Synaptic proteins in frontal and control brain regions of rats after exposure to spatial problems

Synaptic proteins D1, D2, D3, synaptin and 14-3-2, as well as the glial protein glutamine synthetase, were measured by crossed immunoelectrophoresis in the anteromedial (prefrontal) cortex, occipital (visual) cortex and the anterior and posterior parts of the neostriatum of rats. The 3 experimental groups consisted of rats trained to criterion in a spatial delayed alternation, those run as yoked controls and, finally, rats kept in individual cages and not subjected to any training. Statistical analysis showed that two variables: behavioral procedures and brain regions, had a significant effect. Their interaction was also significant. Further analysis revealed that only in the prefrontal cortex of the yoked control animals was there a significant decrease of the synaptic membrane proteins D1, D2 and D3. Thus, particular behavioral treatment seems capable of affecting synapses in a specific 'association' cortical area. The change is more easily related to the amount of 'work' than to formation of 'memory trace' within the critical area.