Changes Of Expressions Of NR2A And NR2B In AnteriorCingulate Cortex Of Post-inflammatory Visceral Hypersensitive Rat

Objective：Recurrent abdominal pain (RAP)is a common functional gastrointestinaldisorders(FGIDs)．The pathophysiology underlying RAPS remains elusive．However,visceral hypersensitivity(VH) is currently the leading hypothesis to explain painfulsymptoms experienced by RAPS patients. As many as22％of patients suffered fromacute gastroenteritis that resolved before developing RAPS．The onset of RAPS withthe appearance of VH following infection has now been recognized．Post-infection VHmay partially result from the sensitization of primary afferent fibers innervating thegastrointestinal tract，while central neuroplastic changes also contributes to itsdeveloped N-methyl-D-aspartate(NMDA)，is member of the ionotropic glutamatereceptor(iGluR) family and this receptor contributes to inflammatory pain，nociceptionand hyperalgesia．In this study,we have examined whether there are some changes ofNR2A and NR2B(the subunits of NMDA receptor) in anterior cingulatecoaex(ACC)in post inflammatory viscerallv hypersensitive rats.Methods：Experimentswere performed on infant Sprague-Dawley rats(80-100g)．Rats were randomly dividedinto six groups：three VH groups and three control groups．mustard oil was instilledinto the rat colon to establish post-inflammatory VH rat model，rats in the controlgroup received saline instead of mustard oil．After mustard oil or saline injection，ratswere used for studying visceral sensitivity separately at15-day-old,22-day-old,36-day-old，immunofluorescence and western blot．Results：Mustard oil significantlyincreased colorectal sensitivity to colorectal distention，immunofluorescence indicatedthat the expression of NR2B was increased and NR2A decreased in ACC of VH groupcompared with control (P<0．05)．Western blot also suggested the quantity of theNR2B up-regulated and NR2A down-regulated in ACC of VH rats compared withcontrols (P<0．05)．Conclusion：In the mustard oil induced VH rats，the NR2B isup-regulated but NR2A down-regulated in ACC，which means iGluRs might play anrole in modulation of post-inflammatory visceral hypersensitivity．...