Calabresi P, Misgeld U, Dodt H U
Neuroscience. 1987 Jan;20(1):293-303. doi: 10.1016/0306-4522(87)90021-2.
Electroresponsiveness of neostriatal neurons was studied by intracellular recording in a rat brain slice preparation maintained in standard solution or in solution containing K-channel blockers. In standard solution, the neurons fired repetitively at increasing frequencies with increasing amplitude of direct depolarization. The firing pattern was independent of the membrane potential from which firing was induced. In the presence of tetraethylammonium (20 mM), long-lasting (300-500 ms) plateau potentials could be elicited by the injection of short (5-10 ms) current pulses. Plateau potentials persisted in Na-free solution, in the presence of tetrodotoxin (1-3 microM) and if Ca in the perifusate was replaced by Ba. The plateau was blocked by Cd (500 microM). The plateaux were followed by depolarizing after-potentials. When the plateau potential failed due to fatigue, a small slow depolarization of short duration (10-30 ms) was elicited in Na-free or tetrodotoxin-containing solution, which increased in amplitude with membrane hyperpolarization. This slow depolarization was blocked by Cd, indicating that it was also mediated by Ca. By intrastriatal stimulation in the presence of 4-aminopyridine a long-lasting, voltage-dependent depolarization was triggered from the enhanced postsynaptic potential. In contrast, in the presence of tetraethylammonium, postsynaptic potentials were only slightly increased if they were compared at sizes subthreshold for the plateau potentials. It is concluded that neostriatal neurons, although being characterized as "silent" and "non-bursting", possess slow conductances for inward currents which they share with other mammalian central neurons. However, in contrast, to other central neurons, their Ca-spikes are suppressed by their K-conductances and, in contrast to oscillating neurons, low-threshold Ca-potentials are not prominent.
通过在维持于标准溶液或含有钾通道阻滞剂的溶液中的大鼠脑片标本上进行细胞内记录，研究了新纹状体神经元的电反应性。在标准溶液中，神经元随着直接去极化幅度的增加而以不断增加的频率重复放电。放电模式与诱发放电的膜电位无关。在存在四乙铵（20 mM）的情况下，通过注入短（5 - 10 ms）电流脉冲可诱发持续时间长（300 - 500 ms）的平台电位。平台电位在无钠溶液中、存在河豚毒素（1 - 3 μM）时以及灌流液中的钙被钡替代时仍持续存在。该平台被镉（500 μM）阻断。平台电位之后是去极化后电位。当平台电位因疲劳而消失时，在无钠或含河豚毒素的溶液中会诱发持续时间短（10 - 30 ms）的小的缓慢去极化，其幅度随膜超极化而增加。这种缓慢去极化被镉阻断，表明它也是由钙介导的。在存在4 - 氨基吡啶的情况下，通过纹状体内刺激从增强的突触后电位触发了持续时间长、电压依赖性的去极化。相反，在存在四乙铵的情况下，如果将突触后电位与平台电位的阈下大小进行比较，突触后电位仅略有增加。得出的结论是，新纹状体神经元尽管被描述为“沉默”和“非爆发性”，但具有与其他哺乳动物中枢神经元共有的内向电流慢电导。然而，与其他中枢神经元相比，它们的钙峰被钾电导抑制，并且与振荡神经元相比，低阈值钙电位不突出。
