Gastrointestinal dysfunction and nitric oxide changes of myenteric plexus in a rodent model of Parkinson's disease

Objective To investigate the gastrointestinal dysfunction and the alteration of nitric oxide in the myenteric plexuses of rat model of Parkinson's disease induced by 6-hydroxydopamine(6-OHDA).Methods Sixty SD rats were randomly divided into two groups:control group and 6-OHDA group,thirty rats each group.Rat model of Parkinson's disease was induced by 6-hydroxydopamine(6-OHDA).Four weeks later,the one-hour fecal output,stool water content and residual solid food in the stomach at 2h after feeding were measured.Changes in neuronal nitric oxide synthase(nNOS)in the gastrointestinal myenteric plexus were studied by immunohistochemistry,and changes in nNOS mRNA level in the gastric antrum and colon tissue were determined via reverse transcription(RT)-polymerase chain reaction(PCR).Results Compared with control group,the wet weight,dry weight and water content of the feces within 1 hour from 6-OHDA group decreased significantly(P0.01),the percentage of residual solid food increased significantly(P0.01).The average integrated optical densities of nNOS-positive areas in the myenteric plexus of the gastric antrum and colon tissue decreased significantly(P0.01).nNOS mRNA levels in the gastric antrum and colon tissue decreased(P0.01).Conclusions Gastrointestinal dysfunction of PD rats might be related to nNOS decrease in the enteric nervous system.