OBJECTIVE: To investigate the effect of tizanidine (an alpha(2) noradrenergic agonist) on transmission in the interneuronal pathway coactivated by group I and group II afferents in post-stroke patients with spastic hemiplegia. METHODS: Early and late facilitation of the quadriceps H reflex elicited in the common peroneal nerve--attributed to non-monosynaptic group I and group II excitation, respectively--was investigated in 14 spastic hemiplegic patients. All received a single dose of tizanidine (150 microg/kg) or placebo in randomised order at 10 day intervals. Repeated measurements were made at baseline (T0), 45-90 min, and 120 min after drug intake. Spasticity was assessed by modified Ashworth score in the quadriceps muscle and by a leg tone score calculated by the sum of the modified Ashworth score in five muscle groups. RESULTS: On the spastic side a decrease in late group II and, to a lesser extent, early group I common peroneal nerve induced quadriceps H reflex facilitation occurred with tizanidine (group II, mean (SEM) difference T0-T90: 34.3 (10.2)%, p<0.001; group I, T0-T120: 19.8 (9)%, p<0.05), but not with placebo (group II, difference T0-T90: 12.5 (8)%, NS; group I, T0-T120: 3.2 (7)%, NS). Tizanidine but not placebo decreased the quadriceps muscle and global lower limbAshworth scores (2.9 (0.2) to 1.9 (0.3), p<0.001; and 12 (0.7) to 9.5 (0.8), p<0.0001, respectively). CONCLUSIONS: Enhancement of group II-group I facilitation of the quadriceps motor neurones on the spastic side of hemiplegic patients is modulated by alpha(2) noradrenergic agonists. This strengthens the view that late facilitation of quadriceps motor neurones is mediated by group II afferents and suggests that group II pathways may be involved in lower limb spasticity.
RCT Entities:
OBJECTIVE: To investigate the effect of tizanidine (an alpha(2) noradrenergic agonist) on transmission in the interneuronal pathway coactivated by group I and group II afferents in post-strokepatients with spastic hemiplegia. METHODS: Early and late facilitation of the quadriceps H reflex elicited in the common peroneal nerve--attributed to non-monosynaptic group I and group II excitation, respectively--was investigated in 14 spastic hemiplegicpatients. All received a single dose of tizanidine (150 microg/kg) or placebo in randomised order at 10 day intervals. Repeated measurements were made at baseline (T0), 45-90 min, and 120 min after drug intake. Spasticity was assessed by modified Ashworth score in the quadriceps muscle and by a leg tone score calculated by the sum of the modified Ashworth score in five muscle groups. RESULTS: On the spastic side a decrease in late group II and, to a lesser extent, early group I common peroneal nerve induced quadriceps H reflex facilitation occurred with tizanidine (group II, mean (SEM) difference T0-T90: 34.3 (10.2)%, p<0.001; group I, T0-T120: 19.8 (9)%, p<0.05), but not with placebo (group II, difference T0-T90: 12.5 (8)%, NS; group I, T0-T120: 3.2 (7)%, NS). Tizanidine but not placebo decreased the quadriceps muscle and global lower limb Ashworth scores (2.9 (0.2) to 1.9 (0.3), p<0.001; and 12 (0.7) to 9.5 (0.8), p<0.0001, respectively). CONCLUSIONS: Enhancement of group II-group I facilitation of the quadriceps motor neurones on the spastic side of hemiplegic patients is modulated by alpha(2) noradrenergic agonists. This strengthens the view that late facilitation of quadriceps motor neurones is mediated by group II afferents and suggests that group II pathways may be involved in lower limb spasticity.
Authors: Gilles Hoffmann; Derek G Kamper; Jennifer H Kahn; William Z Rymer; Brian D Schmit Journal: J Neurophysiol Date: 2009-07-01 Impact factor: 2.714
Authors: Carel G M Meskers; Alfred C Schouten; Marieke M L Rich; Jurriaan H de Groot; Jasper Schuurmans; J H Arendzen Journal: Exp Brain Res Date: 2009-11-26 Impact factor: 1.972
Authors: Joseph-Omer Dyer; Eric Maupas; Sibele de Andrade Melo; Daniel Bourbonnais; Jean Fleury; Robert Forget Journal: PLoS One Date: 2009-01-05 Impact factor: 3.240