兔颈动脉体小球细胞中的 TASK-1（K3）和 TASK-3（K9）。
TASK-1 (K3) and TASK-3 (K9) in Rabbit Carotid Body Glomus Cells.
机构信息
Department of Physiology and Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, South Korea.
Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA.
出版信息
Adv Exp Med Biol. 2018;1071:35-41. doi: 10.1007/978-3-319-91137-3_4.
Glomus cells isolated from rabbit and rat/mouse carotid bodies have been used for many years to study the role of ion channels in hypoxia sensing. Studies show that hypoxia inhibits the inactivating K channels (Kv4) in rabbits, but inhibits TASK in rats/mice to elicit the hypoxic response. Because the role of TASK in rabbit glomus cells is not known, we isolated glomus cells from rabbits and studied the expression of TASK mRNA in the whole carotid body (CB), changes in [Ca] and TASK activity. RT-PCR showed that rabbit CB expressed mRNA for TASK-3 and several Kv (Kv2.1, Kv3.1 and Kv3.3). In rabbit glomus cells in which 20 mM KCl elevated [Ca], anoxia also elicited a strong rise in [Ca]. In cell-attached patches with 140 mM KCl in the pipette, basal openings of ion channels with single-channel conductance levels of 16-pS, 34-pS, and 42-pS were present. TREK-like channels were also observed. In inside-out patches with high [Ca], BK was activated. The 42-pS channel opened spontaneously and briefly. The 16-pS and 34-pS channels showed properties similar to those of TASK-1 and TASK-3, respectively. TASK activity in cell-attached patches was lower than that in rat glomus cells under identical recording conditions. Hypoxia (~0.5%O) reduced TASK activity by ~52% and depolarized the cells by ~30 mV. Our results show that the O-sensitive TASK contributes to the hypoxic response in rabbit glomus cells.
多年来，人们一直从兔和鼠/兔颈动脉体中分离出球细胞，用于研究离子通道在缺氧感应中的作用。研究表明，缺氧抑制兔的失活 K 通道（Kv4），但抑制鼠/兔的 TASK 以引发缺氧反应。由于 TASK 在兔球细胞中的作用尚不清楚，我们从兔中分离出球细胞，并研究了整个颈动脉体（CB）中 TASK mRNA 的表达、[Ca]的变化和 TASK 活性。RT-PCR 显示兔 CB 表达 TASK-3 和几种 Kv（Kv2.1、Kv3.1 和 Kv3.3）的 mRNA。在兔球细胞中，用 20 mM KCl 升高 [Ca]，缺氧也会引起 [Ca]的强烈升高。在细胞附着的斑块中，用 140 mM KCl 填充吸管，存在具有 16-pS、34-pS 和 42-pS 单通道电导水平的离子通道的基础开放。还观察到 TREK 样通道。在高[Ca]的内向外斑块中，BK 被激活。42-pS 通道自发短暂打开。16-pS 和 34-pS 通道的特性分别与 TASK-1 和 TASK-3 相似。在相同的记录条件下，细胞附着斑块中的 TASK 活性低于鼠球细胞中的 TASK 活性。缺氧（~0.5%O）使 TASK 活性降低约 52%，并使细胞去极化约 30 mV。我们的结果表明，O 敏感的 TASK 有助于兔球细胞的缺氧反应。
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