Abstract
Objective: There are four currently motor features characterizing Parkinson's disease (PD). These include rigidity of muscles, bradykinesia, tremors at rest, and instability of posture. Along the course of PD, the impairment 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 pathological process leading to PD. Materials and Methods: Six male adult control AS rats (normal control) and six male adults AS/AGU rats (model of PD) were sacrificed. A rectangular strip from the body of the stomach and a cross-section from the duodenum were dissected and processed for histological staining with hematoxylin and eosin, and immunohistochemical staining for detection of nNOS (neuronal NOS), S100 protein (astrocyte marker), and alpha-synuclein (alpha-synuclein). Results: The histological analysis of the stomach and duodenum of AS/AGU rats demonstrated necrotic smooth muscle cells of muscularis externa. The immunohistochemical analysis of AS/AGU rats showed a statistically significant increase in the expression of nNOS, S100 protein, and alpha-synuclein expression of myenteric plexuses compared to the control strain AS rats. Conclusion: Gastroduodenal tract of AS/AGU rats showed marked histopathological changes and immunohistochemical overexpression of nNOS, S100, and alpha-synuclein.