Forti L, Pietrobon D
Department of Biomedical Sciences, C.N.R. Center of Physiology and Mitochondria, University of Padova, Italy.
Neuron. 1993 Mar;10(3):437-50. doi: 10.1016/0896-6273(93)90332-l.
Single-channel recordings show that functionally different L-type Ca2+ channels coexist in rat cerebellar granules. Besides two different dihydropyridine (DHP)-sensitive gating patterns with properties similar to those of cardiac L-type channels, cerebellar granules contain a third DHP-sensitive gating pattern with unusual voltage-dependent properties and slightly different conductance. This "anomalous gating" is characterized, on one hand, by rare, short openings with very low open probability even at high positive voltages and, on the other hand, by long openings with high open probability at negative voltages after a predepolarization. L-type channels with anomalous gating appear suited to generate a surge of Ca2+ influx following strong neuronal activity. The anomalous gating can be explained by a model in which voltage controls the equilibrium between two gating modes.
单通道记录表明，功能不同的L型Ca2+通道共存于大鼠小脑颗粒细胞中。除了两种不同的对二氢吡啶（DHP）敏感的门控模式，其特性与心脏L型通道相似外，小脑颗粒细胞还包含第三种对DHP敏感的门控模式，具有不寻常的电压依赖性特性和略有不同的电导。这种“异常门控”一方面表现为即使在高正电压下也很少有短暂开放且开放概率极低，另一方面表现为在预去极化后负电压下有高开放概率的长时开放。具有异常门控的L型通道似乎适合在强烈神经元活动后产生Ca2+内流激增。异常门控可以用一个电压控制两种门控模式之间平衡的模型来解释。
