Adolescent methylmercury exposure affects choice and delay discounting in mice
Adolescent methylmercury exposure affects choice and delay discounting in mice
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DOI：
10.1016/j.neuro.2016.09.016
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发表时间：
2016-12-01
期刊：
影响因子：
3.4
通讯作者：
Newland, M. Christopher
中科院分区：
文献类型：
--
作者：
Boomhower, Steven R.;Newland, M. Christopher
发育中的胎儿易受低水平甲基汞（甲基汞）的影响，甲基汞是一种环境神经毒物，但青少年时期接触甲基汞的后果几乎仍不清楚。目前的实验旨在评估低水平的甲基汞暴露在青春期的延迟折扣，偏好小，立即的折扣，大，延迟的影响，使用小鼠模型。36只雄性C57 BL/6 n小鼠从出生后第21天至第59天通过饮用水暴露于0、0.3或3.0 ppm汞（以甲基汞计），包括小鼠青春期。作为成年人，小鼠按下杠杆，立即递送0.01 cc的乳溶液液滴或延迟后递送4滴0.01 cc的乳溶液液滴。延迟范围从1.26到70.79秒，所有这些都是在一次会议上提出的。基于广义匹配定律的模型表明，甲基汞暴露的小鼠相对于对照组对辐射强度的敏感性较低，表明甲基汞暴露的小鼠对较大辐射的反应相对无关紧要。与对照组相比，03-ppm组对延迟的敏感性降低（延迟折扣降低），但3.0-ppm组未降低。青春期是大脑和行为易受甲基汞影响的发育期。与妊娠期接触甲基汞一样，其影响反映在强化刺激的影响上。(C)2016爱思唯尔B. V.保留所有权利。
The developing fetus is vulnerable to low-level exposure to methylmercury (MeHg), an environmental neurotoxicant, but the consequences of exposure during the adolescent period remain virtually unknown. The current experiments were designed to assess the effects of low-level MeHg exposure during adolescence on delay discounting, preference for small, immediate reinforcers over large, delayed ones, using a mouse model. Thirty-six male C57BL/6n mice were exposed to 0, 0.3, or 3.0 ppm mercury (as MeHg) via drinking water from postnatal day 21 through 59, encompassing the murine adolescent period. As adults, mice lever pressed for a 0.01-cc droplet of milk solution delivered immediately or four 0.01-cc droplets delivered after a delay. Delays ranged from 1.26 to 70.79 s, and all were presented within a session. A model based on the Generalized Matching Law indicated that sensitivity to reinforcer magnitude was lower for MeHg-exposed mice relative to controls, indicating that responding in MeHg-exposed mice was relatively indifferent to the larger reinforcer. Sensitivity to reinforcer delay was reduced (delay discounting was decreased) in the 03-ppm group, but not in the 3.0-ppm group, compared to controls. Adolescence is a developmental period during which the brain and behavior may be vulnerable to MeHg exposure. As with gestational MeHg exposure, the effects are reflected in the impact of reinforcing stimuli. (C) 2016 Elsevier B.V. All rights reserved.