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Updated: Aug 20, 2026
Complete Spinal Cord Injury and Brain Dissection Protocol for Subsequent Wholemount In Situ Hybridization in Larval Sea Lamprey
Published on: October 14, 2014
Magnetization transfer micro-MR imaging of live excised lamprey spinal cord: characterization and immunohistochemical
Hidemasa Uematsu1, Andra Popescu, Guixin Zhang
1Department of Radiology, University of Fukui, 23 Shimoaizuki, Matsuoka-cho, Yoshida-gun, Fukui, 910-1193, Japan.
Background And Purpose:
Membrane constituents may play a key role in the magnetization transfer (MT) effect. In lamprey spinal cord, axonal diameters range from <1 microm in the dorsal region to 20-40 microm in the ventral region. There is a corresponding range of axonal, and hence cell membrane, density. These characteristics permit determination of the effect of cell membrane density on MT. The purpose of this study was to characterize regional MT effects in lamprey spinal cord.
Methods:
Excised spinal cords from eight sea lampreys were measured with a 9.4-T MR imaging system. MT saturation was applied for spin-echo sequences. The MT ratio (MTR) was calculated in each location (dorsal, lateral, and ventral columns). Spinal cords from five other lampreys were prepared with an antibody to lamprey glial keratin (LCM 29). The percentage of area staining with LCM29 was calculated for each location.
Results:
Mean MTR (+/- SD) for the dorsal, lateral, and ventral columns were 62.4 +/- 4.2, 59.2 +/- 2.7, and 56.9 +/- 3.0, respectively; all differences were significant (P < .05). Mean LCM29-positive areas for the dorsal, lateral, and ventral columns were 85.1%, 69.7%, and 50.9%, respectively. MTR and percentage LCM29-positive area were significantly correlated (r(2) = 0.98).
Conclusion:
Regional differences in MT effect exist in the lamprey spinal cord. MTR is well correlated with percentage LCM29-positive area. These results support the hypothesis that membrane constituents are at least partly responsible for regional variations in MT effect.
Insights
Magnetization transfer (MT) effects vary regionally in the lamprey spinal cord. Higher cell membrane density, indicated by lamprey glial keratin (LCM 29) staining, strongly correlates with increased MT ratio (MTR).
Area of Science:
- Neuroscience
- Biophysics
- Magnetic Resonance Imaging (MRI)
Background:
- Cell membrane density is hypothesized to influence magnetization transfer (MT) effects.
- Lamprey spinal cord exhibits regional variations in axonal diameter and cell membrane density.
- These variations allow for the investigation of membrane density's role in MT.
Purpose of the Study:
- To characterize regional differences in MT effects within the lamprey spinal cord.
- To determine the relationship between cell membrane density and MT effects.
Main Methods:
- Excised lamprey spinal cords were analyzed using a 9.4-T MR imaging system.
- Magnetization transfer saturation was applied during spin-echo sequences.
- MT ratio (MTR) and percentage of lamprey glial keratin (LCM 29)-positive area were quantified regionally.
Main Results:
- Significant regional differences in MTR were observed across dorsal, lateral, and ventral spinal cord columns.
- The percentage of LCM 29-positive area also varied significantly by region.
- A strong positive correlation (r² = 0.98) was found between MTR and LCM 29-positive area.
Conclusions:
- Regional variations in MT effects are present in the lamprey spinal cord.
- The MT ratio is highly correlated with cell membrane density, as indicated by LCM 29 staining.
- These findings support the role of membrane constituents in regional MT variations.
