McMillen B A, Chamberlain J K, DaVanzo J P
Department of Pharmacology, School of Medicine, East Carolina University, Greenville, North Carolina.
J Neural Transm. 1988;71(2):123-32. doi: 10.1007/BF01245254.
Mouse killing by rats represents a predatory behavior that can be modified by drugs from several different therapeutic classes and by environmental conditions. Buspirone and gepirone, non-benzodiazepine anxiolytics that stimulate serotonergic receptors (5HT1a) and inhibit isolation-induced intraspecies aggression, were tested for inhibition of muricidal behavior by isolated rats. Neither buspirone (3.0 mg/kg s.c.) nor gepirone (from 5.0 to 40 mg/kg) inhibited muricide. Additional rats were housed, either aggregated or isolated, and tested for muricidal behavior 9 times over 5 weeks to establish which animals were muricidal: thus, there were 4 groups of rats: muricidal or non-muricidal under either isolated or aggregated housing condition. [3H]-Spiperone was used to determine striatal D2 receptor Bmax and Kd and prefrontal cortex D2 and 5HT2 receptor binding. There were no changes across the four groups. Binding of [3H]-5-hydroxytryptamine (5HT) to 5HT1a receptors decreased in septum of both groups of isolated rats and binding to 5HT1b receptors decreased 50% in hippocampus of isolated and aggregated muricidal rats. Binding of [3H]-5HT to either receptor was unchanged in amygdaloid area and hypothalamus across all groups. Thus, stimulating pre- and postsynaptic 5HT1a receptors does not alter muricidal behavior and changes in 5HT1 receptor binding occurs in limited areas. Whether this limited change in hippocampal 5HT1b binding is important for establishing muricidal behavior is unclear; however the direction of the change is consistent with reports that decreased serotonergic activity increases predatory behavior.
大鼠捕杀小鼠是一种捕食行为，可被来自几种不同治疗类别的药物以及环境条件所改变。丁螺环酮和吉哌隆是非苯二氮䓬类抗焦虑药，可刺激5-羟色胺能受体（5HT1a）并抑制隔离诱导的种内攻击行为，本研究对其抑制隔离大鼠杀鼠行为的作用进行了测试。丁螺环酮（3.0mg/kg皮下注射）和吉哌隆（5.0至40mg/kg）均未抑制杀鼠行为。另外，将大鼠分组饲养，分为群居或隔离饲养，并在5周内进行9次杀鼠行为测试，以确定哪些动物具有杀鼠行为：因此，共有4组大鼠：在隔离或群居饲养条件下具有或不具有杀鼠行为。使用[3H]-螺哌隆来测定纹状体D2受体的Bmax和Kd以及前额叶皮质D2和5HT2受体结合。四组之间没有变化。两组隔离大鼠的隔区中，[³H]-5-羟色胺（5HT）与5HT1a受体的结合均减少，而在隔离和群居的杀鼠大鼠海马中，与5HT1b受体的结合减少了50%。在所有组的杏仁核区和下丘脑中，[³H]-5HT与任一受体的结合均未改变。因此，刺激突触前和突触后5HT1a受体不会改变杀鼠行为，5HT1受体结合的变化仅发生在有限的区域。尚不清楚海马中5HT1b结合的这种有限变化对于确立杀鼠行为是否重要；然而，这种变化的方向与血清素能活性降低会增加捕食行为的报道一致。
