After 1, 2, 3, 4, 5, 7, 9 and 11 weeks of cold exposure (CF.) , whole brain tissue was taken out and the content of 14 free amino acids (FAA )in rat- brain tissue was measured with amino aad analyzer .

• 经冷暴露1；2；3；4；5；7；9和11周后；用氨基酸分析仪测定大鼠全脑组织中14种游离氨基酸的含量.