Fluck E, Hogg S, Mabbutt P S, File S E
Psychopharmacology Research Unit, UMDS Division of Pharmacology, Guy's Hospital, London, UK.
Pharmacol Biochem Behav. 1996 May;54(1):85-91. doi: 10.1016/0091-3057(95)02170-1.
In the first experiment male chicks were exposed to neutral and cat odours at days 4, 7, or 10 after hatching. Of the chicks tested at day 4, few made contact with either odour cloth, but those tested at day 7 made fewer contacts with the cat odour cloth, compared with the neutral odour, spent less time in contact with it, and spent more time in the zone furthest from the cloth. These clear differences were not seen in the group tested at day 10. In a second experiment, the behaviour of day 7 male chicks was compared in the presence of neutral, disinfectant, chick blood or cat odours, and the most extreme differences were between neutral and cat odours. In a third experiment, both male and female chicks were exposed to cat odour at day 7 and both showed similar avoidance. After exposure to cat odour both sexes showed significantly reduced GABA enhancement of benzodiazepine binding; which is a change associated with increased fear. However, after exposure to cat odour, they also showed significant decreases in 5-HT availability evidenced by lower basal and K(+)-evoked [3H]-5-HT release and, in the male chicks only, by an increased [3H]-5-HT uptake from archistriatal slices. These changes in 5-HT function are in the direction associated with reduced fear and would, therefore, seem to be adaptive and compensatory in function. Neither male nor female chicks showed any differences in [14C]-GABA release or uptake as a result of exposure to cat odour. Although the pattern of response to cat odour was the same in both male and female chicks at day 7, there were significant sex differences in 5-HT and GABA tone and benzodiazepine binding; these sex differences were also found in day 10 chicks. The importance of these for sex differences in trait anxiety is discussed.
在第一个实验中，雄性雏鸡在孵化后的第4天、第7天或第10天接触中性气味和猫的气味。在第4天接受测试的雏鸡中，很少有雏鸡与任何一种气味布接触，但在第7天接受测试的雏鸡与猫气味布的接触比与中性气味布的接触少，与猫气味布接触的时间更短，且在离布最远的区域停留的时间更长。在第10天接受测试的组中未观察到这些明显差异。在第二个实验中，比较了第7天雄性雏鸡在中性、消毒剂、雏鸡血或猫气味存在时的行为，最显著的差异存在于中性气味和猫气味之间。在第三个实验中，雄性和雌性雏鸡在第7天均接触猫气味，二者表现出相似的回避行为。接触猫气味后，两性的γ-氨基丁酸（GABA）对苯二氮䓬结合的增强作用均显著降低；这是一种与恐惧增加相关的变化。然而，接触猫气味后，它们的5-羟色胺（5-HT）可用性也显著降低，表现为基础和钾离子（K⁺）诱发的[³H]-5-HT释放降低，且仅在雄性雏鸡中，纹状体前部切片的[³H]-5-HT摄取增加。5-HT功能的这些变化是朝着与恐惧减轻相关的方向发展的，因此，在功能上似乎具有适应性和补偿性。雄性和雌性雏鸡接触猫气味后，[¹⁴C]-GABA的释放或摄取均未表现出任何差异。尽管第7天雄性和雌性雏鸡对猫气味的反应模式相同，但在5-HT、GABA张力和苯二氮䓬结合方面存在显著的性别差异；在第10天的雏鸡中也发现了这些性别差异。文中讨论了这些差异对于特质焦虑性别差异的重要性。
