Department of Biology, Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, Republic of Korea.
Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul, Republic of Korea.
Biochem Biophys Res Commun. 2019 Jan 22;508(4):1182-1187. doi: 10.1016/j.bbrc.2018.12.073. Epub 2018 Dec 14.
The ventral subiculum (vSub), a representative output structure of the hippocampus, serves as a main limbic region in mediating the brain's response to stress. There are three subtypes of subicular pyramidal neurons based on their firing patterns: regular-spiking (RS), weak-bursting (WB) and strong-bursting (SB) neurons, located differently along proximal-distal axis. Here, we found that chronic social defeat stress (CSDS) in mice increased the population of SB neurons but decreased RS neurons in the proximal vSub. Specific blockers of T-type calcium channels inhibited the burst firings with a concomitant reduction of afterdepolarization, suggesting that T-type calcium channels underlie the burst-spiking activity. Consistently, CSDS increased both T-type calcium currents and expression of Cav3.1 proteins, a subtype of T-type calcium channels, in the proximal vSub. Therefore, we conclude that CSDS-induced enhancement of Cav3.1 expression increased bursting neuronal population in the vSub, which may contribute to stress-related behaviors.
腹侧下托（vSub），作为海马体的代表性输出结构，是调节大脑对应激反应的主要边缘区域。根据放电模式，可将下托锥体神经元分为三种亚型：规则放电（RS）、弱爆发（WB）和强爆发（SB）神经元，它们沿着近-远轴的位置不同。在这里，我们发现慢性社会挫败应激（CSDS）会增加小鼠近端 vSub 中 SB 神经元的数量，同时减少 RS 神经元的数量。T 型钙通道的特异性阻断剂抑制爆发放电，同时伴随着去极化后电位的减少，这表明 T 型钙通道是爆发式放电活动的基础。一致地，CSDS 增加了近端 vSub 中 T 型钙电流和 Cav3.1 蛋白（T 型钙通道的一种亚型）的表达。因此，我们得出结论，CSDS 诱导的 Cav3.1 表达增强增加了 vSub 中爆发神经元的数量，这可能有助于与应激相关的行为。
