Effect of L-DOPA on nitric oxide production in striatum of freely mobile mice.
In Parkinson's disease, nitric oxide (NO) and other free radicals are thought to be involved in neuronal degeneration. Furthermore, L-DOPA is suggested to have a cytotoxic action on dopaminergic neurons. We studied 24-h NO production and the effect of L-DOPA on this in freely mobile mice using in vivo microdialysis. A microdialysis probe was implanted into the right striatum 12 h before the experiment. This dialysis probe was perfused with Ringer solution for 100 min, then with 20, 50, or 100 nM L-DOPA for 20 min, and finally with Ringer solution. Dialysate fractions were collected every 20 min for 4 h. Production of nitrite and total NO were significantly higher during daytime than during nighttime. Nitrate production was increased significantly by L-DOPA. NO production in the striatum appears to exhibit a diurnal rhythm and to increase with exposure to L-DOPA.
Itokawa
Kaori
K
Department of Neurology, Saitama Medical University, 38 Moro Hongo, Moroyama-cho, Iruma-gun, Saitama, Japan. kitokawa@saitama-med.ac.jp
Ohkuma
Aya
A
Araki
Nobuo
N
Tamura
Naotoshi
N
Shimazu
Kunio
K
D000704:Analysis of Variance; D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D015259:Dopamine Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D051379:Mice; D017551:Microdialysis / Q000379:methods; D009569:Nitric Oxide / Q000378:metabolism*; D013997:Time Factors; D014851:Wakefulness
D015259:Dopamine Agents; D009569:Nitric Oxide; D007980:Levodopa