Two Methods of Modeling of Spinal Superreflexia in Rats
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We studied the relations between conditions of induction and quantitative characteristics of abnormally amplified monosynaptic reflex discharges (MSD) in ventral roots (VR) observed in two experimental situations: (i) 5 days after simultaneously performed denervation (transection of the sciatic nerve) and spinalization at the L1 level, and (ii) 5 days after preliminary denervation and with systemic injection of 4-aminopyridine (4-AP) in the course of the acute experiment. In both situations, the amplitude of the MSD conducted via the VR was close to the threshold of excitation of fibers in this root or even exceeded this value (a superreflexia phenomenon). Under both (i) and (ii) conditions, we observed generation of the second component of MSD in the VR, which was probably related to transition of excitation from excited to “silent” fibers in the VR. The latter of the above variants of induction superreflexia (5 days after denervation and with the effect of 4-AP in the acute experiment) is preferred because there is practically no death of the experimental animals in the course of the chronic experiment, there are no negative post-spinalization changes in the spinal cord, and the possibility of supraspinal activation of motoneurons is preserved.
Keywordsmonosynaptic reflex discharges spinal cord denervation 4-aminopyridine chronic spinalization superreflexia
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