哺乳动物骨骼肌中氯离子外流的测量。

Chloride efflux measurements in mammalian skeletal muscle.

作者信息

Hayward B S, Barchi R L

出版信息

Muscle Nerve. 1980 May-Jun;3(3):207-15. doi: 10.1002/mus.880030304.

Abstract

A rapid sampling technique has been used to resolve the components of 36Cl efflux from isolated extensor digitorum longus (EDL) muscles of young rats. Four distinct fluxes with apparent rate constants of 4.40 +/- 0.02 min-1 (k1), 1.30 +/- 0.04 min-1 (k2), 0.24 +/- 0.04 min-1 (k3), and 0.048 +/- 0.05 min-1 (k4) at 30 degrees C were identified. Together, these fluxes accounted for the movement of more than 98% of exchangeable muscle chloride (Cl) ions. The muscle compartment associated with the fastest flux (k1) contained 23% +/- 2% of the total muscle Cl corresponding to the extracellular space as determined with inulin or mannitol. The compartment associated with k2 accounted for 71% of the intracellular volume, and k2 was assumed to represent 36Cl efflux across the surface membrane. The rate constant k2 was temperature-dependent with a Q10 of 1.11 between 5 degrees C and 30 degrees C. Aromatic carboxylic acids known to block sarcolemmal Cl conductance (GCl) specifically lowered k2 by 25% at 30 degrees C, as did replacement of external Cl with nitrate.

摘要

一种快速采样技术已被用于解析来自幼年大鼠分离的趾长伸肌（EDL）中³⁶Cl流出的成分。在30℃下，确定了四种不同的通量，其表观速率常数分别为4.40±0.02 min⁻¹（k1）、1.30±0.04 min⁻¹（k2）、0.24±0.04 min⁻¹（k3）和0.048±0.05 min⁻¹（k4）。这些通量共同占可交换肌肉氯化物（Cl）离子移动的98%以上。与最快通量（k1）相关的肌肉隔室包含总肌肉Cl的23%±2%，这与用菊粉或甘露醇测定的细胞外空间相对应。与k2相关的隔室占细胞内体积的71%，并且k2被认为代表³⁶Cl跨表面膜的流出。速率常数k2与温度有关，在5℃至30℃之间的Q10为1.11。已知能特异性阻断肌膜Cl电导（GCl）的芳香族羧酸在30℃时可使k2降低25%，用硝酸盐替代外部Cl时也是如此。