放射性钾在离体大鼠神经节中的移动。

Movements of radioactive potassium in isolated rat ganglia.

Scholfield C N

J Physiol. 1977 Jun;268(1):123-37. doi: 10.1113/jphysiol.1977.sp011850.

Abstract

Isolated rat superior cervical ganglia were continuously superfused with (42)K (or (86)Rb) solution and the amount of radioactivity taken up was monitored using scintillation counting.2. Entry of (42)K into the ganglia could be resolved into two components, one amounting to 83% of the total (42)K uptake, with a rate constant of 0.015 min(-1), and the other of 17% of the total, with a rate constant of 0.15 min(-1).3. With 6 mM-K in the bathing solution, the equilibrium uptake of (42)K after 4 hr corresponded to an intracellular concentration of 147 mM-K. Changes in the K concentration of the bathing solution (0.5-20 mM) had little effect on this value.4. Carbachol or nicotine caused a rapid net loss of (42)K. (42)K was recaptured on washing out the depolarizing agents, with a rate constant of about 0.3 min(-1). This recapture rate was slowed by ouabain, dinitrophenol, cyanide, mersalyl and by reducing the K concentration in the bathing solution.5. Efflux of (42)K from preloaded ganglia occurred with a rate constant of 0.017 min(-1). This rate was increased about sixfold by 180 muM carbachol in 6 mM-K but not in 150 mM-K suggesting that the increase in efflux was mainly a consequence of the depolarization caused by carbachol.6. (86)Rb fluxes and the effects of carbachol thereon were similar.

摘要

将离体大鼠颈上神经节用（42）K（或（86）Rb）溶液持续灌流，并用闪烁计数法监测摄取的放射性量。
（42）K进入神经节可分为两个成分，一个占总（42）K摄取量的83%，速率常数为0.015 min⁻¹，另一个占总量的17%，速率常数为0.15 min⁻¹。
在浴液中含6 mM - K时，4小时后（42）K的平衡摄取量相当于细胞内浓度为147 mM - K。浴液中K浓度（0.5 - 20 mM）的变化对此值影响很小。
卡巴胆碱或尼古丁导致（42）K快速净流失。洗脱去极化剂后（42）K被重新摄取，速率常数约为0.3 min⁻¹。哇巴因、二硝基酚、氰化物、汞撒利以及降低浴液中K浓度会使这种重新摄取速率减慢。
预加载神经节的（42）K外流速率常数为0.017 min⁻¹。在6 mM - K中，180 μM卡巴胆碱使该速率增加约六倍，但在150 mM - K中则不然，这表明外流增加主要是卡巴胆碱引起的去极化的结果。
（86）Rb通量及其对卡巴胆碱的反应与之相似。