Premium
The effects of spinal cord isolation on rat hindlimb α‐motoneurone (α‐Mns) electrophysiological properties
Author(s) -
Button Duane Calvin,
Gardiner Kalan,
Cahill Farrell,
Marqueste Tanguy,
Zhong Hui,
Roy Roland R,
Edgerton V Reggie,
Gardiner Phillip
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1415-c
The objective of this study was to determine if SI, a method to eliminate the supraspinal and peripheral activation of α‐Mns, influences their electrophysiological properties. Rats were subjected to SI via complete mid‐thoracic and high sacral spinal cord transections, and bilateral dorsal rhizotomy between the transection sites. About 1 month post‐surgery, α‐Mns (n = 20 for SI and n = 45 for control) located in the lumbar enlargement (identified by antidromically stimulated field potentials of the sciatic nerve) of anesthetized (ketamine‐xylazine) rats were impaled via sharp glass microelectrodes to measure their passive and active electrophysiological properties. Results demonstrated that SI significantly (p < 0.01) increased α‐Mns afterhyperpolarization (AHP) amplitude and input resistance by 29 and 41%, respectively, and decreased rheobase by 26% compared to control. Furthermore, SI significantly (p < 0.05) decreased α‐Mns maximal steady‐state firing frequency, f‐I gain, and late adaptation by 30, 25, and 30%, respectively compared to controls. These changes suggest that the passive and active properties of α‐Mns are altered by SI, becoming smaller, less excitable, and quicker to adapt during the late phase of adaptation (>5 s) compared to age‐matched controls. Supported by funds from CIHR, CSA, NSERC, and NIH NS16333.