LOCUS-COERULEUS LESIONS POTENTIATE NEUROTOXIC EFFECTS OF MPTP IN DOPAMINERGIC-NEURONS OF THE SUBSTANTIA-NIGRA

The observation that Parkinson's disease (PD) is associated with locus coeruleus (LC) noradrenergic neuronal degeneration suggests that the LC noradrenergic system may be involved in the pathogenesis and natura l progression of the destruction of the substantia nigra (SN) dopamine rgic neurons in Parkinson's disease. The relationship of these two sys tems was examined by injection of subtoxic doses of MPTP into unilater al LC 6-hydroxydopamine (6-OHDA) lesioned mice. A significant loss of dopaminergic cells was only found in the SN on the side of the LC lesi ons. These results suggest that the LC may have protective effects on SN dopaminergic neurons.