Potassium secretion by nonsensory region of gerbil utricle in vitro.
Potassium secretion by nonsensory region of gerbil utricle in vitro.
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DOI：
10.1152/ajprenal.1987.253.4.f613
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发表时间：
1987-10
期刊：
影响因子：
--
通讯作者：
N. Marcus;D. C. Marcus
中科院分区：
文献类型：
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作者：
N. Marcus;D. C. Marcus
体外分离的沙鼠椭圆囊非感觉区域在哺乳动物林格溶液（5 mM K 和 150 mM Na）中沐浴时产生+5.7 mV 的管腔阳性跨上皮电位差（VT）和含有 106 mM K 的管腔液体。该区域的管腔在体外用无 K 溶液灌注，并在对照条件下灌注之前和之后以及向浴中添加布美他尼 (0.1 mM) 或哇巴因 (1 mM) 后测量管腔 [K]、VT 和跨上皮阻力 (RT)。由于用Ca选择性微电极测量的体内椭圆囊内淋巴的平均值(0.28+/-0.03mM)是外淋巴的38%，所以灌注液中[Ca]含量降低。在对照条件下，灌注后管腔[K]最初以2.13 mumol X cm-2 X h-1的速率增加；净分泌持续直至管腔[K]恢复至灌注前水平。该通量率相当于 57 微安/平方厘米。发现“等效短路电流”（Equiv. Isc；VT/RT）平均为 61 microA/cm2。 K 分泌和 VT 均被布美他尼和哇巴因完全抑制。 Luminal 在无 K 溶液中应用 Ba (5 mM) 对 K 分泌的初始速率没有影响，但确实阻止了 Luminal [K] 完全恢复到对照水平。这些结果是对椭圆囊非感觉细胞 K 分泌的首次估计，并且是第一个直接证明布美他尼抑制内耳 K 分泌和哇巴因抑制椭圆囊非感觉组织 K 分泌的结果。
The isolated nonsensory region of the gerbil utricle in vitro produced a lumen-positive transepithelial electrical potential difference (VT) of +5.7 mV and a luminal fluid containing 106 mM K when bathed in mammalian Ringer solution (5 mM K and 150 mM Na). The lumen of this region was perfused in vitro with K-free solution and the luminal [K], VT, and transepithelial resistance (RT) were measured before and following perfusion under control conditions and after addition of bumetanide (0.1 mM) or ouabain (1 mM) to the bath. The perfusate contained a reduced [Ca], since the average value of utricular endolymph in vivo (0.28 +/- 0.03 mM) measured with Ca-selective microelectrodes was 38% of that in perilymph. Under control conditions, the luminal [K] initially increased at a rate of 2.13 mumol X cm-2 X h-1 after perfusion; net secretion continued until the luminal [K] returned to its preperfusion level. This flux rate corresponds to 57 microA/cm2. The "equivalent short-circuit current" (Equiv. Isc; VT/RT) was found to average 61 microA/cm2. Both K secretion and VT were fully inhibited by bumetanide and by ouabain. Luminal application of Ba (5 mM) in K-free solution had no effect on the initial rate of K secretion, but did prevent full recovery of luminal [K] to the control level. These results are the first estimates of K secretion by the nonsensory cells of the utricle and are the first to directly demonstrate inhibition of K secretion in the inner ear by bumetanide and in the nonsensory tissue of the utricle by ouabain.