Role of serotonergic neurons in L-DOPA-derived extracellular dopamine in the striatum of 6-OHDA-lesioned rats.
The effect of L-dihydroxyphenylalanine (L-DOPA) on extracellular dopamine (DA) in the striatum was determined by microdialysis in 6-hydroxydopamine (6-OHDA)-lesioned rats treated with and without the serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT). At the same time the intensity of L-DOPA-induced rotational behavior was assessed. In 6-OHDA-lesioned rats treated with 5,7-DHT, L-DOPA (50 mg/kg, i.p.) increased extracellular DA only to 20% of that measured in animals not treated with 5,7-DHT. Likewise, 6-OHDA-lesioned rats treated with 5,7-DHT exhibited a significantly lower number of L-DOPA-induced rotations. These results suggest that serotonergic terminals in the striatum can convert exogenously administered L-DOPA into DA that can be released into the extracellular space.
Tanaka
H
H
Department of Neurology, Institute of Neurological Diseases, Hirosaki University School of Medicine, Japan.
Kannari
K
K
Maeda
T
T
Tomiyama
M
M
Suda
T
T
Matsunaga
M
M
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000096:biosynthesis* / Q000378:metabolism; D015259:Dopamine Agents / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism*; D007980:Levodopa / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D009474:Neurons / Q000502:physiology*; D016627:Oxidopamine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012399:Rotation; D012701:Serotonin / Q000378:metabolism / Q000502:physiology*; D018490:Serotonin Agents / Q000494:pharmacology; D013239:Stereotyped Behavior / Q000502:physiology
D015259:Dopamine Agents; D018490:Serotonin Agents; D015102:3,4-Dihydroxyphenylacetic Acid; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D007980:Levodopa; D016627:Oxidopamine; D001058:Apomorphine; D004298:Dopamine