Nigral neurons are likely to die of a mechanism other than classical apoptosis in Parkinson's disease

The finding of apoptosis in Parkinson's disease (PD) represents a contentious issue. In fact, there is increasing evidence that an alternative mechanism of cell death is at work in the parkinsonian substantia nigra, which we tentatively term aposklesis. Unlike apoptosis, aposklesis (“withering”) lacks the morphological signs of apoptosis and takes a slow course which is in agreement with the predicted rate of dopaminergic cell death in PD. Cells undergoing aposklesis may stain positive in the TUNEL reaction and show a reticular nuclear labeling but lack any significant chromatin condensation and the formation of apoptotic bodies. Not only neurons but also glial cells appear to undergo this form of cell death, which represents a relatively common finding in degenerative diseases of the CNS.