Bittar E E, Nwoga J, Huang Y P
Department of Physiology, University of Wisconsin, Madison 53706.
Toxicol Appl Pharmacol. 1990 Jan;102(1):174-85. doi: 10.1016/0041-008x(90)90094-b.
A study has been made of the behavior of the Na efflux in single muscle fibers from the barnacle, Balanus nubilus, toward the microinjection of AlCl3. The effect of microinjecting AlCl3 is either biphasic with inhibition following transitory stimulation, or monophasic with inhibition occurring promptly and taking about 1 hr to reach a maximum. The magnitude of the inhibition is dose dependent and the minimally effective concentration is 10 mM. This is diluted by the myoplasm by a factor of roughly 100. Fibers injected with 1 M AlCl3 are found to be insensitive to 10(-4) M ouabain, whereas fibers injected with 0.5 M AlCl3 show a further fall in Na efflux, which is smaller than that seen in control fibers. The response of the ouabain-insensitive Na efflux to the injection of 0.5 M AlCl3 is biphasic: stimulation is followed by inhibition. The stimulatory phase is largely dependent on the presence of external Ca2+ and is reversed by the sudden omission of Ca2+ from the bathing medium. Fibers also injected with 0.5 M AlCl3 show a marked reduction in the response of the Na efflux to high external K. Injection of ATPMg before or after the injection of AlCl3 fails in most instances to abolish or reverse the inhibitory effect. By contrast, fibers preinjected with deferoxamine show little or no effect following the injection of AlCl3. However, external application of deferoxamine is ineffective.
对大型藤壶（Balanus nubilus）单根肌纤维中钠流出行为对微量注射氯化铝的反应进行了研究。微量注射氯化铝的影响要么是双相的，即短暂刺激后出现抑制，要么是单相的，即立即出现抑制，约1小时达到最大值。抑制程度呈剂量依赖性，最小有效浓度为10 mM。这在肌浆中被稀释了约100倍。发现注射1 M氯化铝的纤维对10^(-4) M哇巴因不敏感，而注射0.5 M氯化铝的纤维钠流出进一步下降，但其下降幅度小于对照纤维。对哇巴因不敏感的钠流出对注射0.5 M氯化铝的反应是双相的：先是刺激，然后是抑制。刺激阶段很大程度上依赖于细胞外钙离子的存在，当突然从浴液中去除钙离子时，刺激作用会逆转。同样注射0.5 M氯化铝的纤维对高细胞外钾的钠流出反应也显著降低。在注射氯化铝之前或之后注射ATP镁在大多数情况下都不能消除或逆转抑制作用。相比之下，预先注射去铁胺的纤维在注射氯化铝后几乎没有影响。然而，细胞外应用去铁胺是无效的。
