Inhibitory interactions between spiny projection neurons in the rat striatum
Inhibitory interactions between spiny projection neurons in the rat striatum
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DOI：
10.1152/jn.2002.88.3.1263
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发表时间：
2002-09-01
影响因子：
2.5
通讯作者：
Wickens, JR
中科院分区：
文献类型：
--
作者：
Tunstall, MJ;Oorschot, DE;Wickens, JR
到目前为止，棘突投射神经元是数量最多的纹状体神经元。除了纹状体的主要投射神经元外，棘突投射神经元还具有广泛的局部轴突侧支网络，它们通过这些网络与其他纹状体投射神经元建立突触联系。然而，到目前为止，还没有直接的生理学证据表明棘突投射神经元之间存在功能抑制相互作用。在这里，我们提出了纹状体投射神经元通过功能性抑制性突触相互连接的新证据。为探讨单位抑制性突触后电位(IPSP)的生理特性，在成年大鼠纹状体脑片上进行了双细胞内记录。在45对神经元中，有9对发现了由单个突触前动作电位触发的平均200条轨迹的突触相互作用。在所有病例中，突触的相互作用都是单向的，没有检测到双向相互作用。单个突触前动作电位诱发的单一IPSP在不同连接中的峰值波幅范围为157~319 mV(平均277+/-46 mV，n=9)。单次动作电位诱发单一IPSP的失败率为9%~63%(平均38+/-14%，n=9)。荷包牡丹碱可逆性阻断整体性IPSP(n=4)，其逆转电位为-62.4+/-0.7 mV(n=5)，与GABA介导的抑制作用一致。本研究的结果与棘突投射神经元之间局部突触连接的解剖学证据很好地相关，并表明侧抑制在纹状体的信息处理操作中起着重要作用。
The spiny projection neurons are by far the most numerous type of striatal neuron. In addition to being the principal projection neurons of the striatum, the spiny projection neurons also have an extensive network of local axon collaterals by which they make synaptic connections with other striatal projection neurons. However, up to now there has been no direct physiological evidence for functional inhibitory interactions between spiny projection neurons. Here we present new evidence that striatal projection neurons are interconnected by functional inhibitory synapses. To examine the physiological properties of unitary inhibitory postsynaptic potentials (IPSPs), dual intracellular recordings were made from pairs of spiny projection neurons in brain slices of adult rat striatum. Synaptic interactions were found in 9 of 45 pairs of neurons using averages of 200 traces that were triggered by a single presynaptic action potential. In all cases, synaptic interactions were unidirectional, and no bidirectional interactions were detected. Unitary IPSPs evoked by a single presynaptic action potential had a peak amplitude ranging from 157 to 319 muV in different connections (mean: 277 +/- 46 muV, n = 9). The percentage of failures of single action potentials to evoke a unitary IPSP was estimated and ranged from 9 to 63% (mean: 38 +/- 14%, n = 9). Unitary IPSPs were reversibly blocked by bicuculline (n = 4) and had a reversal potential of -62.4 +/- 0.7 mV (n = 5), consistent with GABA-mediated inhibition. The findings of the present study correlate very well with anatomical evidence for local synaptic connectivity between spiny projection neurons and suggest that lateral inhibition plays a significant role in the information processing operations of the striatum.