L-Dopa decreases cutaneous nociceptive inhibition of motor activity in Parkinson's disease.
OBJECTIVE
To estimate changes in motor inhibitory mechanisms at the spinal level in Parkinson's disease (PD) patients by measuring cutaneous silent responses to nociceptive stimuli in the course of L-Dopa therapy.


METHODS
Fourteen patients with idiopathic PD (Group 1) and 13 patients with other forms of parkinsonism (Group 2) participated in the study. The cutaneous silent period (CSP) from the hand and clinical scores (UPDRS, part III) were measured "off" therapy (T0), after a single dose of L-Dopa (T1) and 3 months after the beginning of L-Dopa daily therapy (T2).


RESULTS
At T0 the duration of the CSP was significantly prolonged in Group 1 and Group 2. At T1 and T2 the mean duration of the CSP significantly decreased in Group 1 (P < 0.05) and a significant correlation was found between the shortening of the CSP and the improvement of rigidity and bradikynesia in the upper limb.


CONCLUSIONS
Our findings show that L-Dopa decreases the cutaneous nociceptive inhibition of motor activity in PD patients. CSP may be useful to assess L-Dopa responsiveness during the clinical course of PD.
Serrao
M
M
Istituto di Clinica delle Malattie Nervose e Mentali, Università degli Studi di Roma La Sapienza, Italy.
Parisi
L
L
Valente
G
G
Martini
A
A
Fattapposta
F
F
Pierelli
F
F
Rossi
P
P
D000284:Administration, Oral; D000368:Aged; D000978:Antiparkinson Agents / Q000494:pharmacology*; D005260:Female; D006225:Hand; D006801:Humans; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology*; D010146:Pain; D010300:Parkinson Disease / Q000188:drug therapy / Q000503:physiopathology*; D013127:Spinal Nerves / Q000502:physiology
D000978:Antiparkinson Agents; D007980:Levodopa