ABSTRACT
Objective: There are four currently motor features characterizing Parkinson's disease (PD). These includerigidity of muscles, bradykinesia, tremors at rest, and instability of posture. Along the course of PD, theimpairment of motor functions is commonly preceded by nonmotor symptoms (NMS) such as olfactory deficit,difficult swallowing (dysphagia), drooling (sialorrhea), constipation, urinary bladder dysfunction, depression,and sleep disorder. It was suggested that the enteric nervous system could be the initial site for the pathologicalprocess leading to PD. Materials and Methods: Six male adult control AS rats (normal control) and six maleadults AS/AGU rats (model of PD) were sacrificed. A rectangular strip from the body of the stomach and across-section from the duodenum were dissected and processed for histological staining with hematoxylin andeosin, and immunohistochemical staining for detection of nNOS (neuronal NOS), S100 protein (astrocytemarker), and alpha-synuclein (α-synuclein). Results: The histological analysis of the stomach and duodenum ofAS/AGU rats demonstrated necrotic smooth muscle cells of muscularis externa. The immunohistochemicalanalysis of AS/AGU rats showed a statistically significant increase in the expression of nNOS, S100 protein, andα-synuclein expression of myenteric plexuses compared to the control strain AS rats. Conclusion:Gastroduodenal tract of AS/AGU rats showed marked histopathological changes and immunohistochemicaloverexpression of nNOS, S100, and α-synuclein.