Masini Cher V, Sasse Sarah K, Garcia Robert J, Nyhuis Tara J, Day Heidi E W, Campeau Serge
Department of Psychology and Neuroscience & Center for Neuroscience, Boulder, CO 80309-0345, USA.
Brain Res. 2009 Sep 8;1288:79-87. doi: 10.1016/j.brainres.2009.07.011. Epub 2009 Jul 15.
Investigations of the neural pathways associated with responses to predators have implicated the medial amygdala (MeA) as an important region involved in defensive behaviors. To our knowledge, however, the involvement of the MeA in neuroendocrine responses to predator odor exposure has not been investigated. Therefore, the present study examined the effects of MeA disruption in rats exposed to ferret or control odor on hypothalamo-pituitary-adrenocortical (HPA) axis activation. Bilateral lesions of the MeA were made in Sprague-Dawley rats with the neurotoxin ibotenic acid (10 microg/microl; 0.3 microl / side). As a control for regional specificity, additional groups of rats were given lesions in the central amygdala (CeA). One week after recovery, the rats were exposed to ferret or strawberry control towels in small cages to examine HPA axis responses as determined by plasma corticosterone and adrenocorticotropin hormone (ACTH) levels. Rats with complete bilateral MeA but not CeA lesions displayed significantly less corticosterone and ACTH release compared to sham-operated control rats only in the ferret odor conditions. These results suggest that the MeA is an important structure involved in the HPA axis responses to predator odors, in support of previous studies investigating behavioral responses under similar conditions.
对与捕食者反应相关的神经通路的研究表明，内侧杏仁核（MeA）是参与防御行为的重要区域。然而，据我们所知，尚未研究MeA在对捕食者气味暴露的神经内分泌反应中的作用。因此，本研究考察了破坏MeA对暴露于雪貂或对照气味的大鼠下丘脑-垂体-肾上腺皮质（HPA）轴激活的影响。用神经毒素鹅膏蕈氨酸（10微克/微升；每侧0.3微升）对Sprague-Dawley大鼠进行MeA双侧损伤。作为区域特异性的对照，另外几组大鼠在中央杏仁核（CeA）进行损伤。恢复一周后，将大鼠置于小笼中，暴露于雪貂或草莓对照毛巾中，通过血浆皮质酮和促肾上腺皮质激素（ACTH）水平来检测HPA轴反应。仅在雪貂气味条件下，与假手术对照大鼠相比，双侧MeA完全损伤但CeA未损伤的大鼠表现出显著较少的皮质酮和ACTH释放。这些结果表明，MeA是参与HPA轴对捕食者气味反应的重要结构，支持了先前在类似条件下研究行为反应的研究。
