Plasma and gastric juice substance P (SP), vasoactive intestinal peptide (VIP) and leu-enkephalin (LEK) were measured by radioimmunoassay kit.
血浆和胃液物质P（sP）、血管活性肠肽（VIP）和亮脑啡肽（LEK）均用放射免疫法测定。
2
Objective To investigate the effect of conditioned taste aversion (CTA) acquisition and retention on the expression of endogenous leu-enkephalin (LEK) in rats.