MECHANISMS OF FUNCTIONAL RECOVERY AND REGENERATION AFTER SPINAL CORD TRANSECTION IN LARVAL SEA LAMPREY

J. Physiol, 1978 · DOI: · Published: January 1, 1978

Spinal Cord Injury Neurology Regenerative Medicine & Stem Cells

Simple Explanation

This study investigates how larval sea lampreys regain swimming ability after their spinal cords are completely severed. The researchers observed the process of recovery, looking at both the behavior of the lampreys and the changes in their spinal cords. The study found that recovery was faster in warmer conditions. The research team also discovered that the lampreys could respond to stimuli even when tissues around the spinal cord were removed, suggesting the spinal cord itself was regenerating. The researchers suggest that instead of long nerve fibers reconnecting, short fibers might be sprouting and forming new connections. These new connections would then relay information, allowing the lampreys to swim again.

Study Duration

17 weeks

Participants

Ten larval sea lampreys (Petramyzon marinu8) 11-15 cm long

Evidence Level

Not specified

Key Findings

1
Large sea lamprey larvae regained swimming co-ordination after several weeks following complete spinal cord transaction. Recovery was much faster when animals were kept at 23 than at 12 0C.
2
The behavioural recovery involved a regenerative mechanism in the spinal cord, since stimulation of the head resulted in tail curling, even when all tissue other than spinal cord and notocord was stripped away
3
Twelve of eighteen large reticulospinal axons followed in serial sections regenerated across the glial-ependymal scar, but branched abnormally and migrated away from their customary locations.

Research Summary

Large sea lamprey larvae can recover swimming coordination after spinal cord transaction, with faster recovery at higher temperatures. Behavioral recovery involves spinal cord regeneration, as evidenced by tail curling upon head stimulation even after removing surrounding tissues. Functional recovery may occur through axon sprouting across the transaction, forming new synapses with propriospinal interneurons, rather than long axon tract regeneration.

Practical Implications

Temperature Sensitivity

Recovery from spinal cord injury can be influenced by temperature, suggesting a potential therapeutic target.

Regenerative Mechanisms

The spinal cord's ability to regenerate and create new connections highlights the potential for interventions promoting nerve regeneration.

Sprouting Mechanism

Axon sprouting and synapse formation may be key to functional recovery, offering a target for therapies promoting local circuit repair.

Study Limitations

1
The exact mechanisms of axon sprouting and synapse formation remain unproven.
2
The study focused on larval sea lampreys, and results may not directly translate to higher vertebrates.
3
The role of glial scar formation in preventing or allowing regeneration requires further investigation.

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