Torborg Christine L, Berg Allison P, Jeffries Brian W, Bayliss Douglas A, McBain Chris J
Laboratory of Cellular and Synaptic Neurophysiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
J Neurosci. 2006 Jul 12;26(28):7362-7. doi: 10.1523/JNEUROSCI.1257-06.2006.
TASK-1 (KCNK3) and TASK-3 (KCNK9) are members of the two-pore domain potassium channel family and form either homomeric or heteromeric open-rectifier (leak) channels. Recent evidence suggests that these channels contribute to the resting potential and input resistance in several neuron types, including hippocampal CA1 pyramidal cells. However, the evidence for TWIK-related acid-sensitive potassium (TASK)-like conductances in inhibitory interneurons is less clear, and mRNA expression has suggested that TASK channels are expressed in only a subpopulation of interneurons. Here we use immunocytochemistry to demonstrate prominent TASK-3 protein expression in both parvalbumin-positive- and a subpopulation of glutamic acid decarboxylase (GAD)67-positive interneurons. In addition, a TASK-like current (modulated by both pH and bupivacaine) was detected in 30-50% of CA1 stratum oriens interneurons of various morphological classes. In most neurons, basic shifts in pH had a larger effect on the TASK-like current than acidic, suggesting that the current is mediated by TASK-1/TASK-3 heterodimers. These data suggest that TASK-like conductances are more prevalent in inhibitory interneurons than previously supposed.
TASK-1（KCNK3）和TASK-3（KCNK9）是双孔域钾通道家族的成员，可形成同型或异型开放整流（渗漏）通道。最近的证据表明，这些通道有助于几种神经元类型的静息电位和输入电阻，包括海马CA1锥体神经元。然而，抑制性中间神经元中TWIK相关酸敏感钾（TASK）样电导的证据尚不清楚，并且mRNA表达表明TASK通道仅在中间神经元的一个亚群中表达。在这里，我们使用免疫细胞化学来证明在小白蛋白阳性和谷氨酸脱羧酶（GAD）67阳性中间神经元的一个亚群中都有显著的TASK-3蛋白表达。此外，在30%-50%的各种形态学类别的CA1海马层中间神经元中检测到一种TASK样电流（受pH值和布比卡因调节）。在大多数神经元中，pH值的碱性变化对TASK样电流的影响比酸性变化更大，这表明该电流是由TASK-1/TASK-3异二聚体介导的。这些数据表明，TASK样电导在抑制性中间神经元中比以前认为的更普遍。
