Circadian Discrimination of Reward: Evidence for Simultaneous Yet Separable Food-and Drug-Entrained Rhythms in the Rat
Circadian Discrimination of Reward: Evidence for Simultaneous Yet Separable Food-and Drug-Entrained Rhythms in the Rat
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DOI：
10.3109/07420528.2012.667467
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发表时间：
2012-01-01
影响因子：
2.8
通讯作者：
Sorg, Barbara A.
中科院分区：
文献类型：
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作者：
Jansen, Heiko T.;Sergeeva, Anna;Sorg, Barbara A.
一个独特的视交叉上核（SCN）振荡器，独立于光振荡器的操作，已被假设为产生进食和药物相关的节奏。为了测试这一假设的有效性，假损伤（Sham）和SCN损伤（SCNx）大鼠被安置在恒定的昏暗的红色照明（LLred），并接受每日可卡因注射，每24小时为7天（实验1）。在第二个实验中，大鼠每天进行3小时的限制性喂养（RF），然后在12天后加入每日可卡因注射，每25小时与RF组合，直到两个时间表处于反相。在两个实验中，连续监测体温和总活动。从实验1的结果显示，可卡因，但不是生理盐水，注射产生预期的增加，在SCNx和假大鼠的温度和活动。从可卡因戒断后，SCNx大鼠的自由运行温度节律持续2-10天。在实验2中，强大的预期温度和活动的增加与RF和可卡因注射，然而，喂养周期（23.9小时）占主导地位的可卡因周期。在药物戒断期间，作者观察到Sham和SCNx大鼠的温度和活动的两种自由运行节律持续> 14天。自由运行节律的周期与喂食夹带（周期分别为23.7和24.0 h）和药物夹带（周期分别为25.7和26.1 h）相似。同样在戒断期间，Sham和SCNx大鼠的活动与温度之间的正常密切相关性被极大地破坏。总之，这些结果不支持存在一个单一的振荡器介导的奖励性质的食物和可卡因。相反，他们认为这两种高回报的行为可以暂时隔离，特别是在药物戒断期间。在稳定的双重夹带条件下，食物奖励似乎比药物奖励表现出稍大的昼夜节律影响。在食物和药物联合暴露后产生不同频率的自由运行温度节律的能力可能反映了一种可能导致成瘾过程和药物复发的内部抑郁状态。（作者通讯：heiko@vetmed.wsu.edu）
A unique extra-suprachiasmatic nucleus (SCN) oscillator, operating independently of the light-entrainable oscillator, has been hypothesized to generate feeding and drug-related rhythms. To test the validity of this hypothesis, sham-lesioned (Sham) and SCN-lesioned (SCNx) rats were housed in constant dim-red illumination (LLred) and received a daily cocaine injection every 24 h for 7 d (Experiment 1). In a second experiment, rats underwent 3-h daily restricted feeding (RF) followed 12 d later by the addition of daily cocaine injections given every 25 h in combination with RF until the two schedules were in antiphase. In both experiments, body temperature and total activity were monitored continuously. Results from Experiment 1 revealed that cocaine, but not saline, injections produced anticipatory increases in temperature and activity in SCNx and Sham rats. Following withdrawal from cocaine, free-running temperature rhythms persisted for 2-10 d in SCNx rats. In Experiment 2, robust anticipatory increases in temperature and activity were associated with RF and cocaine injections; however, the feeding periodicity (23.9 h) predominated over the cocaine periodicity. During drug withdrawal, the authors observed two free-running rhythms of temperature and activity that persisted for > 14 d in both Sham and SCNx rats. The periods of the free-running rhythms were similar to the feeding entrainment (period = 23.7 and 24.0 h, respectively) and drug entrainment (period = 25.7 and 26.1 h, respectively). Also during withdrawal, the normally close correlation between activity and temperature was greatly disrupted in Sham and SCNx rats. Taken together, these results do not support the existence of a single oscillator mediating the rewarding properties of both food and cocaine. Rather, they suggest that these two highly rewarding behaviors can be temporally isolated, especially during drug withdrawal. Under stable dual-entrainment conditions, food reward appears to exhibit a slightly greater circadian influence than drug reward. The ability to generate free-running temperature rhythms of different frequencies following combined food and drug exposures could reflect a state of internal desynchrony that may contribute to the addiction process and drug relapse. (Author correspondence: heiko@vetmed.wsu.edu)