Enhancement of recurrent inhibition by intravenous administration of L-acetylcarnitine in spastic patients.
The recurrent inhibition of the soleus alpha-motoneurons at rest, evaluated by a specially designed method of paired H reflexes, was estimated in 10 patients with spastic paraparesis. In three of these patients, Renshaw cell activity produced inhibition of the corresponding alpha-motor neurons comparable to that obtained in normal subjects, while the inhibition was reduced in five and absent in two. The effects of intravenously administered L-acetylcarnitine on the activity of Renshaw cells were studied in these patients. In all patients except the two with no evidence of recurrent inhibition, L-acetylcarnitine was found to significantly increase the amount of recurrent inhibition. Its effect became evident at about 30 minutes, reached a maximum around 50 minutes and vanished about 70 minutes from the onset of administration. A significant correlation was found between Renshaw cell activity and the ability of the drug to increase it. L-acetylcarnitine appeared to act specifically by enhancing recurrent inhibition, since no variation in the excitability of the monosynaptic reflex arc was observed.
Mazzocchio
R
R
Istituto di Scienze Neurologiche, Universita di Siena, Italy.
Schieppati
M
M
Scarpini
C
C
Rossi
A
A
D000108:Acetylcarnitine / Q000494:pharmacology*; D000293:Adolescent; D000328:Adult; D002331:Carnitine / Q000031:analogs & derivatives*; D005260:Female; D006181:H-Reflex / Q000187:drug effects; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000187:drug effects*; D015493:Paraparesis, Tropical Spastic / Q000503:physiopathology*; D013116:Spinal Cord / Q000166:cytology
D000108:Acetylcarnitine; D002331:Carnitine