The substantia nigra is a part of the basal ganglia that is present in the midbrain. It is 
characterized by the presence of dopaminergic neurons in the substantia nigra pars compacta.
Parkinsonism disease is one of the most common neurodegenerative diseases affecting elderly 
patients. It occurs due to progressive degeneration of dopaminergic neurons in the substantia 
nigra. In this work, Parkinsonism was induced in rats by daily subcutaneous injection of 
0.5mg/Kg of rotenone for 28 days. Twenty rats were divided randomly into 2 groups; control 
and Parkinsonism groups. Brain specimens were obtained for H&E stain. In Parkinsonism 
group, shrunken dopaminergic neurons with small dense nuclei and were surrounded with 
wide pericellular hallows were frequently observed in the substantia nigra. Acidophilic lewy 
bodies are a very characteristic finding in Parkonsonism group. There was also vacuolation in 
the neuropil.