Jiangsu Province Key Laboratory of Anesthesiology,Xuzhou Medical College,Xuzhou,221002,China;
Jiangsu Province People′s Hospital of Yixing,Yixing,214200,China;
Jiangsu Province Key Laboratory of Anesthesiology,Xuzhou Medical College,Xuzhou,221002,China;
Jiangsu Province People′s Hospital of Yixing,Yixing,214200,China;
propofol; spinal cord; antinociception; prazosin; yohimbine; norepinephrine;