Department of Drug Science and Technology, NIS Center, CNISM, University of Torino, Torino, Italy.
PLoS One. 2012;7(7):e41530. doi: 10.1371/journal.pone.0041530. Epub 2012 Jul 25.
Besides regulating energy balance and reducing body-weight, the adipokine leptin has been recently shown to be neuroprotective and antiapoptotic by promoting neuronal survival after excitotoxic and oxidative insults. Here, we investigated the firing properties of mouse hippocampal neurons and the effects of leptin pretreatment on hypoxic damage (2 hours, 3% O(2)). Experiments were carried out by means of the microelectrode array (MEA) technology, monitoring hippocampal neurons activity from 11 to 18 days in vitro (DIV). Under normoxic conditions, hippocampal neurons were spontaneously firing, either with prevailing isolated and randomly distributed spikes (11 DIV), or with patterns characterized by synchronized bursts (18 DIV). Exposure to hypoxia severely impaired the spontaneous activity of hippocampal neurons, reducing their firing frequency by 54% and 69%, at 11 and 18 DIV respectively, and synchronized their firing activity. Pretreatment with 50 nM leptin reduced the firing frequency of normoxic neurons and contrasted the hypoxia-induced depressive action, either by limiting the firing frequency reduction (at both ages) or by increasing it to 126% (in younger neurons). In order to find out whether leptin exerts its effect by activating large conductance Ca(2+)-activated K(+) channels (BK), as shown on rat hippocampal neurons, we applied the BK channel blocker paxilline (1 µM). Our data show that paxilline reversed the effects of leptin, both on normoxic and hypoxic neurons, suggesting that the adipokine counteracts hypoxia through BK channels activation in mouse hippocampal neurons.
除了调节能量平衡和减轻体重外，脂肪细胞因子瘦素最近还被证明具有神经保护和抗细胞凋亡作用，可促进兴奋性和氧化应激损伤后的神经元存活。在这里，我们研究了小鼠海马神经元的放电特性以及瘦素预处理对缺氧损伤（2 小时，3%O2）的影响。实验通过微电极阵列（MEA）技术进行，监测体外培养 11 至 18 天（DIV）的海马神经元活性。在正常氧条件下，海马神经元自主放电，要么是主要是孤立且随机分布的尖峰（11DIV），要么是具有同步爆发特征的模式（18DIV）。暴露于缺氧严重损害了海马神经元的自发性活动，将其放电频率分别降低了 54%和 69%，在 11 和 18DIV 时，同步了它们的放电活动。用 50nM 瘦素预处理可降低正常氧神经元的放电频率，并对抗缺氧诱导的抑制作用，无论是通过限制放电频率降低（在两个年龄），还是将其增加到 126%（在年轻神经元）。为了找出瘦素是否通过激活大鼠海马神经元上显示的大电导钙激活钾通道（BK）发挥作用，我们应用了 BK 通道阻断剂 paxilline（1µM）。我们的数据表明，paxilline 逆转了瘦素对正常氧和缺氧神经元的作用，表明这种脂肪细胞因子通过激活小鼠海马神经元中的 BK 通道来对抗缺氧。
