Studies on retinal amacrine cells using slice-patch method

无突细胞是一类重要的次级神经元，能表现出各种各样的光诱发反应。无突细胞的主要兴奋输入被认为来自双极细胞，而无突细胞本身被认为向神经节细胞提供主要抑制输入。金鱼视网膜无增毛细胞的光诱发反应可分为三大类，在这三大类中又有细分。根据细胞间记录，金鱼视网膜的无尖细胞可以对光刺激产生短暂的、持续的去极化或持续的超极化反应。产生这些不同的光诱发反应的机制仍未完全了解。为了阐明可能影响无毛细胞不同反应的一些因素，我们对金鱼视网膜无毛细胞进行了切片制备的全细胞膜片钳研究。观察到无毛细胞的三种主要形态亚型。在无毛细胞中发现了四种电压门控电流：持续向外钾电流I_K、瞬态向外钾电流I_A、持续向内钙电流I_<Ca>和瞬态向内钠电流I_<Na>。此外，在大多数无毛细胞中记录到氯离子通过GABA_A受体携带的自发电流事件。

The amacrine cells are an important group of secondary neurons which can exhibit a wide variety of light-evoked responses. The main excitatory inputs to the amacrine cells are believed to originate from the bipolar cells while the amacrine cell itself is thought to provide the main inhibitory inputs to the ganglion cells. The light-evoked responses of the amacrine cells in the goldfish retina have been classified into three main groups with some subdivisions within these three main groups. As determined by intercellular recordings, amacrine cells of the goldfish retina can respond to a light stimulus by yielding a transient, a sustained depolarizing, or a sustained hyperpolarizing response. The mechanisms by which these variety of light-evoked responses is generated is still not completely understood. To elucidate some of the factors which might affect the differing responses of amacrine cells, we undertook the whole-cell patch clamp study of the amacrine cells of the goldfish retina in a slice preparation. Three main morphological subtypes of amacrine cells were observed. Four types of voltage-gated currents were identified in the amacrine cell : a sustained outward potassium current, I_K, a transient outward potassium current, I_A, a sustained inward calcium current, I_<Ca>, and a transient inward sodium current, I_<Na>. In addition, spontaneous current events, carried by chloride ions through GABA_A receptors, were recorded in most of the amacrine cells.