The role of synaptic plasticity in a rat model of visceral hypersensitivity induced by acute restraint stress / 中华消化杂志

ABSTRACT

Objective To explore the role of synaptic plasticity on the formation of visceral hyper- sensitivity induced by acute restraint stress in rats.Methods Twenty male Sprague-Dawley rats were randomly divided into control group and acute restraint stress group(model group).Visceral hypersensi- tivity was made by acute restraint stress for 1 h.The colorectal distension(CRD) with different pressure were performed and the abdominal electromyography(EMG) was recorded.The visceral sensitivity was determined by the frequency of EMG.The ultrastrueture of synapse was observed with transmission electron microscope.The expression of synaptophysin was measured by RT-PCR and Western-blot. Results①The frequency of EMG was significantly correlated with CRD pressure(control group,r=0.992, P=0.008;model group,r=0.978,P=0.022).The frequencies of EMG in model group(at 40,60 and 80 mm Hg) were significantly more than that in control group(P value=0.043,0.024,0.038,respectively).②There were more synaptic vesicles accumulated in presynaptical terminal.The post synaptic density was increased in model group compared to control group.③In the proximal and distant colon,the expressions of rnRNA and protein of synaptophysin were higher in model group (P