The effect of L-threo-DOPS on synaptic transmission to soleus motoneuron in normal subjects and patients with Parkinson's disease.
The effect of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) on synaptic transmission to the soleus motoneurons was studied using the H-reflex method in 12 normal subjects and in 4 patients with Parkinson's disease. A long-lasting depression of the test H-reflex, which was evoked by a conditioning group I volley in the homonymous tibial nerve with an onset latency of ca. 30 ms and a duration of more than 1 s and was regarded to represent the transmitter depletion caused by a preceding volley, diminished significantly after the oral administration of L-threo-DOPS both in the normal subjects and in the patients. On the other hand, no change was recognized in the slow depression which was caused by a group I volley of the heteronymous common peroneal nerve and was regarded as the presynaptic inhibition. The findings suggest that L-threo-DOPS influences the reduction of transmitter depletion.
Nakajima
Y
Y
Department of Neurology, Juntendo University, School of Medicine, Tokyo, Japan.
Kagamihara
Y
Y
Nagaoka
M
M
Tanaka
R
R
D000328:Adult; D000368:Aged; D015103:Droxidopa / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007980:Levodopa / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology*; D009132:Muscles / Q000187:drug effects / Q000294:innervation*; D010300:Parkinson Disease / Q000503:physiopathology*; D012016:Reference Values; D012694:Serine / Q000031:analogs & derivatives*; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects*
D012694:Serine; D007980:Levodopa; D015103:Droxidopa