RESUMO
OBJECTIVE: To explore the effect of delta-opioid receptor (DOR) in electroacupuncture (EA) protecting the brain against acute ischemic injury. METHODS: Fifty-one rats were randomly divided into sham ischemia group, ischemia group, sham EA group, EA group, and EA+DOR antagonist (naltrindole) group. Transient focal cerebral ischemia (1 hour) was induced in rat brain by middle cerebral artery occlusion (MCAO) method. EA was applied on Shuigou (GV 26) and Neiguan (PC 6) for 30 min, starting immediately after the onset of reperfusion. Neurological deficit scores and volume of cerebral infarction were detected after 24-hour reperfusion. Other 12 rats were randomly divided into sham ischemia group, ischemia group, EA group and EA + naltrindole group. DOR protein expressions were assessed by Western blotting after 24-hour reperfusion. RESULTS: In comparison with the ischemia group and sham EA group, EA significantly reduced ischemic infarction and neurological deficits (P<0.05); EA significantly increased the expression of 60 kD DOR protein (P<0.05) and tended to increase that of 36 kD DOR protein (P>0.05). When naltrindole was combined with EA, the naltrindole completely abolished the EA-induced protection in ischemic infarction and neurological deficits, and also arrested the expression of DOR. CONCLUSION: EA can up-regulate DOR expression and protect the brain from ischemia-reperfusion injury.