Canteras Newton S, Kroon Juliana A V, Do-Monte Fabrício H M, Pavesi Eloisa, Carobrez Antonio P
Departamento de Anatomia, Instituto de Ciências Biomédicas, Universidade de São Paulo, 05508-000, São Paulo, SP, Brazil.
Neurosci Biobehav Rev. 2008 Sep;32(7):1228-35. doi: 10.1016/j.neubiorev.2008.05.009. Epub 2008 May 13.
The dorsal premammillary nucleus (PMd) has a critical role on the expression of defensive responses to predator odor. Anatomical evidence suggests that the PMd should also modulate memory processing through a projecting branch to the anterior thalamus. By using a pharmacological blockade of the PMd with the NMDA-receptor antagonist 2-amino-5-phosphonopentanoic acid (AP5), we were able to confirm its role in the expression of unconditioned defensive responses, and further revealed that the nucleus is also involved in influencing associative mechanisms linking predatory threats to the related context. We have also tested whether olfactory fear conditioning, using coffee odor as CS, would be useful to model predator odor. Similar to cat odor, shock-paired coffee odor produced robust defensive behavior during exposure to the odor and to the associated context. Shock-paired coffee odor also up-regulated Fos expression in the PMd, and, as with cat odor, we showed that this nucleus is involved in the conditioned defensive responses to the shock-paired coffee odor and the contextual responses to the associated environment.
乳头体背侧核（PMd）在对捕食者气味的防御反应表达中起关键作用。解剖学证据表明，PMd还应通过向前丘脑的投射分支调节记忆处理。通过使用NMDA受体拮抗剂2-氨基-5-磷酸戊酸（AP5）对PMd进行药理学阻断，我们能够证实其在无条件防御反应表达中的作用，并进一步揭示该核也参与影响将捕食性威胁与相关情境联系起来的联想机制。我们还测试了以咖啡气味作为条件刺激（CS）的嗅觉恐惧条件反射是否有助于模拟捕食者气味。与猫气味类似，与电击配对的咖啡气味在暴露于气味和相关情境时会产生强烈的防御行为。与电击配对的咖啡气味还上调了PMd中的Fos表达，并且与猫气味一样，我们表明该核参与了对与电击配对的咖啡气味的条件防御反应以及对相关环境的情境反应。
