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神经激发、抑制及药物上瘾（LTP）
生物谷报道：激发性突触（促使目标神经细胞更多被激发的神经细胞连接）会随着持续的使用而变得更强。这一被称为LTP（长期增强）的过程与学习和记忆有关。用大鼠的大脑所做的一项体外研究表明，这种激发性增强会在大鼠大脑的ventraltegmental区域（该区域已知与药物上瘾有关）中的相邻抑制性突触上产生镜像作用，吗啡能够抑制在抑制性突触上的长期增强，说明破坏神经激发和抑制之间的平衡也许能够增强上瘾早期阶段多巴胺能神经元的激发。因此，以GABAa受体为目标也许是解决上瘾性药物的上瘾效应的一种手段。这项研究结果发表于最新一期的《Nature》杂志上。
FIGURE 1. GABAergic synapses on dopamine neurons are potentiated after HFS.
a, LTPGABA in a dopamine neuron using whole-cell recording methods. HFS was delivered at the arrow. Inset: averaged IPSCs before (black) and 25 min after HFS (grey). In this and all figures, ten consecutive IPSCs from each condition were averaged for illustration. Calibration for insets: 10 ms, 50 pA. The dotted line in this and other figures is an approximation of the mean response before HFS. b, Average of 71 experiments from dopamine cells. LTPGABA was not triggered in all cells, but data from all cells are included in this and subsequent graphs. The dotted line represents the mean normalized IPSC value before HFS. c, LTPGABA in a dopamine neuron using gramicidin-perforated patch recording. Inset: averaged IPSCs before (black) and 25 min after HFS (grey). d, Average of eight gramicidin-perforated patch experiments from dopamine cells (LTPGABA, 146 4% of pre-HFS values; n = 8). All cells but one exhibited LTP. e, LTPGABA in dopamine cells was accompanied by a decrease in the paired-pulse ratio (PPR, IPSC2/IPSC1; n = 35). f, LTPGABA was accompanied by an increase in 1/CV2 (squared mean IPSC amplitude divided by IPSC variance; n = 35). Error bars in all figures indicate means s.e.m.
原文出处：
Volume 446 Number 7139
Opioids block long-term potentiation of inhibitory synapses p1086
Fereshteh S. Nugent, Esther C. Penick
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