BACKGROUND & AIMS Severe burn injury has been demonstrated to delay gastric emptying. The aim of this study was to investigate effects and cellular mechanisms of auricular electroacupuncture (AEA) at the acupoints innervated by the auricular branch of vagus nerve (ABVN) on burn-induced gastric dysmotility in rats. METHODS Propranolol (β-adrenoceptor antagonist) was injected intraperitoneally after the rats underwent burn injury. All experiments were performed six hours following burn/sham burn injury. AEA was performed at bilateral auricular acupoints for 45min. Electrocardiogram was recorded for 30min. Plasma hormones were measured; cyclooxygenase (COX)-2 expressions in gastric tissue were measured using western blotting and real time RT-PCR. RESULTS 1) Burn injury delayed gastric emptying (P=0.006) and AEA increased gastric emptying by 49% (P=0.045). 2) Burn injury evoked a significant elevation in plasma noradrenaline, which was suppressed by AEA. 3) Burn injury significantly increased protein and mRNA expressions of COX-2 in gastric fundus and antrum. AEA suppressed burn-induced increase in protein expressions but not mRNA expressions of COX-2. CONCLUSIONS Burn injury delays gastric emptying by up-regulating COX-2 attributed to sympathetic overactivity. AEA improves burn-induced delay in gastric emptying, possibly mediated via the sympathetic-COX-2 pathway.

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