CPA in control and peptone infusion rats with or without CCK-A-R antagonist or capsaicin pretreatment. For the CPA score the amount of time spent in the conditioning compartment on the post-conditioning days were subtracted from the amount of time spent in the same compartment on the pre-conditioning day. Compared with control rats, intraduodenal infusion of 5% peptone (3 ml in 15 min) after conditioning trainings significantly increased CPA scores in post-conditioning day 1 and 5, respectively. The enhanced effects of peptone infusion on CRD-induced CPA were blocked by pretreatment of CCK-A receptor antagonist CR-1409 or perivagal capsaicin application. Results were presented as means ± SE. Statistical significance was determined by Two-way Repeated measurement ANOVA followed by Bonferroni posttests. ** P < 0.01, *** P < 0.001 compared between peptone infusion group and control group, n=5 for each group.