed that GAT-1 mRNA (a prevalent presynaptic component) was correlated with avoidances and escapes in rat cerebellum, while glial fibrillary acid protein mRNA (an astrocytic component) level in cerebellum and cerebral cortex was correlated with 'freezing' response. However, the modulation of mRNAs levels was not observed when the animals were trained for a spatial test (Lat maze), suggesting that the effect was selectively associated to a specific learning task.

Conclusion: 

These observations support the hypothesis that local expression of both neuronal and glial genes may play an important role in brain synaptic plasticity.