A method for potentiating Renshaw cell activity in humans.
Owing to the introduction of a special electrophysiological method [3] it has been possible to study spinal recurrent inhibition in humans. The method, however, is indirect and, being based on an H reflex technique, can only be tested in motor nuclei from which a large monosynaptic response can be obtained. We have developed a complementary method by which pharmacological stimulation of Renshaw cells is obtained [6]. It exploits the central cholinergic properties of L-acetylcarnitine [18], a substance which most likely acts potentiating the synaptic drive of the motoneurone collaterals [7], known to be the main source of excitation of Renshaw cells [15,20]. The use of L-acetylcarnitine has allowed to establish the validity of the original methodology [6] and to confirm the presence of recurrent inhibition, tested either by the H reflex technique [11-13] or, if not possible, by the PSTH technique and/or rectified averaged EMG analysis [1,4], in many limb motor nuclei. Thus, it can be expected that L-acetylcarnitine may be used as an independent means for identifying changes in motoneuronal activity related or attributed to the influence of Renshaw cells.
Mazzocchio
R
R
Unità di Malattie del Sistema Motorio e Scienze del Movimento, Università di Siena, Italy. mazzocchio@unisi.it
Rossi
A
A
D000108:Acetylcarnitine / Q000494:pharmacology; D000328:Adult; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods*; D006181:H-Reflex / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007395:Interneurons / Q000187:drug effects / Q000502:physiology*; D007719:Knee Joint / Q000294:innervation; D009043:Motor Activity; D009046:Motor Neurons / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation; D013116:Spinal Cord / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology; D014955:Wrist Joint / Q000294:innervation
D000108:Acetylcarnitine