Since the caudate nucleus and putamen, there is a path to the black substance secreted by the inhibitory neurotransmitter GABA (gamma aminobutyric acid). In turn, a series of fibers originating in the substantia nigra send axons to the caudate and putamen, secreting an inhibitory neurotransmitter from their terminals, dopamine. This pathway maintains a degree of mutual inhibition of the two areas and the injury causes a series of neurological syndromes, among which is Parkinson’s disease.
The fibers from the cerebral cortex secrete acetylcholine, an excitatory neurotransmitter, in the neostriatum. The causes of abnormal motor activities that make up Parkinson’s disease are related to the loss of the secretion of dopamine by nerve endings in the substantia nigra on the neostriatum (nigrostriatal tract) to the left of suppression.
Thus, neurons that secrete predominantly acetylcholine, excitatory signals broadcast to all basal ganglia, responsible in whole, motor planning and some cognitive functions. It requires a loss of approximately 80% of striatal dopamine to the symptoms.
Histologically, the disease is characterized by the presence of Lewy bodies in the substantia nigra and locus coeruleus, but can also appear in other locations of the extrapyramidal system. These intracytoplasmic inclusions composed of protein, free fatty acids, sphingomyelin, and polysaccharides.
The incidence of Parkinson’s disease, assessment difficult, is variable ranging from 4.5 to 21 cases per 100,000 population per year. It is the most accurate estimate of the disease and the extent of new cases in a period of time. Prevalence is the total number of cases in a population and at the same time.
It can be set in four ways:
1. For the reference of medical centers, as does the Italian National Health System, statistics are borne by general practitioners (found a prevalence of 1.48 to 1.90 patients per 1,000 people)
2. Done in similar fashion but with doctors specializing in neurology (in closed groups of neurological patients the prevalence is, obviously, greater)
3. For the individual test door to door in a given population (the average is higher because they include parkinsonism of various etiologies), and
4. It is based on the amount of anti-parkinsonian drugs consumed by a particular community. The geographic distribution is variable: a range of prevalence of 18 cases per 100,000 people in China to 234 in Montevideo, Uruguay. It is a fact difficult to assess because the low prevalence rate may reflect worsening economic conditions and, consequently given the incidence of Parkinson’s disease in the elderly, short life expectancy.
In Europe, seems to increase towards the north of the continent, along with the United States, report the highest mortality rate (increases above 75 years). In the countries studied deaths from this disease increased between 1920 and 1950. This has been reduced after the introduction of levodopa.
Tags: Neurological diseases, Neurological Disorders, Neurology Diagnostics, Parkinson's Disease, Pathophysiology of Parkinson's Disease,
