Related Experiment Video
Updated: Aug 10, 2026
A Phenotyping Regimen for Genetically Modified Mice Used to Study Genes Implicated in Human Diseases of Aging
Published on: July 14, 2016
Myelin turnover in hyperphenylalaninaemia. A re-evaluation with the HPH-5 mouse
1Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912-2100.
Abstract:
Myelin turnover has been studied in the 25-day-old HPH-5 mouse, a phenylalanine hydroxylase-deficient mouse mutant. The half-life of the fast component of myelin decreased from 15 days in control mice to 4.5 days at blood phenylalanine levels of 2.5 mmol/L. The slow component of myelin seems also to be affected by the high phenylalanine level. These observations confirm similar observations obtained with chemically induced models of hyperphenylalaninaemia and are therefore due to the hyperphenylalaninaemia per se, independently of the inhibitors of phenylalanine hydroxylase. An intermediate blood level of phenylalanine (0.7 mmol/L) likewise seems to interfere with myelin metabolism, although to a lesser degree.
Insights
High phenylalanine levels significantly accelerate myelin turnover in mice, impacting both fast and slow myelin components. This suggests hyperphenylalaninemia directly affects myelin metabolism.
Area of Science:
- Neuroscience
- Biochemistry
- Genetics
Background:
- Myelin is crucial for nerve impulse conduction.
- Phenylalanine hydroxylase deficiency leads to hyperphenylalaninemia.
- Understanding myelin metabolism is vital for neurological health.
Purpose of the Study:
- To investigate the impact of hyperphenylalaninemia on myelin turnover.
- To determine the relationship between phenylalanine levels and myelin degradation.
Main Methods:
- Utilized the HPH-5 mouse mutant, deficient in phenylalanine hydroxylase.
- Measured myelin component half-life at varying blood phenylalanine concentrations.
Main Results:
- The fast myelin component's half-life decreased from 15 days (control) to 4.5 days at 2.5 mmol/L phenylalanine.
- High phenylalanine levels appeared to affect the slow myelin component as well.
- Intermediate phenylalanine levels (0.7 mmol/L) also interfered with myelin metabolism, though less severely.
Conclusions:
- Hyperphenylalaninemia directly accelerates myelin turnover.
- Both fast and slow myelin components are susceptible to high phenylalanine levels.
- Myelin metabolism is sensitive to phenylalanine concentrations, with implications for neurological function.
More Related Videos
06:35In Vivo Electrophysiological Measurement of Compound Muscle Action Potential from the Forelimbs in Mouse Models of Motor Neuron Degeneration
Published on: June 15, 2018
08:27Single Synapse Indicators of Glutamate Release and Uptake in Acute Brain Slices from Normal and Huntington Mice
Published on: March 11, 2020