Related Experiment Videos
Incorporation of plasma palmitate into the brain of the rat during development
Insights
The rate of palmitate incorporation into the brain (Jpalm) increases in young rats and then declines, mirroring the process of myelination. This technique effectively measures brain lipid synthesis and turnover during development.
Area of Science:
- Neuroscience
- Biochemistry
- Developmental Biology
Background:
- Brain lipid synthesis and turnover are crucial for development.
- Palmitate is a key fatty acid in brain lipids, particularly during myelination.
Purpose of the Study:
- To quantify the rate of plasma palmitate incorporation into the brain (Jpalm) in developing rats.
- To correlate Jpalm with the developmental stages of myelination.
Main Methods:
- Intravenous injection of [14C]palmitate in awake Fischer-344 rats at various ages.
- Measurement of plasma-specific activity and brain radioactivity via quantitative autoradiography.
- Calculation of Jpalm as brain radioactivity divided by integrated plasma palmitate-specific activity.
Main Results:
- Jpalm increased between 15 and 20 days of age in both gray and white matter.
- Jpalm significantly declined by 38 days of age, reaching adult levels by 3 months.
- The white/gray matter Jpalm ratio decreased with age, indicating slower white matter lipid turnover in mature brains.
Conclusions:
- The Jpalm technique is a valid method for assessing brain lipid synthesis and turnover.
- Jpalm closely reflects the developmental timeline of myelination in the rat brain.
- Changes in Jpalm correlate with parallel shifts in palmitate incorporation rates in gray and white matter during development.
Abstract:
Jpalm, the rate of incorporation of plasma palmitate into brain, was determined in awake Fischer-344 rats at 15, 20, 25 and 38 days of age, by a modification of the method of Kimes et al. [14C]palmitate was injected intravenously and plasma-specific activity of unesterified palmitate was followed until the animals were killed at 4 h, when radioactivity was determined by quantitative autoradiography in 45 individual brain regions. Jpalm was calculated as the 4 h brain radioactivity divided by integrated plasma palmitate-specific activity to 4 h. Jpalm rose between 15 and 20 days of age in gray and white matter regions, then declined 4-5-fold in gray matter and 7-10-fold in white matter by 38 days and reached adult levels by 3 months. The white/gray ratio for Jpalm declined significantly between 20 and 38 days, and between 38 days and 3 months of age, consistent with a lower rate of turnover of white matter lipids in the mature brain. The results support the use of the Jpalm technique to measure brain lipid synthesis and turnover. They show that Jpalm corresponds to the time course of myelination during development of the rat brain, when there are parallel changes in the rates of palmitate incorporation into gray and white matter regions.