Related Experiment Videos
Microcephalic cerebrum with hypomyelination in the pygmy mouse (pg)
T Sugisaki1, W G Beamer, T Noguchi
1Department of Physiology, Toho University School of Medicine, Tokyo, Japan.
Summary
Somatomedin directly impacts brain development. This study shows pygmy mice with normal somatomedin levels have reduced brain growth, suggesting its crucial role in glial cell proliferation and myelin formation.
Area of Science:
- Neuroscience
- Developmental Biology
- Genetics
Background:
- Growth hormone's role in brain development is debated.
- Somatomedin's direct influence on the central nervous system is not fully understood.
- The pygmy mouse (pg) mutant offers a model to study somatomedin's effects due to normal somatomedin activity.
Purpose of the Study:
- To investigate the direct action of somatomedin on cerebral development.
- To differentiate somatomedin's direct effects from indirect growth hormone actions.
- To elucidate the role of somatomedin in brain growth and maturation.
Main Methods:
- Comparative analysis of pygmy mouse (pg/pg) central nervous system with normal controls (pg/+).
- Measurement of brain region weights, total DNA and RNA content.
- Assay of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) activity.
- Observation of behavioral activity patterns.
Main Results:
- Significantly reduced cerebrum (14%) and cerebellum (15%) weights in pg/pg mice.
- Reduced total DNA content (17%) in both cerebrum and cerebellum of pg/pg mice.
- Proportional reduction in total RNA content mirroring DNA reduction.
- Selective 25% reduction in cerebrum CNPase activity in pg/pg mice.
- Pybgmy mice displayed reduced activity with indistinct diurnal patterns.
Conclusions:
- Somatomedin appears to have a direct role in cerebral development.
- Findings suggest somatomedin is essential for glial cell proliferation and maturation.
- This action is likely a prerequisite for proper myelin formation in the brain.