Larson E T, Summers C H
Department of Biology and Neuroscience Group, University of South Dakota, 414 E. Clark Street, 57069-2390, Vermillion, SD, USA
Behav Brain Res. 2001 Jun;121(1-2):95-102. doi: 10.1016/s0166-4328(00)00393-4.
Social stress from aggressive interaction is expressed differently in specific brain regions of dominant and subordinate male Anolis carolinensis. Prior to aggressive behavior, the outcome is predictable via the celerity of postorbital coloration: Dominant males exhibit more rapid eyespot darkening. Serotonergic activation is manifest rapidly (1 h) in hippocampus, nucleus accumbens and brainstem of subordinate males, and is expressed more rapidly in dominant males. Amygdalar serotonergic activation responds rapidly (1 h) in dominant males, but is expressed slowly (1 w) and chronically in subordinate males. We hypothesized that chronic (1 w) serotonin elevation, manipulated by the selective serotonin reuptake inhibitor sertraline, would decrease aggressiveness and result in subordinate status. Dominant status was established in pairs of male A. carolinensis. The pairs were separated and treated with sertraline or vehicle. Sertraline was given in food to either the dominant or the subordinate male, both males or neither male for 1 week. Pairs were reintroduced, and behavior and social status recorded. When both dominant and subordinate males were treated with sertraline (or vehicle), or when subordinate males alone were treated with sertraline, previously established social relationships remained unchanged or became associative. However, when dominant males alone were treated with sertraline, their social status was reversed (43%) or negated (57%). Latency to eyespot darkening was significantly retarded in dominant males treated with sertraline, and aggressive displays and attacks were reduced. Chronic 5-HT elevation is consistent with subordinate status. Social status and aggressive disposition do not appear to be immutable, but may be changed by neuroendocrine mechanisms that mediate adaptation to environmental conditions like stress.
在具有攻击性的互动中产生的社会压力，在占主导地位和从属地位的雄性卡罗来纳安乐蜥的特定脑区中表现不同。在攻击行为发生之前，通过眶后着色的速度可以预测结果：占主导地位的雄性表现出更快的眼斑变黑速度。血清素激活在从属雄性的海马体、伏隔核和脑干中迅速显现（1小时），而在占主导地位的雄性中表现得更快。杏仁核血清素激活在占主导地位的雄性中迅速反应（1小时），但在从属雄性中反应缓慢（1周）且呈慢性反应。我们假设，由选择性血清素再摄取抑制剂舍曲林控制的慢性（1周）血清素升高会降低攻击性并导致从属地位。在成对的雄性卡罗来纳安乐蜥中确立了主导地位。将这些对分开并用舍曲林或赋形剂处理。将舍曲林添加到食物中，给占主导地位的雄性、从属雄性、两只雄性或不给任何雄性服用1周。将这些对重新放在一起，并记录行为和社会地位。当占主导地位和从属地位的雄性都用舍曲林（或赋形剂）处理时，或者当仅从属雄性用舍曲林处理时，先前建立的社会关系保持不变或变得具有关联性。然而，当仅占主导地位的雄性用舍曲林处理时，它们的社会地位被逆转（43%）或被否定（57%）。用舍曲林处理的占主导地位的雄性中，眼斑变黑的潜伏期显著延长，攻击性展示和攻击减少。慢性5-羟色胺升高与从属地位一致。社会地位和攻击倾向似乎并非一成不变，而是可能由介导对压力等环境条件适应的神经内分泌机制所改变。
