Caldwell Heather K, Albers H Elliott
Center for Behavioral Neuroscience, Department of Biology, Atlanta, GA 30303, USA.
Brain Res. 2004 Mar 26;1002(1-2):136-41. doi: 10.1016/j.brainres.2003.12.025.
During long "summer-like" photoperiods, female Syrian hamsters display a regular 4-day estrous cycle. However, during short "winter-like" photoperiods (<12.5 h of light/day) hamsters become anestrus. Short photoperiod exposure eliminates reproductive behavior but social behaviors such as aggression and scent marking continue to be displayed. In long photoperiods, the types and intensity of social behaviors change as a function of the estrous cycle. For example, aggression and scent marking tend to occur at higher levels on diestrus 1 and diestrus 2 than on proestrus or estrus. Aggression and scent marking may be regulated, at least in part, by changes in the density of arginine vasopressin-V(1a) receptors (V(1a)R). In Experiment 1, it was hypothesized that the density of V(1a)R would change across the estrous cycle in several subcortical regions implicated in the regulation of aggression and scent marking. In Experiment 2, it was hypothesized that exposure to short photoperiod would alter the density of V(1a)R in several regions involved in the regulation of social behavior. Interestingly, there were no dramatic changes in V(1a)R binding across the estrous cycle within any of the neuroanatomical areas measured. However, in hamsters housed in short photoperiod, there were lower levels of V(1a)R binding within the medial preoptic nucleus (MPN), medial preoptic area (MPO), lateral hypothalamus (LH), central nucleus of the amygdala (Ce) and bed nucleus of the stria terminalis (BST) than in hamsters housed in long photoperiod. These data suggest that photoperiodic mechanisms can alter the density of V(1a)R in subset of V(1a) binding sites thought to be involved in the regulation of social behaviors in female hamsters.
在漫长的“类似夏季”的光周期中，雌性叙利亚仓鼠表现出规律的4天发情周期。然而，在短暂的“类似冬季”的光周期（每天光照<12.5小时）中，仓鼠进入静止期。短光周期暴露会消除生殖行为，但诸如攻击和气味标记等社会行为仍会表现出来。在长光周期中，社会行为的类型和强度会随着发情周期而变化。例如，攻击和气味标记在动情间期1和动情间期2的发生水平往往高于发情前期或发情期。攻击和气味标记可能至少部分地受精氨酸加压素-V(1a)受体（V(1a)R）密度变化的调节。在实验1中，假设V(1a)R的密度会在发情周期中在几个与攻击和气味标记调节有关的皮层下区域发生变化。在实验2中，假设暴露于短光周期会改变几个参与社会行为调节区域的V(1a)R密度。有趣的是，在所测量的任何神经解剖区域内，发情周期中V(1a)R结合都没有显著变化。然而，与饲养在长光周期的仓鼠相比，饲养在短光周期的仓鼠视前内侧核（MPN）中V(1a)R结合水平较低，视前内侧区（MPO）、下丘脑外侧区（LH）、杏仁核中央核（Ce）和终纹床核（BST）也是如此。这些数据表明，光周期机制可以改变被认为参与雌性仓鼠社会行为调节的V(1a)结合位点子集中V(1a)R的密度。
