断乳前棕色田鼠幼仔对双亲和可卡因的条件位置偏爱（英文）

Primary investigation on the conditioned place preference to parents and cocaine in pre-weanling mandarin vole pups

个体间的社会互作是一种天然奖赏,这种社会性奖赏诱导的条件位置偏爱(Conditioned place preference,CPP)是通过环境信息和社会互作奖赏效应间建立条件反射形成的,与药物奖赏诱导的CPP相似。棕色田鼠(Microtus mandarinus)是一种社会性单配制田鼠,具有紧密的亲-子联系和社会互作;雄鼠对断乳前幼仔也提供较高水平的亲本抚育。幼仔强化能够诱导母鼠及父鼠形成CPP,但双亲对幼仔是否也具有强化效应还不清楚。为探讨断乳前幼仔与双亲形成的奖赏联系,本实验检测了出生后13-17 d和19-23 d两个发育龄段的棕色田鼠幼仔对母鼠、父鼠以及可卡因(20 mg/kg)的CPP反应。数据显示在分别用母鼠、父鼠或可卡因强化后,两个年龄段的幼仔在CPP箱的强化室与非强化室所处时间没有显著性差异。这些结果表明断乳前棕色田鼠幼仔不能形成对母鼠、父鼠及可卡因的位置偏爱。

Social interaction is a substantial natural reward. Similar to drug-induced conditioned place preference（ CPP）,social reward-CPP is established via a Pavlovian association between the environment and the rewarding effects of social interaction. Socially monogamous mandarin voles（ Microtus mandarinus） engage in a suite of close social interactions that include parent-offspring bonding; like females,males also provide high levels of parental care to pre-weanling pups. The reinforcing property of pups in parents is known. However,it remains unclear whether parents could become reinforcing to pre-weanling pups. To evaluate the reward associations that pre-weanling pups formed with their parents,the CPP response to dams,sires and a pharmacologic reinforcer（ cocaine,20 mg / kg） was assessed in postnatal day（ PND） 13- 17 and PND 19- 23 mandarin vole pups. We found that the time that the pups spent in the reinforcing agent-paired chamber and opposite chamber of the apparatus was not statistically different whether conditioned to dams,sires or cocaine respectively.These results indicate that pre-weanling mandarin vole pups failed to form place preferences to their fathers,mothers,or cocaine（ at the doses tested）.