The onset of hyperreflexia in the rat following complete spinal cord transection.

Abstract

STUDY DESIGN:

Hyperreflexia occurs after spinal cord injury (SCI) and can be assessed by measuring low frequency-dependent depression of the H-reflex. Previous studies showed the time course for the onset of hyperreflexia to occur between 6-28 days in the contusion model of SCI.

OBJECTIVE:

To determine the time course of the onset of hyperreflexia in the transection model of SCI and examine changes in Connexin-36 (Cx-36) protein levels in the lumbar enlargement of animals.

SETTING:

Spinal Cord Injury Mobilization Program of the Center for Translational Neuroscience, the research arm of the Jackson T. Stephens Neuroscience Institute, Little Rock, AR, USA.

METHODS:

Adult female rats underwent transection at T10 level. Low frequency-dependent depression of the H-reflex was tested at 7, 14 and 30 days post-transection. Lumbar enlargement tissue was harvested following reflex testing and western blots were performed after immunoprecipitation to compare Cx-36 protein levels.

RESULTS:

Significant decreases in low frequency-dependent depression of the H-reflex were observed in animals tested 14 and 30 days post-transection compared with control animals, but it was not different from control animals at 7 days. Significant decreases in Cx-36 protein levels were observed in animals 7 days post-transection compared with controls.

CONCLUSION:

Rats transition to a state of hyperreflexia between 7 and 14 days post-transection. Cx-36 protein levels decreased at 7 days post-transection and gradually returned to control levels by 30 days post-transection. These data suggest there may be a relationship between changes in neuronal gap junction protein levels and the delayed onset of hyperreflexia.

• Authors: C Yates, A Charlesworth, S R Allen, N B Reese, R D Skinner, E Garcia-Rill
• Journal: Spinal cord (Spinal Cord) Vol. 46 Issue 12 Pg. 798-803 (Dec 2008) ISSN: 1362-4393 [Print] England
• PMID: 18542097 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Biomarkers
• Connexins
• connexin 36

Topics

• Animals
• Biomarkers (analysis, metabolism)
• Connexins (analysis, metabolism)
• Disease Models, Animal
• Disease Progression
• Down-Regulation (physiology)
• Female
• Gap Junctions (metabolism)
• H-Reflex (physiology)
• Neurophysiology
• Physical Stimulation
• Predictive Value of Tests
• Rats
• Rats, Sprague-Dawley
• Reflex, Abnormal (physiology)
• Spinal Cord (physiopathology)
• Spinal Cord Injuries (physiopathology)
• Thoracic Vertebrae
• Time Factors