Amyloid precursor protein knockout mice show age-dependent deficits in passive avoidance learning

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Amyloid precursor protein (APP) is implicated in Alzheimer's disease (AD) pathogenesis.
• The specific role of APP in cognitive functions remains incompletely understood.
• Previous studies on APP knockout (KO) models reported motor and learning deficits.

Purpose of the Study:

• To investigate the in vivo function of APP and its derivatives in cognitive processes.
• To assess the impact of APP absence on neuromuscular, locomotor, and cognitive functions in mice.
• To evaluate age-dependent effects on APP KO mice behavior.

Main Methods:

• Behavioral testing of APP KO mice and wild-type controls at 3 and 8 months of age.
• Assessment of long-term memory using a passive avoidance response test.
• Evaluation of spatial short-term memory via spontaneous alternation in a Y-maze.
• Confirmation of APP absence using Western blotting on hippocampal tissue.

Main Results:

• APP KO mice exhibited deficits in forelimb grip strength and locomotor activity.
• No significant reduction in spontaneous alternation (short-term spatial memory) was observed in APP KO mice.
• APP KO mice demonstrated an age-related deficit in long-term memory retention in the passive avoidance test.

Conclusions:

• APP and/or its proteolytic derivatives are suggested to play a role in long-term memory.
• APP may be essential for the development and maintenance of neuronal networks involved in long-term memory.
• These findings highlight a potential role for APP in cognitive functions beyond its known association with Alzheimer's disease.