Journal of Neurology

, Volume 250, Issue 12, pp 1475–1481

Assessing dopaminergic function in Parkinson’s disease: levodopa kinetic-dynamic modeling and SPECT

Authors

    • Neurology Clinic, Department of Neurological SciencesUniversity of Bologna
  • Paolo Martinelli
    • Neurology Clinic, Department of Neurological SciencesUniversity of Bologna
  • Roberto Riva
    • Neurology Clinic, Department of Neurological SciencesUniversity of Bologna
  • Maurizio Dondi
    • Department of Diagnostic ImagingMaggiore Hospital
  • Stefano Fanti
    • Nuclear MedicineS. Orsola-Malpighi Hospital
  • Cinzia Pettinato
    • Nuclear MedicineS. Orsola-Malpighi Hospital
  • Cesa Scaglione
    • Neurology Clinic, Department of Neurological SciencesUniversity of Bologna
  • Fiorenzo Albani
    • Neurology Clinic, Department of Neurological SciencesUniversity of Bologna
  • Agostino Baruzzi
    • Neurology Clinic, Department of Neurological SciencesUniversity of Bologna
ORIGINAL COMMUNICATION

DOI: 10.1007/s00415-003-0257-3

Cite this article as:
Contin, M., Martinelli, P., Riva, R. et al. J Neurol (2003) 250: 1475. doi:10.1007/s00415-003-0257-3

Abstract.

Levodopa pharmacokinetic-phamacodynamic (PK-PD) modeling may be able to test the functional integrity of the nigrostriatal dopaminergic system in Parkinson’s disease (PD). [123I]-FP-CIT SPECT imaging of striatal dopamine transporters has also been introduced for the evaluation of presynaptic dopaminergic homeostasis. We aimed to assess the intrapatient relation between levodopa PK-PD and SPECT measures of dopaminergic function in PD. Thirty-five PD patients, 1 to 4 on the Hoehn and Yahr (H&Y) scale, enrolled in the study. Each patient was examined by levodopa PK-PD modeling and SPECT imaging. Primary measure outcomes were the levodopa half-life in the effect compartment (t1/2eq) for PKPD modeling and the ratio of specific to non specific (SP/NSP) tracer striatal uptake for SPECT. Levodopa t1/2eq was highly significantly correlated with H&Y scale (r = –0.815, p < 0.0001), Unified Parkinson’s disease Rating Scale (UPDRS) (r = –0.691, p < 0.0001) and PD symptom duration (r = –0.647, p < 0.0001). SPECT contralateral putamen SP/NSP ratio showed the most significant correlations with clinical indicators of disease severity: H&Y, r = –0.526, p < 0.002; UPDRS, r = –0.523, p < 0.002; symptom duration, r = –0.513, p < 0.002. Significant correlations were observed between levodopa t1/2eq and putamen SP/NSP ratios, yielding the closest correlation for the contralateral region (r = 0.522, p < 0.002). An indirect PK-PD dopaminergic functional variable and direct SPECT measures of presynaptic dopaminergic system homeostasis were in close agreement with clinical data and correlated to each other. Levodopa PK-PD modeling can be a practical clinical tool indirectly assessing the functional integrity of the nigrostriatal dopaminergic system in PD patients.

Key words

LevodopaPharmacokinetic-pharmacodynamic modeling[123I]-FP-CIT SPECTParkinson’s disease
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© Steinkopff Verlag 2003