Rodgers R J, Blanchard D C, Wong L K, Blanchard R J
Department of Psychology, University of Leeds, England.
Pharmacol Biochem Behav. 1990 Jul;36(3):575-83. doi: 10.1016/0091-3057(90)90258-j.
Two experiments were designed to investigate the effects of scopolamine hydrobromide (0.25-1.0 mg/kg), and its methyl derivative, on the defensive reactions of rats to nonpainful threat stimuli. In the first experiment, over the dose range studied neither compound significantly altered avoidance, freezing, defensive threat or attack in wild Rattus rattus confronted by the experimenter and other predator-related stimuli. Scopolamine hydrobromide did, however, produce a dose-dependent increase in flight distance; this effect was not seen with the methyl compound, confirming central cholinergic mediation. In the second experiment, no dose of either compound significantly altered the behaviour of Long-Evans rats prior to cat exposure. During cat exposure, however, scopolamine hydrobromide (but not methyl scopolamine) increased the amount of time spent in the vicinity of the cat, increased scanning and rearing, and reduced grooming behaviour. Although reliable, the latter effects were not pronounced. Together, these data do not support a major involvement of central muscarinic receptor mechanisms in the regulation of defensive patterns in wild or laboratory rats.
设计了两项实验来研究氢溴酸东莨菪碱（0.25 - 1.0毫克/千克）及其甲基衍生物对大鼠针对非疼痛性威胁刺激的防御反应的影响。在第一个实验中，在所研究的剂量范围内，这两种化合物均未显著改变野生褐家鼠面对实验者及其他与捕食者相关刺激时的回避、僵住、防御性威胁或攻击行为。然而，氢溴酸东莨菪碱确实使逃窜距离呈剂量依赖性增加；甲基化合物未出现这种效应，证实了中枢胆碱能介导作用。在第二个实验中，任何剂量的这两种化合物在让朗-埃文斯大鼠接触猫之前均未显著改变其行为。然而，在接触猫期间，氢溴酸东莨菪碱（而非甲基东莨菪碱）增加了在猫附近停留的时间，增加了扫视和竖身行为，并减少了梳理行为。尽管这些效应可靠，但并不明显。总体而言，这些数据并不支持中枢毒蕈碱受体机制在野生或实验大鼠防御模式调节中起主要作用。
