Training old rats selectively modulates synaptosomal protein synthesis

Area of Science:

• Neuroscience
• Molecular Biology
• Behavioral Neuroscience

Background:

• Previous studies demonstrated enhanced local synthesis of specific synaptic proteins (66.5-kDa and 87.6-kDa) in adult rats trained for a two-way active avoidance task.
• This suggests that synaptic protein synthesis is a modifiable process linked to learning and memory.

Purpose of the Study:

• To investigate whether a similar response in synaptic protein synthesis occurs in aged male rats (2-year-old) trained on the same avoidance task.
• To compare the patterns of protein synthesis and their correlations with behavioral responses between aged and adult rats.

Main Methods:

• Training 2-year-old male rats on a two-way active avoidance task.
• Measuring the local synthesis of 66.5-kDa and 87.6-kDa synaptic proteins in various brain regions (cerebral cortex, brainstem, cerebellum).
• Correlating the synthesis of these proteins with specific behaviors (avoidances, escapes, freezings).

Main Results:

• Aged rats showed a marked increase in 66.5-kDa protein synthesis in the cerebral cortex, brainstem, and cerebellum, with a smaller increase in 87.6-kDa protein synthesis.
• In aged rats, newly synthesized 87.6-kDa protein correlated with avoidances and escapes and inversely with freezings in the cerebral cortex and brainstem.
• These correlative patterns in aged rats differed significantly from those observed in trained adult rats.

Conclusions:

• Training selectively modulates the local system of synaptic protein synthesis across different age groups.
• The synaptic protein synthesis response to training in aged rats differs from that in adult rats, as evidenced by distinct protein synthesis levels and behavioral correlations.
• These findings highlight age-related differences in the neurobiological adaptations to learning tasks.