| Parkinson Disease Parkinson disease (PD) is characterized by a slowing of voluntary movements, bradykinesia, muscular rigidity and tremor at rest. These abnormalities result from a reduction of neurons that make dopamine in the pars compacta of the substantia nigra. The axons of these neurons normally release this neurotransmitter where they synapse, in parts of the basal ganglia called the caudate nucleus and putamen or, collectively, the corpus striatum. Dopamine usually works as an inhibitory neurotransmitter in the corpus striatum where it acts on cholinergic neurons. Lewy bodies, a hyaline inclusion, are seen microscopically in the cytoplasm of residual neurons in the substantia nigra of nearly all patients with Parkinsonism. The loss of neurons results in a grossly evident depigmentation of the substantia nigra because those dopaminergic neurons also contain the pigment neuromelanin in their cytoplasm. There are various causes for the loss of dopaminergic neurons in the substantia nigra and the resultant signs of PD. Some evidence exists for involvement of genetic factors in the pathogenesis of PD. For example, several large families with an autosomal, dominant inheritance pattern of PD have now been described, and the first genetic locus for PD has been identified in one of those families. For more information concerning Parkinson Disease please visit the web-site below. |
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 This was Parkinson's house; there is no photograph of him. Parkinson, James 1755-1828 |
