Depto Histología y Embriología, Facultad de Medicina, Universidad de la República, Montevideo 11800, Uruguay; Unidad Bases Neurales de la Conducta, Departamento de Neurofisiología Celular y Molecular, IIBCE, Montevideo 11600, Uruguay.
Instituto de Fundamentos y Métodos, Facultad de Psicología, Universidad de la República, Montevideo 11800, Uruguay.
Horm Behav. 2024 Feb;158:105446. doi: 10.1016/j.yhbeh.2023.105446. Epub 2023 Nov 8.
The establishment of the dominant-subordinate status implies a clear behavioral asymmetry between contenders that arises immediately after the resolution of the agonistic encounter and persists during the maintenance of stable dominance hierarchies. Changes in the activity of the brain social behavior network (SBN) are postulated to be responsible for the establishment and maintenance of the dominant-subordinate status. The hypothalamic nonapeptides of the vasopressin (AVP) and oxytocin (OT) families are known to modulate the activity of the SBN in a context-dependent manner across vertebrates, including status-dependent modulations. We searched for status-dependent asymmetries in AVP-like (vasotocin, AVT) and OT-like (isotocin, IT) cell number and activation immediately after the establishment of dominance in males of the weakly electric fish, Gymnotus omarorum, which displays the best understood example of non-breeding territorial aggression among teleosts. We used immunolabeling (FOS, AVT, and IT) of preoptic area (POA) neurons after dyadic agonistic encounters. This study is among the first to show in teleosts that AVT, but not IT, is involved in the establishment of the dominant-subordinate status. We also found status-dependent subregion-specific changes of AVT cell number and activation. These results confirm the involvement of AVT in the establishment of dominance and support the speculation that AVT is released from dominants' AVT neurons.
支配-从属地位的建立意味着竞争者之间存在明显的行为不对称性，这种不对称性立即在竞争冲突解决后出现，并在稳定的支配等级制度维持期间持续存在。据推测，大脑社会行为网络（SBN）的活动变化负责支配-从属地位的建立和维持。已知下丘脑的加压素（AVP）和催产素（OT）家族的神经肽以依赖于情境的方式调节包括依赖于地位的调节在内的脊椎动物 SBN 的活动。我们在非繁殖领域攻击性在硬骨鱼类中表现得最为明显的例子，即弱电鱼 Gymnotus omarorum 中，寻找支配地位建立后雄性体内 AVP 样（加压素，AVT）和 OT 样（缩宫素，IT）细胞数量和活性的依赖于地位的不对称性。我们使用了二联体竞争冲突后的视前区（POA）神经元的免疫标记（FOS、AVT 和 IT）。这项研究首次在硬骨鱼类中表明，AVT 而不是 IT 参与了支配地位的建立。我们还发现了 AVT 细胞数量和活性的依赖于地位的特定亚区变化。这些结果证实了 AVT 在支配地位建立中的参与，并支持了 AVT 从支配者的 AVT 神经元中释放的推测。
