Tizanidine does not affect the linear relation of stretch duration to the long latency M2 response of m. flexor carpi radialis.
The long latency M2 electromyographic response of a suddenly stretched active muscle is stretch duration dependent of which the nature is unclear. We investigated the influence of the group II afferent blocker tizanidine on M2 response characteristics of the m. flexor carpi radialis (FCR). M2 response magnitude and eliciting probability in a group of subjects receiving 4 mg of tizanidine orally were found to be significantly depressed by tizanidine while tizanidine did not affect the significant linear relation of the M2 response to stretch duration. The effect of tizanidine on the M2 response of FCR is supportive of a group II afferent contribution to a compound response of which the stretch duration dependency originates from a different mechanism, e.g., rebound Ia firing.
Meskers
Carel G M
CG
Department of Rehabilitation Medicine, Leiden University Medical Centre B0-Q, P.O. Box 9600, 2300 RC, Leiden, The Netherlands. c.g.m.meskers@lumc.nl
Schouten
Alfred C
AC
Rich
Marieke M L
MM
de Groot
Jurriaan H
JH
Schuurmans
Jasper
J
Arendzen
J H
JH
D000284:Administration, Oral; D000328:Adult; D001288:Attention / Q000187:drug effects; D003000:Clonidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D004576:Electromyography; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D005260:Female; D005542:Forearm / Q000502:physiology; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology*; D010276:Parasympatholytics / Q000008:administration & dosage / Q000494:pharmacology*; D011336:Probability; D012026:Reflex, Stretch / Q000187:drug effects* / Q000502:physiology*; D013997:Time Factors
D010276:Parasympatholytics; C023754:tizanidine; D003000:Clonidine