AUTORADIOGRAPHIC LOCALIZATION AND DENSITY OF [I-125] FERROTRANSFERRINBINDING-SITES IN THE BASAL GANGLIA OF CONTROL SUBJECTS, PATIENTS WITHPARKINSONS-DISEASE AND MPTP-LESIONED MONKEYS

Degeneration of the nigro-striatal dopaminergic neurons occuring in Pa rkinson's disease is associated with an increase in iron concentration s in the substantia nigra. As this metal catalyzes the production of f ree radicals, and oxidative stress may participate in the cascade of e vents ending in cell death, this increase in iron content may be invol ved in dopaminergic neuronal death. The localization and number of rec eptors for transferrin were investigated postmortem by quantitative au toradiography of iodinated-ferrotransferrin binding in the basal gangl ia from controls, parkinsonian patients and MPTP-lesioned monkeys. In human controls, specific [I-125]ferrotransferrin binding-site density was highest in the putamen and the caudate nucleus, and lowest in the globus pallidus. In parkinsonian patients, it was increased in the put amen and caudate nucleus, while in MPTP-intoxicated monkeys, there was a tendency for levels to decrease in these two regions. An inverse re lationship between binding density and iron content reported in the st udied regions supports the assumption of a possible capture of iron at the level of dopaminergic terminals and, in parkinsonian patients, on other cellular elements as well. These results suggest an involvement of transferrin receptors in iron uptake in the striatum of patients w ith Parkinson's disease, with differences between the 'acute' nigro-st riatal MPTP-induced degeneration syndrome and the chronic long lasting human disease.