Okamoto K, Kimura H, Sakai Y
Brain Res. 1983 Feb 7;260(2):261-9. doi: 10.1016/0006-8993(83)90679-0.
The ionic mechanisms underlying the inhibitory action of taurine on Purkinje cell dendrites in guinea pig cerebellar slices were investigated with the Ca spikes intracellularly recorded from the dendrites of Purkinje cells. Taurine-induced hyperpolarization was found to be inverted at a membrane potential of about--125 mV and was largely reduced by the decrease of external Cl- concentration. As the hyperpolarization was associated with an increase in a membrane conductance, it was suggested that taurine hyperpolarizes the Purkinje cell dendrite primarily by increasing a Cl conductance. It was also found that taurine greatly flattened the rising phase of the Ca spike, suggesting that taurine may abolish Ca spikes by blocking the entry of Ca ions into Purkinje cell dendrites. The after-hyperpolarization following each Ca spike was also found to be decreased by taurine, probably as a consequence of the blockade of the entry of Ca ions into the dendrite. This taurine-induced decrease of the after-hyperpolarization appears to be responsible for the transient small depolarization which usually occurs before Ca spikes are abolished by taurine.
利用细胞内记录豚鼠小脑切片浦肯野细胞树突的钙峰，研究了牛磺酸对豚鼠小脑切片浦肯野细胞树突抑制作用的离子机制。发现牛磺酸诱导的超极化在约-125 mV的膜电位处反转，并且随着细胞外Cl-浓度的降低而大大减弱。由于超极化与膜电导增加相关，提示牛磺酸主要通过增加Cl电导使浦肯野细胞树突超极化。还发现牛磺酸使钙峰的上升相大大变平，提示牛磺酸可能通过阻断Ca离子进入浦肯野细胞树突而消除钙峰。每次钙峰后的超极化后电位也被牛磺酸降低，这可能是由于阻断了Ca离子进入树突所致。牛磺酸诱导的超极化后电位降低似乎是通常在牛磺酸消除钙峰之前出现的短暂小去极化的原因。
