Parkinson's Disease Substantia Nigra Research Articles

Increased iron (III) and total iron content in post mortem substantia nigra of parkinsonian brain.

Significant differences in the content of iron (III) and total iron were found in post mortem substantia nigra of Parkinson's disease. There was an increase of 176% in the levels of total iron and 225% of iron (III) in the substantia nigra of the parkinsonian patients compared to age matched controls. In the cortex (Brodmann area 21), hippocampus, putamen, and globus pallidus there was no significant difference in the levels of iron (III) and total iron. Thus the changes in total iron, iron (III) and the iron (II)/iron (III) ratio in the parkinsonian substantia nigra are likely to be involved in the pathophysiology and treatment of this disorder.

Idiopathic Parkinson's disease, progressive supranuclear palsy and glutathione metabolism in the substantia nigra of patients

Glutathione transferase activity and total glutathione (GSH) content were measured in several regions of autopsied brain from patients dying with idiopathic Parkinson's disease (PD) or progressive supranuclear palsy (PSP), and from control subjects. A significant deficiency of GSH was found in the substantia nigra, but not in 5 other brain regions of PD patients, nor in PSP patients' brains. Glutathione transferase activity was similar in the substantia nigra of PD, PSP and control patients. Since total GSH is consumed only by conjugation in detoxification processes, nigral GSH deficiency in PD patients implies continued local presence of a possible causative neurotoxin up to the time of death.

Glutathione peroxidase activity in Parkinson's disease brain

Glutathione peroxidase is an enzyme of major importance in the detoxification of peroxides in brain. Using the spectrophotometric procedure of Paglia and Valentine [8] and Beutler [2] we measured the activity of this enzyme in autopsied brain from 12 patients dying with idiopathic Parkinson's disease and 11 neurologically normal adults matched with respect to age and postmortem interval. In the Parkinson's disease patients glutathione peroxidase activity was slightly but significantly reduced in several brain areas including substantia nigra. Although the magnitude of the glutathione peroxidase deficiency in Parkinson's disease substantia nigra was small (19% reduction), coupled with the reported marked deficiency of reduced glutathione [9] it may represent one of the contributing factors leading to nigral dopamine neurone loss.

Neuronal vascular relationships in the zona compacta of normal and parkinsonian substantia nigra

Observations were made on neurons of the substantia nigra in 10 cases of idiopathic Parkinsonism and 5 age-matched controls. It was found that the melanin-containing neurons of the zona compacta in the normal brain have a close spatial relationship with the blood circulation. The capillary walls appear fused to the membranes of neuronal perikarya and processes. In the Parkinsonian zona compacta the close contact between nigral neuron and capillary is lost. The findings suggest that this is due to the infiltration of the proliferated glia between cell surface and capillary wall. This neuronal vascular contact in the zona compacta of the normal brain must be of importance for the functional metabolism of this area, since interruption of this contact was the only detectable nigral lesion in several patients with overt symptoms of recent date. Histochemical reactions of normal and Parkinsonian melanin-containing neurons showed that the nigral cells of the patients have a larger amount of lipofuscin component in the melanin area than those of the controls. Increased basophilia was observed in the Parkinsonian neurons and was inversely related to their melanin content. It is interpreted as an expression of reduced firing activity, indicating regression of function.