Biology, Swarthmore College, Swarthmore, Pennsylvania, USA.
Neuroscience Institute and Center for Behavioral Neuroscience, Georgia State University, Atlanta, Georgia, USA.
Brain Behav Evol. 2022;97(3-4):184-196. doi: 10.1159/000524217. Epub 2022 Mar 23.
Dynamic fluctuations in the distribution of catecholamines across the brain modulate the responsiveness of vertebrates to social stimuli. Previous work demonstrates that green anoles (Anolis carolinensis) increase chemosensory behavior in response to males treated with exogenous arginine vasotocin (AVT), but the neurochemical mechanisms underlying this behavioral shift remains unclear. Since central catecholamine systems, including dopamine, rapidly activate in response to social stimuli, we tested whether exogenous AVT in signalers (stimulus animals) impacts catecholamine concentrations in the forebrain (where olfactory and visual information are integrated and processed) of untreated lizard responders. We also tested whether AVT influences the relationship between forebrain catecholamine concentrations and communication behavior in untreated receivers. We measured global catecholamine (dopamine = DA, epinephrine = Epi, and norepinephrine = NE) concentrations in the forebrain of untreated responders using high-performance liquid chromatography-mass spectrometry following either a 30-min social interaction with a stimulus male or a period of social isolation. Stimulus males were injected with exogenous AVT or vehicle saline (SAL). We found that global DA, but not Epi or NE, concentrations were elevated in lizards responding to SAL-males relative to isolated lizards. Lizards interacting with AVT-males had DA, Epi and NE concentrations that were not significantly different from SAL or isolated groups. For behavior, we found a significant effect of social treatment (AVT vs. SAL) on the relationships between (1) DA concentrations and the motivation to perform a chemical display (latency to tongue flick) and (2) Epi concentrations and time spent displaying mostly green body coloration. We also found a significant negative correlation between DA concentrations and the latency to perform a visual display but found no effect of social treatment on this relationship. These data suggest that catecholamine concentrations in the forebrain of untreated responders are associated with chemical and visual communication in lizards and that signaler AVT alters this relationship for some, but not all, aspects of social communication.
大脑中儿茶酚胺分布的动态波动调节脊椎动物对社会刺激的反应。先前的工作表明，绿安乐蜥（Anolis carolinensis）会增加对接受外源性精氨酸加压素（AVT）处理的雄性的化学感觉行为，但这种行为转变的神经化学机制尚不清楚。由于包括多巴胺在内的中枢儿茶酚胺系统会迅速对社会刺激产生反应，我们测试了信号发出者（刺激动物）中的外源性 AVT 是否会影响未处理蜥蜴反应者的前脑（嗅觉和视觉信息在此处整合和处理）中的儿茶酚胺浓度。我们还测试了 AVT 是否会影响未处理接收者的前脑儿茶酚胺浓度与交流行为之间的关系。我们使用高效液相色谱-质谱法测量了未处理反应者的前脑中的整体儿茶酚胺（多巴胺=DA、肾上腺素=Epi 和去甲肾上腺素=NE）浓度，这些反应者在与刺激雄性进行 30 分钟的社交互动后或进行社交隔离后进行测量。刺激雄性接受外源性 AVT 或载体盐水（SAL）注射。我们发现，与隔离蜥蜴相比，对 SAL 雄性做出反应的蜥蜴中的 DA，但不是 Epi 或 NE，浓度升高。与 AVT 雄性互动的蜥蜴中的 DA、Epi 和 NE 浓度与 SAL 或隔离组没有显着差异。对于行为，我们发现社会处理（AVT 与 SAL）对（1）DA 浓度与执行化学展示（舌头轻弹潜伏期）的动机之间的关系和（2）Epi 浓度与主要显示绿色体色的时间之间的关系有显着影响。我们还发现 DA 浓度与进行视觉展示的潜伏期之间存在显着负相关，但未发现社会处理对这种关系的影响。这些数据表明，未处理反应者的前脑儿茶酚胺浓度与蜥蜴的化学和视觉通讯有关，而信号发出者的 AVT 改变了这种关系，对于某些而非所有社会通讯方面。
