Effects of L-DOPA on striatal iodine-123-FP-CIT binding and behavioral parameters in the rat.
Nucl Med Commun
; 34(12): 1223-32, 2013 Dec.
Article
en En
| MEDLINE
| ID: mdl-23982164
ABSTRACT
PURPOSE:
The effect of clinical L-3,4-dihydroxyphenylalanine (L-DOPA) doses on the binding of [121I]N-Ω-fluoropropyl-2ß-carbomethoxy-3ß-(4-iodophenyl)nortropane (121[I]FP-CIT) to the rat dopamine transporter (DAT) was investigated using small animal single-photon emission computed tomography. MATERIALS ANDMETHODS:
DAT binding was measured at baseline, after challenge with the aromatic L-amino acid decarboxylase inhibitor benserazide, and after challenge with either 5 or 10 mg/kg L-DOPA plus benserazide. For baseline and challenges, striatal equilibrium ratios (V3'') were computed as an estimation of the binding potential. Moreover, striatal V3'' values were correlated with parameters of motor and exploratory behavior.RESULTS:
V3'' differed significantly between baseline and either dose of L-DOPA/benserazide. Moreover, V3'' differed significantly between L-DOPA treatment groups. After 5 mg/kg L-DOPA/benserazide, DAT binding was inversely correlated with sitting duration (1-5 min) and sitting frequency (10-15 min). After 10 mg/kg L-DOPA/benserazide, an inverse correlation was found between DAT binding and sitting duration (1-30 min), whereas DAT binding and duration of ambulatory activity (1-30 min) as well as head and shoulder motility (10-15 min) exhibited a positive correlation.CONCLUSION:
Challenge with 5 and 10 mg/kg L-DOPA/benserazide led to mean reductions in DAT binding by 34 and 20%, respectively. Results indicate a biphasic response with a higher effect on DAT after the lower dose of L-DOPA. The reduction in DAT binding may be interpreted in terms of competition between [123I]FP-CIT and endogenous dopamine. Moreover, there is preliminary evidence of an association between striatal DAT and motor and exploratory parameters.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Tropanos
/
Conducta Animal
/
Levodopa
/
Neostriado
Límite:
Animals
Idioma:
En
Revista:
Nucl Med Commun
Año:
2013
Tipo del documento:
Article
País de afiliación:
Alemania