Total score of morphine withdrawal symptoms.

On the 3rd, 5th, 7th, and 10th day after intrathecal injection, withdrawal scores were decreased markedly in the Ad-EM2 group compared to that in the Ad-EGFPand NS groups (^bP<0.0001). Endomorphin-2 was indicated as EM2; adenovirus with EM2 was indicated as Ad-EM2; adenovirus with enhanced green fluorescence protein was indicated as Ad-EGFP; normal saline group with subcutaneous morphine injection and intrathecal NS administration was indicated as NS; Sham group with subcutaneous NS injection and intrathecal NS administration was indicated as Sham.