Bossu J L, Fagni L, Feltz A
Laboratoire d'Etude des Régulations Physiologiques, associé à l'Université Louis Pasteur, Centre National de la Recherche Scientifique, Strasbourg, France.
Pflugers Arch. 1989 May;414(1):92-4. doi: 10.1007/BF00585632.
Cell-attached patch recordings were used to study calcium channels on the dendritic membrane of rat cerebellar Purkinje cells maintained in culture. Experiments were performed with isotonic BaCl2 (110 mM) in the pipette and isotonic potassium gluconate in the bath to zero the cell membrane potential. Two distinct types of voltage-activated calcium channels were identified. The first one had a small conductance (9 pS), was activated at a low threshold (congruent to -50 mV) and could be inactivated by holding the membrane potential at -30 mV. This channel had the same characteristics as the T channel described in other neuronal preparations. The second type of Ca channel activated at a high threshold (-30 or +10 mV depending on whether BAY K 8644 was added or not to the pipette solution) and was still activatable even when the membrane was held at -40 mV. In the presence of BAY K 8644 this channel had a conductance of 21 pS with long openings. All these characteristics are similar to those of the S (L) Ca channel described in many preparations. The present study is in agreement with our previous experiments on Purkinje dendrites, where we identified low and high threshold Ca currents using the whole-cell configuration. Up to now, no channel corresponding to the N current has been observed but we cannot exclude its presence.
采用细胞贴附式膜片钳记录技术，研究培养的大鼠小脑浦肯野细胞树突膜上的钙通道。实验中，移液管内使用等渗氯化钡（110 mM），浴槽内使用等渗葡萄糖酸钾，以使细胞膜电位归零。鉴定出两种不同类型的电压激活钙通道。第一种通道电导较小（9 pS），在低阈值（约-50 mV）时被激活，通过将膜电位保持在-30 mV可使其失活。该通道具有与其他神经元标本中描述的T通道相同的特性。第二种钙通道在高阈值（-30或+10 mV，取决于移液管溶液中是否添加了BAY K 8644）时被激活，即使膜电位保持在-40 mV时仍可激活。在存在BAY K 8644的情况下，该通道的电导为21 pS，开放时间长。所有这些特性与许多标本中描述的S（L）钙通道相似。本研究与我们之前对浦肯野树突的实验一致，在之前的实验中，我们使用全细胞模式鉴定出了低阈值和高阈值钙电流。到目前为止，尚未观察到与N电流相对应的通道，但我们不能排除其存在。
