Nijsen M J, Croiset G, Diamant M, Broekhoven M H, De Wied D, Wiegant V M
Rudolf Magnus Institute for Neurosciences, Department of Medical Pharmacology, Utrecht University, The Netherlands.
Physiol Behav. 1998 Jan;63(2):233-9. doi: 10.1016/s0031-9384(97)00431-9.
The effects of repeated exposure to a novel test box on cardiac and behavioral activities (locomotion, rearing, grooming, scanning, and immobility) were studied in rats tested during the dark phase ("dark" rats) or the light phase ("light" rats) of the lighting cycle, using a telemetry system for registration of ECGs during the first and fifth tests. Heart rate (HR) was used to monitor sympathetic and parasympathetic activity; the PQ interval was used to monitor parasympathetic activity. Behavior was videotaped simultaneously. In light rats, the first and fifth exposures to the test box resulted in higher increases of active behavior and HR than in dark rats, whereas the duration of the PQ interval of the ECG was increased in light rats only. This indicates that in the light phase novelty induces active behavior associated with an increase in both sympathetic and vagal outflow, whereas in the dark phase behavioral activation is predominantly associated with increased sympathetic activity, without appreciable changes in vagal outflow. In addition, light rats showed less active behavior during the fifth than during the first exposure, indicating behavioral habituation. This behavioral habituation to the test box in the light phase coincided with vagal habituation (a diminution of the PQ interval). The increase of the tachycardiac response during the fifth exposure as compared to the first exposure suggests that it is not likely that sympathetic outflow was part of the habituation process. In dark rats no behavioral or cardiac habituation was found.
在光照周期的暗期（“暗期”大鼠）或明期（“明期”大鼠）对大鼠进行测试，使用遥测系统在第一次和第五次测试期间记录心电图，研究反复暴露于新型测试箱对心脏和行为活动（运动、竖毛、梳理、探究和静止）的影响。心率（HR）用于监测交感神经和副交感神经活动；PQ间期用于监测副交感神经活动。同时对行为进行录像。在明期大鼠中，与暗期大鼠相比，第一次和第五次暴露于测试箱导致主动行为和心率的升高幅度更大，而仅在明期大鼠中心电图的PQ间期持续时间增加。这表明在明期，新奇性诱导与交感神经和迷走神经传出增加相关的主动行为，而在暗期，行为激活主要与交感神经活动增加相关，迷走神经传出没有明显变化。此外，明期大鼠在第五次暴露时比第一次暴露时表现出较少的主动行为，表明存在行为习惯化。明期大鼠对测试箱的这种行为习惯化与迷走神经习惯化（PQ间期缩短）一致。与第一次暴露相比，第五次暴露时心动过速反应的增加表明交感神经传出不太可能是习惯化过程的一部分。在暗期大鼠中未发现行为或心脏习惯化。
