Effects of morphine and naltrexone on impulsive decision making in rats
Effects of morphine and naltrexone on impulsive decision making in rats
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DOI：
10.1007/s00213-003-1697-2
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发表时间：
2004-04-01
影响因子：
3.4
通讯作者：
Richards, JB
中科院分区：
文献类型：
--
作者：
Kieres, AK;Hausknecht, KA;Richards, JB
基本原理。有报道称，人类鸦片成瘾者比非成瘾者更容易对延迟奖励打折，这表明他们更冲动。然而，目前尚不清楚这种差异是否反映了先前存在的特征，或者是接触阿片类药物的影响。目标。本研究旨在探讨阿片激动剂和拮抗剂对大鼠延迟折扣的影响。本研究有三个目标：(1)阿片激动剂吗啡(MOR)对延迟折扣的急性效应；(2)阿片拮抗剂纳曲酮(NAL)对延迟折扣的急性效应；(3)NAL是否逆转MOR对延迟折扣的影响。方法：研究方法。调整金额程序(AdjAmt)被用来确定动物对延迟奖励的价值有多大程度的折扣。对15只大鼠分别给予吗啡(0.3、1.0、1.8 mg/kg SC)、NAL(0.01、0.1、1.0、10 mg/kg SC)和NAL(0.1 mg/kg SC)，然后再给予吗啡(1.8 mg/kg SC)。结果。更多的剂量依赖地增加了延迟折扣率(即，使动物更冲动)。NAL单独对延迟奖赏效应无影响，但NAL可阻断MOR的效应。结论。这些结果表明，吗啡的直接影响可能与阿片类药物使用者的高水平冲动行为有关。
Rationale. It has been reported that human opiate addicts discount delayed rewards more than non-addicts, indicating that they are more impulsive. However, it is not clear whether this difference reflects pre-existing traits, or the effects of exposure to the opiates. Objectives. This study was designed to investigate the effects of an opioid agonist and antagonist on delay discounting in rats. The study had three objectives: to determine (1) the acute effects of the opioid agonist morphine (MOR) on delay discounting, (2) the acute effects of the opioid antagonist naltrexone (NAL) on delay discounting, and (3) whether NAL reverses the effects of MOR on delay discounting. Methods. An adjusting amount procedure (AdjAmt) was used to determine how much animals discounted the value of delayed rewards. Acute doses of MOR (0.3, 1.0, and 1.8 mg/kg SC), NAL (0.01, 0.1, 1.0, and 10 mg/kg SC) and NAL (0.1 mg/kg SC) prior to MOR (1.8 mg/kg SC) were tested in 15 rats. Results. MOR dose dependently increased the rate of delay discounting (i.e., made the animals more impulsive). NAL alone had no effect on the value of delayed rewards, but NAL blocked the effects of MOR. Conclusions. These results suggested that the direct effects of MOR may contribute to the high level of impulsive behavior seen among opiate users.