Lieben Cindy K J, Steinbusch Harry W M, Blokland Arjan
Department of Psychiatry and Neuropsychology (Basal Neuroscience), University of Maastricht, Maastricht, The Netherlands.
Behav Brain Res. 2006 Apr 3;168(2):197-207. doi: 10.1016/j.bbr.2005.11.003. Epub 2005 Dec 19.
Previous studies with acute tryptophan depletion, leading to transient central 5-HT reductions, showed no effects on affective behavior but impaired object memory. In the present study, the behavioral effects of a 5,7-dihydroxytryptamine (5,7-DHT) lesion in the dorsal raphe were evaluated in animal models of anxiety (open field test), depression (forced swimming test), behavioral inhibition (discrete fixed interval test) and cognition (object recognition task). The corticosterone response to a stress condition was examined at several intervals after 5,7-DHT treatment. The substantial reduction in neuronal 5-HT markers in the dorsal raphe did not affect anxiety-related, depressive-like or impulsive behavior. Compared to the SHAM group, the lesioned rats showed a lower response latency to obtain a reward, indicating a quick and accurate reaction to a stimulus. No differences were found in the progressive ratio test for food motivation. A marked impairment in object recognition was found. The 5,7-DHT treatment did not affect the corticosterone response to a stressful situation. Overall, these results corroborate studies with acute tryptophan depletion suggesting a role of 5-HT in object memory, but not affective behavior.
先前的急性色氨酸耗竭研究导致中枢5-羟色胺（5-HT）短暂减少，结果显示对情感行为无影响，但损害了物体记忆。在本研究中，在焦虑（旷场试验）、抑郁（强迫游泳试验）、行为抑制（离散固定间隔试验）和认知（物体识别任务）的动物模型中评估了中缝背核5,7-二羟基色胺（5,7-DHT）损伤的行为效应。在5,7-DHT治疗后的几个时间点检查了对应激条件的皮质酮反应。中缝背核中神经元5-HT标志物的大幅减少并未影响与焦虑相关、抑郁样或冲动行为。与假手术组相比，损伤大鼠获得奖励的反应潜伏期较短，表明对刺激的反应快速且准确。在食物动机的累进比率试验中未发现差异。发现物体识别存在明显损害。5,7-DHT治疗不影响对应激情况的皮质酮反应。总体而言，这些结果证实了急性色氨酸耗竭研究，表明5-HT在物体记忆而非情感行为中起作用。
