Doctors call synucleinopathies those neurological diseases characterized by the presence, within certain neurons of the central nervous system, of alpha-synuclein-based protein aggregates, better known as Lewy bodies (NB: Lewy is the name of the researcher who identified them for the first time in 1912).
The alpha-synuclein is a protein of up to 140 amino acids, expressed above all in the encephalon and from functions not yet completely clarified.
According to the most reliable hypotheses, it would reside at the level of presynaptic terminations of brain neurons and, here, it would provide for the sorting of cell vesicles containing dopamine and acetylcholine .
Dopamine and acetylcholine both play an essential role for motor activity : the first allows harmonic and fine execution of movements; the second is responsible for the process of muscle contraction.
Returning to the synucleinopathies, the three most important are:
- Parkinson's disease . It is a neurodegenerative disease, characterized by the progressive death of neurons located at the level of the substantia nigra . Located at the level of the basal ganglia, between the midbrain and the diencephalon, the substantia nigra provides for the production of dopamine.
- Dementia with Lewy bodies . It is the third most common form of dementia in the world, after Alzheimer's disease and vascular dementia. The Lewy bodies can also be located in some neurons of the cerebral cortex, as well as at the level of the basal ganglia.
In addition to determining Parkinson-like symptoms, dementia with Lewy bodies also causes problems with attention, alertness, memory, three-dimensional perception, etc.
- Multi systemic atrophy . It is a progressive neurological disease, in which the degeneration of brain neurons particularly affects the basal ganglia (hence the substantia nigra ), the cerebellum and the brainstem. Similar in some respects to Parkinson's, it is also responsible for disorders of automatic functions (bladder control, arterial pressure, etc.) and problems with balance, coordination and language.