Lee Grace, Gammie Stephen C
Department of Zoology, University of Wisconsin, Madison, Wisconsin 53706, USA.
Behav Neurosci. 2009 Dec;123(6):1169-77. doi: 10.1037/a0017535.
Maternal aggression (maternal defense) is a fierce aggression produced by lactating females toward intruders that plays an important role in protection of vulnerable offspring. Enhancement of GABA(A) receptor signaling by benzodiazepines increases maternal aggression, and we recently found indirect evidence that lateral septum (LS) could be a key site where benzodiazepines elevate aggression. In this study, we directly tested the hypothesis that activation of GABA(A) receptors in LS would promote maternal aggression while inhibition of this receptor would decrease aggression. Site-directed injections to LS were made using the GABA(A) receptor antagonist, bicuculline (3-30 ng), or the GABA(A) receptor agonists, chlordiazepoxide, a benzodiazepine (2.5-5 microg), and muscimol (0.05-5 ng). Maternal aggression and other behavioral measures were then evaluated in lactating mice. Neither GABA(A) receptor agonist elevated aggression, which could reflect a ceiling effect. However, 7 ng of the GABA(A) receptor antagonist, bicuculline, in LS significantly decreased maternal aggression without altering other maternal behaviors or light-dark box performance, suggesting some GABA(A) receptor signaling in LS is required for full maternal aggression expression. Together, these results confirm a role for GABA(A) receptor signaling in LS in the regulation of maternal aggression.
母性攻击行为（母性防御）是哺乳期雌性动物对入侵者产生的一种激烈攻击行为，在保护脆弱后代方面发挥着重要作用。苯二氮䓬类药物增强γ-氨基丁酸A（GABA(A)）受体信号传导会增加母性攻击行为，我们最近发现间接证据表明外侧隔区（LS）可能是苯二氮䓬类药物提高攻击行为的关键部位。在本研究中，我们直接测试了以下假设：激活LS中的GABA(A)受体会促进母性攻击行为，而抑制该受体会减少攻击行为。使用GABA(A)受体拮抗剂荷包牡丹碱（3 - 30纳克）、GABA(A)受体激动剂氯氮䓬（一种苯二氮䓬类药物，2.5 - 5微克）和蝇蕈醇（0.05 - 5纳克）对LS进行定点注射。然后在哺乳期小鼠中评估母性攻击行为和其他行为指标。两种GABA(A)受体激动剂均未提高攻击行为，这可能反映了一种天花板效应。然而，向LS注射7纳克的GABA(A)受体拮抗剂荷包牡丹碱可显著降低母性攻击行为，且不改变其他母性行为或明暗箱实验表现，这表明LS中某些GABA(A)受体信号传导是母性攻击行为充分表达所必需的。总之，这些结果证实了LS中GABA(A)受体信号传导在调节母性攻击行为中的作用。
