CHARACTERIZATION OF NEUROTENSIN-LIKE IMMUNOREACTIVITY IN HUMAN BASAL GANGLIA - INCREASED NEUROTENSIN LEVELS IN SUBSTANTIA-NIGRA IN PARKINSONS-DISEASE

A method that combines high performance liquid chromatography with rad ioimmunoassay (HPLC/RIA) has been used to characterize neurotensin-lik e immunoreactivity (NT-IR) in the basal ganglia from control subjects and Parkinson's disease (PD) patients. In samples from the caudate nuc leus and putamen, NT-IR eluted as two HPLC peaks. One was indistinguis hable from the synthetic tridecapeptide, while the other peak correspo nded to oxidized NT, as judged by its chromatographic behaviour and it s reaction with the antiserum employed. There were marked discrepancie s between the IR detected in crude extracts and that in HPLC purified samples. NT levels (HPLC/RIA) were unaltered in the caudate nucleus, p utamen and both segments of the globus pallidus in the parkinsonian br ain. In contrast, there was a two-fold increase in NT content: in both zona compacta and zona reticulata of the substantia nigra in PD patie nts compared to controls. Degeneration of the nigrostriatal pathway an d/or prolonged antiparkinsonian treatment in PD appears to alter neuro tensin levels in an attempt to activate the dopaminergic nigrostriatal pathway.