Muscle disuse caused by botulinum toxin injection leads to increased central gain of the stretch reflex in the rat
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Muscle disuse caused by botulinum toxin injection leads to increased central gain of the stretch reflex in the rat. / Pingel, Jessica; Hultborn, Hans; Naslund-Koch, Lui; Jensen, Dennis Bo; Wienecke, Jacob; Nielsen, Jens Bo.
I: Journal of Neurophysiology, Bind 118, Nr. 4, 2017, s. 1962-1969.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Muscle disuse caused by botulinum toxin injection leads to increased central gain of the stretch reflex in the rat
AU - Pingel, Jessica
AU - Hultborn, Hans
AU - Naslund-Koch, Lui
AU - Jensen, Dennis Bo
AU - Wienecke, Jacob
AU - Nielsen, Jens Bo
N1 - CURIS 2017 NEXS 264
PY - 2017
Y1 - 2017
N2 - Botulinum toxin (Btx) is used in children with cerebral palsy and other neurological patients to diminish spasticity and reduce the risk of development of contractures. Here, we investigated changes in the central gain of the stretch reflex circuitry in response to botulinum toxin injection in the triceps surae muscle in rats. Experiments were performed in 21 rats. 8 rats were in a control group and 13 rats were injected with 6 IU of Btx in the left triceps surae muscle. Two weeks after Btx injection larger monosynaptic reflexes (MSR) were recorded from the left (injected) than the right (non-injected) L4 + L5 ventral roots following stimulation of the corresponding dorsal roots. A similar increase on the left side was observed in response to stimulation of descending motor tracts, suggesting that increased excitability of spinal motor neurones may at least partly explain the increased reflexes. However, significant changes were also observed in post-activation depression of the MSR suggesting that plastic changes in transmission from Ia afferent to the motor neurons may also be involved. The data demonstrate that muscle paralysis induced by Btx injection is accompanied by plastic adaptations in the central stretch reflex circuitry, which counteract the antispastic effect of Btx.
AB - Botulinum toxin (Btx) is used in children with cerebral palsy and other neurological patients to diminish spasticity and reduce the risk of development of contractures. Here, we investigated changes in the central gain of the stretch reflex circuitry in response to botulinum toxin injection in the triceps surae muscle in rats. Experiments were performed in 21 rats. 8 rats were in a control group and 13 rats were injected with 6 IU of Btx in the left triceps surae muscle. Two weeks after Btx injection larger monosynaptic reflexes (MSR) were recorded from the left (injected) than the right (non-injected) L4 + L5 ventral roots following stimulation of the corresponding dorsal roots. A similar increase on the left side was observed in response to stimulation of descending motor tracts, suggesting that increased excitability of spinal motor neurones may at least partly explain the increased reflexes. However, significant changes were also observed in post-activation depression of the MSR suggesting that plastic changes in transmission from Ia afferent to the motor neurons may also be involved. The data demonstrate that muscle paralysis induced by Btx injection is accompanied by plastic adaptations in the central stretch reflex circuitry, which counteract the antispastic effect of Btx.
KW - Botulinum toxin
KW - Rat
KW - Reflex
KW - Spasticity
U2 - 10.1152/jn.00276.2017
DO - 10.1152/jn.00276.2017
M3 - Journal article
C2 - 28724781
VL - 118
SP - 1962
EP - 1969
JO - Journal of Neurophysiology
JF - Journal of Neurophysiology
SN - 0022-3077
IS - 4
ER -
ID: 181938054